A friend of mine is in the market for a new triathlon bike, so she went in for a bike fit. The recommendation, which was from someone with a background in road cycling, was to switch from a bike with 650c wheels to 700c wheels.
My friend is 5’ 7" and I think that at this height a 650c tri bike would be optimal. I could understand this recommendation if she was taller, say 6 feet. Also, she spent $250 for the bike fit, so she feels obligated to follow the advice.
I know much has been written and debated on this issue. I’ve been searching for articles, but couldn’t find the exact information I was looking for. Didn’t Dan write some articles on this subject? Can someone point me to some links to the articles on the subject, please? (At what height a tri bike with 700c vs. 650c would be optimal?)
Thanks!
I’m not a bike pro…so take it with a grain of salt…but I have been struggling with the same thing. I, too, am 5’7" and have used both a 700 and 650. I think it depends on the course as well as your size. Longer distances, she might be happier with a 700 (harder to get rolling, but once it’s rolling, it easier to keep it rolling…). But for hills and shorter distances, I like the 650 - it’s easier climbing and a more aero bike for the short stuff, although maybe not as comfy as a 700 for IM distance. I’m going to try the 650 for IM CDA because of the hills on the course…hopefully I won’t regret that.
I’m sure Tom D will say something similar, but you want to make sure your fitter has experience fitting triathletes. If he or she has only fitted roadies, you might want to look elswhere.
If she is 5’ 7" and wants to be setup for triathlons, and wants to ever have chance of being aero, then 650c is the only way to go. With 700c wheels, it will be difficult for her to achieve a flat back. I’ve been there so I have first hand knowledge. I am 5’ 8" with a 30" inseam (short legs). The headtube on 700c frames is too long so I never could get enough drop in the front end to get aero. But it really depends on her riding style and goals. She may want to ride more upright and not low and aero. I have training partners that are my height riding 700c frames and they do fine. They’re just not low and flat. Their saddle is almost the same height as their elbow pads.
Height is not the only thing to look at when selecting wheel size. You’ve got to look at the overall fit. For instance, I am 5’8" and most “tri-wisdom” says I should race on 650C. But I use 700C because my inseam is 33.5" and I have plenty of drop from saddle to bars. On the otherhand, my brother is 5’7" but his inseam is only 31" so he went with 650C.
Opposite end of the scale here. I am 5’10" and have rode 650s since 1997 on four different bikes. It is what I am use to and love them. I know weight isn’t suppose to be a big factor but I do like to be as light as possbile and a 650 wheel/tire combo is lighter. I have a Litespeed Blade and a Cevelo P3 with 650’s on both.
I too am 5’7" and ride a 54cm 650C bike (Cervelo P2K).
Here in Godzone tires can be a bugger to find but the internet fixes that problem.
Remember, after all is said and done, on a 650C bike you will look bigger! and therefore more intimidating rather than look like an ant with 1cm of seat tube showing on a 700C bike!
I am 5’8" with a 30 inch in seam and ride a 52c P3 with 700 wheels and fit fine with plenty of the seat tube still showing and definitely wouldn’t want any shorter top tube.
As far as being more aero there really isn’t that much difference as the head tube length on the 700’s run shorter than the 650’s. It just comes down to what you’re more comfortable on. So ride both and you decide.