Tell me the truth about wheel upgrades....

[Froze]

This thread went off on a tangent about tires, but the OP asked about the usefulness of wheel upgrades.

Aero tests show that the difference between the best aero wheels (ie, Zipp 808) and worst-performing wheels aerodynamically (ie, Mavic R Sys) is about 13-15 watts @ 50 kph. That equates roughly to a 0.5 kph difference in speed. Whether or not that is "worth it" is *completely up to you*. Smaller differences in wheel depth and shape will obviously have smaller differences. One thing that I can say for certain is that this difference is pretty much undetectable to human perception.

Having said that though, I'll gladly take that advantage in a TT, for example, as it could make the difference between getting on the podium or not.

For a non-racer is it necessary? Again, only you can answer that question

That was my original point that came out all weird but kind of on purpose! The difference between watts saved using expensive racing tires vs better wheels is nowhere near the same as you pointed out. Your not going to save 15 watts going from cheap tires to expensive ones, you might save 5 to 8 watts, and mid grade tires are the best deal because their cheaper the expensive ones and the watts lost is only about 2 to 3. And by the time you spend money on expensive tires that don't last as long as mid grade tires over the course of 40,000 miles you could have bought expensive wheels like the ones you mentioned and got a lot more watts in return.

But for a non racer expensive wheels is just eye candy with no practicable application, just as expensive tires are.

 

[campbellj]

But for a non racer expensive wheels is just eye candy with no practicable application, just as expensive tires are.

That's exactly what I was figuring. I do plan on getting into the local crits on wed. nights, but even then wheels probably won't make any difference being in the slow group at first. Everyone likes a little bling though, and that's all I'd be getting. I guess my biggest upgrade first should be my endurance and strength, then better tires, then wheels should be last on the list.

 

[tonyzackery]

That was my original point that came out all weird but kind of on purpose! The difference between watts saved using expensive racing tires vs better wheels is nowhere near the same as you pointed out. Your not going to save 15 watts going from cheap tires to expensive ones, you might save 5 to 8 watts, and mid grade tires are the best deal because their cheaper the expensive ones and the watts lost is only about 2 to 3. And by the time you spend money on expensive tires that don't last as long as mid grade tires over the course of 40,000 miles you could have bought expensive wheels like the ones you mentioned and got a lot more watts in return.

But for a non racer expensive wheels is just eye candy with no practicable application, just as expensive tires are.

Where are you getting your misinformation??? If you paid for it, you definitely should be demanding a refund...

Rolling Resistance of Bicycle Tires - Bike Tires

Especially for you to read and heed, and hopefully educate you about the truth wrt some tires being much fast/slower than others...and also consider this test didn't even include some bargain basement, no-name brand that you can buy for $15/tire - the difference is huge even amongst high performance tires...I can easily envision there being differences of 30+ watts between the high performance and cheapo tires...

Yeah, 30+ watts difference would only be significant for racers and have no practicable application for non-racers...

 

[alienator]

On the flats, where aero concerns are dominant, rolling resistance accounts for about 20% of the forces you have to overcome. On climbs, when the grade kicks up and speeds drop to less than 15 mph, rolling resistance becomes a much bigger factor, even overtaking aero losses.

Tests to derive Crr for tires have been pretty consistent, at least in the ranking order of tires. Some tests have shown differences in Crr of upwards of 100% between some tires.

Of course, there is debate about how accurate the tests are on smooth drums. On the road testing requires controlling quite a few variables to insure that you're really only testing Crr. Also, however you decide to inflate the tires throws additional uncertainty into the numbers. After all, no tire is exactly the same size, and of course construction varies between manufacturers. Actually, one good use of an iBike power meter is that you can use it to test for Crr. iBike, during calibration, calculates coefficients for a characteristic equation of motion, from which power is derived. Crr (and bearing drag and other drive train losses) is represented by a coefficient on the linear term of the equation. By doing a lot of calibrations for a given tire, you could derive an average value for Crr. By doing a bunch of tires on the same bike, you can remove the bearing and drive train losses, leaving only Crr (as a relative value).

Power savings from using tires with lower Crr may not matter to everyone (maybe not even all racers), but if a person is looking to spice their ride up, a bit, changing tires can be a pretty cheap thing to try.

 

[tonyzackery]

OP, obviously (to me and some others, anyway) tires are the way to go. Nonetheless, if you really want to get tricked-out and scientific, do that sneekiest method of decreasing rolling resistance (aka increasing speed for the same effort) which is universal across all tires - put more air in your tires...

I will admit bling (carbon wheels) are pretty cool though - I'll admit to having 3 sets...supposition has it that there's value in psychologically feeling faster...

 

[dhk2]

Froze, understand your point about shorter tire life on race tires, but doubt most racers who paid for deep CF aero rims wouldn't also spend a little more for the fastest tires to go with them. Obvious way to cover both bases is of course to have two or more sets of wheels and save the expensive, faster-wearing stuff for race days.