Originally Posted by
old's'cool
"I want to install clip-less on my sixties
Peugeot PX10 but the cranks are 1/2" French thread. I did purchase a new set of 9/16" pedal taps but have not had the courage to use them yet. I certainly have the skill to tap a set of cranks. The problem is, do I want to destroy the original nature of these lovely old 49D cranks?"
You know, you could tear down the pedals and take the spindles to a machine shop and get them to cut the pedal threads down to 1/2". Possible issue could be the material hardness, the shop should be able to figure out if its doable or not before starting.
Don't do this. If the cranks are really French thread (and they probably are) then they're metric and should be 14 mm. Should be easy to tap them out to 9/16" for compatibility with current pedals. The pitch of the two threads is almost identical (20 TPI or 1.27mm/thread vs. 1.25mm/thread) and the diameter is also very close (14.3 mm vs. 14 mm) so the tap doesn't have to do much.
I switched from clips and straps to SPD MTB pedals. Didn't notice any performance advantage, but there was improved comfort on long rides. The clips and straps would push down on the tops of my feet and start hurting after 50 miles or more. The shoes I wear with the SPD pedals are very comfortable for walking and I've even used them on some extended hikes. Never had an issue with being unable to get my foot out of the clipless pedals in time but did have a couple tumbles when using clips and straps.