Problem with Nimbus Cranks, is this common?

Unicycles and Equipment
1

I am working right now at a Unicycle Camp in California, alot of my students have the nimbus trials uni.

The problem is that on the right hand crank the pedal is stripping the threads from the crank. All of these unicycles are less than 4 months old and have not been ridden hard at all. They all have qu-ax cranks on the uni.com cromo hub. It has crossed my mind that perhaps the pedals may have been cross threaded and that riding on them for a while may have caused the crank to strip out all the way.

Is this a major problem for other people too?

Is there a bunch of defective cranks out on the market that have been recalled?

You can probably imagine that these students are very dissapointed in their new unicycles, I would like to try and help sort out the problem if it is possible, but I’m not sure that just putting re-tapping the crank will help. Should I contact unicycle dot com and see if they can do anything, or should I just tell my students to buy a new set of cranks.

Thanks for your help guys

Mike

2

Hello…
You are talking about the nimbus hopley with the quax cranks right ?

so… i bought one of the hopley and i got it for a month i think… riding hard since i got it…

i did some searchs on the forum and this problems look to be normal on some splined cranks…
After a lot of searchs, and a clean up on my uni the problem just stayed boring me…
i contacted the udc and they said to i put some LocTite on the cranks thread.

I loctited my thread and its look a lot of normal now… i was having to thigten up my cranks like 4 times on a 5 hours riding.

Loctite or threadlocker is like a glue for threads and works perfectly.

One of my question to the udc was.
If i loctite my cranks… it will be stucked forever?

they said that you can take off the thread by aply some force .
Some guys here at the forum said that if heat the thread the loctite will loose the power.

3

I think Chex is referring to non splined cranks. Make sure they aren’t riding them backwards.

4

the nimbus trial uni dont have splined cranks

checkernuts take a look at this topic about cranks… i spoke about my problem there

5

He seems to be referring to non splined cranks made by qu-ax (those octogonal ones I’m guessing).

6

Yea, these are all square tapered cranks.

The problem is not with the crank comming loose, but rather it is with the pedal interface.

I am sure that these kids are not riding them backwards that is the first thing I checked. Also I do not think they started riding them with loose cranks. While loctight may help things from comming loose I do not think it helps with threads getting stripped out from normal riding.

Due to the large number of unicycles that I have seen with this problem (5 of them here at camp) it leads me to believe that there is something wrong not on the part of the rider, but a problem in the equipment.

Please let me know if anyone else has stripped a pedal from one of these unicycles.

Cheers
Mike

7

It could be that the cranks are on right, but the pedals are on the wrong side.

It does seem like a defect though. Its kinda hard to believe that about 5 unicycles of the same make, would all have the same problem.

8

have you posted this thread twice?

To put a pedal into the wrong crank requires a certain amount of stupidity and brute force, as you are using the pedal to tap a new thread into the crank. So is much more likely they are both wrong

Remember to check the left and right are correct when the bike is the right way up, not upside-down

jim

9

the same thing happened to my cranks. i jsut got a new set of pedals and it was fixed.

10

Yea I checked all the kids frames to see if there was any problem with riding them backwards (ie the left crank on the right side) but this was not the case.

I’m going to email unicycle.com about it, thanks for the help.

Cheers.

Mike

11

my freind have this exact problem with his crank i think.