Schlumpf hubs: general discussion

I never even rode my cranks loose. It just happens to get closer to the bearings everytime I take them off. I’ll just grind my adapter and wont ever take my cranks off anymore.

I’ll try to put the on not as tight, but just enough so it doesn’t rub on the adapter, unsing locktight obviously.

Just out of curiosity, why do you take the cranks off so often, or at all? As you know, the tapered aluminum splines become enlarged a bit each time you remove and reinstall, which is why I try never to remove them.

I realize that c-clips can’t take a lot of force, but they should be just fine for stopping creep if the cranks are snug. Obviously you don’t want to tighten hard against a spacer.

KH Himself supports and suggests spacers for On Board Disc crank setups… weather that helps any at all.

I have 2 geared hubs, one old design, one the latest model and had them in a few different Kh frames with no issues with clearance between the frame, Bearing Cups and Hub it self.

Spacer fixed the disc bolt clearance on that side. Kris has mentioned the use of spacers in the forums here last month. I dont remember which topic we were talking on though sorry

A custom spacer tightened to the spindle (so that there is no load on the bearings) seems like an obvious solution here - is anybody up to making some?

Alternative or possibly in addition to Ben’s solution for a custom stop up there is a stop which engages with the end of the splines, so not just relying on friction. The question is, are any of the splines still showing when the crank is tightened on (I don’t know as I only have a Square Taper Schlumpf, though an ISIS one is doubtless in my future)?

Here’s the thread of which you speak: http://www.unicyclist.com/forums/showthread.php?t=113112

Because I still haven’t bought a second pair of cranks for my DH uni. So whenever I want to go ride big drops/techy stuff, I put the cranks on my ungeared wheel.

I’ll get a new pair of spirits and put those ones on my ungeared wheel. Now I need a second pair of Straitline pedals…

A spacer with the ISIS Standard that would block the crank from going closer to the hub? I’d buy one, but having these made will cost alot. I’ll see if I can make anything to help that wont damage the hub.

The problem will be to take it off though if you ever need to. Like if you ever get a problem and have to send it back to Florian, it will be a pain to pull off. Just like taking a crank off without a puller, but with less grip…

Not necessarily. I’m not envisaging something which fits on the ISIS taper, but something which fits around the spindle like a normal spacer, but has tangs which engage with the semi-circular bits at the end of the splines. Shouldn’t be any harder to remove than a normal spacer - the only question is whether you can make it strong enough.

Also not all that hard for somebody with access to a CNC milling machine to make (I don’t).

I’ve read through that thread a couple of times and can’t see Kris commenting on using spacers with a Schlumpf - he appears to just be talking about using them with an ungeared hub (personally I hadn’t realised people were using ISIS cranks without spacers except on Schlumpfs - given the original bicycle ISIS spec includes a stop, you’re not using it properly without one - and despite comments otherwise all my Nimbus unis have come fitted with them).

I agree with you. Let this be a cautionary tale to not trust people who half-remember what someone else may have said once upon a time.

This could work. Probably it could be even tightened by side screw the same way as left crank of the type attached below, if the space permits.

it was similar to old QU-AX yellow hub, and 1 side crank always loose …

No, I’m not talking about it being mounted on the splines, but on the smooth portion of the spindle. It would appear like a low profile seat post clamp, probably one bolt would do if used an assembly loctite.

Alternatively you could machine a a thin steel “washer” that fit at the innermost portion of the splines to serve as a hard stop, but this also might require some machining of the cranks.

I’m holding out for a revised hub, hopefully in the coming year.

Ben - I’m suggesting a spacer which mounts mostly on the smooth portion of the spindle, but has tangs which engage with the end of the splines (past the point where the taper ends).

See figure 1 on page 6 of http://www.isisdrive.com/isisdrive/ISIS_Drive_Standard_Document_revD.pdf - I’m suggesting engaging the stop with the taper at the end of the flutes.

this is impossible as we are using 22mm bearing inside dimeter (see drawing isis drive splines after page 10/10)

You misunderstand (or I misunderstand you) - I’m not suggesting having a crank stop in the way shown in that figure - clearly the bearing couldn’t get past the stop machined into the spindle (and in any case we’re talking about doing something with a Schlumpf, so no modifying of the spindle allowed). I’m simply using it to illustrate the position of the end of the splines relative to the stop.

Yes, I know what you are suggesting. I brought this idea to the forum a while back, it’d work if someone can do the machining. It would probably be easier to make a compression style bearing spacer that goes on the smooth portion of the spindle.

Either way, this is going to be retro as I am nearly certain that the next gen hub will have a different spindle to accomodate for crank creep.

If some enterprising individual were to make a spacer that prevented crank creep, I am sure they could recover their costs, $50 a set, sell 100 sets, that ought to cover it.

I think better with pictures. Is this the kind of thing you are suggesting? (Item in green.)

Schlumpf w_crank spacer1.JPG

Schlumpf w_crank spacer2.JPG

that would do it… no crank pressure on the outside of the bearings