Just got my KH26 with Schlumpf hub yesterday from Municycle.com. I noticed that wheel has sort of small attrition at some exact point. First I thought it was because of brakes (but no, it wasnt). Then I suspected the gap between the frame and bearing, but on closer inspection I noticed, that gap is enough. Then I took of the frame bearing housing caps - and then free rotation of the wheel was very good without any noticeable friction. When I put back caps and tightened back screws to about 1…3Nm - still ok. But then torqued more with 4…5Nm - friction appeared again (though less).
I am a little bit worried about it - is it ok that there is some friction? Shouldn’t it destroy the bearings?
As long as you don’t overtighten the caps you will be fine. The knurled bearing side can be tightened to 6Nm and the smooth bearing side to 5Nm. Some resistance is normal especially when new as the hub breaks in. Hopefully your torque wrench is accurate!
if your worried 5nm isnt enough or if in the event the bearing case slips in the mounts on the frame, Another idea i use is Carbon fibre parts grease or carbon grip or firbe grip what ever people and brands come to name it.
Its a ‘grease’ kind of used mainly on carbon road bikes to stop their seat posts slipping and so they dont need to overtighten the clamps and risk cracking the frame or unlikely the post. It works well on the Schlumpf and you really only need it on the knurlled bearing side. if that slips it might be a disaster in top gear or loading a brake if you have one. Its a non lubricating paste with grit through it. Just wipe excess away from any bearing seals just incase and you’ll never risk overtightening the bearings making them tight or wear excessively
both my hubs have a slight resistance. There is alot of things going on inside one of these hubs and new the grease inside is nice and thick ready to last you many many hours of riding! Take care of the hub and enjoy it no end