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new pedal on old crank won't work. why?(7 posts)

new pedal on old crank won't work. why?moschika
May 4, 2003 9:35 PM
i just bought a new pair of shimano spd pedals to go on an old pair of stronglight cranks. but they don't screw in. do i need special pedals for this crank? anyone running modern pedals on their old stronglights?

any ideas would be appreciated as the old pedals are literally falling apart.

thanks.
stronglight=french threads?wspokes
May 5, 2003 5:53 AM
Possibly the threading is French. I had 2 stronglights and both had french threads. Good luck finding spds in french threads, you may just want to re-tap the threads. Have fun!
how to tell?moschika
May 5, 2003 9:02 AM
so how would i tell? would both pedals be right-threaded like the bb? or is it a tpi thing?
tpi...wspokes
May 5, 2003 9:53 AM
TPI I think, I believe there is just a very slight deviation. You will know simply like I found out, begin to thread and...Hmmmm, why isn't this catching....It just doesn't catch. then you discover...oh it's french and therefore doesn't want to cooperate (sorry for the pun!) I can't remember if the french threads are smaller or not. I can almost guarentee this is the problem though.
re-tappingmoschika
May 5, 2003 12:52 PM
it seemed that they would thread in maybe a quarter turn then not go in any further.

i guess i'll have to take the cranks and pedals into where i bought the pedals and see if they can re-tap the threads.

Thanks
re: tpi...Sheldon Brown says...Straightblock
May 5, 2003 1:05 PM
French-thread Pedals

Most French bikes sold in the U.S. used standard thread pedals:
9/16" x 20 TPI (14.29 mm/.527" x 1.27)

But older bikes made for the French market used a slightly smaller thread:
14 mm x 1.25 (.551" x 20.32 TPI)

If your cranks are made for standard-thread pedals, a French-thread pedals will fit in, but be very loose and will be unusable. It is not possible to put a standard pedal into a French crank without considerable violence.

It is possible to re-tap French cranks to take standard pedals.
re: new pedal on old crank won't work. why?markkar
May 6, 2003 3:23 PM
Stronglight cranks typically had French pedal threading, 14mm x 1.25 as opposed to the British standard, 9/16 x 20 tpi. I have stronglight cranks on my fixed gear and had them tapped out so I could use Look pedals for around $10.
Find a good old school bike shop that has all the Campy frame tools. Pedals with the French threading are pretty much obsolete.