700c fork on a 650c frame?
 

So recently I picked up a Velovie Vitesse 500 for very cheap. the thing is its a factory defect, so only a 650c can fit on the rear. Its a 51cm but fits more closer to a 55cm.

I'm curious if I can put a 700c fork on the front, and still use a 650c wheelset just fine?

Am I going to have horrible toe overlap? what other complications am I getting myself into?...

Odds are you can get away with the 700s fork. Handling will be different, but it's impossible to predict if it's be different enough to be a problem.

However, the biggest issue will be brake reach if you use 650 wheel in a 700c fork.

it would help to know the nature of the defect. for instance, was the frame made for 700c wheels and the rear triangle is designed for 650c? or was it designed for 650c wheels and the fork is wrong?

or maybe you don't know? and can't find out?

is there a fork on the frame now? if so, what size?

Pics would be interesting....

Most jerry rigged bikes, to the degree that the OP suggests, don't tend to work well enough to stay on the road for the test of time. Unless the OP is of a body fit that is on the edges of the bell curve it's hard for me to believe that a weird bike will fit and ride well. Andy.

as an experiment, i once put MTB wheels (only 12 millimeters in diameter less than a 650c rim) on a bke make for 27" wheels. it rode noticeablly closer to the ground, but that was just a minor inconvenience compared to the severe "death wobble" steering effect at any speed above 10MPH. unbelieveably bad.

its a 700c frame, but as you stated the rear triangle had a defect of being to short so only allows 650c. I currently dont have a fork with the frame.

What sort of defect would prevent a 700c wheel from fitting a frame that is designed for that size wheel? What part of the rear triangle is too short?

well... hmmm, that's a problem. i suspect, and as mentioned, there's no way to tell for sure without what may turn out to be a failed and possibly expensive experiment, whether or not a 700c fork and a 650c rear wheel, or a 650c fork and two 650c wheels, is the better option.

if i had to guess i'd say matching 650c wheels. after all, the frame may be designed for 650c, seeing as how the rear triangle is obviously a 650c rear triangle. but it's just a guess. i hope the frame was really, really cheap. :lol:

to facilitate a 650c/650c test, i might look into borrowing set of old mtb wheels. they are readily available, can be cheap, tires can be had down to about 25mms, and a 650c fork will usually accommodate them. you may need a long reach caliper brake. i ran my 650c road bike for years on a nice set of mtb wheels. good luck to you.

i googled that frame and it looks like a nice one, it would be sad if it turned out to be unusable.

Most likely defect is the wrong word here. These are build as super tight frames for 700c wheels, and odds are that the issue isn't that 700c wheels won't fit, but that they'll fit only with tires smaller than 25mm (or less).

If you search for a photo of the frame or bike, you'll see the near zero clearance behind the seat tube, which is cut away to follw the curve of the wheel, with no room to spare.

The difference in diameter between a 650c wheel and a 700 c wheel is 51mm, which would drop the bottom bracket by about 1" and also increase brake reach by the same amount

Put a 700c fork and wheel on the front like it was designed. Then modify the rear to take 700c. There are tons of cheap 1 1/8 carbon forks on ebay you can strip and paint.

Interesting. Especially since the wheel base didn't change. I am currently in the middle of a build using a mid 70s Schwinn frame and fork. It's designed for a rim/tire combo that measures 26.65 inch diameter. I'll be using 700c rim/tire combo that'll measure 28.14 inches in diameter. I wonder what surprises are in store for me. :)

I once bought a bike for my son that had a rear triangle so tight that you had to deflate the rear 700 x 23c tire in order to get it past the chainstays. If you have access to the bike see if you can mount a 700 wheel and tire by deflating the tire and tube.

I suspect that was on a bike with horizontal dropouts, and it was a fairly common on super tight bikes BITD. I credit this issue with contributing to the current dominance of verticals which usually have the slot aligned (very slightly back pointing) to solve that problem.

I suspect that old Schwinn was made around the 597ISO rim diameter. A pair of narrow 700c wheels and tires won't be too much larger in diameter and the fore/aft balance will remain the same. Although the rotating masses will be far different. Andy.

Yes, 597, but the 700c replacements will not be narrow. Total diameter increase will be 38mm. I'll be forced to partially deflate the rear tire for removal and installation.

No, vertical dropouts, Specialized Allez 9-speed, about 10 years ago.