Stripped second set of cranks in a row - what can help?

Hi, I have a Nimbus Trials unicycle. I bought the thing and have ridden it with stock parts very very hard for about a couple of years. I did not have to touch anything. The unicycle saw some heavy use and abuse on the mountains and doing (attempting to do) tricks for a long period of time. Then i moved and did not have much time to ride. By this time the tire was wore out. I bought my first and only replacement piece - a new tire - and had it put on at a pro bike shop. I started unicycling out on a trail and after a while the right pedal started to lump. I had stripped the hell out of the threads. The threading on the crank and pedal were completely melted. I did notice that this started up after i ate it really hard too.

I tried JB Welding it in but that did not work. The JB weld broke before i even got one block.

So i ordered replacement parts
- i think i bought these in the proper stock size
- and these which are the actual stock pedals

I took it to the same pro shop and had them put it together for me. They used some lock tight greese of some sorts and everything. Afterwards i probably got in about 1 day of good riding. The next week i was at the beach and i felt the lump in the right pedal. I got off ASAP and luckily there was a bike shop near by. he tightened the pedals down real good and tight, but it was too late… within the hour the pedals were totaly melted. Sadly the setup was pretty new. I had only ridden on them here and there and then only did one serious day of doing tricks and crashing etc… the slightest fraction of what i put the original unicycle through!

Is this unheard of? Did i just get unlucky the second time around? Could the bike shop be messing something up?

Also what would be a good set of cranks and pedals so i dont burn through equipment/money like this?

Thank you

seems like that tire created some bad luck

What do you mean by “melted”? Could you post some pics of the damage?..Unless you crossthreaded or put the wrong pedals on the wrong sides both times then they should have been fine. Pics of the cranks and pedals threads would probably help identify the problem.

And on a side note, you are far better to ask here and correct the problem yourself than to take it to a bike shop…IME they kno jacksh*t about unis and ussually dont care.

It sounds like the threads got mized up. I had a friend who had the left pedal on the right and right on the left, and it would loosen after every 20mins until I looked at it and realized they were on wrong.

Look on your cranks, they will have a marking that says L or R. Have the R on the right side of the uni, L on the left. Now, look at your pedals, they will have the same R and L indentation. Make sure the R pedal is on the R crank, and the L pedal is on the L crank.

melted? im not sure what you’re referring to.
unless you have the pedals on wrong or something i have no idea why they would break just during normal riding.

it’s doubtful the shop messed anything up. unis are pretty simple compared to bikes and there’s usually a guy or two who know how to uni and are competant to fix them. we need pictures of the damage to tell you what happened. from your description you either got really unlucky or royally crossthreaded/otherwise damaged your cranks/pedals before they “melted”/.

hmm, its so easy to not notice that your pedals are loose, and then just keep riding and wear them out, then they start to wobble and by that time the threads are smashed(usually ruined) ppl, make sure you tighten your pedals… mine on my dx came loose and I luckily it just unscrewed itself on the way to the school because the wheel was on backwards

and I did that to my cheap uni too
I got the strongest Epoxy that I could find and smeared it in there (there is no air anywhere in the thing and it is holding up quite well, make sure you clean it very well, maybe fill up a cup w/ rubbing alchohol and swish it around in therethen wipe it off very well

im out… see you guys later

or the wheel was installed backwards after the tire change.

That was the first thing I thought.

wheel’s put on backwards… pedal starts to come loose… wooble wooble plink… stripped threads… crank no good… buy new set of cranks… wheel isn’t removed and flipped around… new cranks installed… pedal starts to come loose… wooble wooble plink… stripped threads… crank no good…

fill it w/ epoxy and try that :slight_smile:
if that doesn’t work then thread the crank and put a set screw in there and tighten it reallly tight

oh man! I posted this at work. I just got home and looked at the lettering. I’m pissed off at 2 people.

  1. i told the guy 4 times to mind the left and right. I told him over and over pointing at the letters as i pulled them out of the packaging till it was embarasing and he was like like “yeah yeah i got it” and i felt like i was telling him he couldn’t do his job right.

  2. i’m pissed off at myself cause afterwards i just didn’t think to check it.

obviously the damn left and rights were swapped. Never again! Looks like i better invest in some tools and do it myself next time. Its like that one guy said. They just don’t know and/or give a shit.

Sorry about the “melted” term. The threads shred and shave off until theres nothing left and all the threading is mashed down. if you keep going it runs it so flat you can just about yank the pedal in and out of the hole.

what kind of cranks/pedals did you have? I hope the weren’t very nice…


sounds like a case of royally cross threadded pedals. i could be wrong though.

i have links at the top. they were cheapies… 25$cranks 15$pedals

the right pedal is on the right crank. the left pedal is on the left crank… but those units are swapped… so i was loosening them while riding. They get munched REALLY fast that way…

Take em back to the shop, and tell them that they put it back together backwards, and it’s broken because of that.

They broke it, they should pay for it to be fixed this time.

But you’re right, next time get a crank tool and then you don’t need to deal with useless bike shop employees again. If you’ve ever looked at unicycles in bike shops, they seem to have a 50/50 success rate of putting the wheels on the right way round, it’d be incredibly rare to find a bike shop that you could trust your uni to.


Some cranks use 1/2 threads and some use 9/16. If they’re 1/2 have them drilled and rethreaded for 9/16. If they’re 9/16 you’ll have to either replace them or try and drill them out and have a helicoil (sp?) installed to the correct thread size. Epoxy ain’t gonna work… the helicoil usually doesn’t work for long either.

I’d go back to the same shop and explain to them what THEY did. The wheel was installed backwards to begin with. Then they installed the cranks backwards AGAIN! You shouldn’t have to buy TWO sets of cranks for there screw ups. And in the furture always look for a shop with a USCF Certified Mechanic. Not that they won’t screw up sometimes but they should at least know better.

how about any non-moronic mechanic should know better? that sucks. i’d definitely go back and bitch and if they give you any hassle go to a differnet shop.