Thanks for the link. Very interesting.

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Searching for the bliss of ultimate exertion.

I only had a moment to give this a quick glance before dashing out the door, but:

What's up with the tire pressures used in the study? Only 101 for the clinchers is a bit below what most folks would run. 101 and 87 is significantly below what most folks would put in a tubular. I thought part of the advantage of the tubular was that you could generally run a higher psi. Why didn't they test and compare at a higher psi?

I think this comparison is probably relevant to compare one clincher to another. As for comparing tubulars to clinchers, or tubulars to other tubulars, they're so far below the manufacturers recommended psi levels the data could be rather worthless.

Bob C.

Higher pressures than that, with that sort of weight, would make the tires slower on roads. Responsible manufacturers print "maximum" pressures on their tires, not "recommended." The people at Michelin and Vittoria recommend pressures in the 100-120 range for road riding. As you can see on the tubular chart, increasing the pressure made only a very tiny difference (in watts), and that's on a testing rig. The difference is nil, or negative, on an asphalt road.

It's an urban myth that high pressure tires are faster. They're not -- only on the track does high pressure work.

Ashburn, do you think it would be reasonable to assume that 100psi would correspond to a total weight of 85kg and 120psi would be for heavier riders - meaning there would be no need for a rider ~85kg to run higher psi?.

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Searching for the bliss of ultimate exertion.

no dugast silks?

dissapointing...

g

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greg
www.wattagetraining.com

I wish they would have included the Tufo clincher-tubulars as well. Also, if I remember correctly from a pervious post, narrower tires do not improve rolling resistance, is that right?

Dave in VA

As the article describes, narrower tires have increased rolling resistance.

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"Go yell at an M&M"

Interesting article Ken. Not exactly sure why I spent all that money on those race tubulars.

How then does one account for the following (from the article)?

"In general terms, the total drag of a cyclist will consist of 80% tire rolling resistance and 20% wind resistance at 10 km/h or 6 mph. At 40 km/h or 25 mph the numbers will reverse, with total drag consisting of 80% wind resistance and 20% tire rolling resistance."

&

"When pumped up very hard in excess of 9.5 bar (~140 psi), rolling perfomance will improve quite dramatically."

It seems to me that these two points taken together mean that going fast would require a tire which, together with the rim formed as smooth an aero section as possible, was quite wide, and was pumped up very hard indeed.

The higher the internal pressure the less the tire will deform when loaded, which I would have thought would give a contact patch more in line with the fatter tire diagram.

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Stuff I like:
PBscience Triathlon Coaching and Lab Testing

The pic in the article shows they used a steel drum test which I think was talked about in other threads. Basically that test will return a higher value for tubulars vs. clinchers, but we don't race on steel roads. I think the test is probably good for comparing tubie vs tubie and so on, but not clincher vs tubular.

I am no expert on this, just repeating what others have said. I am debating a race wheel purchase. With all the info I have heard from people in the industry and watching pro's I believe that tubulars have to be faster. As much as I hate to say that. I think tubulars are a pain in the ass to deal with, but if they are faster, I will just bite the bullet and go for it.

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Brian

If I am reading the clincher info right, buy Michelins. Best RR annd puncture resistence?

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_________________________________
I'll be what I am
A solitary man

Would you care to elaborate why a tubular will return a higher value than a clincher on a steel drum, but not on the road?



-jens

AS I understand it, if the tire has to bounce over every little bump, this slow one down. The bike is going up and down, thus increasing resistance. The stell drum or smooth velodrome has none of this.

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_________________
Dick

Take everything I say with a grain of salt. I know nothing.

Seems like a good compromise. I happen to use Michelin Pro Races (and the last Conti tires I have on my wheels will be replaced post haste; I'm sick of the sidewalls/base coming apart).

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"Go yell at an M&M"

OK. So why does a tubular bounce less than a clincher?



-jens

This is what joshatzipp had to say. I respect his opinion. It is kind of a long write up but worth the read.

"I have seen the same theoretical data that you talk about showing higher RR for tubulars than clinchers, but this isn't actually nearly as clear cut a case as that data would suggest. Mainly, all RR tests use a simple machined drum for testing the tires and that is not very true to real life. Some data was taken a few years ago using a different system, similar to that developed at CALSPAN in California. This system is more like a treadmill but the belt is steel with various types of tarmac surfaces bonded to the surface. In these tests the tubular tires actually fare slightly better than clinchers on more realistic, rough road surfaces; more or less because the structure of the tire allows the tire to conform to the rough surface with fewer losses. The clincher tire on a smooth drum only needs to defore really at the contact patch and partially in the casing, but on rough pavement the additional deformability of the tubular tire carcass seems to be helping out. The other thing to remember for all the tubular bashers is that clinchers only show better or equal in these tests when used with thin latex tubes, these tubes have significantly less RR than butyl so if you want to run clinchers for racing you really have to run latex tubes, which is something that very few people do. Overall that's why the 13 minute over IM distance is not so realistic, if it were you would see it affecting results, and you would have certain pros with wildly different bike splits in similar events when they switch sponsorship between clincher and tubular wheel manufacturers and so on, but it just doesn't happen that way. I think that the other thing generally not mentioned is that most tubular tires have a puncture resistance belt under the rubber that adds a bit of weight and RR, but improves durability of the tire. Clincher tires that test very well for RR usually don't have similar puncture resistance belts, but these are not the clincher tires most of us want to use and we certainly don't recommend racing on them as a flat will cost you way more time than any RR savings will get you.

Also, the tire bed shape is critical. Older aluminum rims (which are used in many of these older RR tests) would have a large single radius curve shaped tire bed, generally 23-25mm diameter, and eyelets that protrude into the tire bed. These rims can significantly increase RR when a tire is used that has an effective inflated diameter smaller than the rim bed as the entire casing of the tire is deflected at the contact patch. This is made worse by the stitches under the base tape which protrude slightly, requiring additional glue to fill the airspace, and further deforming the casing locally. With some proper design the tire bed can very closely mimic the tire profile eliminating these problems, and also resulting in the need for significantly less glue as the glue can be very thin on the rim. Also the elimination of eyelets eliminates excess glue as well as what were effectively high-spots in the wheel that show up in testing as an increase in RR. The same 21mm tire will show 15-20% less RR on a Zipp rim due to these design elements than on an older GL330 or similar tubular rim, and that is not at all trivial. This is another reason we strongly recommend 21mm tires on all of our wheels.

triguy is correct that we have probably done more work than anybody in studying the tire/rim interface, but is not right in saying that clinchers are superior here. With considerble work on both models we have ultimately ended up with nearly equal drag on clincher/tubular products. To get there, the clincher rims are generally slightly wider and have a little bit of a different shape, but at least with our product there is no appreciable difference between tubular and clincher in terms of aerodynamics.

As for the question why the pros run them, there are a few very simple answers. 1. they flat less, since most flats in pro racing are pinch flats (the roads are generally pre-swept or somewhat cleaned) tubulars eliminate the majority of flats. Plus road pros race on all sorts of crap pavement and cobbles where clincher tires just don't hold up 2. in a downhill or fast situation a flat with a tubular is far safter than with a clincher as the tubular flat can be ridden with much less drama. The tubular flat can also be ridden faster and longer giving the team car more time to get to the rider, so he isn't stuck on the side of the road. 3. they can be run at lower pressures. Everybody always talks about how tubulars can be run so high, but really the pros want lower pressures for better grip (particularly in the wet) and more comfort. It is common to see road pros in Europe running 90-95 psi in the rain and 100-110 in the dry, so on the roads they generally ride, these pressures would be very problematic with clinchers.

There is really no clear cut answer here, and as with a lot of things it is largely personal opinion, but there is lots of data showing the superiority of one vs the other and so on, but in reality the differences are quite small. We prefer tubulars as they are much lighter, the tires are more puncture resistant despite being lighter, can be pressure optimized to road surface (can run much lower to much higher), generally have more consistent and higher cornering grip, and when properly glued offer an extra margin of safety. "

---

Brian

Popular belief and tradition say that sew ups are faster. An increasingly large body of data says that, in fact, clinchers are faster, except for highly specialized track tires. While sew ups may have a few advantages over tubulars, being faster isn't one of them

I think each probably is better for different reasons, but really it would need to be looked at as a whole system (wheel and tire). Again, I have no evidence, but as I understand it the clincher rim is a aerodynamic mess. I really would like to believe that clinchers are just as good as tubulars, if not better, but from what I have read I have made the decision as a whole the tubular system is faster.

   

Right. I read this before and josh is generally credible. The truth is out there (tm). Of course, those of us who have actually tested both tubulars and clinchers on real roads know the truth.



--jens

[reply][reply]
AS I understand it, if the tire has to bounce over every little bump, this slow one down. The bike is going up and down, thus increasing resistance. The stell drum or smooth velodrome has none of this. [/reply]


OK. So why does a tubular bounce less than a clincher?



-jens[/reply]

Damned if I know. I thought it bounced less, but the data on rolling resistance is consistent, in that clinchers roll better. Maybe it is that tubies usually have tread, and smooth tires roll better.??????????????

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_________________
Dick

Take everything I say with a grain of salt. I know nothing.

glad to know that my race wheels (tubies) are not outmoded.

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_________________
Dick

Take everything I say with a grain of salt. I know nothing.

I was away all day. Just dropped in here late in the day to view this thread and see what's transpired. It's just as I suspected. The bottom line is, nobody really knows. Everyone THINKS they know, but they don't. Josh at Zipp would seem to have the most informed perspective, but even he ultimately comes to the conclusion that any real differences are small.

Whatever.

Bob C.

[quote]Everyone THINKS they know, but they don't. Josh at Zipp would seem to have the most informed perspective, but even he ultimately comes to the conclusion that any real differences are small. [/quote]


He may SEEM to have the most informed perspective, but that doesn't necessarily mean he does. His reply is full of more holes than a block of swiss cheese...

For example, most of the best testing clinchers DO have puncture belts (Michelin Pro Race and Vittoria Open Corsa to name a couple).

Oh yeah, here's another: the posted test results (Tour) are also with the clinchers using a butyl tube (not latex)...and they're STILL gobs better.

Let's see...one more....tubies have a structure (glue interface) which inherently causes higher energy losses for a given deformation, yet when tested on a CALSPAN type rig, somehow this structure results in fewer losses? Come again?

Anyway...I wonder what the difference is in margin on a given carbon tubular vs. the same model clincher rim? Hmmmm....

In all honesty, it actually warms my heart to see people still claiming that tubulars are as good as clinchers :-)

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http://bikeblather.blogspot.com/

ARe these tests on asphalt or a track?????

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_________________
Dick

Take everything I say with a grain of salt. I know nothing.

A number of us have tested tubulars and clinchers on real asphalt. The results are consistent and repeatable.



-jens

yeah but, yeah but, yeah but, .... :)

rmur

Man, just imagine if Jan had been running clinchers instead of tubulars all these years. Maybe he'd be the one with Sheryl.

<<A number of us have tested tubulars and clinchers on real asphalt. The results are consistent and repeatable.>>

You've said this a few times......so what's the answer?

The best tubular in the Tour magazine test (the veloflex carbon) does not do as well as any of the better clinchers.



-jens

<<The best tubular in the Tour magazine test (the veloflex carbon) does not do as well as any of the better clinchers.>>

No need to be vague, I'm not challenging the results of your test, just want to know what they are.

Which tires should I use? (for maximum speed)

Michelin Pro Race 2. No one has ever done a rolling resistance test that had this tire perform less than near the top and the puncture resistance is far better than other tires with similar RR.

I would go so far as to say, this may be one of the ONLY clear cut choices a person could make for building the fastest bike. Racing with a disk might be another, but then you still have to choose which disk. As for tires... Buy the Pro Race 2 and then move on to other areas as your tire choice is taken care of. Done deal. No second guessing. No worries the competition has better gear in that department. It is easy and everyone can sleep well.

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Justin in Austin, get it? :)

Cool races:
- Redman
- Desoto American Triple T

Well.... look at the list above. The top 4 clinchers are all quite good. I've tested all of them.

-jens

or michelin carbons...they last a heck of a lot longer than the pro race 2's and will flat a lot less. You're not giving up that much either.

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----------------------------------------------------------------

My training

That would be my guess -- if only to avoid pinch-flats. I weigh ~85kg (with bike) and I found that 100 is too light; I got pinch flats. 110 seems to do the trick, and my measured rolling resistance is as low as the charts above indicate (for the upper-range clinchers).

It's the repeating of things that were, in the original, merely made up or conjectured that creates all these persistent myths.

Others have test on drums, roads and the whole range of surfaces and they keep getting the same results.

But -- I heartily encourage people to keep riding tubulars. Put sealant in them. Glue them softly so you can get them off in races. And, by all means, pump them to the max pressure printed on the sidewall. I especially encourage everyone in the M45-49 AG to do this. See you at Nat's!

Hmmm... I wouldn't consider a Michelin Carbon for racing. That would require ignoring factors directly related to speed. Rolling resistance and weight. I get 5000+ miles out of Pro/Pro Race/Pro Race 2. I'm still riding a Michelin Pro (older than the Pro Race, and Pro Race 2) as a training tire. Can't see any reason to look for a tire that lasts longer.

For a training tire, the Carbon might be a good choice. Personally, I dont' race on the tires I train with. After a few races the race tires become the training tires.

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Justin in Austin, get it? :)

Cool races:
- Redman
- Desoto American Triple T

[reply]In all honesty, it actually warms my heart to see people still claiming that tubulars are as good as clinchers :-)[/reply]

Thanks for replying so thoroughly so I didn't have to try to figure out how to say the same thing while jetlagged from my trip to China. ;-)

BTW-I agree with Jens on the tire choice, and what really annoys me about the data is they say "narrow is higher RR" but don't have a single comparison with the same tire and 2 widths. I found pressure to be more important than tire width. Also, the RR on clinchers changes pretty substantially from 100 to 120psi, lower as you go higher. The same effect isn't true of tubulars for some reason, I found a couple actually increasing in RR as pressure increased. Seeing a couple of the tires I've ran in the same order and approximate magnitude percentage different makes me feel better about my test setup. :)

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---

Less deformation is not always what you want. It works on a track (or steel drum), but can slow a tire down on asphalt roads -- even smooth ones. The tire bounces over imperfections, rather than deforms around them. The net is a loss of speed. A tire that is supple, and deforms readily, and returns to shape readily, is what makes a low Crr number. So, hard is not better, again except on tracks and metal drums. The same feature that makes a fast tire on a test rig (one that deforms at the contact patch and returns to shape without heating up or squiggling on the glue) makes it fast on real roads, but only so long as it isn't pumped up too high.

On the other note: The lower one's CdA, the more that Crr matters. It eats up a greater proportion of the power. A rider with a CdA of 0.32 doesn't have the Crr worries of a guy with a CdA of 0.25.

As always, the idea is a nice slick aero setup, with low Crr tires. Folks can argue the numbers all they want, but I have yet to have a triathlete (about my size) step forward who can go as fast as guys like Jens and me at the same power output.

OK, if I've distilled all this discussion down correctly, I understand that there are very good clinchers that are probably lower in rolling resistance than the best tubular. At worst, they're just as good. Taking into account wanting a bit of deformation (for comfort and lower Crr) and good puncture resistance because having to stop negates all of this, I should use:

23 mm Michelin Pro Race 2s with a latex tube.

But which wheels for that 'nice slick aero setup' go with these? Or does that not matter as all clincher interfaces are ~ equal?

[quote]OK, if I've distilled all this discussion down correctly, I understand that there are very good clinchers that are probably lower in rolling resistance than the best tubular.[/quote]

Not "probably"...they are demonstrably better.

[quote]I should use:

23 mm Michelin Pro Race 2s with a latex tube.[/quote]


That's a tough combo to beat. Don't use the Vittoria tube...stick with the Michelin. The Vittoria's have "issues".

[quote]But which wheels for that 'nice slick aero setup' go with these? Or does that not matter as all clincher interfaces are ~ equal?
[/quote]

Whichever clinchers you prefer...the interfaces are ~equal. Zipp, however, does claim to have done some shape optimization to make their wheels work better with clinchers...

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http://bikeblather.blogspot.com/

So, are you and Ashburn racing on clinchers or tubies?

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_________________
Dick

Take everything I say with a grain of salt. I know nothing.

If you consider the 30+watt difference between my old Tufos and my current ProRace2s (observed BEFORE reading this article) to be SMALL then more power to you and I heartily encourage all guys 30-39 to do lots of squats and race tubbies to your hearts content. I, personally, would like to be be 10-20 minutes faster at my next IM.

Tubbies are a much bigger PITA, are slower, are less durable (in my experience) and far more expensive. This isn't a tough decision.

ot

I am glad this talk came up when it did. I am trying to decide what to race on next year, and likely the next few years. I am leaning towards a 999 setup since I am racing flat courses next year, maybe get a 404 front for the following year when I will be more on hills. So then it comes down to tubular vs clincher. Here are my thoughts, you can hate them if you want. These are the facts first.

Tubie:

Pro:

lighter wheels

Con:

Glue, harder to carry a spare, I can change a clincher faster, should change out brake pads on hilly courses.

Clinchers:

Pro:

eaiser to deal with - carrying a spare and changing

Con:

Heavier

Now the thing that I wonder about is not so much the rolling resisance, but which is more aero. I have read things about the clincher tire/rim interface being an aero mess. I will tell you I have done a 5:58 on clinchers at IMLP and a 5:18 on tubulars at IMFL, but I was in better shape at FL. Obviously the results are impacted by numerous things, but the point is to me that those times are somewhatclose considering the courses. Really there is no test that has shown the differences conclusively. Probably would need some type of animatronic (sp) person sized rider in a wind tunnel on a asphalt covered treadmill, with the same wheel just c vs. t. Is that too much too ask.

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Brian

Really? Where?

In September, I did a $5,000 cash purse sprint triathlon that included a steep, ~1mile climb (I averaged about 9mph and ~275W on it) in the middle of the 14.3 mile bike leg. Of the >400 entrants, I saw about half a dozen disks in transition; I usually see scores and scores of them at local races. Three or four of the top ten finishers (myself included) had disks. The overall winner, whose bike split was 3:00 faster than the next fastest, used a disk.

You won't be doing any course where the weight penalty of a disk outweighs the aero benefit.

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"Go yell at an M&M"

I just had to check out your website:

---

Power testing:

Can you pump out 1000 watts? Lance can for over an hour. Done with the
help of our Compu-Trainer, we can test your limits, and recommend position
changes to increase power production. Of course power is only a part of the
equation for speed. Power + Aero position + Comfort = Speed. The power
test includes initial test and 2 month follow-up.

---

1000 watts for an hour? Hmmm.

---

My latest book: "Out of the Melting Pot, Into the Fire" is on sale on Amazon and at other online and local booksellers

Another 'easy' one. A powertapped rear (clincher) wheel with CH aerocover (unless you are SRM level rich) and an aero front clincher wheel of your choosing will make you into a faster and smarter racer.

I've been where you are and I did the whole Zipp tubbie thing...now I wish I hadn't invested the time and money and sacrificed a season (2004) of race results. You are free to believe whatever you'd like but personal experience backed up by study after study of 'unscientific tests' consistently reaching the same conclusions makes for more than enough validation to me.

ot

The other thing to remember for all the tubular bashers is that clinchers only show better or equal in these tests when used with thin latex tubes, these tubes have significantly less RR than butyl so if you want to run clinchers for racing you really have to run latex tubes, which is something that very few people do.
---
I glanced at the article quickly but didn't see this information. do you know if they did use latex or butyl tubes?

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Josef
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blog

Thanks for the info you've posted on this subject previously. Have your tests compared latex v. butyl tubes? Is there much difference?

Thanks. HH

PS: I've pretty much decided to get rid of my tubular race wheels and get clinchers.

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________
It doesn't really matter what Phil is saying, the music of his voice is the appropriate soundtrack for a bicycle race. HTupolev

"You won't be doing any course where the weight penalty of a disk outweighs the aero benefit."

Ken,

I did a Oly race last year on a course that featured lots of rolling hills, but also a number of very sharp, steep hills with very fast, twisting descents coming down the back sides of those hills. I hadn't ridden a disk before last year and I really didn't like the handling of my Renn 575/HED Alps (650 tubies) in corners and sharp curves. I previewed that course and decided I'd attack the course with more confidence on wheels I had more miles/experience on. I ended up riding my Bontrager Race Aero clinchers (basically my training wheels) with Vittoria Corsa Evo CX tires to the second fastest bike split of the day ... my best result. I was very happy with my choice that day.

I'm just curious how you've found the handling of your disk to be on more technical courses.

BTW, the fastest split was Peter Kotland (Kortland? Cortland?) and I don't recall if he was on a disk or not.

Bob C.

I ride my "disk" all the time in training (it's a PT/Open pro with a homemade cover), with no issues. I've done some courses with hairy turns (ask armytriguy about the Lighter Than Air duathlon bike course) that I've taken at higher speed than was safe. I did a bike route I love (52 miles, ~6600' climbing in 14 climbs nearing 20% in places) with this wheel and set a PR (normalized power of 273W over 3:20!). I don't know if there's anything about a "real" disk that would be different. Stiffness?

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"Go yell at an M&M"

Ken, I'm not too sure we are comparing apples to apples here. A spoked wheel with a cover handles like a spoked wheel, with a cover. I have several discs and they do feel different compared to each other, but handle tight corners a lot scarier than most spoked wheels will. Some of the low spoke count carbon rims are on the other end of the spectrum with me as they are too flexy and can get scary too, where the disc is so stiff it trys to skip instead of flexing.

When people tell me that their disc seems scary on technical courses, I believe them 100%. That may be another selling point for wheel covers as an open Pro 32 hole rim 3 crossed with a cover is a very nice riding wheel . Also lowering the air pressure to 100-120 ish will take some of the bad manners out of disc wheels.

I think some posters replies to the re-posting of some things I have said seem to believe that we have some secret reason for advocating tubulars or are trying to pull the wool over everybody's eyes on this tubular/clincher debate. Since we make and sell all of our products in both, we certainly could care less what you buy or use, but saying that clinchers are better due to lower RR in one specific type of test if underestimating things a bit, sort of like the Triathlon Germany wheel aerodynamic testing on the indoor velodrome, these tests do conclusively show superiority in this particular test scenario, but from the testing I have been privy to and worked with there are many real world situations where the tubular will have equal or lower RR, specifically poor road surfaces. Having said that, even if clinchers can surpass tubulars in all RR situations tubulars will continue to be most prevalent in pro road racing due to the safety issues and ability to ride when flat, as well as the weight discrepancy which will remain indefinitely due to the necessary design limitations of clincher rims.

Also somewhere it was said that clinchers were an aerodynamic mess. They are not a mess, they are just different than tubulars, so that using the same rim shape for both will leave one of the products lacking when compared. This forces us to design the clincher and tubular versions of a rim as two different products, so that they share rim depth and marketing but from engineerings point of view they are totally different products. All of our clincher products more or less mimic the performance of the tubulars with the 404 clinchers having a slight advantage actually over the tubies and the 808 tubulars having a slight advantage over the clinchers. To give you an idea of how different things are, however, here is a photo of our new clincher disc (shipping in a few months). We really had to work some sidewall curvature into the shape to clean up the airflow off of the tire, and blend the aluminum to carbon interface so as not to have a hard lip between the two as that lip can cause 3-4 watts of drag in some designs. But you can see that the final product essentially looks nothing like our tubular disc, yet the performance is nearly identical.

---

http://www.SILCA.cc
Check out my podcast, inside stories from more than 20 years of product and tech innovation from inside the Pro Peloton and Pro Triathlon worlds!
http://www.marginalgainspodcast.cc

"I have several discs and they do feel different compared to each other, but handle tight corners a lot scarier than most spoked wheels will ... the disc is so stiff it trys to skip instead of flexing."



What he said.

[quote]but from the testing I have been privy to and worked with there are many real world situations where the tubular will have equal or lower RR, specifically poor road surfaces.[/quote]

As a former co-worker would always tell me: "Show me the data!"

At the least, can you (or anyone, for that matter) put for a plausible hypothesis of why a tubular would suddenly have lower RR on the road. To my knowledge, the only situation where tubulars have an advantage RR-wise is on a smooth track...and that's only because you can pump the snot out of the pressure high enough to overcome the inherent losses.


[quote]Having said that, even if clinchers can surpass tubulars in all RR situations tubulars will continue to be most prevalent in pro road racing due to the safety issues and ability to ride when flat, as well as the weight discrepancy which will remain indefinitely due to the necessary design limitations of clincher rims.[/quote]

That's a fallacy...in fact, just recently I witnessed someone riding (safely) 2 miles down an twisty 8% grade and then ~4 miles along the flats (at speeds up to 20mph) on a flatted FRONT clincher. Granted, some combinations of rims and tires are more secure than others, but getting a flat with a clincher doesn't necessarily result in an instant "yard sale" like most believe.

Also, weight isn't the issue everyone thinks it is. In fact, do you recall why Ivan Basso used heavier 404 rims (instead of lighter 303s or 202s?) on the Alp'd Huez TT 2 years ago?

Oh yeah...I've run the numbers of tubular vs. clincher on climbs. Using identical wheels (Zipp 404 and Vittoria Corsas) it takes up to an 8% grade for the ~1lb weight advantage of the tubular combination to make up for the disadvantage in RR. At all grades below that, the heavier clincher version is ahead.

---

http://bikeblather.blogspot.com/

[quote] think some posters replies to the re-posting of some things I have said seem to believe that we have some secret reason for advocating tubulars or are trying to pull the wool over everybody's eyes on this tubular/clincher debate. Since we make and sell all of our products in both, we certainly could care less what you buy or use,...

...Also somewhere it was said that clinchers were an aerodynamic mess. They are not a mess, they are just different than tubulars, so that using the same rim shape for both will leave one of the products lacking when compared. This forces us to design the clincher and tubular versions of a rim as two different products, so that they share rim depth and marketing but from engineerings point of view they are totally different products. All of our clincher products more or less mimic the performance of the tubulars with the 404 clinchers having a slight advantage actually over the tubies and the 808 tubulars having a slight advantage over the clinchers. To give you an idea of how different things are, however, here is a photo of our new clincher disc (shipping in a few months). We really had to work some sidewall curvature into the shape to clean up the airflow off of the tire, and blend the aluminum to carbon interface so as not to have a hard lip between the two as that lip can cause 3-4 watts of drag in some designs. But you can see that the final product essentially looks nothing like our tubular disc, yet the performance is nearly identical.
[/quote]

I almost forgot...is the price for this clincher version higher, lower, or the same as the equivalent performing tubular disc?

If it's the same...how do you recoup the extra development cost and the higher manufacturing costs due to extra steps and part required? Just curious ;-)

I'm not saying there is any intentionl misleading going on...I'm just pointing out that there could be at least a subconcious monetary incentive to favor, or at the very least, not give up so easily on, tubular wheels.

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http://bikeblather.blogspot.com/

"That's a fallacy...in fact, just recently I witnessed someone riding (safely) 2 miles down an twisty 8% grade and then ~4 miles along the flats (at speeds up to 20mph) on a flatted FRONT clincher. Granted, some combinations of rims and tires are more secure than others, but getting a flat with a clincher doesn't necessarily result in an instant "yard sale" like most believe. "


I don't think that is a lot of data. One guy does it for you ? a clincher rim is safer then a tubular rim with a flat ? I would rather be on tubbies in that situation. I know it is just me and I ain't the brightest bulb in the box but just look at the shape of the rims. I have had this happen with both rims.

I think you are getting clincher madness. ; -)


Thom

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Slowtwitch bitchist place on planet earth

[quote]a clincher rim is safer then a tubular rim with a flat ?[/quote]

I never said that.

Besides, the example I gave may be just an n=1 experiment, but isn't that all you need to disprove the notion that tubulars are ALWAYS safer to ride flat? The way I've always seen it stated, once you flat a clincher you have to immediately stop or you'll instantly eat pavement...it just ain't so.


[quote]I think you are getting clincher madness. ; -) [/quote]

I think I'd rather have "Reefer Madness" :-)

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http://bikeblather.blogspot.com/

By me, a flat on the front clincher means stop, or either roll the tire off the rim and risk damage to the rim,fork and rider. At best riding on the rear rim on a clincher means a lot of wear on the rim or possibly trashing it all together. I have ridden 4 miles in a flat TT on a rear sewup with no visibal damage to the rim. I have limped to the pit, but riding on flat fronts with sewups. in a crit or two . In a cross race a have ridden almost a lap with a flat front tire. I know I would have been walking with a clincher in that instance. I personally think in a crit it is faster and safer to run to the pit than ride a flat front clincher. In a Triathlon I guess it a judgement call on how far out to change a tire or ride in. Again I think the advantage is to a sewup as to how far out I would ride into the transition from a flat.

No, I did everything with normal thick butyl training tubes in the clinchers. Don't know much about latex tubes. Only what I've read.

Tom,

I think you misunderstand the economics of a disc wheel. A tubular disc is very expensive as we have to essentially make a superlight carbon rim and then construct that into a disc. With the clincher disc we have to do the same thing with an aluminum clincher rim which is cheaper than a carbon rim, but then it has to be constructed into a disc as well, so the costs really aren't all that different. The development costs aren't really that different either as you are assuming that the tubular development was fast and easy, it wasn't. Since the cost of the development of the dimpled composite process is attached to the tubular disc, the clincher disc could use considerable resources and wind tunnel time in development before getting close to the cost of the tubular disc development. All in all it took us some 2 years to develop and refine this clincher disc concept into something that worked as well as it does, but then again it took us nearly 3 years to determine the most effective dimple pattern, dimple shape, dimple depth, etc.. then determine how to actually do the dimpled composite molding, and lastly how to construct the tooling since nobody had ever done it before, plus we filed patents for all of this which is very expensive.

The thing I don't see here is how or why anybody would think I have some vested interest in selling tubulars to everybody...we sell clinchers and tubulars for the same price because the manufactured costs are very similar (tubies have more carbon in them, so more labor in the layup process as well as more expensive materials, the clinchers use less carbon but the aluminum hoop does have to be completely prepped for bonding and post machined, both processes which add considerable labor cost so it is really a wash), so a wheelset is a wheelset as far as that goes, I'm just here relating some things I've seen and experienced in this business that may help some folks out instead of just confusing them with marketing gobledygook that some sales guy came up with.

The theory on why a tubular has less RR than a clincher on rougher pavement from what I have discussed with this tire manufacturer is that the tubular carcass can better distribute the displacement of a small impact over a larger portion of tire carcass with less localized deformation and lower localized shear forces in the tire tread or casing. I really can't print or publish data that isn't mine, the test I saw was done by a very major tire manufacturer and I was fortunate enough to be involved, but that surely won't happen again if I go around publishing data I didn't pay for on the internet. The real point is probably that the test I took part in utilized a rough surface and the Tour test utilized a machined drum, these are totally different tests with very different outcomes...

As for Basso on Alpe d'Huez, I was actually there that day with the team and we had actually calculated that Z3's would be fastest due to the weight/aero balance of that wheelset, but a difference in scale calibration left Basso's bike too light with Z3's when the UCI weighed it and with only a few minutes to his start time the easiest way to add weight was to change the wheelset. That bike already had some 340 grams of chain dropped down the seat tube as ballast, and the bike did weigh 6.8 kilos according to the CSC scale, but not the UCI, so the wheel choice had nothing to do with anything other than meeting the 6.8k limit.

cheers

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http://www.SILCA.cc
Check out my podcast, inside stories from more than 20 years of product and tech innovation from inside the Pro Peloton and Pro Triathlon worlds!
http://www.marginalgainspodcast.cc

Thanks for your contributions to this thread (and this forum, for that matter), Josh. I'm sure I speak for more than just myself when I say that I appreciate all the insight and experience you contribute.

Love the first-hand Basso story.

Bob C.

There is one negative about tubulars that is relevant to most ST readers--- If you race in a triathlon with tubulars, you have to carry one or two tubular spares. These are whole 250+ gram tires versus just carrying 50 gram inner-tubes. Besides adding up to a pound of extra weight, they take up a large volume so both disturb aerodynamics and take up space that could be used for other things like water bottles. I see guys who paid for dimples on their wheels and carbon handlebars with spare tubulars flapping in the breeze.

For Ironman Canada, I tried to clean up my bike aerodynamics by putting my tubular and toolkit in a bottle in my bottle cage--- That solved aerodynamics, but when I dropped my bag of gels I really missed the extra calories I would otherwise have had in that bottle. I know there are other solutions for carrying spare tubies but nothing beats not having to carry those big spare tires in the first place.

I have tubulars and have raced on them for 25 years, but if my race wheels weren't in perfect condtion I would switch over to clinchers just to get rid of that spare tubular I have to pack for races.

As far as road racing goes, tubulars are my strong preference--- They give a noticably improved ride and handling and spare wheels are carried in the support vehicles.

-Marc

[quote]I think you misunderstand the economics of a disc wheel...snip[/quote]

Thank you for answering my question! It's great that it works out for you that "a disc is a disc".


[quote]The theory on why a tubular has less RR than a clincher on rougher pavement from what I have discussed with this tire manufacturer is that the tubular carcass can better distribute the displacement of a small impact over a larger portion of tire carcass with less localized deformation and lower localized shear forces in the tire tread or casing.[/quote]

If that's the case, why isn't that also true for the contact patch deformations on a smooth drum? Deformations are deformations...


[quote]The real point is probably that the test I took part in utilized a rough surface and the Tour test utilized a machined drum, these are totally different tests with very different outcomes...
[/quote]

But, that test doesn't match the data from either the smooth drum testing OR field testing on real world roads. Coupled with the lack of a reasonable theory about why this should be, I think I'd be questioning the results of that particular test.


[quote]As for Basso on Alpe d'Huez, I was actually there that day...so the wheel choice had nothing to do with anything other than meeting the 6.8k limit.
[/quote]

That's exactly the story I had heard. The point I was making was that bikes and components are so light as it is, the fact that a 404 is heavier than a 303 didn't mean anything...you could take the better aerodynamics of the 404 and still be under the weight limit.

You guys should've ditched the 340 grams of chain and set Ivan up with a pair of clincher 404s...he would've been smokin'!!! :-)

Then again, he probably had Dugast silks epoxied onto those tubies anyway, huh? ;-)

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http://bikeblather.blogspot.com/

I think that the difference in displacements is that the smooth drum test is essentially modelling a steady state contact patch at only one tire deflection, a deflection which is relatively small. On rough roads, the contact patch is constantly changing shape due to road surface so the tire is deflecting in various ways which range from less than to more than that seen on the drum. The closest real world testing to this I have seen was at Tour of Georgia where we sent a bunch of clincher wheels to the team so that they wouldn't have to bring so many wheels from Europe. We were interested in seeing how wheel weight affected power on rolling terrain (especially with more than one company touting 'better rolling' with heavier aero wheels). On mildly rolling terrain, we really couldn't see any difference between the two taken as an average over time, but maybe the better RR of the clincher wheels was offsetting the weight penalty :-)

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http://www.SILCA.cc
Check out my podcast, inside stories from more than 20 years of product and tech innovation from inside the Pro Peloton and Pro Triathlon worlds!
http://www.marginalgainspodcast.cc

 >>I get 5000+ miles out of Pro/Pro Race/Pro Race 2.

I get about 400-500 miles if I run a Pro Race 2 on the rear at which point it is usually cut up so bad I would be too nervous to rotate the tire or continue to ride it as a rear tire. Handles well, wears poorly. I have no idea how to get 5000 miles on a Pro Race2 short of staying on the track the entire time, then maybe.

Thats been my experience as well...great tires but I can only use them for racing (use gp3000s for training). Of course, my Tufos that I trained on once in a while didn't even last that long.

ot

Same here. I rode mine for about 2000km and when I put the bike on the trainer for my winter training I noticed the front tire was all cut up.

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Searching for the bliss of ultimate exertion.

I guess this is a little apples and oranges. I don't race the tire at 5000 miles. Just a few hundred miles and the tire becomes a training tire. I also never use a Pro XXX on a trainer as a rear tire, which means after the tire is relegated to training it sees most of it's time on the front.

The point still remains. There is no reason to chose a Michelin Carbon for longevity since the Pro lasts long enough as a race tire and makes a better race tire. One logical choice would be to train on Carbons and race only on Pro's, but if I were to do that there are even cheaper, and more durable tires to use for training than the Carbon. And that is the point I was trying to make.

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Justin in Austin, get it? :)

Cool races:
- Redman
- Desoto American Triple T

I can't believe I just read this whole thread. I've got to get out of this place... I'm going to swim.

Very good point, what negative aero effect is created by the extra tubulars.

How many spares to most people carry, weight?

How much drag? Tubular spares vs $$ spent on dimples, carbon, etc.

Clinchers w/ 2 spare tubes & air vs Tubular w/ 2 tubulars & air: Compare Weight/Drag

Who wins?

Put a blue hub on it and I'll buy one, Great looking wheel

You needed to run them in a race to see how wheel weight affected power, and you expected to be able to ascribe any differences to tubular vs. clincher? That's pretty surprising.

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"Go yell at an M&M"

Thanks for the reply. I appreciate your numerous posts on slowtwitch and elsewhere on this subject. I'm sold (on clinchers).

HH

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It doesn't really matter what Phil is saying, the music of his voice is the appropriate soundtrack for a bicycle race. HTupolev

yes more on the new clincher disk :) How many watts am I likely to save versus say a Renn at 45 kph or 350W? I volunteer for beta field testing if you need some help :)

I don't know about drag, but in the limited case of 404s, the #s break down like this:

Total Weight Tubular w/ 2 spares: 2317 grams

Total Weight Clincher w/ 2 spares: 2391 g

That's a 71 g or .16 pound difference. That's assuming M Pro 2s w/ latex tubes and Velo Carbon tubulars (in the test they had the lowest RR)

Switch to regular weight conti butyl tubes and the difference stretches to 277 grams or .61 pounds.

Add a third spare and clinchers flop to the lower weight set-up; drop to 1 spare and you have the 277 gram difference again (tubular advantage).

Now if you switched the clincher to the Pariba Revolution which, according to this test, has a RR close to the Velo Carbons, the gap with 2 spares tightens to 47 grams, or .1 lb.

So at ~ the same RR, in this very limited sample, the tubulars are lighter by the weight of a pair of carbon cages. According to Josh, it seems that the aero on the 2 is ~ the same for the wheels, so... How much drag is added by strapping 2 tubulars to your frame? Enough to negate the miniscule weight advantage? I don't know.

It's fun to run the numbers.

Now back to the important things

1) Loss some fat by Race day

2) Ride, weights and ride to improve engine

3) Decide if white bar tape is faster then black

4) Buy carbon stuff

5) Buy cool looking tri clothes, after fat loss

repeat 1 & 2

Tublular Con: Being used as a highlight clip on what can go wrong, Seeing Norman Stadler at Kona: Priceless

I read about how fast people can change a tubular, but I seem to hear alot more "nightmare stories" about changing tubulars. Very few about clinchers.

Somewhere I read in this thread about how "You can ride longer on a flat tubular vs clincher" That's great if you are near the end of the ride"

Somewhere I read in this thread about how "You can ride longer on a flat tubular vs clincher" That's great if you are near the end of the ride"
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that applies more to road races where you have a wheel car in the back of the pack. you can ride it longer while communicating you need a spare.

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Josef
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[quote]that applies more to road races where you have a wheel car in the back of the pack. you can ride it longer while communicating you need a spare.
[/quote]

Prove it!...:-)

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http://bikeblather.blogspot.com/

However, the mechanism that gives tubulars higher RR on a smooth drum (hysteresis) is present both when the deflection is steady state vs. varying. Are you surmising that the somehow there is a difference in the hysteresis performance during changes in deformation amplitude?....and that it favors the tubular construction despite it having a structure with higher inherent losses (i.e. glue)?

I guess I'm trying to figure out how tubulars could have more RR at any given deflection amplitude at steady-state (just differences in wheel load or air pressure would cause this) yet they would somehow "magically" have less losses during the transitions between varying maximum amplitudes.



Exactly! Of course, data taken from a race isn't exactly "controlled", now is it?

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http://bikeblather.blogspot.com/

anecdotal data and personal communication. to be published. ;-)

[clincher rider here]

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Josef
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[quote]anecdotal data and personal communication. to be published. ;-) [/quote]

I've been told many times that "the plural of anecdote is NOT data" :-)

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http://bikeblather.blogspot.com/

LOL ... I got one for you right here: "it's not research until it's been published. Until then, it's just screwing around."

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Josef
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