pstock

is there any reason I should not be able to use modern SPD pedals on my vintage Campagnolo Strada cranks? LIke thread pitch or diameter differences?
I would like to periodically use modern pedals on an Olmo / Campagnolo build but I am having a terrible time fitting either of two pairs of modern SPD pedals.
One won't started to thread on at all (or wants to go off on an angle) and the other fits but is very very very snug, I really have to reef down on it to get it on (though once on it seems straight)

the cranks are marked "9/16 x 20F"

And I have had enough trouble (not my causing) with cross threaded and stripped cranks that I don't want to force anything.
So, I thought I would inquire here first.

Peter

bikemig 

Have a bike shop chase the threads for you. It sounds from your description that the threads are a bit buggered on the cranks.

Pars 

My Campy NR cranks were tight (threading-wise) when I put a set of Eggbeaters in, but no problems. I think the threading back then was closer tolerance or something. They went in just fine. My vintage NR pedals still fit fine.

One hint: begin by turning the thread backwards to the thread direction, and wait for it to drop into the thread. You should be able to feel it. And always start by hand to avoid cross-threading.

Not a bad idea to have the LBS chase them either.

mrv 

I'll go +3 on chasing the threads. I've done this on several sets of cranks. One was a bike with '80s Campy Super Record (i think....) and my new SPDs would not go in smoothly. My LBS chased the threads, everything went in smoothly and stayed there.
Then a week ago I had a pedal come out while I was riding (different set of Campy cranks, different bike, different pedals than the first). I think I failed to tighten it properly. It buggered up the last few threads, so I had to chase the threads to clean the whole deal up. Now the pedals is back in place.... and tight!

pstock

thanks for the suggestions.
I should have added that a pair of vintage Campy pedals fit perfectly and easily. Not sure what the difference is but I'll do the chase thing.

mrv 

Bicycle Pedals -- types, installation, Maintenance.

The always helpful Sheldon Brown, if you want some history.

jyl

I had the same problem with a set of Campagnolo Super Record cranks from about 1978. A modern pedal would thread in, but with significant resistance. I had the pedal threads chased by my regular bike shop. A small, but visible, amount of metal was removed.

Some research turned up the suggestion that the older Italian interpretation of 9/16 x 20 thread was very slightly different from standard, something about the shape of the shoulders of the threads. After chasing, modern pedals thread in smoothly. The original pedals still threaded in fine.

After that I bought a set of pedal taps. The next bike I bought had French thread pedals, so the taps came in handy right away.

daf1009

+10 on the chasing...should make them go in without a problem...and...if you do it a lot, a set of taps is not too expensive...