KH/Schlumpf Hub -> loose bearing cup??

I’ve never had this happen before. A bearing cup came loose while I was riding. I did a ~35mile ride yesterday with a mix of asphalt and dirt, and toward the end after a UPD I noticed that the wheel looked crooked. When I looked more closely I saw that the non-tightened down bearing cup on my geared KH29 had come loose. The bolts had backed themselves out somehow, fortunately not enough for them to fall out.

Has anyone else had this happen? Do you think it is specific to using the geared hub? Maybe the shortish 125 mm cranks? Too much bumpy offroad or climbing while geared up?

Loose bearing cups/holders can happen on any unicycle. You were lucky to notice while you still had the bolts! Back in the bad old days, inexpensive unicycles with main cap bearings just had lockwashers, if those. We replaced them with those self-locking nuts with the nylon inside. Those seem to stay put much better than anything else.

Any time you reassemble the wheel into the frame, expect to need to tighten those bolts after a bit of riding. It’s when you forget to do this you usually have problems (I speak from experience)…

The same applies to square taper cranks.

What seems strange to me is that I’ve never had a bearing cup go that loose before, and I had just checked all the bolts right before my ride yesterday. Maybe I need to loctite them.

Is this with a new Kris Holm frame? When they are a new there is often some blue stuff on the bolts which I think is threadlock, if you were re-using an old frame this threadlock might have worn off.

Just an idea.

It may be the bearing cups need tightening more with KH Schlumpf hubs - I don’t own one of these hubs so am not an expert.


I’ve had this happen several times. Now I use blue loctite on the bolt threads each time I remove and reinstall those bolts.

Yeah, I wouldn’t worry about it. A bit of loctite should do you fine, methinks. I have stuff go loose all the time, and I loctite it, and it helps (and most of the time, completely cures), but I always still bring my tools along.

I had the same bearing cap on the same side come loose while I was riding my kh/schlumpf guni…and I lost a bolt. It was because I did not have that side tightened as much as I should…this was the only time as bearing cap has come loose for me as well, so I made sure to tighten that side a little more than usual as well.