menelaos

is it possible to change the wheels from an on an old peugeot from 28 to700 without having to make changes to the brake bosses or some other major change?thanks

meb

I've tried 650C rims on a caliper equiped mountain bike without modifying anything, the braking is reduced some due the pad-rim strike angle.

You've probably got enough adjustment on the brakepads to get the rim diameter seating adjusted the 6mm you need, but it is close. That is about the same rim diameter change you are making that I made. Harris Cyclery sells drop bolts for 27 to 700 conversion, should your diameter adjustability be insufficient, that is another option:
www.sheldonbrown.com/dpdropbolt.html


I suspect the seat angle at contact will have the pads mating at an angle with the rim with the pads striking the rim inner diameter first. Should be more pronounced with your wide-V to narrow boxy rim profile than my change.

dafydd

what type of brakes do you have? 28" usually means rod brakes, for which you need a specially shaped rim.

menelaos

not sure about the brakes but i only have the frame and wheels so the rest is on me

Gonzo Bob

28" is sometimes synonymous with 700C (622mm bead diameter). I have many sew-up tires for my 700C wheels that say 28" on them.

meb

I considered that possibility but since he said old and swap, I figured he meant 635 roadster wheels rather than 622-else there'd be no reason to convert.

If some 700C actually have 28" on them that muddies the water some- maybe we need further clarification on what 28" tires he has.