- Crank arm "rounded thread"
If anyone is interested I have the old cranks set and just tried the pedal screwing it the correct way and what would you know it works fine. The robbing barstewards, been using them for years aswell.
Now could the ed please delete the thread to save my blushes (wishful thinking perhaps)Posted 4 years ago
During my ride today it felt like my pedal ‘chain side’ hit something hard and and broke, although there was no rocks or anything about. Turns out the internals of the pedal gave up, which isn’t really a problem as I have been using some older spd m505’s just while I get used to spds and was planning an upgrade very soon anyway.
However when I took the pedals off the one on the other side was very very tight and now it seems the thread is rounded as no pedals will screw in, I’ve only lightly tried as dont want to make things worse.
The problem is I’ve got a new set of deore cranks on there and I will not be pleased if I need new cranks again. They were fitted by my local bike shop. Would them being over tightened of caused any damage?
Do you guys think there definetly rounded from my probably quite confusing post. I was going to order some deore xt’s online and fit them myself, but would it be wise to buy through the shop and ask them to fit so matters are not made worse.
If it is definetly rounded is that game over for the cranks?
Sorry for the long and waffled post but any advice would be greatly appreciated.
Ps forgot to mention the last crank arm was also rounded when I got the bike hence why I bought new ones, could the pedals be causing some upset? Although the bike shop seemed to fit them on okPosted 4 years agosteviecaptMember
buy 2 pedal taps, or if you know a friend who works in a machine shop use theirs, ive done plenty for friends as ima tool maker by trade and have access to a engineering work shop, just make sure you use the left hand thread tap, on the non drive side crank, cheers stevePosted 4 years agomick_rSubscriber
I’m guessing you mean a stripped thread not rounded. Was it tight to loosen or tight all the way out when unscrewing?
Do the threads on pedal and crank look good or are there missing sections of thread or bits where the top of the thread is flattened?
If the pedal thread is undamaged, maybe try screwing the pedal in from the reverse side – it might clean up the crank thread a bit and allow it to start from the correct side. If it OK most of the way through from the reverse side then a quick clean with a pedal tap will probably work.
If it is properly trashed then there are various helicoil and bushing pedal thread repair systems about – a good bike shop should be able to rethread them if just a regular aluminium thread (i.e. if there isn’t already a steel insert).Posted 4 years agoGreybeardMember
You say that the pedal won’t screw in – I’m guessing you mean that the thread won’t engage, not that it screws in and keeps turning (which would be a stripped thread). Failing to engage is usually due to either the pedal thread or the thread in the hole being damaged. If the pedal screws into your old cranks, it’s probably OK, so as suggested above, try screwing it in from the back of the crank to clear the thread in the crank.
If you have any other pedals, try them on the crank – which should help test which is the problem.Posted 4 years ago
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