Dang, that has to be an expensive blow to teams gearing up with many disc equipped bikes. Not that rules can't change, but this is pretty last minute.

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with good reason....


Fran-Ventoso-disc-brake-cut-1-1024x600.jpg

http://cyclingtips.com/...ion-on-giant-knives/

I read an article - can't remember where - that said the injury was a lower-leg laceration to the bone - apparently the tibia was visible. It said that the operation was to clean out the wound and stitch everything up. As to exactly what happened - I have not seen a detailed description anywhere other than he fell on someone else's disc brake.

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Ed O'Malley
www.VeloVetta.com
Founder of VeloVetta Cycling Shoes
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Just saw more details and the photo. Yikes.

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Advanced Aero TopTube Storage for Road, Gravel, & Tri...ZeroSlip & Direct-mount, made in the USA.
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The article I read said that he did not fall, but was forced to ride extremely close to another rider, and their disc cut his leg to the bone.

It was pretty much a marketing push anyway. (The best thing about disc brakes: you need new wheels and a whole new bike.)

In cyclocross, where disc brakes are nominally more "necessary" than on the road, both the men's and women's reigning world champions chose rim brakes over discs for the biggest rides of their lives. I think the pro road pelotons will do okay with rim brakes while the bike industry re-invents discs.

That's even scarier....

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Ed O'Malley
www.VeloVetta.com
Founder of VeloVetta Cycling Shoes
Instagram • Facebook

Please stop with the "marketing" canard....the reality is that consumers are looking for bikes with discs. It is the market responding to demand.

I have been behind the development of road discs for some time, but have been hesitant about their benefit on full road bikes (clearly a place on CX and gravel bikes). But the development process is iterative and takes time. Road discs are still very much "adopted" technology (i.e. Basically MTB tech on road bikes). There is a lot of development that still needs to happen.

What happens from here will be interesting....unfortunately, if they are never sanctioned for racing, development may stay at the current stage...MTB tech on road bikes.

But there is no "marketing" conspiracy to get you to buy discs on road bikes.....

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Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams

A pro cyclist getting a cut in the shin to the bone is what, maybe 5mm deep? The photo looks like a tear not a cut.

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Pactimo brand ambassador, ask me about promo codes

Conspiracy was your word, not mine. I would describe it more like endless ad copy dribble to convince people they need hammers to use thumbtacks. If, on the other hand, you want to argue the industry's altruist motives for reinventing the wheel...

Here's the quote:

Ventoso was behind a crash on the Quérénaing à Maing sector of pavé, around the 140km mark. According to Ventoso, he didn’t go down but merely rode up against the bike in front of him, which had disc brakes, as many riders tried to avoid crashing. He didn’t notice the deep slash on his leg until he had began riding again.
“Shortly afterwards [after the crash], I have a glance at that leg: it doesn’t hurt, there’s not a lot of blood covering it, but I can clearly see part of the periosteum, the membrane or surface that covers my tibia,” Ventoso wrote. “I get off my bike, throw myself against the right-hand side of the road over the grass, cover my face with my hands in shock and disbelief, start to feel sick… I could only wait for my team car and the ambulance, while a lot of things come through my mind.”
http://www.cyclingnews.com/news/ventoso-blasts-the-use-of-disc-brakes-in-the-peloton/?utm_content=bufferd3de3&utm_medium=social&utm_source=facebook.com&utm_campaign=buffer

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http://bikeblather.blogspot.com/

It seems perfectly reasonable to assume more of us freds will buy them if we see the pros riding them on TV. It's a big reason bike companies spend so much on sponsorships.

I was not looking for electronic shifting. But now I have it.

Exactly. It's hardly as if that demand forms itself organically in some sort of vacuum ~ consumers are responding to a perceived 'need' that's being aggressively marketed to them all the same. It's not like a grocery store suddenly selling more eggs because there's a spike in demand for something that's essentially the same as it's ever been; if the notoriously copycat bike industry decides to start offering a majority of its models with disc brakes and then (surprise) their sales data shows more people buying disc bikes, that's pretty artificial 'demand' driven as much or more by the limited range of choices available to the avg buyer at the avg shop.

It seems like they could mandate rotors with a circular exterior (no indents) and the edge has to be rounded (not the current flat edge with sharp corners).

Any reason that wouldn't address the issue?

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ECMGN Therapy Silicon Valley:
Depression, Neurocognitive problems, Dementias (Testing and Evaluation), Trauma and PTSD, Traumatic Brain Injury (TBI)

I just put my fingers on my disc brake edges and they are not sharp.

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Dave Campbell | Facebook | @DaveECampbell | h2ofun@h2ofun.net

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Lions don't lose sleep worrying about the sheep

Spin it up to 30mph and try again....

Try putting your finger in a spoke at 30mph....


Jeff

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You can't fix stupid ..

Yeah, you tried this one before....except in this case, you are wrong. YOU are the one asking for a faster horse...IOW, an improved vision of what already is the "norm".

And just in case you need a reminder, I have already said I have reservations about the need for discs on a road bike....but again, product development is often an iterative process. The current crop of road discs is just a stop on the development timeline.

---

Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams

You honestly have no idea what you are talking about....."aggressively marketed to them". LOL...that is some funny schitt.

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Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams

and just compromised your braking performance. womp womp

How does one not fall off their bike and by riding closely to another bike cut their LEFT leg on the disc brake of another bike?

Yea I'm calling bullshit that the "cut" was made by a disc. Especially since he is claiming he was still riding... The injury doesn't match the supposed mechanism that caused it

Via pileups like this. It's a cluster of bikes and limbs. (and motos)

pic.twitter.com/pGPFmRfFvf

That's the same question I've been asking...

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The above poster has eschewed traditional employment and is currently undertaking the ill-conceived task of launching his own hardgoods company. Statements are not made on behalf of nor reflective of anything in any manner... unless they're good, then they count.
http://www.AGNCYINNOVATION.com

It has to be a BS description.

To get your bike close enough you have to be inside the handlebar width, have no pedal interference and no hands on your bars (or theirs) and nobody in a seat.

I went down the basement and tried to line up two bikes. They would have to have the bars over the cross bar, and over the wheel, assuming there wasn't a body on either bike. Add to that to get a shin anywhere near the front or rear required that your pedal was inside the spokes. What sort of rider keeps pedaling in those circumstances.

There is something missing from all this.

Last night after all the discussion I examined the discs on my 2 mtb and 1 cross/commuter/road bike. All sharp edges to my touch and I would expect to receive a cut if I came into forceful contact with the rotor during a crash.

Doing a bit of research there are some standard methods to determine sharpness. UL1439 was the first I came across with a standard test method and commercially available tools: Essentially a layer or two of tape is rubbed across the edge and then inspected for cutting.

https://sharpedgetester.com/...les/tool_in_hand.jpg

If he was a hockey player he would have finished the race.

Hockey players don't "throw themselves into the grass" and "cover their faces and hands in shock and disbelief." Such drama!

As a guy who races at a professional level and experiencing the accelerations and decelerations of NRC crits and mountain descents with 200 guys I would have to disagree with your "remarkably poor" assessment of carbon rim braking. My brakes work great! I can smoke the tires right off the bike before I lose purchase on the rim. In the rain, things require a bit more finesse but most of the trouble is still with traction on the road and not with the lack of brake power. In fact, I think the power of discs in the wet could throw your bike down really quickly in a rainy crit.

In summary, I think discs lack any big time benefit in racing performance and are detrimental in terms of weight, aero, pain in the ass factor and now injury risk. People compare the cutting hazard to the risk of flying chainrings in a crash and I agree. Why add two more sharp spinning (and heated) edges to the mix in mass crash?

They might be a fun toy but they don't belong in high level racing.

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i dont buy the description of events, especially when the rider himself claims he didn't notice it immediately.
physics and simple measurements don't support his apparent version of events.

Yip, it just doesn't seem possible to still be on your bike and have your left leg cut by a disk (on the left side of the bike you are hitting). I feel he has just jumped to conclusions on how he got injured

Just posted this in the other thread....

OK, those pics help.....guess I can see a scenario where this happens now. Rider in front skids / falls of slightly, bike pointing off to the left and leaning down towards Ventoso as he approaches. Ventoso, skids / stops but veering to the right, so his left leg is sliding towards a disc which is now angled up at him...voila, it catches the side if his calf next to his shin and lifts the flap of skin up.

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Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams

I still don't see it, the rim would come in to contact with body or bike first and prevent the disk from hitting you

It's also not uncommon to pile into each other with blades that are far sharper than any discs.

with good reason....

Not. I think disc brakes on road bikes are stupid, but not because they are dangerous. That's just silly.

I severed a hamstring tendon in a pileup at the Manhattan Beach Grand Prix a million years ago. Still missing that tendon. Thank you 3rd world medicine! For that expensive ambulance ride and nothing done at the hospital except apply stitches.

Apparently someone's chain came off and the big ring did it. Now, those suckers are *really* sharp. Should have been outlawed long ago. Why aren't we on shaft drive and automatic gears like any civilized vehicle?

I disagree completely.

The reasons for worse performance in terms of weight & aero come down to being a relatively recent technological development; given several more years of development, you'll see them become somewhat more practical in these areas (really, they'd probably be just as, if not more aero, than caliper brakes if a bike incorporated an integrated fairing in front of the disc caliper to direct air around it, just like what is done for caliper brakes on many super bikes)*. Additionally, who wouldn't want to save seconds on their time by being able to reliably and certainly brake quicker before a turn?

You cannot cite their hydraulic nature as a disadvantage (PITA factor) due to the emergence of the hydraulic rim brakes currently found on some superbikes and it's prevalence on MTB systems; the technology is very reliable and stable (assuming proper setup), as MTB systems have shown, and allowed for superior modulation of stopping power and cable management on tri systems. The fact that good disc calipers necessitate hydraulic lines are nothing but a positive.

Most new bike technologies have been met with accusations of being unsafe and therefore unworthy of development (carbon frames, aerobars from what I can recall). By this logic, we should all use Rohloff speed hubs and belt drives. The discussion in this thread even shows that the disc brake being at fault for the injury isn't certain.

The biggest flaw in reasoning against the disc brake, especially for tri, is the reality that caliper rim brakes slowly destroy one of the most expensive components on the bike. The fact that disc brakes would offer reliable braking performance without causing wear to a several thousand dollar wheel-set, is by it self, the single biggest reason to be pro disc, keeping in mind that this will be the case regardless of weather, road conditions, or rim material. Without the constraint of a rim brake track, who knows how much more aero Zipp et al. could make a set of their TOTL wheels? Additionally, many AGers who spend thousands on wheelsets wouldn't see their purchase evaporate in to thin air the moment delamination occurs on the brake track (I shudder to think how I'd feel if I put a ruler to a set of H3s and found the braketrack to be somewhat concave and close to useless).

There is really no reasonable argument that has been put forward that demonstrates that discs are not the way forward when it comes to bicycle braking technology.


*I recall some testing done by Specialized a few years ago wherein they found that disc brakes offered no great aero disadvantage vs. rim calipers, but I might be misremembering the article.

Still doesn't pass the smell test, in order for the left front of his lower left leg to hit an object mounted in the left center of either wheel of another bike doesn't seem possible without a pileup collision, not a I didn't fall and all of a sudden I have a gash colliision. Now if they were jousting, we have a probability of contact, so I spose it is possible that he's right.

What looks more possible given the photos provided is he smashed into the cassette of another rider, the injury pattern and what appears to be black residue would support that as well.

Yip... The rider is just using this injury as a way to voice his own opinion on discs. Unfortunately for innovation the uci have listened. I hope it comes out that it wasn't discs that caused it

I rekon he slashed it open on a garmin pod of a power pedal.
Easy to see how this happens, rides in close to the other bike while they are still pedaling and the gamin pod sticks out straight at his leg as the other rider is on the back part of the pedal stroke.

Ban garmin pedal pods.

It could even have been contact with a tyre at speed, it's a rip not a cut.

This is all just a disc beatup.

I don't think that comparison holds up to scrutiny.
Disks were functionally desirable for MTB due to specific shortcomings of rim brakes (mud clearance, don't work on damaged rims, poor performance when dirty, etc). Having experienced good disk brakes, many of those riding cyclocross and road bikes are not content with the performance of their brakes and want to have the benefits seen to be provided by disks.

Electronic shifting does not fill a gaping gap and I think is very clearly a "nice to have" feature. Whatever accusations you throw at marketing, at least take responsibility for your own choices. I bought 2 new bikes and a new set of race wheels in the last 2 years. One road, one tri. Neither has electronic shifting or carbon rims. I don't see any major benefit to Di2 so it wasn't worth the money to me. I didn't want to compromise on braking for the sake of a small weight saving so I got a set of Swiss Side Hadrons with alloy braking surfaces. marketing may lead you to water but it can't make you drink.
If I could have had a mature disk brake design on these bikes I would have gone that route.

They also happen to wear a crapton of hard plastic protective gear.

As for the "discs are dangerous" argument....not quite buying it. Biking on the road is extremely dangerous, should we just move on to velodrome racing? Racers get hurt on all sorts of things. Sure, a rotor is one extra thing but I still can't see the rotor as very likely to injure someone often enough where it would make sense to not use it. I don't have data supporting my claim....but Ventoso also doesn't have data supporting his claim that they're inherently dangerous. He's got a single point of information, an anecdote, and a shin that may or may not have gotten cut by someone's rotor.

Yup.

And if we're making a parallel to the infamous Duke Lacrosse rape trial, TomA is Nancy Grace. :)

you make good points about the wear of breaks on expensive carbon wheels. But, for me...

Even though I ride in the mountains. I use my race wheels for - racing. As a triathlete my goal is to use the brakes as little as possible. Even on a hilly course such as Wildflower LC - I'd expect to brake so little that my wheels would not wear out in 10 of my lifetimes of racing. So, as a practical matter wearing out the rim is not an issue, nor is brake performance (I want to keep my loss of watts as low as possible). In a Mountain Bike race - much different animal. Braking late and fast into corners, etc. can be the difference between winning and losing.

Interesting discussion, though.

---

I saw this on a white board in a window box at my daughters middle school...
List of what life owes you:
1. __________
2. __________
3. __________

And that's a guy who sells disc-braked road bikes (or at least: his name is on them), and stands to make a profit when road cyclists adopt discs.

ETA: out of an abundance of caution, I'm afraid I've got to pull this one. Sorry.

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Carl Matson

"..that's one magic loogie!"

I must admit I didn't read the whole thread, but why don't they just put a small disc guard over the discs. Seems simple enough.

Thanks for the demo, much more informative than trying to picture it in your head.

I don't agree on the point regarding the UCI's response though; they seem to move at a glacial pace in most regards, case-in-point on course vehicles. It was last year's Classics season when this topic started to gain traction, as Jesse Sergent and Sebastien Chavanel were punted off by Shimano Neutral Service vehicles to kick off a seemingly constant stream of incidents throughout the season.

Yet, we're 12 months down the line, a rider has died from being struck by an on-course moto and they're still sitting on their hands! As far as I'm aware, all they've done is announce that they're "reviewing the regulations". I'm surprised they've acted so quickly in response to this one incident, especially given the ramifications for teams and the industry; it makes me wonder if anything else has gone on behind the scenes.

Weight. UCI rules on fairings and covers. Makes wheel changes harder. Even uglier. Pick one or more.

Of the two injuries reportedly caused by disc rotors, one of the injured parties (Maes) has been shown to have "misremembered" what actually caused his injury:

http://road.cc/...led-injuries-peloton

In addition to what uo5nVEtj9 said, heat. Covering the discs reduces cooling from airflow.

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Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)

I see what you guys are saying, and I am not familiar with UCI rules. I just have the impression they suppress innovation. Heat can be managed with cooling louvers or something similar. You only have to keep it from cutting someone if that is what happens. If its just a question of safety, teams will just have to sacrifice wheel change time/ complexity with braking performance, or use rim brakes. But really if the guard is mounted to caliper mount it shouldn't affect wheel changes. Drag impact would likely be minimal compared to the cylindrical tubes everywhere on the road bikes, or go back to rim brakes. At least a guard would give the option of a disc brake if safety is that big of a concern.

Which pro teams use Garmin pedals? even Garmin didn't use them...

Haven't done it myself... but saw the bike of guy that was off the front of a Half I raced a few years ago. A couple missing spokes in the front wheel, a couple mangled ones and some blood spattered about. Supposedly he lost a digit or two trying to monkey with his front brake while riding.

Lots can go wrong with riding bikes fast, it isn't a "safe" sport... although what this guy did just wasn't smart.

This is the best comment from that article

"The proof Fran Ventoso cut was not made from a brake disc is in the direction of the cut. In the picture above it clearly runs horizontally across his shin. This would very difficult to achieve as the rest of the wheel is in way. This natural shield does a far better job than the exposed teeth of a chainring (which is most likely culprit for that cut). A disc brake cut is almost always going to run horizontally down a riders body. If it happened as DrJDog said the cut would be knee to ankle, not horizontal.

Riders need to be told to stop whining about it and do their jobs. Manufacturers sponsor teams to sell bikes. If the cycling public want disc brakes - which it appears they do, manufacturers will make them and pro's will be forced to ride them. If pro's refuse, the manufacturers won't bother sponsoring them and the cost of running a pro team will increase, putting many riders’ jobs at risk"

Every disc equipped bike I have ridden has been overwhelming better when it came to descending confidently on steep, windy roads, especially the ones around here that also tend to have loose gravel on the turns. Even in heavy traffic when commuting or just riding to my training grounds, I felt a lot safer on the disc bike due to the lighter feel of the levers and the greater stopping power. As soon as specialized sort out their stupid Inhouse standard and move to the same as the industry, I will be buying a disc Tarmac to add to the fleet

You are thinking about the nature of the cut in a linear fashion...i.e. he came up to it with the disc parallel to his leg. See the scenario I lined out previously.

The rider with the discs comes to a stop, but with the bike facing and leaning over to the left. Ventoso is following, sees the stoppage ahead, slams on his brakes but ends up facing and leaning to the right. So as he comes in contact with the disc, his left calf is exposed the the disc in a perpendicular fashion. This explains the triangular nature of the wound. The disc pierced his leg at an angle, and cut at an angle, going deeper (and making the wound wider) the farther it went into his leg.

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Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams

Did you kiss the part where there is an entire wheel in the way?

It's not....he is coming in underneath the wheel with the disc angled up towards his leg.

Visualize two bikes lined up side by side, with their left sides facing each other (so one is facing one direction, the other bike in the other direction). Lean them over so the "disc bike" is leaning to the left (disc side) and "Ventoso's bike" is leaning to the right (drivetrain side) and you will see what I mean.

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Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams

Disks are on the left side of the bike. Ventoso's injury is on his left leg. Ventoso did not crash, he kept riding along. 1 of these things don't add up, and that's a disk causing the injury.

That's what I was thinking; the only way he gets cut by the rotor on the left leg, is if it's a head-on encounter

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"What's your claim?" - Ben Gravy
"Your best work is the work you're excited about" - Rick Rubin

The only way I could see it happening is if the wheel had bounced out of the frame, and taco'd, leaving the disk exposed... and then I have a hard time believing the disk would cause a cut like that in those circumstances.

Yeah, no schitt....did you read my last post?

Rider with discs comes to a stop facing and leaning to the left. Ventoso comes up,brakes / skids to a stop, but facing the opposite direction. His left leg is now facing the discs...angle bikes as I described above and you can inflict the type of wound that Ventoso suffered.

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Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams

WTF are you talking about?

The bikes were not going in opposite directions.

I'll eat my bike if they are able to prove that a disc caused that injury.

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Jason
None of the secrets of success will work unless you do.

Umm...no one is talking about going in opposite directions...Ventoso says he had to break and came into contact with the rider who had stopped in front of him...they both stopped, Ventoso just didn't go down. Re-read what I wrote and apply some critical thinking.

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Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams

Yip, I really don't understand his explanation. If the first bike is leaning left, and ventoso's bike was leaning right, either a) he would have avoided hitting all together or b) his leg would have contacted the drivetrain (and caused the injury...)

Go line up two bikes with the non-drive sides facing each other. One bike will be facing left (bike with disc) and the other will be facing right (Ventoso). His left leg is now up against the disc brake side of the other bike.

Remember, they are now both perpendicular to the direction of the race...

Was this the way it happened? I dunno....but that is how he could have suffered a left leg injury and the shape of the wound supports that idea.

---

Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams

I have read it at least a dozen times and cannot figure out what you are trying to describe. I tend to think that I am good at critical thinking but you may have to draw me a picture.....

If the left sides of the bikes (each bike) are facing each other, then the bikes are by definition going in opposite directions, which you say, "(so one is facing one direction, the other bike in the other direction)"....

This is not at all what is described by the injured rider in the link in the first post. As near as I can tell, neither rider went down and the injured rider has no memory of contacting the other bike. But by all means, feel free to invent a scenario where monkeys can fly.

ETA. The visual just became apparent to me. I get what you are describing. I think that there is absolutely no way that this could have happened without both riders going down (both riders facing at right angles to their actual direction of travel) but at least I now understand. I don't think it happened but, alas.

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Jason
None of the secrets of success will work unless you do.

Apparently your critical thinking skills aren't as good as you give yourself credit for.....I outlined this originally....first rider hits his brakes and comes to a stop facing the left side of the road, so dis rake side is now facing oncoming riders. Ventoso grabs his brakes to avoid the pile-up but ends up facing right....his left leg is now facing the discs of the first rider. Now angle the bikes and that allows Ventoso's calf to slide into the rotor.

Go get a plate and hold it flat against the front of your calf. Now angle it so the bottom of the plate is away from your calf and only the top is touching it. If that plate was a disc rotor and it was jammed into your calf from there, it would create the exact type of would Ventoso suffered.

That is the only way a disc could have caused that type of wound on his left leg (at least as far as I can figure out). Is it what happened? Hell if I know....but it is certainly a possible scenario.

---

Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams

I read Ventoso's first hand account of the accident.

With the knowledge of what he said happened I could not visualize your scenario because it doesn't fit at all with the rider's description.

I can now understand your scenario. Again, it doesn't match what was described but I at least understand what you were trying to hypothesize.

I still offer to eat my bike if that is what happened :-)

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Jason
None of the secrets of success will work unless you do.

I THINK I GOT IT!!!

The rider in front, locks up & slides across the peloton from the right to the left, exposing his rotors to the oncoming traffic

Ventoso sees this obstacle and, as you said "grabs his brakes to avoid the pile-up but ends up facing right" ... maybe he thought or saw more room to move on that side, or perhaps, RIGHT is his natural instinct, just as LEFT was the first rider's ... however, he slid out and hit Ventoso this way === while moving this way llll

So, the collision wasn't head-on, but a sideways slide ... like a hockey player checking someone into the boards

If it's PERFECTLY perpendicular there's no issue, but even the slightest /// or \\\ and someone could get sliced

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"What's your claim?" - Ben Gravy
"Your best work is the work you're excited about" - Rick Rubin

Exactly....it is the only way I can see a disc causing the injury that Ventoso suffered.

I am not saying it DID happen that way, just proposing a scenario that could have occurred and is consistent with his injury.

---

Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams

Then why didn't you say that in the first place?

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"What's your claim?" - Ben Gravy
"Your best work is the work you're excited about" - Rick Rubin

Photo of injury on cyclingtips

Height of injury just above hub height, assuming slanted upright bikes and foot on ground. The higher scratch stripe (low left in photo) has to be a spoke imprint surely? If you hit the disc rotor, you won't touch the spokes. My take is that this is a freak cut as bikes and riders pile into each other whilst fundamentally upright "
I’ve got to break but I can’t avoid crashing against the rider in front of me, who was also trying not to hit the ones ahead. I didn’t actually fall down: it was only my leg touching the back of his bike."
- Ventoso pokes his lean knobbly knee out a shade left and catches a near horizontal spoke on the driveside, aft of hub, of the bike ahead and to his left. The angle of the wheel and cobbled surface prevents wheel from being forced sideways and the spoke digs in at the top of the shin. That is a straight blade making an oblique incision, not a pizza cutter laceration IMO.
What were the circumstances of a Spinergy slicing into someone's kneecap (Jalabert?) about 20 years ago?

Michele Bartoli, not Jalabert.

I'm not certain how you could could an area that size in between spokes in a manner that would allow it to cut like that....I'd also think that, given the prevalence of bladed spokes over the years, it would have happened before this.

But the area that you think are spoke marks certainly is interesting....but the angle of the upper mark doesn't line up with the wound on the other side.

---

Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams

This is a bit of an apples to oranges comparison in my eyes. The very best don't need disc brakes, but us mortals can see some real benefits. At this years challenging cx nats course I road back to back laps on cantis and discs. My next cx bike will have discs, no question. When I develop the talent of a world champion I'll happily go back to cantis.

He didn't hit another rider at all but rather ran into the back of a moto and the almost perfect circular cut is from the exhaust. In his embarrassment he blamed it on discs.

So we just got two mountain bikes and there is no way that we could organise the two bikes for a person still on their bike to come into contact with a disc on the other bike on the left shin.
Actually, we couldn't even get contact anywhere.
There is simply to much body, pedals, shoes, frame structure and things in the way.
And this is with larger diameter MTB discs, not tiny road rear discs.

It's a crock of shite.

It may have. There are injuries in just about every race. We never cared about the specifics much before this.

That said I think rear discs (wheels) would be a measurable safety benefit. My track disc has saved my ass multiple times - because it prevents other peoples bike or body parts from getting in my spokes during crashes and taking me down.

Where do you race, on what roads? If you want to save SECONDS from your time, pick your race line right and never brake. I'm not even going to comment on triathlon, in crit racing those that can go 50-60km/h in the corner win the race, those that brake are being screamed at. Racing is not about braking at all.

I'm just waiting for someone to suggest disk brakes on track bikes, they are so good, surly must be usefully.

Here is how you race, pedal through those corners in most aero position you can tuck in to, if you brake they will catch you.

https://www.youtube.com/watch?v=RxXqQqAc2pA


Commuters, MTB, and all others sure knock yourself out.

Few things about this entire UCI ban seems very strange. We are all concentrating on how it happen: is it possible or not possible etc. It is all irrelevant.

What is strange about this ordeal: We have 2 injuries, potentially caused by disks, and UCI bans the technology. Wow how many injuries we had because of bad carbon frames/wheels and those never got banned.

Almost unreal how easily UCI pull the plug on it, and nobody really complains no attack back... Rotor is probably pissing their pants off now...

Here is my theory. After safety ban: bike manufactures will go back to the drawing board, spend “millions” on making it all “secure\safe\and awesome”:

They will come up with some new futuristic “safe” shapes: eg: Integrated covers in forks and frame. Those surly violate current UCI rules, but since they are solution to safety, UCI will have to bend backwards suck it up and accept new designs and solutions.
That’s how manufactures can have a shot at changing ancient UCI rules, it is not going to happen overnight, mark my words big changes are coming. Disks itself are small market mover, but when you add entire frame design change, that will make every manufacture happy, and a lot of money from “I need to have this new cool looking bike” people.

As someone once said "First one to use the brakes, loses"

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"What's your claim?" - Ben Gravy
"Your best work is the work you're excited about" - Rick Rubin

Unless you are descending at over 100km/h... Or did you guys forget about situations like that?

So homeboy didn't notice his leg get sliced open to the bone, but noticed the guy in front of him had disc brakes? WHAT?

There's another one: "Brakes are means of expressing Fear"

Use the brakes ... go ahead, it's sensible ... but the first one to do so, is still gonna lose

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"What's your claim?" - Ben Gravy
"Your best work is the work you're excited about" - Rick Rubin

And those discs will let you brake later... Oh does that mean you saved seconds? Why yes I think it does

I've never quite understood this argument. Isn't the limiter with both style of brakes essentially locking up your wheel? Unless your discs offer an ABS, how do they let you brake later?

About 35 years, while surfing, I had a somewhat similar incident. I wiped, felt the board smack my leg, but other than thinking it was probably going to be a pretty good bruise I didn't think much of it. I paddled back to shore, and as I got out noticed people staring at me. I looked down, and saw that my left shin had been completely shredded, with a few inches of bone showing. It never actually hurt, but right then I went into shock...

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"I'm thinking of a number between 1 and 10, and I don't know why!"

I get the not noticing the injury part. Happens all the time. Just curious that he knew a disc caused this unless he saw the disc on his leg.

I really don't care. If discs go away, great. If they stay, whatever. I know that as long as I have a choice, I won't use them on the road.

It's only an argument if you don't know how to brake with normal brakes.

I love hydraulic brakes on my p5, but surely don't think I'm short on braking power on any of my road bikes to need disc brakes. I live in Colorado and have never thought decending about lack of power. You're gonna skid well before you run out of power.

"Isn't the limiter with both style of brakes essentially locking up your wheel? Unless your discs offer an ABS, how do they let you brake later?"

I believe the case is that the greater modulation provided by disc brakes allows for surfing the line of max braking w/out skidding. That and performance in wet conditions or those where constant braking for extended periods is required. Joseba Beloki probably wishes he'd had disc brakes back in '03.

https://www.youtube.com/watch?v=uHFSSXOSnxs

Constant braking for extended periods doesn't work that well for discs, either. All that heat generated has to go somewhere, and on hydraulic systems that's often into the brake fluid. Ride your brakes long enough, and you can find that suddenly your lever just pulls to the bar and you have no brakes whatsoever. Even on Shimano's road brake system, which jumps through all kinds of hoops in order to prevent overheating, there can be issues. I haven't heard of anyone boiling the fluid on those yet, but I've seen a few instances of the aluminum portion of the Freeza rotors melting from overheating. If you tend to ride your brakes on descents, all switching to discs does is trade one set of potential issues for a new set...

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"I'm thinking of a number between 1 and 10, and I don't know why!"

And I've never understood the modulation thing. Depending on how they're set up, I'm happy with the control I get with cantis, mini Vs, and calipers. I don't notice my disc brakes being all that much easier to finesse. Is modulation something measurable?

Of course, I don't need much hand strength to use my disc brakes. One finger instead of two. But that's because they're hydraulic, isn't it?

If one setup does offer more modulation than another, how much is that because it's disc or because it's hydraulic?

If someone is achieving that with discs they would have killed their rim or ripped through the pads well before that...

What you mention above is my experience as well. I've long said that if your braking lacks modulation and power, then you may want to reconsider your equipment and setup choices. Excellent braking IS possible using the "integrated 622mm diameter disc" :-)

I'm also convinced that what most people consider "modulation" is actually light lever force prior to the brakes being engaged. This tends to reduce arm "pump" when doing frequent brake applications (as in a descent)). It was the main thing I observed as different when I switched my MTB from well set up Vs to seperate braking discs. Again, with prudent equipment choices and setup, light lever pull is easily achievable with cable actuated setups. Hydraulics makes it easier (at the expense of complexity) to get this, even with rim calipers.

It's funny...but it seems as if whenever someone mentions some of the performance drawbacks of separate disc systems, they are put down and ridiculed. Not to mention the obvious weight and aerodynamics drawbacks of "un-integrating" the braking "disc" from the rim, I personally have been called "crazy" because I had pointed out that at very low wheel speeds (such as when negotiating a tight switchback...without skidding, that is...on a MTB) that separate braking discs tend to be "grabby", and that I actually preferred the characteristics of rim brakes in that particular situation. The disc proponents I was relating this to refused to acknowledge there could be ANY drawbacks. Mind boggling...especially considering that when I asked the best MTB bike handler I know about this, he agreed with me.

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http://bikeblather.blogspot.com/

It's tough to really get a well-articulated straight answer on the "modulation" story.

There are lots of physics and engineering trade spaces involved. Pad/rotor surface area. Pad-rotor velocity (higher at the rim). Effective distance of the rotor/rim from the axle and the effect on stopping torque (much more torque at rim than near the axle). Pad/rotor materials (far more limited with rim brakes). Force transmission mechanism (e.g. hydraulic vs. cable). I'm probably missing some.

My lay research hasn't resulted in a totally clear answer. It seems that the answer to what "modulation" means at the brake lever is represented by the below graphic (stolen from here).


Like I said, I don't know the real answer as to why disc brakes have more "modulation" but I have two suspicions.

One suspicion is that disc brakes are located in a location where they have less mechanical advantage over the wheel. That seems like a bad thing at first. But it might be good in terms of "feel." As a simplistic example, lets say you need 10 N-m of torque at the rim to lock up the wheel. With little high-friction pads. When translated to force at the lever it's a pretty small range of forces, and it may be hard to provide "feel" to the rider. Anecdotally, brake manufacturers have to build some flex into calipers to avoid having excessively "grabby" feel to the brakes.

Disc brakes need to provide much more torque down near the axle to reach lock up. Let's call it 100 N-m. And they have much more pad area to work with, and they can work with different (lower) pad frictions. That can translate to a wider range of forces that can be "felt" at the brake lever. And it's my understanding that disc brake systems can be built much stiffer, so that modulation occurs at the pad-rotor interface rather than in caliper flex. More feel to the rider.


I think the cable vs. hydraulic differences are just in lower friction for hydraulic (more feel to the rider, just like less caliper flex), and less flex in the material itself (cables stretch a little bit, while fluids are almost perfectly uncompressible).

This is just my Google-fu. An actual brake engineer might come on here and take me to school. And I hope one does. Because I'd like to learn. There's precious little good information on this in the bike media provided to consumers. The maxim that "disc brakes provide more modulation" is just repeated over and over with little explanation, even by "tech-savvy" industry writers.

Nitpick: cables don't "stretch", per se (try to stretch a brake cable outside of the housing)...but, more accurately, the housings (and interfaces) distort and/or compress. One can go a LONG way towards minimizing this by using compressionless housings (I've had good luck lately with Jagwire Link housings) and careful routing.

Other than that, the graphic is pretty good IMO.

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http://bikeblather.blogspot.com/

Serious question - how comfortable do you feel in wet conditions and carbon brake surface? I like the P5's hydraulic brakes but still feel iffy when I get to ride in hills (I live in FL). I know alot of it is experie and practice, which is hard for me to get but curious how I'd ultimately feel if I lived in a place where braking was needed.

"Carbon brake surface"...yeah, don't do that. That's one of the equipment decisions I mentioned that should be reconsidered if you don't have good braking. Seriously.

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http://bikeblather.blogspot.com/

It doesn't take very much to overheat many brakes' fluid. Just ride the brake a little longer than normal. Nothing that would kill an aluminum rim or destroy a set of pads. You might overheat your aluminum rim to the point that your tire blows, or glaze your pads, or melt a lower quality carbon rim with the same effort, but you are not going to burn through an aluminum rim just like that. I didn't say that rim brakes were immune to heat related issues, just that with discs you are trading one set of potential (note: "potential") problems with another set of potential problems...

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"I'm thinking of a number between 1 and 10, and I don't know why!"

While I'm not a brake engineer, I have tested literally hundreds of different brakes (mostly mtb, still relatively few road discs out there). The amount of "modulation" on discs runs a wider gamut than on rim brakes. I have a set of sample mtb disc brakes that have about as close to zero modulation as possible. And these are mechanical, not hydraulic, so even with a bit of housing compression they're still more solid feeling than any hydraulic I've tried. They feel rock solid at the lever, and lock up almost instantly. I can easily skid with just my pinky. I've never come across a hydraulic brake that grabbed as hard as these do. But these also have pads about the size of dime, and would fade almost instantly. Hard to keep from locking them up at the start of a descent, and no brakes at all halfway down...

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"I'm thinking of a number between 1 and 10, and I don't know why!"

That diagram simply shows mechanical advantage ratio and has nothing to do with modulation.
Modulation is the feedback at the lever and lack of friction in the system allowing very fine adjustments to power applied to the pads unhindered by stiction.

This is totally separate from amount of lever movement to move the pads.

So is modulation measurable? In modern disc setups, is modulation improved (over various rim disk systems) by the disc pad and rotor itself or by the hydraulic controls? Do you agree that modulation varies from one disc brake setup to another? Why or how?

Having worked in a bike shop that does exclusively high end road, road discs are definitely not being asked for from the customers. We usually bring in a few road disc bike because we have to, and we may sell one throughout the season. The rest we have to put on clearout and sell at our cost just to move them. I maybe get 2-3 customers a year ask about discs, thats it. Customers aren't asking for them. Companies are pushing them.

Discs also create huge problems for bike manufacturers as they have many hurdles to go through to design an effective clamping mechanism. Want thru-axles? To get proper chainline you need longer chainstays, which will make slower handling. Use QR's? The disc may not be properly aligned. That is why many companies are forced into making their own standards, that simply create headaches for the consumers.


As far as safety goes, I've seen a few nasty cuts from people on mountain bikes hitting rotors. The two most recent crashes I can recall had 30+ stitches each. But for however many crashes I've seen/experienced on mountain bikes, it certainly is exceptionally rare for the rotor to cause any kind of cut.

I did a charity ride today and maybe it was my heightened awareness but I saw waayy more disc road bikes than 1. Ive seen in the past and 2. I'd expect to see (especially being in FL). Guessing 2% of the bikes. Still not a lot but more than one a season, which is what I sensed was the rate. Noticed demographic was generally slightly older riders who weren't fast but weren't slow either.

+1,
As i hear the same from my shop (both from a younger and an older mechanic).
To say the industry is not aggressively marketing road discs to consumers, is like admitting to not understanding business.

I ride both, and prefer the calipers on my race bikes.
I really hate to deal with a heavy stiff fork that still flexes and shortens it's trail under disc brake action...necessitating steering adjustments between entering and executing high speed turns.

Biggest drawback of disk brakes, IMO.

One shop that deals exclusively in high end road.....yep, that is clearly indicative of the entire market.

Consumers are absolutely looking for road discs. They may not be shopping in the store where you worked, but they are looking for them.

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Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams

A fair demand for mid and lower range road bikes with discs in the UK.

It rains here. People ride on less than perfect surfaces. This promotes the use of larger tyres and mudguards. Rims can wear quickly too in these conditions. This makes discs attractive.

My next winter/commuter bike will have discs.

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Developing aero, fit and other fun stuff at Red is Faster

Modulation gains in disc systems over conventional rim brakes come from multiple reasons.

Obviously the big one is hydraulics lack of cable friction and housing flex. So the same can be had from hydraulic rim brakes in this regard.

Another major one is the very much higher clamping forces of discs so that pads are made from very solid material, so more hand pressure means more braking, unlike rubber rim pads that compress and loose a lot of the hand force to merely squishing. This is why even cable discs can be very good compared to same level rim brake.

Rim brakes have long levers to reach around the tyre to the rim, flexy no matter what you do. Disc brakes have a very compact setup with no tyre to reach around, so very little flex.

Disc pads can be run extremely close compared to a rim brake, so designers are free to make use of what would have been wasted lever movement on a rim brake which must run with reasonable rim clearance.
This is not a modulation thing, but it is the reason that disc brakes can be made very powerful as the full lever movement can be used for braking and not waste the first third or half to rim clearance.

Because the disc setup does not squish pads and flex long arms, there is no loss of power in the extreme high power end of travel, so that more of the lever movement can be devoted to more common partial braking inputs, whereas a rim brake needs to keep a fair portion of the lever travel available to allow for flex under full power braking.

Differing disc brake feel can come from many sources also.
Shimano XT trail brakes can feel a bit on/off to those that are not used to them, they actually modulate very well, but the short lever movement made possible by the varying pivot point of the lever (servo wave) brings the pads in contact very quickly and then the lever enters into a very high power mode that catches some users moving from lesser powerful brakes to these brakes.
Organic pads also tend to have very high initial bite compared to metallic or semi metallic pads, so pads can play a large role in the feel of the brake, just like rim brakes.
Some pads have high initial bite but don't gain power linearly at high forces, so different lever feel, but the modulation is still there.

Many people (most) mix and match the meaning of modulation with lever ratios, so the conversation gets very confusing when you have no idea if the reviewer is talking lever ratios or actual modulation.
Poor modulation is just a shit brake to use at the limit, no matter the lever pull.
Good modulation is a great brake to use at the limit, no matter the lever pull.
It's just some great modulating brakes with short lever pull take a while for you to reset your brain to the extreme power available.
But a poor modulating brake is never good near the limit as fine control is masked by flex and friction losses.

Notice that this conversation has nothing whatsoever to do with being able to lock the wheel, just simply the ability for fine control at the limit where it is required most.
You know the times, over cooked it coming into the corner (or simply out braked your mates to get position or that dickhead dived right into your line forcing you to change to a slower line.) and need to keep braking at the limit whilst negotiating the corner on the limit, this is where modulation shines.

The shortening of the wheelbase due to rearward fork flex under braking actually increases trail as the wheel contact point is moved further behind the steering axis.
Disc braked and rim braked applies the same reward force to the fork during braking.
It's due to the wheel trying to drag the fork backwards along with it.
Nothing whatsoever to do with the braking system involved.

Back to unknowledgable keyboard trolling for you.

Interesting, thanks.

Whether or not they're asking for them, I do see people being forced to discs as they go to buy their next relaxed geometry bike. If you want a 105 level or better Synapse, you'll likely find it's only available in a disc. The same applies to the Roubaix (non Di2) bikes.

I've actually worked for 3 different shops over the last 6 years. But this one the last 3. Same thing applies. Selling a road disc bike is exceptionally rare. We do have a few lower end road bikes (starting around 1200), and people seem fine on calipers. Often times its a matter of cost vs. benefit. Disc bikes usually seem to add a few hundred dollars to the end price tag, with little benefit (we don't have mountains here).

To the poster above me, the roubaix has a non disc version. We carried both, and the disc version did not sell until we put it on sale at cost. The owner only brought in one Roubaix with disc this year, just as a show piece.

Bike manufacturers are pushing it.

A little tangent topic , but I thought I heard or read someplace that hanging a hydraulic brake bike upside down by the wheels is a bad idea. Something about the fluid getting pooled wrong and causing the need to bleed the brakes.

Is that true ?

Can be, any air in the system can over time make it's way up to the caliper.
Shouldn't be air in the system though.

So 3 different shops over 6 years....so the majority of time before discs became readily available.

Gotcha.

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Chicago Cubs - 2016 WORLD SERIES Champions!!!!

"If ever the time should come, when vain and aspiring men shall possess the highest seats in government, our country will stand in need of its experienced patriots to prevent its ruin." - Samuel Adams

It's fine on any new (last 5-8yr old) disc brake system. There shouldn't be any air in the system, but even if it is, as soon as you flip right side up and pump the brakes it'll be back to normal.

Actually, if you suspect air has made its way into the caliper, the best thing you can do is pop offf the wheels and push the pistons back into the housing to ensure none gets trapped there where it can do the most harm.
Then leave the bike sit right way up forca little while before pulling the levers.

I think a big part of the modulation advantage for disk brakes is the human part of the system. I find on my (crappy) cantilever brakes on a very cheap cross bike I still get enough power to lock up the wheels, it just takes a LOT of hand & forearm muscle to do so. With the disk brakes on my MTB or my new cross bike I find I get all the power I need with 2 fingers. People have much better fine motor control when pulling relatively gently with two fingers than when "grabbing a handful" of brakes.

Back in the day I had an MTB with regular brakes, and some long descents my forearms would be completely pumped and my hands would be cramping up.

I think a bit part of the disc brake advantage is the finesse you can have when you only need one or two fingers to brake. That being said, while I love my discs off road I don't feel a need for them on road.

Yes. This can be a key factor, and as you point out isn't limited to separate disc braking systems. However, even cable actuated systems can be significantly improved in this regard with prudent cable and housing selection and setup.


This is where you go off the rails...just because the pads are an elastomeric compound, it doesn't mean they are easy to compress.


Not necessarily. There are plenty of integrated braking disc calipers that don't have "long levers reaching around the tire". TriRig Omega is one. The new centerpull brakes on the Madone are another. The Magura hydraulic rim brakes too.


Here is where you go off the rails again...the disc pads HAVE to be run with close clearance because they have to be set up with large "leverage" (i.e. high force/low travel) between the master cylinder and the pads. This is necessary because the clamping forces HAVE to be high due to the small (relative to a rim brakes 622mm diameter "disc") diameter of the braking surface and the proportionally lower braking torque generated for a given clamp force and friction coefficient.


Again, not true...in fact, certain brake types can be designed with a progressive actuation, with large travel during the first part of the lever application and lower travel/higher leverage in the latter portions. That's something that's difficult to do with hydraulic separate braking disc systems


Yep, and it's that "bite" that is one of the things I dislike about separate braking disc systems...then tend to be "grabby" at times...especially under very low wheel speed conditions (like when negotiating a tight switchback on a MTB). The pads also don't last very long in sloppy conditions...and beware if you're out riding on the road as it first starts raining. It's fairly easy to contaminate the pads with road oils and drastically reduce the braking power...be careful when washing your bike as well, for that matter, for the same reason.


The problem I see here is that you have your mind made up about what each braking system can and can't do...and aren't interested in exploring why or why not that is. Oh well.

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http://bikeblather.blogspot.com/

Interestingly enough, I've been using a 2-finger rear, 1-finger front braking technique on both road and MTB since...oh...about 1986 :-/

One thing I noticed when first switching my MTB to discs was that the "free" lever travel (i.e. the travel prior to pads hitting) was a lot lighter on the disc systems than on the V-brakes on there previously. That REALLY cut down on the "forearm pump" and "hand cramping" on long descents...and is why I mentioned above that I have the opinion that this is a big part of what most folks describe as "modulation" ability. The good news is, it's possible to get the same type of lever feel with rim brake systems.

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http://bikeblather.blogspot.com/

I bet Jonny Hoogerland wishes the UCI would ban barbed wire fences.

I'm glad no-one has every been hurt by a bike equipped with rim brakes.

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TriDork

"Happiness is a myth. All you can hope for is to get laid once in a while, drunk once in a while and to eat chocolate every day"

The photo appeared to be his left leg that was injured. I'm not sure how that would happen with the disc's being on the left side of the bike. Maybe if the offending bike was tumbling around or some other way facing the opposite direction, it might possibly happen, but I can't see it.

About 5 years ago, I was rushing to get to work. I jogged my bike from the shed to the driveway and tripped. I had the bike to my right and ended up tripping and landing on the rear wheel/ I drove my knee into the spokes and did a minor version of the accident in question. My right leg, just below the knee, got ripped to shreds by the spoke. It wasn't even a bladed spoke and it was a rim brake bike, with the nearest disc being back in the shed. :-)

Accidents can happen.

I suspect it wasn't the disc at all, but a spoke, and he's just jealous his team doesn't have disc brakes :-). If he had disc brakes, he could have stopped before the pile up. Rim brakes are at fault here, not the disc brakes on someone else's bike.

I hope he recovers fast. (looks like a vet did the staples!)

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TriDork

"Happiness is a myth. All you can hope for is to get laid once in a while, drunk once in a while and to eat chocolate every day"

To quote RChung, "Logic isn't your strong suit, huh?

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http://bikeblather.blogspot.com/

Logic is only 3rd on my list of skills. Vain attempts at humour is 1st on the list. Achieving humour is well down on page 2 of my skill set :-)

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TriDork

"Happiness is a myth. All you can hope for is to get laid once in a while, drunk once in a while and to eat chocolate every day"

To quote Norm Crosby, "Hey! I resemble that comment!" :-)

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http://bikeblather.blogspot.com/

:-)

Indeed

now, back to our regular program.....

(your seat is too high!)

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TriDork

"Happiness is a myth. All you can hope for is to get laid once in a while, drunk once in a while and to eat chocolate every day"

Thanks for lecturing me so politely!
Maybe I didn't express the phenomenon correctly:
Yes, the increased (thank you) trail at the highest brake force applied may be the same.
However, a force applied to the hub directly changes trail not exactly the same way as a force applied indirectly through the wheel.

Can you explain to me how modulation of trail (and the direct versus indirect action of brake force on dropouts) results in the same brake power modulation or power curve?

If we talk about modulation, I do not believe this to be true (spoke flex comes to mind).

Polite response welcome.

Disc brakes are on one side (unless you use two discs on your front wheel.) That twists the fork in addition to the rearward motion, so they do steer different. You can, of course, make the fork stiffer with more material and more weight.

Let's talk asymmetries..

Jump on the brakes hard or maybe ride through a dipsy do and watch your forks as you do this.
They move, they move big time. You will see them flex with what seems to be alarming amounts when you are not used to seeing this.

When you use rim brakes they make use of the already substantial material near the crown of the fork that is required for strength anyways, to mount the brakes.
When you use discs, the disc tries to rotate the axle out of the dropout, hence the need for different dropout angles for disc over rim brake forks.
But this is a moot point now as the new standard is a 12mm through axle, so the wheel is contained and only the fork blades need beefing up on the bottom third to handle the rotational force force of the brake.
This is helped by the through axle which adds total stiffness to the fork.
The asymmetrical bending of the fork are movements that are a tiny, very tiny component of total fork movement. (Like, you know, the fork has been designed to compensate for this. as well.)
The fork is beefed up in the bottom third for the disc, but designers will then thin out further up to bring compliance of the fork back into line with a normal rim braked fork.
I mean nobody wants a rough riding fork.

MTB designs have air spring on side and damping on the other as well as huge discs.
All this mounted to a twisty suspension thing that is alarmingly flexible if you take the through axle out and grab the forks and twist them.
Yet they seem to manage.
Put on some road tyres, lock out the fork and they handle amazingly well on high grip bitumen.
So, worrying about asymmetry in your fork is not really something that should be keeping you up at night.
My disc braked, QR, get around flat bar bike has never let me know in the handling department that there was a disc on there.

A disc fork will be heavier, can't get around that.
But now you can use carbon rims and get that back and still have better brakes.

But that heavy fork will have the same road handling characteristics you are used to.
They are simply designed to feel the way the manufacturer wants them to.
You can lay the things up to do whatever you want.
Look at today's aero forks, the shape is all aero but they still manage to engineer in the required stiffness and compliance they seek.

How much flex will there be in the spokes?
Well just look to your rear wheel to get an idea.
Can you honestly say that you can feel the spoke windup when you stomp on it? When it is blurred by tyre flex, frame flex, axle flex etc?
Even a loosely spoked wheel is amazingly stiff, far, far stiffer than the frame or tyre.(many orders of magnitude in fact)
Spoke windup is a nonevent for discs, spokes will be crossed to counter this, at least on one side and the wheel will be dished, again creating asymmetries, but can you honestly say that you can feel the much greater dish that a rear wheel has when you are bombing down a hill now?

You can't, because each side is as stiff as the other, they have to be because they work in opposition, they are in balance.
The dished side will be weaker, but they are equally stiff.
Just lean hard on your bike with a bias to one side, you will see the wheel sit crooked in the frame, thats frame and axle flex, You will also easily see the tyre deform, but you won't be able to eyeball any wheel flex.
Wheels are far stiffer than frames and tyres.
Your bike is full of asymmetries.
Most rear stays are different drive side to non drive side.
Many BB's are different side to side.
Disc brake asymmetry is a nonstarter in concerns.

Now back to that pesky fork flex with it's corresponding trail changes.
The road contact doesn't change.
The wheel will still try to pull the fork back under the bike and the two operating bits are the fork where the wheel attaches and the tyre where it contacts the road.
It doesn't matter how the wheel is being slowed, the backward force is still applied through the axle to the fork.
A rim brake will be tried to be pried forward out of the crown and the disc brake will twist the fork leg trying to get out of the frame, but the tyre will transmit the retarding force created by braking to the rest of the bike by the axle in both cases.
Imagine if you can, the front wheel rigidly fixed to the ground at the tyre contact point.
Now without using any brakes, try and push the bike forward.
What happens?
The fork bends toward the frame and the bike moves forward the amount it is allowed by the fork flex.
So you can see that the brake is not what causes the flex.
It's the fact that the wheel is being retarded somewhere, doesn't matter how.
In that example, it is being retarded by the link to the ground.
So it doesn't matter if it is at the crown, the lower fork leg or the ground, the position of the retardation will not effect the trail change that the fork causes when the wheel is retarded.

So it is also still transmitted via the spokes in all cases as well.
The force gets from the place of retardation to the axle/fork tip via the spokes, it does however do that twice with disc brakes, but can you feel the spokes wind up now when you use the rim brakes?
It will be double that, minus the quite considerable flex in the rim brake arms.
So probably less really.

Ever noticed that one side of your rim brake pads wears out quicker than the other?
One arm is longer and the force applied is asymmetrical.
Should we worry about this?
It is a pain in the arse if you are using fast wearing carbon wheel pads, but I don't think that I will loose sleep over it.
When you stomp on the pedals, the right side is supported by the chain tension and the other is not.
One stay is compressed, one is not.
Surely that must stuff up the handling.........

In the end. the handling differences you may have felt riding disc braked road bikes is simply a reflection of the current tendency to put discs on to grand fondo type bikes, not racing bikes.
Different geometries from the get go.

Starting to ramble and really I should sit down and write out something more structured, but this way my mumblings will leave a few crumbs for Tom A to try and misinterpret, and that after all is what this thread is all about, keeping Tom active in his vilification of all things disc.