Wheels 650 vs 700
Well It's ptobably a little late for this question b/c I've already bought my bike, but I have to know more.
I am 5"4' about 120 lbs at my heaviest. Last year I raced a Specialized Dolce road bike with 700 wheels. When I got fitted at All 3 Sports this past Christ mas my best choices for bikes that fit me were a 54" Cervlo P2 (650), or a 54" Quintana Roo Dulce (700). I decided on the Cervelo, b/c it had better components. I raced Kansas last weekend on it and I'm racking my brain as to why my time was slower by 10 minutes (obviosly could be many things). Raced on the Specialized last year. I didn't even consider the difference in tires when I was making the purchase but later learned from a friend that b/c the circumfrence is smaller I'm going less farther, with the same power. But also pushing larger wheels could wear you out. faster.
So what the difference between the two,
Thanks Jessica
Comments
First of all I am shocked you are on a 54cm bike at 5'4". My husband is 5'10" and on the P3 54cm with 700 wheels. I am 5'2 1/2 and on a 48cm P2C with 650 wheels. We just looked up Cervelo bikes and 650's only come on the 48cm.
I am curious to know if there is a power difference/speed with same power difference between wheel sizes. So far I find the bike to be blazing fast.
If you are truly on a 54 and only 5'4" you may be having trouble getting in an aero position??
Just some thoughts.
I've been riding a 650 since 2000. Of course, given the same gearing (say, 53/12), each pedal revolution will move the bike 7% less than the same gearing and rpm on a 700. Even so, I don't see how that translates into "going slower with the same power." Power basically represents the work done to overcome air resistance, gravity, and tire/road surface friction. None of those factors are affected by the radius of the wheels. (Maybe smaller wheels have slightly less air resistance?). I go way faster on my 650 TT bike than on my 700 road bike, due mainly to a much more aero profile.
While lots of reasons are given for the value of a 650, the only one that makes sense to me is smaller wheels allow a lower front end, making it possible for shorter persons to have a good TT position, which might not be as easy, or even possible, on a 700 bike for someone of your height. (I'm about at the upper limit of height which can take advantage of this - I'm somewhere between 5'9' and 5'10", and getting shorter every year.)
The biggest problem I have with the 650 size is finding wheels, tires, and tubes - much harder and fewer options.
In heels
tom