A place to ask bicycle repair questions, and for bike shop monkeys to share advanced non commercial wrenching resources (no YouTube self promotion). This is only for repair related topics.
The photo was from a site that no longer seems to be up. The pedal on the right, measuring at 15.7mm is the same size that the pedal on my indoor spin bike uses and I want to use standard 9/16 threaded pedals instead.
Has anyone come across this size??? Do adapters exist to step up standard 9/16 to 15.7mm?
The pedal on the right seems to have some sort of adapter on it? If you can't find anything bike specific you can get general purpose coils (helicoil i think? ) for for bolting stuff in oversized threads , no idea if that will hold up probably not great if you need to remove them often.
If you can’t find anything bike specific you can get general purpose coils (helicoil i think? ) for for bolting stuff in oversized threads , no idea if that will hold up probably not great if you need to remove them often.
I didn't know if that might work, but thanks for the suggestion. I don't plan to really take the next set of pedals off, unless for servicing, so this might be an option. Never used them before, but know of them.
I think the right pedal has a Unior thread adapter on it. These are used to repair a stripped crank arm. When the 9/16"x20 threads strip out you ream the hole and re-tap it with a 5/8"x24 thread, then and use the adapter to make the pedals fit.
https://uniorusa.com/products/pedal-thread-inserts-10-pieces-set-right-58x24
What this guy said
Very interesting! Now that I see it, I can't unsee it! That's pretty interesting, but I think finding a solution is either going to be too expensive or just not worth the effort. Maybe I'll see if I can just remove the crank arms and put on a standard pair!
Unfortunately, this might not be easy to find a solution for. The larger thread size doesn't seem to be a standard bike pedal thread, so finding a specific adapter is probably not possible.
Another solution might be to use some kind of threaded inserts in the cranks (this would probably require drilling the cranks out for a larger thread). But the standard pedal thread of 9/16-20 is not widely used anywhere else, so finding the inserts (let alone a left-handed ones is probably next to impossible.
You can use one of these to determine the thread type
https://www.amazon.com/ChgImposs-Imperial-Whitworth-Industrial-Measurement/dp/B07J9V9JTK