Moment Eating Schlumpf
25 Mar 2009

Moment Eating Schlumpf

Unfortunately nothing I do seems to stop my Schlumpf hub from eating Moment

25 Mar 2009

Unfortunately nothing I do seems to stop my Schlumpf hub from eating Moment cranks. By that I mean eventually a crank (on either side) will progressively move close to the frame to the point of almost touching it – at which time I replace the cranks rather than damage either myself, the frame or the hub. I am now onto my third pair of cranks, which is a concern as Moment cranks aren’t cheap.

Give me a Moment!

Give me a Moment!

This problem occurs regardless of whether I follow Schlumpf’s recommended (high!) torque settings for tightening the cranks on the ISIS hub or lower.

Why doesn’t this happen on all my other KH ISIS uni’s? One significant difference is that all single speed KH uni’s have spacers that the cranks end up riding hard against. The Schlumpf hub has no such spacers, so unless everything is perfect the ISIS Moment cranks appear to progressively deform, and slide further along the ISIS spline than they should. That’s my theory anyway!

It’s inconvenient – cranks must be checked each ride – costly and creates doubt while riding – is everything ok down there in crank land? The last thing a GUNI rider wants to have happen is some type of equipment failure at speed.

KH and Schlumpf have announced a revised version of the hub will be released in June, including improved bearings and axles that are 2mm longer. Will it be enought to solve the problem? not sure though it should improve it.

Florian has suggested a solution for the current hub is to mill material from the cranks, which is something I’m going to look into further.

All of that said, man I am loving the 36 GUNI! For all the teething problems If I had to have only one uni, this would be it!

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  1. James July 29th, 2009 7:54AM

    Are you still having problems with your cranks? I never had issues with using KH Moments on my KH/Schlumpf hub, but I have issues using any other crank. I would love to use lightweight ISIS cranks on my geared 36, but from my own experience, I don’t trust any cranks other than Moments on the KH/Schlumpf hub. I may try drilling out some holes from the Moments to save 1/3 lb or so.

  2. admin July 30th, 2009 5:47PM

    My hub isn’t in a wheel atm, so no crank problems 🙂

    Florian suggested milling the KH cranks and an aussie engineer/unicyclist offered to do it — will post about that soon, there also ended up being a decent weight saving.

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