700c -> 650c on a Road Bike

[Eden]

I have a Fuji 44cm frame with 700's and 165 cranks. I've been informed by various sources that the setup shouldn't work at all and that the angles are all weird to accomdate the larger wheels, but it fits me to a tee. I'm short with shorter torso and arms than legs. I used to have a bigger bike and can stand over a taller frame, but I really need the shorter top tube. I have no overlap problems at all- I do have small feet - size 4.5 road shoes. As far as the crank length goes - longer ones would mess up my knee position which is pretty darn perfect now, so even if it wouldn't cause overlap I wouldn't want to change it.

I haven't ever had a bike with 650's so I can't say that I know what the difference would be like. I've heard that smaller wheels climb better, but you end up having to spin faster to keep up on the flats. I've also heard that you can compensate with the gearing. I would love to take one for a test spin someday just to see which feels better to me.

[doc]

Toe overlap is a hugely overrated problem. It only occurs when you turn the wheel a significant amount. When actually riding, one turns the wheel very little and uses a shift in weight to take a turn. Shoe size does affect the degree of toe overlap.
As for crank arm length, there are a lot of formulas out there. The one I see repeated the most is inseam (with shoes on) in cm x 2.14 = crank arm length in mm. Here are some websites:
http://www.nettally.com/palmk/crimplic.html
www.sheldonbrown.com/cranks.htm
and so many more...

[jcl]

JoHunter,
I forgot to mention that the Terry Bikes website has lots of good info on women's fit...
http://www.terrybicycles.com/cycling_savvy/fit.html

[summer]

I've got some similar fit problems to those here, although I'm 5'3" and ride a 51 time trial, so not really a teeny frame. I tried 650 wheels before I bought my bike (on 700s) and I didn't find much difference in practice in climb and acceleration; certainly not enough to make up for losses downhill and on the flat. One thing's for sure; don't put 650 wheels on aframe built for 700s. Nothing will work. Also, there's less choice in wheels and tyres for 650, and if you get into trouble on a ride or at a race it's harder to borrow kit. Try to borrow one first, before you commit.

I have a bit of toe overlap (I also have big feet) and I ride 170 cranks (I actually fit 167.50 but those are hard to find). Out on the road though, it's never been a problem, but maybe I just haven't turned sharp enough (although if you're turning that sharp you probably shouldn't be leading with you're outside leg anyway, for balance). best thing is to get a professional bike fit and then try to get your bike to match it as best you can. Custom bikes sound great, but I've heard of ther examples where frames didn't work so well (including a time trial bike where the rear wheel actually rubbed the seat tube because the cutaway was in the wrong place!)

Good luck!

[madisongrrl]

http://www.slowtwitch.com/mainheadin...650ctoday.html

[Nanci]

Interesting how he says his training partner who weighs less than the others descends faster, and credits this to 650's. I've also noticed my bike descends fast compared to others.

Nanci

[profàvélo]

Toe overlap is a hugely overrated problem. It only occurs when you turn the wheel a significant amount. When actually riding, one turns the wheel very little and uses a shift in weight to take a turn. Shoe size does affect the degree of toe overlap.

I agree with Doc that toe overlap is an overrated (and misunderstood) phenomenon.

The custom fit kit at Seven Cylces has an excellent explanation of toe overlap and how trying to eliminate it completely often means a sacrifice in the bike's handling. I would simply copy it here, but it's a PDF. I highly recommend that you read these few paragraphs (on page 7) before deciding that you must eliminate toe overlap at all costs, because there are probably costs involved.
http://www.sevencycles.com/order/CustomKit2006.pdf

[CycleChic06]

What exactly is toe overlap? Is that when you turn the wheel and it hits the tip of your toe?

If that's the case then I have toe overlap, but only when I turn the wheel at a wicked angle, which never happens when I'm riding. I think I'd kill myself if I turned the wheel at that kind of angle while riding.

[wabisabi]

My Rivendell is 52cm, and has actually 559 wheels (like mtb 26"s). Part of the iconoclastic charm of a Grant Peterson bike--he says you have to have those size wheels to avoid toe overlap and also have room for fenders.

Yeah, it is kind of a cult I've not had another good road bike, so I have no basis for comparison, but it's always felt just great to me.

One downside is that I have to carry my own tubes, and it was a chore to find tires that were 25s (Continental Gran Prix makes them).

[Triskeliongirl]

I agree with Doc that toe overlap is an overrated (and misunderstood) phenomenon.

The custom fit kit at Seven Cylces has an excellent explanation of toe overlap and how trying to eliminate it completely often means a sacrifice in the bike's handling. I would simply copy it here, but it's a PDF. I highly recommend that you read these few paragraphs (on page 7) before deciding that you must eliminate toe overlap at all costs, because there are probably costs involved.
http://www.sevencycles.com/order/CustomKit2006.pdf

FYI, while many solutions do effect bike handling (i.e. messing with the fork rake, head tube angle, fork trail, etc.) Georgena Terry's solution of a 24" front wheel does not effect handling. But, by using a 700cc rear wheel, you can still use gearing designed for a 700cc wheel. I have seen many women in my club hurt with TCO, and I personally won't accept a bike with it. Yes, when we cycle at high speeds we turn mostly with our bodies, but there are situations when one needs to turn the handlebars.