Weight Weenies

Trying to solve all the aero marketing contradictions is a neverending project. All these tests have almost nothing to do with actual riding-racing conditions. IMHO just use high quality 23-25mm tires (tubulars even better) and forget about all this BS.

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Can't you just go to slow twitch where this whole discussion has already been solved?

Marin I am confused at why you think wider tyres are not more comfortable. A larger air volume means greater vibration damping.

retro grouch kgt ... funny 20 years ago most conventional wisdom was to use 19mm for tt and 21 for road racing.

the future is wide. comfort and speed.

http://enve.com/products/ses-4-5-ar/

Flo cycling looked at this for their new carbon clinchers in two blog posts: http://flocycling.blogspot.com/2016/04/ ... study.html and http://flocycling.blogspot.com/2016/06/ ... study.html. They looked at the combined effect of aerodynamics and rolling resistance. For the tires they tested in two sizes the overall speed of the larger was always faster. They were slower aerodynamically but the lower rolling resistance made up for the higher drag and then some. The tires they looked at in multiple sizes were Conti GFP4000, Conti Gatorskin, Schwalbe One, and S works turbo.

Rolling resistance test on rollers? No, thanks.

I run a 23c front and 25c rear GP4000SII...what does it say about that setup?

Zigmeister wrote:I run a 23c front and 25c rear GP4000SII...what does it say about that setup?

Just curious, did you consider going with Conti's Force/Attack setup since you went with that combination of sizes?

cobrakai wrote:Flo cycling looked at this for their new carbon clinchers in two blog posts: http://flocycling.blogspot.com/2016/04/ ... study.html and http://flocycling.blogspot.com/2016/06/ ... study.html. They looked at the combined effect of aerodynamics and rolling resistance. For the tires they tested in two sizes the overall speed of the larger was always faster. They were slower aerodynamically but the lower rolling resistance made up for the higher drag and then some. The tires they looked at in multiple sizes were Conti GFP4000, Conti Gatorskin, Schwalbe One, and S works turbo.

You should note that they did the aero test on the 2016 carbon clincher that has 26.9mm max width and 18c inner width. If you look at the silca article, the results are perfectly in line with the results published by flo. It makes sense that 23c tires were faster than 22c ones on a wide rim because the transition between the tire and rim is better. Would a 23c tire would be faster on a narrower rim (like 25mm) than a 22c? Probably not. HED recommends 22c tires for their 25mm wide rims.

What strikes me about the rolling resistance test is that they didn't use the flo rims for the test. They put the tires on a mavic open pro rim that's narrower, so the tires had a different width and shape on those. I don't know how they combined the two data and how meaningful is that. Maybe it is.

With the results in mind I'd probably still choose a 23mm gp4000 for my flo rim because with tire wear the tire will grow. Also with narrower tire you have a bigger pressure range you can use without effecting the aero benefits of your rim.

Marin wrote:There are no real reasons why wider tires should be more comfortable - they are harder at the same pressure, and they don't get different suspension properties from being larger.

There are no real reasons why wider tires should be faster if you run them at the same level of comfort as a narrower tire, i.e. you drop your pressure to make them as hard as the narrower tire.

There are no real reasons why wider tires should have more grip than narrower ones - increased road contact surface also means less pressure per area, which exactly cancels out. Plus, contact area is more dependent on pressure than on tire size anyway, so not really larger to begin with.

So comfort and grip are mostly a factor of tire quality, not tire size.

Additionally, with rims with wide internal widths, you can't go by manufacturer stated tire width, most "23 mm" tires will be over 25mm wide on an 18c rim.

Conclusion: Get a high-TPI tire in 22 or 23mm stated width, and enjoy a reasonably aerodynamic 24-26mm tire on your wide rims. Everything that comes out over 26mm wide is a mixed surface tire IMO.

http://www.bicyclerollingresistance.com ... i-23-25-28

Marin you made some good pts above.. how would you analyze the findings of the 'Continental GP4000S II Comparison: 23, 25, 28 mm Compared' ?

In short: use a rim that is wide inside (for 23mm tire 19C, for 25mm 21C), lower tire pressure and avoid tire overlap. Fast and comfortable.

In length: see signature.

Beaver wrote:In short: use a rim that is wide inside (for 23mm tire 19C, for 25mm 21C), lower tire pressure and avoid tire overlap. Fast and comfortable.

In length: see signature.

In the lab it comes out.. understand I dealt little of bike aero. Yet back when I designed projectiles for my cast bullet target shooten... real world vs some of the 'theory' contrasts.. again only 'sometimes'. So I'm not blank per aero/flight characters.

What leaves me blank.. is the miniscule/none difference rim aero means overall. Had a chuckle on my birthday ride... the last 21+ miles found me into a "10:30" wind to low 20's mph... gave the space between my ears something to contemplate/mind off the task.. especially w the much of the last 6 straight into what felt like a gale. That quartering wind a bear when tuckered out.. doubt any air-0 wheel a help.. no matter the situation. All this motion making forward advance.. in some instances the traffic adding or negating my advance per turbulence. I DO get total sums over a ride.. mainly if it works on the real estate 'tween your ears. Each there own...works for me.

Yet .. my bright colored shirt to keep the goobers/gooberettes from running my soul over while operating.. filled partially with perspiration over the last half of the ride.. finally some sunlight on this somewhat coolish day. I think the evaporation of said H2O meant more air-O effect.. what say you.

You 1st need to find the pressure where each tire gives the same level of comfort - probably by measuring vibration at the frame - and then compare rolling resistance at that pressure.

If you just want more speed, you can simply run a narrower tire harder, and you'll have better aerodynamics too.

Marin wrote:You 1st need to find the pressure where each tire gives the same level of comfort - probably by measuring vibration at the frame - and then compare rolling resistance at that pressure.

If you just want more speed, you can simply run a narrower tire harder, and you'll have better aerodynamics too.

Agreed ...mostly. Simple way to measure frame vibration.. goober on electronics I am. Thought something to measure shocks at seat post.. that makes most sense to me.. where most of the wt is set into the frame. Simple cost effective method?

My birthday rides will only getter long... dah. Might.. need some advantage if only mental when I hit 80's.. which is a far toss off.

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WinterRider wrote:...

I'm sorry, English is not my 1st language and I sometimes have a hard time following your posts?