I’m running Continental GP4000s (23mm) on both my front and back wheels. In case it matters I have 2008 Mavic Cosmic Carbone SL Premiums. I recently read an article that claims the wrong front tire can take away much of the aerdynamic advantage of your wheels. Should I be runnning a thinner tire infront? Maybe 21mm?
bump
I have the same questions=and I have the same wheels.
I’m running Continental GP4000s (23mm) on both my front and back wheels. In case it matters I have 2008 Mavic Cosmic Carbone SL Premiums. I recently read an article that claims the wrong front tire can take away much of the aerdynamic advantage of your wheels. Should I be runnning a thinner tire infront? Maybe 21mm?
What article is this? Just curious…
Here is the link to the article Scroll down to Tires. http://www.biketechreview.com/reviews/speed_for_sale.htm
“Tires ($50-$100)
One of the better values out there in terms of improved speed for the buck comes from your lowly, neglected tires. Tires will give you a double whammy, since the right tire can simultaneously improve wheel aerodynamics and rolling resistance. Often times, the tire one puts on their expensive upgraded wheels will wipe out the majority of the aerodynamic gains. Pay attention to your tires, and begin asking manufacturers/shops tire performance related questions. The qualitative ratings below are all estimated relative to a mid ranged OEM tire.”
Well i did some testing on aerodynamics of tyre´s in windtunnel and yes they can change the wheel aerodymics.
I did disc wheel ( not mine ) and mounted several differant tyres with the same pressure ,and some some changes in wheel aerodymics
i did test from 0 to 30 degree of yaw
I cannot reveal testing numbers becuase the test was paid by some else ,
But i agree that tyre´s influence and change wheel aerodynamics
test was done at 13,8 ms
Check out the various reports regarding the Zipp tires with the Zipp wheels. I have both and can’t really tell the difference as a rider, but wind tunnel information does indicate that there is something to this. Tim
Here is the link to the article Scroll down to Tires. http://www.biketechreview.com/...s/speed_for_sale.htm
“Tires ($50-$100)
One of the better values out there in terms of improved speed for the buck comes from your lowly, neglected tires. Tires will give you a double whammy, since the right tire can simultaneously improve wheel aerodynamics and rolling resistance. Often times, the tire one puts on their expensive upgraded wheels will wipe out the majority of the aerodynamic gains. Pay attention to your tires, and begin asking manufacturers/shops tire performance related questions. The qualitative ratings below are all estimated relative to a mid ranged OEM tire.”
Hmmm…it’s not exactly clear from that quote, but I think the gist of what the writer was trying to get across was more about the mistake of using a high Crr tire and having that higher Crr wipe out the aero gains from the improved wheel aerodynamics.
Of course, that doesn’t mean that putting tires on a wheel that are wider than the rim is an OK idea aerodynamically, 'cuz it’s not…in fact, I seem to have spent a good amount of typing over the past few days discussing “appropriate width tires” for a given wheel 
But, I don’t think that the difference in aerodynamics between, let’s say, a 23c vs. 20c tire on a deep wheel is the same as the difference between a shallow, high spoke count wheel and a deep, low spoke count wheel.
For example, Damon Rinard revealed some testing data from different width and type of tires on a 50mm deep Bontrager rim here:
http://forum.slowtwitch.com/...rch_string=;#1741343
Using that data, I back-calculated the aero component of the total drag for each combo…and the average aero drag difference (average of values at 5, 10, and 15 deg of yaw) between the RXLPro21 and RXLPro23 on the same rim was only 7g @ 30 mph…that equates to less than ~0.1 seconds/km at race speeds, or 4s over 40K. Although non-zero, that’s significantly less than what can be gained switching from a low profile wheel to a deep rimmed wheel, which can be an order of magnitude greater or more.