Loose crank on my schlumpf (M0648)

Hello all, today I realized my crank had some play.
When dismounting it, I broke the bolt and cannot use it anymore.
I haven’t found anywhere to buy this bolt, it is out of stock on unicycle.co.uk, does anyone know where I can find one or has a soare one?

Have you tried Amazon or eBay?

No, but it is a specific component, that I have only seen on 2-3 websites, but is listed as out of stock on all of them.

But apparently Florian has some, so I am hoping he will be able to send one as soon as possible.


I have receveid a replacement bolt together with spacers since the problem originally came from a loose crank.
BUT when placing the right spacer (gold button side) and tightening the crank, the bearing gets locked, so I cannot use this spacer.
What do I do wrong ?

Do you have photos? I think a visual of the issue would be helpful :eyes:

I don’t have photos right now, and I don’t think it would help, since nothing seems wrong.
I have instinctively placed it with the thinner side towards the hub and the wider side toward the crank.
And when I thigthen the crank, the bearing becomes really hard to turn, and I have no idea why.
If you really want a picture, here is one from the internet. I have put the spacer the other way around, but I don’t think it should change anything.

I think that could be your first problem as they should be installed in my view as per this internet picture.

I know of current hubs there’s a metal O-ring that helps clip these protection rings in place and helps to avoid on-bearing pressure as I think they’re not meant to press up against the bearing wall itself.

I personally still feel a close up of the issue might help but that’s your call! :grinning:


I will work on it this evening and take photos as close as possible.
Hope it is just a minor problem and will be solved fast.

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I would hope so too - I am thinking it might be that that side’s bearing has some lateral movement - I can’t recall how the gold button side is installed (assembled at factory) but if it is a secondary part - moveable perhaps it needs itself pressing inwards on the axle shaft to make more room for cranks and pressure rings.

I’d say as many photos of the whole set up - no cranks or ring right through to when it stops bearing will help.

This forum will help you diagnose the issue, fear not :smiley:

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The gold button is mounted on a thin axle which goes through the tightening bolt. To mount the spacer, I have to remove the button, then the bolt, then the crank and finally install the spacer before putting everything back.
As an information, the bearing is really hard to turn even when the wheel is not mounted in the frame.

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That’s pretty key info. Is this without your cranks installed?

If yes I’d say sadly you’ll have a bearing issue where hub may need a service.

If hard to turn with the cranks installed, then you may still have an issue with unwanted pressure from the way cranks are being installed.

Are they new cranks / and what type?

No, the problem only happens when tightening the crank (and so the spacer on the bearing).

The cranks are not new, they are spirit cranks from KH. If I cannot mount the spacer, I will probably have to buy new cranks with less worn interfaces.

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It appears that the problem came from the big bearing that is apparently damaged and can no longer turn. It seems that some dirt, water and other stuff has gone into it since the bearing protections are no longer stocked in place. Before putting the spacer, there was no side pressure and the small bearing was not pressing on the big one, and its outer flange was spinning inside the inner flange of the big bearing.

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I did not read the whole thread, but #648 would be from a generation that did not use spacers. If you do, it pushes the the C-clip holding the dust cap into the bearing and will make it harder / impossible to turn.

KH Spirits tend to slacken over time (if installed several times). I installed the ones on my Schlumpf when they were new and never took them off. I even have a disk installed but I haven’t put a brake on since hahaha.


It does indeed push the c-clip, but I haven’t got any noticeable difficulty turning the wheel with spacers (except from the very obvious one from the big bearing).

I will have to send the hub to Florian for a maintenance and replacement of the bearing anyway.
In the mean time, I will try to find new spirit cranks in order to not have to use spacers.

Good luck. They now tend to be very rare. I am confident you won’t find them anywhere in stock in France :frowning:

It was no longer available at the cdk, but our good old neighbourgs had them. I will hate brexit pretty soon though.

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I know it’s probably only a typo, but find it amusing to think that post-brexit British people (or maybe those who marched us blindly into brexit without evaluating the consequences) were now known on your side of the channel as Neighborgs!


They have always been our neighbors (and best enemies/rivals).
We basically love hating each others. And it is especially true where I live, 2 kms away from the ferry and maybe 100 km from England by boat

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@Aurelien, it seems you missed the point. You’ve put an extra “h” and an extra “g” in “neighbo(u)r”. @holyroller made a pun about the words “neigh” and “cyborg” - horse-like cyborgs marching blindly without evaluating the consequences.

Am I right, Holyroller? :slight_smile:

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