Looks like Conti Force 24mm has lowest Crr and is the best combination of Crr and aero. So use it on both front and rear...
I've been on supersonics and latex this year on FLOs and it looks like I wasn't too far off. When it's time to get new tires it will be force for me. Never had a flat on SS anyway but the fact that force have the puncture protection and are more aero at the same Crr is cool.

Anyway until the other manufacturers publish this kind of data I'll be staying with FLO. Great job guys! I'll order the new 60 CC to replace my aluminum 90 front in July.

Punch line:

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Suffer Well.

I'm a little surprised at that. The Force loses to the Supersonic at aero until around 11 degrees of yaw. But kicks Supersonic's ass after that.

That means the Force victory is entirely based on the NDRV weighting of higher yaws.

And 35km/h is extremely slow for me (pure roadie). I bet Supersonic wins at higher speed.

On that particular rim, and assuming their yaw weighting (and that particular wheel load and ground speed)...just to be clear ;-)

The takeaway from the results as I saw them is that there is a handful of tires that give nearly equal performance over a fairly wide yaw range on the new Flo 60. That's a bonus for their customers. Choices :-)

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Curious as to why no one tests Conti Grand Prix TT?

Did you do a new batch of testing for these tyres or use your existing data?

I think the takeaway is that the more aero tires are winning even at slow speed (given the yaw profile and load). But Flo's yaw profile is fairly aggressive towards low yaw compared to some others, right?

Really not good news for the Specialized tires.

Right!? I'm very disappointed they didn't.

Honestly, picking apart the study, I would still go:
SS23 front
TT25 rear

Correct! With FLO at least you now know what you're getting. For me paying $1000s more for big claims and no data doesn't make sense

Thanks to Eric Reid, I've had one to test for a bit, but life situations have conspired against me having a chance to roll it. That said, Flo didn't aero test it.

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They sent me their box of tires. I roller tested the ones I hadn't rolled yet. It still was a crap ton of tires ;-)

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http://bikeblather.blogspot.com/

On the Flo rim.

See the similar analysis on my blog for other wheel/tire combos.

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http://bikeblather.blogspot.com/

I have - the one where the Flo90/Supersonic is the outlier, right?

A direct comparison is a little hard because you didn't integrate over yaw like Flo did with the NDRV. Which is nice, because there's more information to see. But, visually, it looks pretty similar to me, like the more aero tires are going to annihilate the Turbo Cotton if run through any but the most aggressively low-yaw profile.

The CLX64 + SW Turbo 22m ends up looking "OK" but not the best at anything, nor the best at any combination of things. Unless maybe grip or flat resistance is taken into account.

Since you used mavic rim, that I imagine ends up with a different road contact shape than a flo 60 would have with the same tire, do you know if the rolling resistance order remains constant, irrespective of contact patch shape?

Why are Slowtwichies so obsessed with Flo wheels... and now tires? I don't get it.
Outside of this microcosm, no one has head of Flo, nor rides them.

Tested and proven: Zipp. Enve. Mavic. Hed.

The rest of us—the world, at large—basically ride Specialized tires and bikes, on Zipp wheels. Race proven, not only wind tunnel tested. That's all.

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Much like the differences in contact patch shape between a flat surface and a roller result in the same percentage differences (and rank order), there's no reason to assume otherwise for differing rim widths.

Edit: I've done some limited testing on various rim widths and at various pressures. On perfectly smooth rollers, the rank orders (and % differences) hold.

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http://bikeblather.blogspot.com/

There is very little independent testing of Enve. Mavic always tested badly, new generation stuff looks to change that but no proof yet.
Zipp and Hed, yes - tested and proven.

A lot of people using something usually shows that it is easy to get hold of and well marketed, not that it's the best.

Because they are owned and operated by real people, who are smart, accessible, innovative and committed to transparently developing a quality product and educating their customers on how to maximize the benefits of that product.

Edit: the study isn't about Flo's tires....it's about what tires to use on Flo rims.

Scott

I think that 1. Flo is a good story about a start up doing it right. 2. The data is educational and is presented in a way that many people find clear. 3. Its interesting.

You have a wheel system 50% cheeper than the big boys that works.

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Force for the win! I did not expect that outcome but I am pleased by it :)

Aerodynamically it should be identical to the Super Sonic but it should be just a tad slower in crr because of the vectran breaker. It's basically a Super Sonic with a puncture protection layer.

I'm going to guess it will be just a touch slower than the Super Sonic. It's basically a SS + Vectran.

So SS / Force combo for the win?

Scott

So what you are saying is that I should run the 25mm gatorskin instead of 23mm?

Great data for sure and it pretty much triple confirms the 23mm conti 4000 is the best tire all things considered.

Which, knowing that this wheel was analytically optimized around the shape of that tire, isn't quite surprising ;-)

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A lot slower in my testing (pair of tyres, in bike). GPTT measures 1.2mm wider (on same rim) which is significant. Narrower than the rim seems to make up for shape sins.

Out of interest since I guess you might have some good background knowledge of this. When you say narrower than rim are we talking brake track width or widest place on rim? I've been wondering about the penalty size of running say, a 26.5mm tire (actual width) on a rim with a 25mm brake track but 28mm maximum width.

Narrower than the brake track in this case - rims tested measure 24.4mm but don't really bulge beyond that.
Hoping to shed more light on wide tyres later in the year.

Thanks for the reply.

I've been wondering where the aerodynamic hit happens in a case like the one I mentioned - tire width somewhere between brake track width and maximum rim width. Already at low yaw or really only (or primarily) due to earlier (and maybe) worse stalling. Maybe a bit of both seeing Tom A's testing of Turbo Cotton.

With something like the HED Jet Plus you have to use very narrow tires to get tire width no more than brake track width - the 23mm tires I've tried all bulge out a little bit.

Conti is the default clincher choice in Europe from my observation. Even the Specialized Concept stores sell them.

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29 years and counting

A bit selfish of me to expect Flo data to help me choose what tires to put on my non-Flo wheels, but do you think we can extrapolate an educated guess for a fairly typical use case?

For my example, I'm on Hed Jet 9 up front and a narrow flat disc at the back.. happens to be Renn 555 in my case. Currently I have 23mm Conti 4000s II on the front, and Attack on the rear. But that tire was chose with aero also in mind and I am conscious of how much my P3C fares the rear wheel. Basically only the bit below the height of the bottom bracket sees much wind at low yaw.

My Hed is C2 so pretty wide rim and the 23mm Conti on there now doesn't bulge wider than the brake track to my eye, perhaps the Flo data is a decent match here. So front is a Force 24mm in all probability. Force on rear as well? With aero less important CRR rules but still good on that tire. Perhaps though I can afford a bit of comfort with my very stiff disc and go 4000s in 25mm without much penalty? I guess Force is still a very good choice and 24mm still wider than my 22mm Attack.

I like this study!

In fact ignore me it seems obvious that Force 24mm is probably best bet front and back in my use case. I was just thinking on whether the combined table is useful for the rear on a frame that fares very well, or whether the crr table becomes dominant. But when it is the same answer either way it doesn't really matter!!

ETA a bit of a shame that over here in the UK the Force is almost always sold in a pair with the Attack, with the Attack ironically meant to be the front tyre.

Pretty much all I see with regard to data on crr and drag for tires is clincher, for those of us still running tubular where do we go to get this level of testing and data? Yes I know the most recent clinchers are faster all around, but I've got AU$2,500 wheels that I'm not going to replace to go with clinchers.

Yep, I'm committed to tubular for a few years yet, for the same reason. I run SLSpeed 24mm tubs on an 808 FC/900 disc.

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29 years and counting

as long as you are using it without a bike. kind of like the BC comic strip

what consideration is there for imaginary power to spin in all this and how a wider tire(more surface area) might increase that as well?

FYI the 24mm Force is absolutely ENORMOUS on Jet+ rims. I would be somewhat surprised if Flo's findings held true for the Jet+ (though I would be happy since my entire rim collection is Jet+ at this point).

You are right that the mounted width of the tire is the key feature here..I know that everybody wants to be able to draw conclusions across makes and models and brands, but at the end of the day, the only way to know for any specific combination is to do the testing.

I have to give massive kudos to FLO for this data. I know everybody always wants more data on more tires and such, but having done what they are doing myself, I can say that this single chart they've published here probably represents $25-30k in expense, not including the time of all involved. This is a huge undertaking.

In 2004 I wrote a white paper that was the basis of our 808 development where we theorized and had some rudimentary data that the rim width had to be at least 105% of the tire width (mounted measurement, not sidewall measure). We later learned with Firecrest that the shape could overcome some of this, but much of what I see today has that 105% number still holding. The difference now is that the bead seats of clinchers have widened which widens the tires considerably. We posted a blog post about this as silca.cc yesterday..but it's much harder now than it was on the tubular days where a 23mm tire was always they same thing on every wheel.. Here's the chart in our blog post..you can see that the same tire can be very different things depending on what wheel you are mounting it on.
Josh

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Am I the only one who is shocked that the 25mm gatorskin is only 4 seconds slower over 40km compared to the S-works turbo (non cotton)?!? Not to mention the Schwalbe one only 2 seconds faster than the gatorskin.

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Thanks for chiming in, Josh.

When you mentioned those 105%, is that brake track width or actual maximum rim width that has to be 105% of the actual mounted tire width? And with with some of the newer blunter (Firecrest'y) shapes this can be a bit less, say 102-103% perhaps?

which to me, implies that we want to run narrower tires on these wider bead rim wheel and not wider. ie making beads wider to accommodate wider tires actually means we need narrower tires to keep them aero. On a jet+ rim, I don't think you can find many 23c tires that will meet the 105% of widest portion of the rim(not going to be narrower than track on those)

I have measured two 23 mm tires on my Jet Black and they are ~26 m and ~27 mm, respectively. I'm not quite sure of the actual maximum width of the Jet Black/Plus. I've tried and measure it with my calipers and getting around ~27mm, but I'm not entirely sure how accurate that measurement is.

I realy wish Zipp and HED would do this for their wheels.

Any bets that the Zipp Tangente tire is best on the Zipp wheels?

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Suffer Well.

If this is true, that's a crazy investment for a company of their size, and that's only on the tires. It's also ridiculously expensive for what it is.

Totally OT, but curious if you have a sense of the capital required and rough operating costs for a win(d) tunnel. There would seem to be a great opportunity for some entrepreneur to create a cycling industry specific wind tunnel somewhere in the eastern corridor, and monetize wind tunnel time on both a B2B and a B2C basis.

One word of caution on the Force data. The values shown were for a Force tire that rolled at a Crr of .0029. I've also tested another tire of that model at .0034. Due to time constraints, when I roller tested the tires that Chris and Jon sent me, I didn't retest their particular Force tire.

Once I am again able to ride a trainer (due to injury that's not possible right now) I plan on rolling the particular tire that they sent me.

So...as with the Conti Attack, it appears that how well it rolls can be a bit of a crapshoot for some reason. Only Conti knows why this may be for those particular models. Other model tires from them (i.e. GP4000S, SS23, etc.) don't seem to vary like they do.

I guess I'm saying that unless you know for sure you got the "fast" Force tires, I wouldn't make such strong conclusions ;-)

(Thanks for pointing that out, Heath!)

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It's not surprising...none of those tires (the 22C S-works Turbo, that is) have stellar Crr.

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http://bikeblather.blogspot.com/

My surprise was leaning more to thinking the gatorskin was worse than this - not that I'd ever run one regardless.

Thanks for spending time on this Tom!

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Quoted for irony.

Scott

Pretty sure the 23mm GP 4000 tested best again for the Zipp wheels.

Agreed - Maybe ST will shut up about people being able to change 17 flats in the time saved by not running Gatorskins for an IM.

Agreed - I have never owned a Gatorskin and probably never will.

Agreed - Tom A. really contributes a lot to the ST community.

I'm sure many of the owners of the new wheels were already planning on buying the force tires based on the article. if they don't see this buried in here on ST, then they'd never know about it. i feel like this should be a huge disclaimer somewhere in the article

I agree...and I apologize for overlooking that fact when I sent the combined data to Chris and Jon.

Chris? Jon? Sounds like a good edit to make on your blog post.

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I'm pretty sure that TomA rides the Specialized Cotton for a good reason.

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Suffer Well.

They're my "go to" tire on the road bike (on Hed Jet+ Blacks). They reside there for more than just aero+Crr reasons ;-)

On the TT bike (Flo 90 front and "wide" covered PT rim on back) I go with Conti SS23s. Then again, on the TT bike, I don't think my range of expected yaw angles is as large as what the Flo NDRV distribution assumes...

YMMV.

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http://bikeblather.blogspot.com/

Thanks again for doing all of this!

It seems this is the first time you tested Schwalbe Ones or published numbers from previous tests. When you originally tested the tubeless and standard clincher versions of their Ironman tires, there was a surprising dropoff between the brand new standard clincher IM and the tubeless specific IM with 335 miles on it. Something like the lightly used tubeless version being 4 watts per tire better at 40km/hr. Schwalbe says they use the same rubber, casing and construction between their IM and the previous generation Ones. The new Pro Ones are a little different.

Which version of the Ones did you test for this project?

As I discovered later, the difference between the tubeless and regular clincher Schwalbe IM tires was due to the fact that Schwalbe omits the under-tread puncture breaker layer on the tubeless versions. As it was eventually explained to me (after specifically ASKING at interbike) this is because they expect the tubeless riders to use sealant, so although that means the tubeless version is more likely to puncture, it also means they are relying on the sealant to take care of that. You can make your own evaluation of the validity of that approach...

The tire tested is the One model, not the Pro One.

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Have you found a correlation amongst tire weight and crr within a particular tire model?

Thanks Flo and Tom for a huge effort. Very good stuff.

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For the record A2 and it's big brother Aerodyne have a background story similar to what you are proposing. Aerodyne was created to meet the need of the NASCAR teams in the area and was bootstrapped & funded by the auto manufacturers to have local testing for their teams. Before Aerodyne most of the teams either used their manufacturers tunnels (located primarily in detroit), or lockheed down in Atlanta. A2 was created as a less expensive tunnel with the original use the lower rungs of the motorsports ladder (think late models), but that didn't pan out when the recession hit, so now it is used by cyclists.

To answer your real question though....tunnels are expensive, the equipment in them are expensive, the people knowledgeable enough to run them are rare and, you guessed it, expensive. This is a pretty fair market, there are more than a couple tunnels available all over the country and they charge what the market can bear. Aerodyne, the bigger tunnel, charges a fair amount more to test in and there is a waiting list to get in.

There is another tunnel in Mooresville/Concord area that is even more expensive, but the floor moves with the air and is a whole other story.

I typically don't weigh the tires, so I don't really know...

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http://bikeblather.blogspot.com/

Thanks for the quick and detailed reply.

I'm assuming you meant the standard clincher, not the tubeless specific one. In a post from a while ago, I talked about taking a video of puncturing a road tubeless tire (with sealant) at 90psi a dozen times with a thumbtack and having virtually no air loss as measured by the hand gauge. You made good points about the tire not being loaded or spinning. You then challenged me to jam a thumbtack into a latex tube and see if the same thing happened. Short story, you can patch latex tubes just like butyl tubes when they won't hold air after purposely popping them :-)

The crr of the (previous generation) One clincher seems to closely match your 2013 crr measurement of a 22 Schwalbe IM clincher at 0.0041. The tubeless version of the 22 Schwalbe IM (brand new) measured 0.0035 in your test. I'm really curious how the results would have looked if it were tubeless specific Ones used for the FLO test. Averaging your 30km/hr and 40km/hr columns and accounting for 1 tire instead of 2 would have me believe the removal of that puncture belt is worth 2-3 watts per tire in the low 20mph range. That would make a much more compelling case on the FLO charts since so much of it is based off crr. The new Pro One is supposed to be even better for crr too.

I feel that tubeless Schwalbe road tires make sense for instances where you want stable psi or are at risk of small punctures from things very similar to my thumbtack. I had Vittoria tubes that each lost 20psi during a ride. The newest tubeless tires don't appear to be giving up much to the cream of the crop 'fast' tires and hold PSI really well. I'm on my 3rd set of road tubeless tires with a 4th pair of 28s ready for my cx bike. I have had one full flat that whole time and it was because the rim tape failed. Dealing with the sealant while throwing a tube in wasn't fun, but it was far from the horror show that ST would make one believe fixing a flat on a tubeless tire would be.

Anyhow, I would still pick the Supersonic (If I can ever find them in stock) and latex tubes (without a patch) when every watt matters. I would probably ride my next IM bike split on well chosen Schwalbe tubeless tires again.

Actually, the tire tested was the One Tubeless version.

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http://bikeblather.blogspot.com/

Please excuse me while I pick myself off the ground and delete my previous posts.

I'm curious how the crr for the 23 One tubeless was so far off from the previous 22 IM tubeless roller test.

Only Schwalbe can answer that. Different tire construction, most likely...maybe they didn't omit the puncture breaker on that tubeless model?

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http://bikeblather.blogspot.com/

That playful Schwalbe...

"Oh no, those IM tubulars are all latex tubes. No wait, we changed to butyl without telling anybody and there's no way to know which is which."

"Yep, the IM and One are identical other than the 'aero' lines on the tread."

You can take a look here as some of the tires tested and weighed.
http://www.bicyclerollingresistance.com/

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<We all know that light travels faster than sound. That's why certain people appear bright until you hear them speak>

It looks like Continental has taken the Black Chilly to most of the tires in their performance line. I wonder if some of the differences are due to a compound change during the time frame the tested tires were purchased. They are also selling version IIs of these tires. It is kind of funny how the Force 24 looks a lot like the GP4000s II 23 and the GP4000s II 25. Hmm.....

ProBikeKit is selling the IIs Attack & Force tires individually.

BTW: PBK has all of the Continentals on sale. I just ordered a pair of the Force for 42 ea. You can get 2 GP4000 23s for 38 ea.

I think you misunderstood. What I was saying is that if you had three different 23mm GP4000S IIs with one weighing X grams, the next being +20grams, and the last weighing +30grams they would end up rolling in that order, the theory being that a lighter tire means less tread which means a faster tire.

And thanks to Tom Ahnalt, this chart doesn't apply to me ;)

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Im curious as well. Sounds like rim width over brake track but what I didnt follow from Josh was 105% wider than tire At Least meaning more is better, no? And that Firecrest made up for that meaning if it was 102% that was hidden buy the rim but still At Least 105% was best.

And then is that for aerodynamics or for both rolling resistance and aerodynamics?

Say for example I have a choice between two tire sizes - 23 and 25. Which for argumets sake measure out at 25 and 28. Max rim width is 30. Both options are at least 105%. 23 tire obviouly even more but the 25 is going to have lower CRR. Which is the better option?

I just bought a new Force/Attack set to replace my 4000S tires, but, based on this data, it looks like it may make the most sense to stay with a 4000S on the front and put the Force on the rear. These will be on a HED Jet 9 front and HED Jet disc.

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Looks like even if using the 0.034 force, it still wouldn't hurt too much, result would still be faster than gp4000s? Gp4000s has the same 0.034 crr but less aero than force according to flo graph.
Unless I depict wrongly.

GPTT measures 1.2mm wider (on same rim) which is significant.

GPTT 23 is quite a bit fatter than an SS 23. It's more like a Force in size.

When Swiss Side tested it for aero, it was pretty bad, while a GP (not 4k, not TT) did much better. Seems like the grooves are generally good for aero on a large tire.

Well, we found Slowtwitch's ignorant post of the week

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really? so i guess a majority of the pros and FOP AG-ers must be off, too.

thanks for clearing that up.

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I don't think you understand Flo's business. Pros will ride whatever gear a company pays them to ride.

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And this is the old Flo90. Tested independently from Flo in the Specialized Wind Tunnel. Lower is better....one wheel sticks out...


[Source: TomA]

Fruit salad. apples :: kiwi fruit + strawberries

Maybe tomA can indicate:
Why not compare Zipp808FC or 808NSW vs Flo9 (since this is the Flo fanboy page, but you could compare w/ Hed Jet9, etc.)
Or, why a Hed H3 when all other wheels are spoked?

Compare wheels of similar depths, lacing patterns, etc.

And again, I'll always, ALWAYS go w/ race-tested > wind tunnel tested every single time.
Specialized CLX w/ S-Works Turbo under a Shiv.
Or, Zipp 808 w/ Tangente tire on bike of choice?

What about looking at wheels/tires systems, not an assemblage of components?

Be critical before your Kool-Aide ferments. ;-)

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I'd still like to see a more real world, complete comparison as a consumer (Zipp 101, lol) but I get why they don't do it. The wheel actually on a bike would be nice too.

While I like seeing the data it falls incomplete in my book so you have to go with the blended average of what all the tests show. Flo makes some great valued wheels that ride really fast. So does Hed with a slightly higher price point. Zipp and Enve are a step over that price wise. Throw a GP4000 on all of them and call it a day. I think the tire comparison also confirms why we already know, GP 4000 is the best overall tire all things considered. Getting a puncture belt in exchange for 1 second over 40k is a fair tradeoff to the SS if you ride Flo wheels (and all the others IMO).

I'll take ERO and A2 Wind Tunnel tested over race tested any day.

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Well since you're now reaching to $4000 wheelsets (NSW) to try to find something that might beat the <$1000 wheelset........

Your choices aren't that great, in my opinion. S-Works Turbo tire is pretty aerodynamically awful and not among the best at rolling resistance. Tangente is OK, but not in the top tier.

I do have Zipp wheels. I use a Zipp 808FC / Zipp 900 with Tangente SL Speed tubulars as a backup wheels to my Flo 90/disc with Supersonics.

 
yeah i'm regretting buying a bunch of turbo cottons. should have stuck with gp4000s.

The only way to get a true real-world complete comparison is to spend the money to go to ERO/A2/LSWT with your own body and your own equipment.

Or do it yourself with somewhat less accuracy (which is what I do).

Why do you think these examples are "my choices"? I guess that is your opinion?

http://velonews.competitor.com/...s-cycling-tires-fast

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Did you read Flo's study? Honest question.

Scott

Always best to use studies that leave out the Conti SS, Attack, Force, TT if you want different tire choice to look good.

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Haha! Yes that pretty much sums up the study ;)

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Co-Founder And Previous Owner Of FLO Cycling

   


Looking at the data as someone who isn't an engineer, how does the 4000S in 25mm at 17.37 watts test the same as the 4000S in 23mm at 17.76 watts, resulting in a virtual tie in terms of time. Is the aerodynamics of the 23mm better and makes up the difference in wattage?

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Agreed,
I get from that data - the supersonic is the best, maybe use the force at Kona with the higher yaws.

Yes. I agree. I just bought 3 23mm SS's for my TT bike. I'd rather be one second slower (40K) and have the puncture protection of the 4000sII. The 4000sII has been my go to tire for years. I've mistakenly been seeking better. I have two S-Works Turbo 24mm tires too. I'll now use them on my road bike post-season in the fall; at least I hear they have good traction.

The "why" about which particular wheel and tire combos were tested to generate that chart is answered here: http://bikeblather.blogspot.com/...playtime-part-1.html

Basically..."don't look a gift horse in the mouth" ;-)

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http://bikeblather.blogspot.com/

Yes. The aerodynamics of the 23 are better than the 25. On the chart below, the 23 is represented in orange. If you are interested, you can compare the aerodynamics of all of the tires tested in part 1 of this tire study.

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Chris Thornham
Co-Founder And Previous Owner Of FLO Cycling

One thing I will say is this is by far the most complete tire comparison any wheel manufacturer has done to date (that I've seen) in a format that is pretty darn easy to read and understand. The same holds true for the wheels and all of the combos and race course testing you released. While there is some marketing in everything we see, this is about as transparent as you can get. Fast wheel. Competitive price. Wheel depth analysis based on terrain. Free tested tire advice. The only decision now is latex or butyl. If only everyone did this we could then spend all of our time debating testing procedures.

No.

You're not hearing


You're not

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You never know. Turbo cotton rear, supersonic front might be the gold standard.

Houston, do you copy? You are breaking up. Come again?

Over.

I follow your logic.

Building on this, anyone else considering a GP 4000 / Force combo? Best case, you get a unicorn in the rear that rolls at .0029. And if not, the 1minute aero penalty of the Force over 112 miles (per Flo study 1) is mitigated by putting it on the rear wheel.

Or, keep it simple and just roll dual GP 4000.

Scott

So did I make a mistake running turbo cottons on a zipp 808 FC and super 9 (24 mm front, 26 mm rear)? I used to run 23 mm gp4000's.

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blog

Depends on how fast you are and what you expect your average yaw angles to be...but, probably not :-)

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I rode Raleigh 70.3 last week avg 24.8 mph.

So for higher yaws and lower speeds: gp4000's?

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blog

In general...

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http://bikeblather.blogspot.com/

That combo (same as mine) begs for a SS23 front/ Force or SS23 rear. That has been my strategy and has worked well. I am trying a GPTT 25 on the rear though for a 70.3 next month.

will a gp force be faster on a fc 808 than a gp4000s?

Yeah I'm thinking about switching to SS's. I may just need someone to push me over the edge to pull the trigger.

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blog

I have been running Force rear and Gran Prix TT front with Challenge latex tubes for years looks like I don't need to change thing:)

Yes

I think I'll put a GP SS 23 on my Jet 9 plus and run the GP TT 23 out back on my Enve Classic rim with disc cover. Been running a Force up front and the Specialized Turbo Cotton out back.

I have been running SS for as long as I can remember with Challenge latex tubes and have never been happier. ZERO flats during a race and I ride them in training as well with ZERO flats.

Sorry to hear you are injured. I hope your recovery goes well.

i felt the same way, Gerlach's words gave me that little push over the edge, been running them in all races on my front wheel for all races in 2016. Zero issues, run them with latex and sealant. I have been running a TC rear but after reading this going to switch the TC out for a force i have laying around. Also have a GP TT 25mm on order.

Take the leap to the dark side of the SS! FYI when you first feel it feels sooooo thin don't be scarred.

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2024: Bevoman, Galveston, Alcatraz, Marble Falls, Santa Cruz

Josh,

So I took some measurements from different tire/wheel combo's I'm running and curious how to interpret the information - or is it just "fun facts"?

Combo 1 (Rear): Max rim width - 30.2, brake track - 25.2, bead - 17, tire width - 26.5
Combo 2 (Front): Max rim width - 30.2, brake track - 25.2, bead - 17, tire width - 24.5
Combo 3 (Rear): Max rim width - 27.5, brake track - 26.5, bead - 17.25, tire width - 25

Assume I'm around 81-82 kg on race day - 160lbs + 18lbs bike/gear.

Two questions - are these width ratios "good" in your opinion (rim greater than 105% of tire) and what pressure would you run? I've been running 95 psi on all these combos.

Thanks!

Hi Tom,

I'm wondering if your injury is gone now (which I hope for you) and you'd be able to test a Force again ?
I need to decide between GP TT and GP Force on Flo 60 CC for my next IM ;-) . I've seeen GP TT testing faster in RR many times so on a low wind day I'd probably go TT (from Swiss Side testing and Flo Testing of now awesome aero tire... we still see under 7.5° tires are close enough for RR to be the most important factor), but just in case it gets very windy it can be smart to have a pair of Force in the car ;-) ... so I'm curious to see if it was the one you tested at 0.0029 that was a very lucky tire or of it was the 0.0034 one that really came from a bad batch !

Thanks,
Pyf

Majoring in minors here. Their are always two things that a wind tunnel cannot measure and they are the most relevant of the entire study--"Relative Wind" (RW) and road surface caused rolling friction. RW is the wind that the bicycle creates going through the air medium combined with the direction of the wind and speed and the direction of the bicycle and speed. RW varies with speed and the regular wind, it varies constantly in both speed and direction and nothing can be done about it. Years ago, the creator of ADA wheels (Cees Beers), instrumented VDB (TDF competitor and World Champion) with sensors all over him and the bicycle to assess the aero of his wheels. Problem was, VDB was unable to maintain a straight line for any length of time due to varying wind conditions. Nevertheless, the results were taken to the Dutch Aerospace Super Computer and input. The computer stalled and had to be cleared--it could not crunch the numbers. My brother is an engineer at Boeing, so I asked him to ask the wind tunnel guys about the various bicycle and wheel aero tests and when he did, they fell out of their chairs laughing, because ALL bicycle wind tunnel tests are bogus. The reason for this is that wind tunnels were created to learn how to make a shape do something with the air it is going through, because they want the wind to do something--like fly the aircraft. However, an aircraft is a relatively stable thing in the air medium, a bicycle isn't. The wheel is constantly vibrating from road impact and the bicycle is constantly moving around, and that interrupts the laminar flow around it and the wheels and the tires and that creates a very high CRR, which instantly invalidates the test--the vibration disturbs all laminar flow. There is no way around it. The cyclist should choose their tires for how they feel to them. If they feel draggy, try other tires, because they probably are draggy, size of the tires should be chosen to match the road surface for the lowest rolling friction. We do know that wheel rims should have a slight taper to the inside of the rim to smooth air flow around them. We also know that a smaller tire cuts air better at high speed, but it can also increase rolling friction due to road conditions. You have to decide what works for the conditions. Also, extensive testing has shown that thin round spokes are better than any aero spoke made (thus destroying the myth of so-called aero spokes). The fewer the spokes the better, because they can really rip up the air, aero or not, and again, the RW always changes, making so-called aero spokes, not so aero. If conditions permit, the use of disc rear wheels makes sense, even though they have a lousy CRR. The reason for this is that the disc fills up the area behind the seat tube which has an even higher CR than the disc. However, a disc wheel, and for that matter, a deep dish front/rear rim have other problems. Any time the RW is from the side there is a force vector from the wind that forces the rider to lean into the wind to correct his course. The larger the cross section of the wheel, then the more lean is induced and the higher the CRR of the wheel/tire combination. This flies against what most people are worried about on this thread, but it has been proven over and over again. So, why do national and international competitors ride what they ride? Simple, they are paid big money to ride the stuff they ride...You, dear reader, aren't. So, ride what works. Personally, have found that Continental tires (both sewup and wired) have a lively, relatively low friction ride, but they are also harsh which are two conflicting attributes. However, when they are cut, the cut tends to spread, because the tire itself is allowed to expand (it's the thread belts that allow this) with air pressure, so the rubber is under tension. The cut can enlarge, thus endangering the tire, and can't be repaired. If you compete, sew-ups are the way to go. Every TdF ever won has been won on sewups. I like wired on, ride them a lot in training--go thru many sets per year. But when I race, it is always on sewups--currently--DuGast silks, or very ancient Veloflex (Egyption Cotton) or Clement Campaniato del Mundo Setas (almost 30 years old). And believe me, none of those sew ups can come close to the Continental Force tire, except that in the real world, their is virtually zero road friction as I fly past guys shod with Continental Force tires. It has little to do with training or leg strength, because I'm 68 yrs old and has everything to do with what works in the real world. My personal recommendations are to use Veloflex or DuGast silk sewups on the lightest Mavic wheels you can afford. Mavic wheels have a superb bearing adjustment and bearings. Go for a very small rim cross section with as few spokes as possible (depending upon rider weight, of course). If wind conditions allow it (Hawaii, Kona never allows disc or deep dish wheels, due to wind conditions) use a disc rear wheel and slight dish front, but be sensitive to wind--any wind from the side, forget the dished wheels. As an aside, Heather Fuhr won the Kona Ironman and the World Championship on ordinary sew up wheels that I trued and balanced, and with ceramic ball bearings that I designed and installed (synthetic clock oil was the lubricant).

I love this guy... Helping me get to Kona since 2008 and now helping me earn a living... Free chicken.

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Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

So what wheel set would you recommend if one could only afford one set for racing?
Cheers

The injury (a fractured pelvis) is mostly healed. Bone is good, now I just need to work through some muscular issues. I've actually been cleared to ride outside now, and since the weather has been awesome, I've really had low motivation to get on the rollers ;-)

I'm hoping to get to test that tire, along with a few others soon....i.e. in the next few weeks.

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http://bikeblather.blogspot.com/

This a lot to unpack. First, I do not know exactly why you replied to my joke about gatorskins. Second, while an airplane is stable in the macro sense, I have seen a bunch of data from accelerometers mounted on various parts of aircraft and it is definitely vibrating. Let alone on landing where you are working the wing hard, there are lots of dynamics. Third, how does the movement create high CRR invalidate the test? Wouldn't it at the very least impact all of the tires equally, so the results would still be meaningful? It would not impact the fastest tires more, making the CRR equal for them all.

How many times have you been in a wind tunnel? How much testing have you done in a wind tunnel? I have done testing in wind tunnels and that testing was all aerospace related. I can assure you that some Boeing engineers believe that some of the wind tunnel tests are meaningful.

If you want to use clinchers, go with a 22-23 mm Veloflex tire on the lightest Mavic wheels you can afford, preferably weighing around 1200-1400 grams (lighter is always best). If you like Continental tires, well...sure, use 'em, have ridden them a lot, not the Force tires, but the 4000 series and they are OK, just think Veloflex is a bit better. I think Mavic is still using Velomax Aerohead rims--love those things. The Aeroheads have a slight aero shape to them that actually works under most conditions, is light and strong enough to spoke up with 28 or less spokes. The Mavic hubs are the best, and feature a bearing adjustment that can be done while installed in the forks.

I built a wind tunnel to test scale models of spokes. My partner has a PHD in physics and was rated #3 in the nation at the time. Sure, aircraft vibrate all over the place, but they do not disturb laminar flow, bicycles do disturb laminar flow.

Ok thanks, so this will be faster than any deep dish wheels? I feel like I've been screwed by advertising, stolen from.

Ok, so windtunnels do not produce relevant results for bike wheels because of the flows wheels see. But you windtunnel testing is meaningful for spokes. Also, why did you need to test scale models of spokes, was it a windtunnel for ants? Spokes full size are not exactly large to test their different cross sections. Seriously, why would you bother making scale models of spokes and dealling with the problems of scaling wind tunnel tests? A Phd in physics could be very relevant to this or it could be completely irrelevant. Maybe your partner should be the one to talk about this and the data from your windtunnel tests is good, because you are making all sorts of weird statements that make me questions the testing.

Also, shape is still important if the flow is not laminar and a correct shape will reduce the flow even turbulent flow. In fact sometimes a shape works better with turbulent flow.

Thank you. I drink a latte every morning which leads to a pretty good burst of energy about 1 mile into my morning ride. By, the way, have been to the GM wind tunnel and the GM Quiet Room while discussing high current liquid cooling and balancing of motors, but that has nothing to do with bicycles, nor does it have anything to do with vibration analysis affecting wing loading during high speed cruising or landing at 160 mph. When you can safely ride a bike at 550 knots, please let me know how it felt.

"The wheel is constantly vibrating from road impact and the bicycle is constantly moving around, and that interrupts the laminar flow around it and the wheels and the tires and that creates a very high CRR, which instantly invalidates the test--the vibration disturbs all laminar flow. There is no way around it. The cyclist should choose their tires for how they feel to them."

Is this possibly throwing the baby out with the bath water? On the surface, it looks like you are arguing that because the system is complexity, no testing is indicative of relative improvements. If so, that seems pretty unscientific, and the recommendation to pick tires on a guess might be worse than using the test data available.

"Also, extensive testing has shown that thin round spokes are better than any aero spoke made (thus destroying the myth of so-called aero spokes)."

Can you cite any of the testing? I have read results from both Zipp and Flo that argues the opposite. I am curious to see what is different between the tests and papers you have seen versus those of a couple leading wheel makers. (They do agree that fewer and shorter are better than more and longer.)

"The larger the cross section of the wheel, then the more lean is induced and the higher the CRR of the wheel/tire combination. This flies against what most people are worried about on this thread, but it has been proven over and over again."

Are you arguing here that deep dish wheels are inferior to traditional box/aero cross section rims (except with very low yaw angle)? If so, could you reference any of the supporting data or studies. It seems like we have a plethora of examples of riders testing on velodromes and measured courses that validate wind tunnel results that deep dish are superior to traditional rims. Maybe some of the system complexity reduces some of the absolute advantage measured in a wind tunnel, but it seems the real life test examples do support the relative advantages.

Not necessarily faster, but different. Advertisers want to sell their wheels and so wind tunnel tests can offer a measurable and repeatable advertising statistic, in their wind tunnel. Aero wheels have their place. You find a smooth flat road with very little wind or even a head wind and as long as everything else is equal, the aero bike will win every time. Problem is, an aero bike is very specialized, it goes to hell and gone under different circumstances, such as climbing, rough roads and capricious winds, which as we all know exist most of the time. The rider has to choose and know what will work under different circumstances. That's all I'm trying to say here. Froome just won the last TdF time trial. Several riders didn't use aero bikes, he did. He won. His aero worked for him. He is also a very good cyclist.

I'm probably going to be sorry I jumped in on this....but here it goes....

How do you, or your brother, or your #3 ranked physicist partner (I'm still not sure what that actually means and what organization ranks physicists) counter the argument that a lot of wind tunnel tests and corresponding outdoor tests using the Virtual Elevation method seem to line up well if wind tunnel tests are bogus?

I am not saying wind tunnel tests, of any kind, are perfect. But I would argue that they are a completely usable tool to determine the aerodynamic drag on most objects at relevant speeds.

p.s. please tell me more about this "high current liquid cooling".

Under certain circumstances, yes. But, have found through years of testing for my own purposes that a semi-aero rim such as a Velocity Aerohead is a very good compromise between no aero and some aero, esp with a low spoke count wheel. At the same time, I still ride ultra light tubular rims such as the Fiamme Ergal with silk casing tires and the sew up tires are faster, and there is no aero about them. For racing I do not use wired on tires, prefer strictly silk, or fine Egyptian cotton casing sew-ups on old style Fiamme Ergals and another brand named Champion Competition Medaille d'Or (sp?). Both are extremely light wheel sets. The Champion rims weigh about 260 grams more or less and the Ergals weigh around 280 grams and are stronger. The sew up tires weigh anything from 220 grams to 315 grams depending upon the road surface, or if somebody insists on weighing my bike (have been getting away with murder for some time, so it's time to move). I can get the bike down to the mid 13 lbs region if needed. Heh, heh, heh....

Nope, can't do it. But you can read about it on the Internet. Start with spray cooling of electronic components.

Aero wheels have evolved pretty substantially over the past few years. I wonder if the current designs and philosophies are consistent with the testing and observations you conducted years ago.

I absolutely agree that tubulars perform better than clinchers. I raced on tubulars decades ago when I was a road racer. I got back on the bike after about twenty years away, and this time around I will only do clinchers. I am just not interested in the mess and hassles of tubulars. I am debating tubeless, but I will probably stick with latex tubes and not go all in for the tubeless.

Yup, aero is still aero, it's still the same old arguments back and forth. At the right time, a good aero wheel set is very fast..no question about it. The big one that used to be hurled at me all the time was that at exactly 12 mph, climbing a hill, the aero rim will generate less aero drag and make up for its increased weight. After that, I presume, the wheel would simply pull itself up the hill. If anything, aero style rims, at least the really expensive ones are a whole lot lighter, they used to be very heavy. However, when it comes to weight, a good tubular rim will always win and the aero style wheel advantage, which can be statistically measured, will still come out to be surprisingly minor, esp. when weight is considered. But the aero advantage of a wheel can be calculated and advertised as a selling point, which is why it is done. My lightest tubular front wheel, without a tire, is 454 grams, exactly one pound. Which would you rather ride up a hill? Sew up tires are messy, geeky, light, delicate and just plain silly at times, but they are fast. I used to get into tremendous arguments with three guys who WERE the nom de plume of American cycling: Jobst Brandt, Eddie B and some clown from Harvard. Neither of the three ever raced. Eddie B told me, personally, in 1998, he had a better way to balance tires (he didn't and didn't understand the concept, plus he drugged all his cyclists). Jobst Brandt's sole claim to fame was that he rode his bicycle in Switzerland...once, and the clown from Harvard was a mathematician that did all the aero calculations for aero bikes. The three of them came together for the 1984 Olympics, using the billion Dollar highest tech aero funny bikes in the World. The team lost terribly, because it emphasized tech over the cyclist and the Euro cyclists just said poop on you, and they got on their bikes and rode the wheels off the Americans. Problem is, triathletes have kept their techy stuff, often ignoring the cyclist, and the legends of Eddie B, Jobst Brandt and the clown from Harvard live on. It's all in the legs and the proper equipment for the territory. IF there is no wind, ride the aero bike. If it will be blustery, hilly and lots of curves, consider a road bike with sew-ups and clip-ons, etc.

Are you a time trial racer? A lot of what you say makes sense for road rides and criteriums. But some of your application does not really make as much sense in the context of a time trial ride, especially a long one.

Well then....now we KNOW you're just trolling...

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http://bikeblather.blogspot.com/

Now, we've gone from balancing bicycle wheels to calling me names. That's interesting. Keep the shiny side up.

I didn't call you a name. I merely described what you are doing.

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http://bikeblather.blogspot.com/

this is like a flashback to rec.bicycles.racing. well done.

Nope, you called me a name. Don't split hairs. In answer to your question, ask two winners of the RAAM. Their wins prove my point. You on the other hand, are merely irritating.

Ummm...what question? I don't recall asking a question of you.

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http://bikeblather.blogspot.com/

All I can say is thank fuck the aeronautical industry doesn't take your approach otherwise we'd still be flying around in bi-planes made out of spruce and muslin like the Wright brothers did.

Oh but hang on, you may or may not be surprised to learn that most of the research the Wright brothers conducted was in a small, homemade wind tunnel.

And holy shit, if I look up in the sky I can see these aeroplanes flying around. Astonishing. But I guess we just kept changing the shape of the metal bits and throwing it up into the air until we found something that worked. I don't think anybody modeled any fluid dynamics on a computer or tried anything out in a wind tunnel, because it just wouldn't have worked properly once you took it outside into the turbulent winds in the actual real life sky. That would be crazytown.

campy.1321 wrote:

<snip>

I agree that you were called a name.

what are your thoughts on this field testing/wind tunnel + math model based plot, campy.1321 :

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Kraig Willett
http://www.biketechreview.com - check out our reduced report pricing
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I was learning for 4.6 pages in this thread, then I became terribly amused.

Oh thank god for this information, now I know that had I run Conti Force when I did IMC (a while back), I would have finished 23 seconds faster in my 13 +hr effort.

Not blowing up in 35c weather and walking almost the entire marathon, might have erased that 23 second deficit.

For the pros this is a problem, but for the rest of us....come on.