so, here's the question-

I am doing a conversion. What is the difference between putting 700 c wheels or 27" wheels? is it simply about brake adjustment? what about chainline. thanks for the help...

zgjd

the difference is 8mm of diameter,
if your frame is a 27 inch, your brakes have to be able to adjust ~4mm further towards the wheel center. if your brakes have enough reach, there is should be no problems.
also you gain a bit of frame clearance for fenders etc.
chainline would be the same as long as the hubs were the same width

yeah- its a 80's puch. made for 27" frame. so, you would say no rear brake, no problem??

anyone else? any reason you wouldn't use 700 c??

I would add that if you do this conversion, you need to watch your brake pads as they wear. I had good brake alignment to start, but as they wore down they actually rubbed against the tire. This is because they meet the rim at a more severe angle. Needless to say I was lucky that I was signifcantly slowed before the front tire popped.

well, no rear brake no problem in the rear,
if your planing on running a front brake, you need to make sure it'll reach.
if it won't, you can always pick up a long reach caliper, they don't look as sleek as the better dual pivots but they'll do the job.

ok- one more then- what happens if i switch out the rear and not the front? wierd?? or not much of a difference /

oh, and what if i use a 20" bmx wheel (kidding)

thanks for the help

well,
those 4mm can be compensated for by tire choice.
really, if its posible for you to get your hands on a 700c wheel and put it on your frame to try out.
personally i don't notice much of a difference. one of my friends bike has a 700 rear wheel, i rode it for a weekend and it didn't matter to me.