how to check pedal size

hey everyone

I recently snapped my pedals so I put my old torker cx pedals on my nimbus cranks. Now that my cranks are stripped I’m curious as to whether these pedals are the wrong size. But I don’t know how to check. any ideas?

edit: I did have them on the right side because only one crank stripped.

There are two main sizes for pedals that I know of, 9/16" which is the main size that unicycles use, and 1/2" (slightly smaller diameter more commonly used in BMX racing I think). You can be pretty sure that your pedals aren’t 1/2" because they would be so loose in the threads that you wouldn’t be able to ride. Pedals unwind when you ride backwards, or ride forwards with the wheel backwards (if you get your frame/seat on the wrong way by mistake) and that can cause them to get stripped if you don’t notice it happening in time to tighten it. Tighten them as soon as you feel them wriggling or wobbling.

Both of those are 9/16". I bet you either put them on backwards (the left pedal will have a “L” and/or the right a “R” somewhere on it), or let them get too loose from riding backwards, idling, or having the wheel on backwards.

I’ve had one pedal loosen to the point that it practically fell off and the other one was still very tight. Luckily I didn’t strip the cranks.

Your crank may not be stripped too badly. Put some new pedals on w/ some Locktite on the striped side (making sure the right IS on the right and you put it back in the frame in the correct direction). If that doesn’t work, take your crank off and take it to your school’s machine shop. Ask the teacher help you drill it out and install a new insert.

You need new cranks

All uni pedals are 9/16, that I have seen. If your alum cranks are really thread stripped, you need new cranks.

There is no harm in trying plastic metal (JB weld etc), it might hold until you get new cranks, if you are easy on it.

old cotter crank schwinns are 1/2 I’m pretty sure

edit: oops surfer1024 on my friends comp

how come they stripped though, the right pedal was on the right crank and the saddle was pointed the right way.

edit, how can the wheel be on backwards?

you can put the wheel backwards in a uni frame very easily, was your right foot deffinitely on the right pedal?

Bad idea.

You can take it to a bicycle repair shop and get it done right for as little as $5.

wait, so you can repair stripped cranks without buying new ones? How!!!

By drilling out the hole, threading it and then screwing in a threaded insert. Can’t believe there’s anywhere that will do it for less than the cost of a pair of cheap cranks though.

I realise that the ads at the bottom of the page change regularly, and are based on content, but I thought I’d screen-shot this as I think it’s the most accurate one I’ve ever seen on here.

(Hope it comes out ok after being resized.)



spencer, don’t tell me you’re not using firefox?

You need extra metal

Cheap cranks won’t have enough metal around the insert to hold IMHO.

It takes an hour to remove the crank, install it in a vise under a drill press to bore out the old threads, twist in the thread tap for the insert, install the insert,and reassemble the uni. It would be a pain to do yourself, and the cost of the insert plus tool wear would be several dollars. Plus $/hr. labor in your town.

IMHO, if you have stripped the threads in a cotterless crank, put a cheap pedal in with plastic metal, ride it easy, and order new cranks.:wink:

Much better then a thread insert to fix stripped cranks would be to weld the hole closed, then drill and re tap it.

The labor cost would buy you at least 5 pairs of excellent cranks. :roll_eyes:

An even easier thing to do would be to just weld the pedal in place. Ok, so you won’t be able to get it out again, but if the crank is hosed anyway, then the cost of a pedal isn’t exactly going to break the bank.

Ummm… too many double negatives for brain to comprehend. Yes, that’s Firefox.


oh, the ads never appear for me in FF