How do I stop stripping cranks?

[tambourineman10]

I've been riding for a couple years (on a torker cx) but only got serious a few months ago when I started doing some low-key trials riding. After a couple weeks of hopping I noticed my left pedal was a little loose, and a few days later it fell off. The crank was completely stripped so I ordered new cranks (I believe they were the torker LX cranks from amazon) and had them installed at a local bike shop. Today (about a month and a half later) I noticed that the left pedal was again coming lose. I stopped riding immediately and brought it to a bike shop to prevent further damage but they told me it was too late and I had already stripped the crank again.

I'm going to keep riding until it actually falls off but how can I keep the cranks from stripping so fast (or at all) in the future? The people at the bike shop seemed to think there was nothing I could do about it but keep buying new cranks every few months. Reading through some other threads suggested that the cranks were on backwards (which sounds like a mistake I could have easily made myself) but I doubt the bike shop would have done so. Also the bikeshop I took it to today is different from the first one and they didn't notice anything out of place.

Should I buy higher quality cranks? Tighten the pedals after each session before they get loose enough to strip the threads? Any input would be appreciated.

P.S. As you can probably tell I'm not very mechanical, but I'm working on it.

[hobo_chuck]

i would keep everything nice and tight...you got a spanner??

heeey nice post #1 and you don't have the standard"confused newbie" thing under your name!!!

lol

[thejdw]

you could get a better unicycle , your pedals may be bad. I'm not sure on the strenth of those cranks.

[hobo_chuck]

he probably meansWITHOUT getting a different uni....

you should probably get an allan key set and a spanner.....

[thejdw]

Originally Posted by hobo_chuck

he probably meansWITHOUT getting a different uni....

you should probably get an allan key set and a spanner.....

getting a new uni solves all hahaha , but costs alot.

[tambourineman10]

A new unicycle is a possibility, I've been considering getting one more suited to trials riding, but I don't want to invest in one unless I'm sure it will solve the problem.

Yes I have a spanner, I'll be sure to keep the pedals tight in the future.

If the strength of the pedals is in question, why don't I get new pedals instead of a whole uni?

Yes the problem did start when I started riding backwards, I just assumed it was the hopping that did it since it's such a higher stress situation, that the pedal would start to loosen and then strip the crank. What goes wrong when you pedal backwards without loctite? Why does only the left crank strip?

[tambourineman10]

I also assumed that the left was stripping because that's the foot I idle with and do the most controlling with in general. Hence my current idea of spinning the seat around and riding with the uni backwards to even out the wear on both pedals.

[john_childs]

It is possible that it's a low quality pedal and not the quality of the crank that is causing the problem. I've had a cheap pedal where the pedal threads were undersized. No matter what you did that pedal would come loose.

The only way to fix that is to get new pedals. Preferably pedals that have higher standard of quality.

If a pedal threads in too easily then the threads may be undersized.

If you get a bike shop to put on the new crank, tell them your concern that the pedal thread may be undersized. They should be able to tell if the pedal is threading in too easily. If that's the case then get new pedals.

[forrestunifreak]

Originally Posted by thejdw

you could get a better unicycle , your pedals may be bad. I'm not sure on the strenth of those cranks.

It's not the unicycle. Under normal use it should hold up just fine if put together properly.

[feel the light]

Is a cheap liquid plastic that hardens overnight into a gummy thread glue. A couple drops will fix you up for 10 cents. It will not lock the pedal tight. That is what red loctite is for (permanent assembly). The pedal will be easy enough to remove later as long as you get the blue stuff.

[SNES350]

I'm going off topic here, but if I ride backwards 50% of the time (practicing my backwards riding, not just randomly riding around), should I loctite my pedal threads? I rode 50% backwards for a few consecutive days and just haven't been able to ride since (due to injury).

[john_childs]

Originally Posted by SNES350

I'm going off topic here, but if I ride backwards 50% of the time (practicing my backwards riding, not just randomly riding around), should I loctite my pedal threads? I rode 50% backwards for a few consecutive days and just haven't been able to ride since (due to injury).

Probably not necessary. Would depend on the quality of the fit of your pedal threads in the crank.

I have never Loctited my pedals and I Loctite everything. It just has not been necessary on any of my unicycles.

Check the pedals and if you ever notice them loose after backwards riding then Loctite them.

If you do Loctite them you'll need to clean out the threads to get rid of the grease. Use some degreaser and make sure all the grease and dirt are gone. The grease and dirt will prevent the Loctite from getting a proper bond. Then use enough Loctite that it can act as a lubricant in lieu of the grease.

For a thread diameter as large as a pedal thread the red "permanent" Loctite is not going to be permanent. You'll still be able to remove it with hand tools without undo effort. The larger diameter the threads the more leverage you'll have on it and the easier it will be to break the bond. Use the red Loctite on a small diameter thread and it can be effectively permanent.

But red is overkill for this purpose. So use the blue medium strength.

I've heard that people doing backwards world record distance rides will swap things around so that the right crank is under the left foot. That way the pedals don't come undone during the ride.

[feel the light]

By going to the auto parts place and buy blue loctite. Install your new cranks yourself, noting the one marked L goes on the left.
Install your pedals with blue loctite on the threads and screw them into the cranks. Note that the left pedal screws in counter clockwise and the right clockwise.
You started pedaling backwards and it's the left crank that stripped right? If your LBS had put loctite on this wouldn't have happened. But people rarely pedal their bikes backwards !