Bicycle Mechanics - Old pedals still good after rethreading cranks?

Hi all,

I've been rebuilding my old '74 TdF Gitane. Everything is clean, greased and running fine now. The bike still has its old Ti clip pedals and I want to replace them with Speedplay X3 taken from another bike. The French thread on the cranks is 14 mm x 1.25 while the Sp pedals are 9/16 x 20 tpi. I can get the cranks rethreaded for the Sp, no problem.

My question is : after rethreading, will it still be possible, if need arises, to put back the old pedals without rethreading to french thread ? I fear the new ISO thread will be too big and the old pedals come loose... Or am I just drinking too much Porto ?

Your old pedals will never fit again. Sell 'em on eBay or swap here on BF (C&V trade sticky) for something you need.

And good choice on the TdF

Tx Bob for your answer but it was a stupid question... I tried it, putting one of those old things onto my new bike. Well, it's not a perfect fit, the pedal is a little loose but it should hold just right with some grease and/or loctite and elbow torque.

I would not gamble with it, if it does not fit just right (as in the threads match exactly, not just close enough with some glue) I could come off at any time with disastrous results. Nowhere near worth the risk involved.

9/16"x20 ~ 14.3mm x 1.27, so it's not a huge difference, but imagine stomping on those pedals up a 15% grade while standing, and that pedal flops out at the top of the stroke. Hope you're wearing a cup.

Don't do it. You can ruin the threads and then you'll be looking for a new crankset. Aluminum threads are easily ruined. It will be very expensive to replace it with another Stronlight 93.

Well, after reading your comments, I guess I will have to put up with those ti clip pedals, after all.

Thank u all...