Cranks destroyed

One of my pedals fell off. It looks like threads where the pedal attaches are gone. From the instructions that came with my uni, it says, “Riding on loose pedals will destroy the cranks.” I hadn’t realized that it was loose until it fell off. Now I guess I need new cranks. I might want to get new pedals, too.

Trouble is, I’m kind of a newbie and I’m not sure what I should get. My uni is a Nimbus II 24. doesn’t seem to sell that exact unicycle anymore. The closest is the Nimbus X. How do I figure out what to get for it? Do I have a choice?

If it is a square hub

They are all the same and cheap as well. If it’s splined, you have to be sure to get the right kind of spline. Counting the splines is a good way to make sure you get the right kind.

The threads on your pedals are likely ok. Let me guess, was it the left pedal ?

Most people learn to idle and ride backwards, favoring the left foot, so that side unscrews first.

Nimbus II isn’t splined…
Fortunately, square taper cotterless cranks are very cheap(upwards of $12 in the states) here

Don’t worry about riding backwards, that only unscrews crank arms that are already loose, though if the crank arms are on the right sides the pedals tend to tighten as you ride forwards, sometimes enough to save the lazy unicycle owner until they start to go backwards…

I bet you’ll get a wrench and check your pedals every once in a while in any case:D

I don’t know what a spline is. When I went to the catalog under unicycle hardware|crank arms and parts and it says

Cottered Cranks
Dust Caps
Splined Cranks
Cotterless Cranks…
ISIS Cranks

so I’m already lost. Fortunately, the page hobo_chuck linked to went to the “cotterless crank” page. The $12 ones, Torker Cotterless Crank Arms, are out of stock for 5 inch. I suppose I could get the Qu-Ax Lightweight Alloy Crank Arms for a little more.

No, I was not riding backwards. I can barely ride forwards. I probably favored my right foot while learning.

I was concerned about the pedals because looked different, but maybe that is on purpose. I’ll clean up the one that came off (right) and see if it looks ok.

Thanks for the responses. What kind of tool do I need to change these?


EDIT:If you don’t already have a wrench that will fit your pedals, go down to the hardware store and get one so this doesn’t happen again
Also, I usually go with shorter than 5 inch cranks, sometimes even half that for around town.

…but the new ones have ISIS splines, and those cranks may be cheap (I have a pair and I hate how they ride - they flex all over the place), but they are also heavier and much weaker than these.

cotterless hub (also called square tapper).

Link Pic didn’t work :frowning:

Splined hub. The splines are the things on the end of the hub that the crank goes over. ISIS has 11 splines.

Thanks for the info. My problem is that I’ve never taken a unicycle (or any cycle) completely apart, so I don’t have an understanding of the parts, hence the descriptions don’t make much sense to me.

Wish me luck with my disassembly and reassembly.

a better crank puller

I have one of these. It’s basically the same as the park model, but it will take off both square and splined cranks, using a little adapter that stores in the handle. Once you take out the crank bolt, you screw this into the crank and turn the handle, and a inner bolt pushes on the end of the uni axle, pushing the crank off the square taper. It is a wedged taper, and will often stick. Put a little grease on, then bang the new ones on a bit with a wood mallet, reinstall the crank bolt, and you are good.

I am suggesting a different puller, because it will save you the cost of buying a second one, should you buy a splined uni later.

Another option is to buy the puller that has no handle. These you have to turn with a wrench, but have the advantage of being able to pull the crank without having to first remove the pedal.

You need a 15 mm wrench-spanner for the pedals.


Oh, my. I now have the tool, but the first instruction says, " Remove the dust cap and crank bolt and washer using the proper wrench."

There doesn’t seem to be a dust cap (not sure what that is), and I don’t have the proper wrench. I guess the instructions assume that I know what the proper wrench is, which I don’t. How do I know what to get, and can I get it at the hardware store? I think this is something called a “hex key.”

I hope I can still do this myself! The rest of the instructions are difficult to understand, but they may become clear once I get there.

If the bolt on the end of the axle has a hexagonal hole in it, you will need a 8mm allen key.
Like this

These should be available at most hardware stores.


Thanks. It looks like I need 3 tools, then. The crank puller that I ordered with the crank arms, the wrench for the pedals (that came with the unicycle - had to turn the house upside down to find that), and a 8mm allen key.

That still doesn’t explain the dust caps. There were two round plastic things that came with my order. I can’t figure out what they do or where they go. Are those dust caps?

Yeah, that sounds like the dust caps. Don’t worry though - they aren’t anything too important.

When you put the wheel back together, make sure the LEFT pedal is in the LEFT crank arm and that they are on the LEFT side. Sometimes people ride with the wheel on backwards with the left pedal and crank on the right side. This will cause you to strip your cranks. I’m 90% sure that is what happened in your case. You have to make sure the wheel is not backwards.

if the cranks use an allen key the chances are they dont have dust caps. Some cranks have a nut instead, and it has a plastic cover that goes over it to stop crap getting in the hole.

Rats. I have the hex key, but I can’t get them loose.

As long as you are sure you have the right key

Force it !:slight_smile: Put vise grips on the key. The hub bolts on both sides turn out counter clockwise.

What a disaster! But kind of a good disaster.

I finally, finally got those bolts off. Had to enlist my very strong neighbor, and even he couldn’t loosen it until we oiled it up well and he applied all his might.

Then, I looked at the cranks and something wasn’t right. It took me a while to figure it out. They are splined cranks! :astonished:

This was a surprise to me because I was pretty sure that the description of the unicycle I bought did not say splined, but in fact, this is my unicycle. I was confused because this was not the one I ordered. Apparently, I got a free upgrade, without even knowing it. They were just switching over to the new Nimbus II with ISIS hubs when I ordered and I got the new one for the price of the old one.

So I have the wrong cranks and the wrong tool. The good news is, I can return the cranks at least and get some of my money back. The bad news is, the correct cranks cost more. However, the bike shop will do the work for me (no more DIY for me, no thanks) very cheap since it is such a quick job (ha ha I’ve wasted quite a bit of time on this already, I’ll spare you the rest of the story).

No unicycling for me until at least the middle of next week. :frowning:

HOLY son of a bike rider…
didn’t see that coming :stuck_out_tongue:

EDIT: there is a lesson in this–if you had posted pictures someone would have immediately been able to tell you that it was indeed splined if the angle in the pic was right–most of us are very familiar with the difference.

also, one question–can you get money back from the crank extractor? you don’t really have any use for that particular one…

There are a few lessons in this. :smiley:

No, I can’t get my money back from the crank extractor, because it doesn’t have any. I can’t get money back for it either, since I opened the package already. Maybe I could rent it out to other people? :smiley:

I actually do have another unicycle, a junk one. I never could learn to ride it. It was very cheap and surely has the square tapered cranks. I only keep it around because it might come in handy when I try to learn to free mount, since it is only 20" and the Nimbus is a 24". If it breaks, I’ll probably just junk it.


first, why doesn’t the crank extractor get a job?
second, I find it very amusing to see all these people learning to ride on splined unis (feel the light, for example, learned on a $600 KH 24" MUni)
your choice:D

I showed it the classifieds. The next step is up to the tool.

It wasn’t my choice to learn on a splined uni. It was thrust upon me. :smiley: