I hope it’s pretty clear on the photo but I can show other angles if i need to, but the pedal keeps unscrewing (i think?)
I’ve only ridden it out once. When I was testing it with my sister, she went to ride it and pushed on the pedal but it fell right off. We put it back on after a bit of struggle and I was about to try and ride it but now it seems like it’s twisting off again. I think if I try to use it, it’ll fall off again but since we’ve already put it on after it fell off I’m not sure how to prevent it or fix it.
I’d just like to know if the pedals been put on wrong and that’s why it’s twisting, or maybe it was damaged when it fell off the first time? The bike is second hand and we got it without pedals so I’m not sure if it could also be the bike itself that’s damaged. I’d really appreciate some advice, thank you!
by tunkunk
9 Comments
Have you tried more tight
Surprised that it would do that. It should tend to tighten if anything.
A bit of medium thread lock might help.
Cross threaded
Pedals are specced for quite some torque. Like ~40Nm. With a normal length 15mm spanner you can really put quite some force into it. With 8mm hex keys (looks like yours don’t allow for a spanner) even more so since they tend to be shorter.
Install with grease so you can remove it at a later point. Usually they tend to seize up (or corrode), not come loose 😉 I guess you could also use threadlocker which would also prevent corrosion.
If it went in on an angle once, or was ridden loose for any length of time the threads in the crank arm are destroyed. You’ll need to either replace the crank or have a helicoil installed, there’s no way you can fix this at home without specialty equipment.
If you can screw it in by hand half way then the threads are prob still good. Chances are you just didn’t tighten it enough.
My friend put pedals on his bike borrowing my long handle pedal wrench no less and when I saw him a week later cause of another issue I went to swap his cheap plastic pedals and was surprised how loose they were even though he said they were tight.
So I would guess it’s the same issue with your pedals since using an allen key to tighten them you didn’t use enough force. Use a pipe or open ended wrench to get more leverage and tighten it up.
The thread on the crank arm is almost certainly messed up.
If you can find a good bike shop with competent mechanics, they should be able to fix it with a Hella coil. A less competent bike shop is going to replace the crank.
Firstly I would try to re-tap the threads just to clean them up, but make sure you are using the proper size metric tap, or you may as well toss it in the bin. Do it by hand too, running a tap on something like this with a drill will fuck it good n proper, after you re tap the hole, blow it out with some compressed air then take the metric die and do the same to the pedal if you see any knicks in the threads. Torque to spec after and it should be alright.
Just get it to a bike shop. They will cut in a ‘bigger’ thread, install a helicoil and charge you like idk we did this for about 15 Euros when the big boss was looking and for tips when he was out of shop or in his office.