Sam, I think you’re probably right. The 30 degrees is the motion of the cranks relative to the wheel. If both cranks and wheel are rotating at the same speed (as in low gear) this free-wheeling could go on for awhile, until you force the pedals to go at a different rate. You know, like when you’re free-wheeling downhill and are trying to stop as fast as possible. 
Geoff
Why are there no crank stops in Schlumpf hubs?
Does the lack of crank stops allow for more button travel, and is it possible to damage the hub if crank stops are used (I noticed the stop would butt a c-clip).
sorry. this is the thread I meant to post in -finally!
I had a strange crank problem on one of my geared KH36 Schlumpfs recently: I tightened the cranks (as per spec using my torque wrench) and they were flush against the bearing holders, and even rubbing slightly. This hub is one of the new, slightly wider ones, which had always had >5mm clearance there. Not knowing what else to try, I swapped the cranks for another pair and there is no problem. Looks and rides normal. Both sets of cranks are Moment (first one is 125/150, second set is 150). I’ve done a big ride after this and all is well, but what went wrong? Bad cranks?
Anyway, regardless of all the problems etc, I LOVE my Schlumpf hubs - just hit 1800 miles on my geared 36er. And Beau and I are headed out today for another big group ride.
This summer, our geared 36ers are going to Mongolia! Mine has already been to India and Africa.
—Nathan
You can also look at it the other way: as long as your cranks are rotating within a 30 degree error with the wheel, you apparently have no need to bring the wheel back under you (either forward or backward), because if you did you would not be pedaling so smoothly. When the need to accelerate or decelerate the wheel arises, you will quickly reach the end of the 30-degree leeway and -click- the cranks engage in the new gear. In other words: pedaling for half a wheel rev with disengaged cranks may feel uncomfortable, but isn’t really “dangerous”. Get used to it. Or intently go to the forward or backward limit of the 30-degree leeway.
Nathan fwiw I had this happen in December 2008 with my first hub:
http://unplannedismounts.com/2008/12/22/crank-problems-in-guni-land/
and not surprisingly it continued on when I put the hub in a different wheel:
http://unplannedismounts.com/2009/03/25/moment-eating-schlumpf/
It ate a few pair of cranks like this. It seemed crazy to keep doing this so I emailed Florian who kindly offered to mill a pair of cranks to create more clearance. As it turned out a fellow uni rider in Australia offered to mill a pair of cranks (thanks Ian!) - no issues with clearance now:
http://unplannedismounts.com/2009/09/09/milled-moment-cranks/
My own (uneducated) view puts this problem down to a few things:
this problem would not occur imo if the ISIS spec was implemented 100%. Where single speed KH uni’s use a spacer to create a stop shoulder, there is no crank stop shoulder on the geared hub.
A critical component of the interface standard is the use of a crank stop
shoulder on the bottom bracket spindle to ensure consistent axial crankarm
location. These stop shoulders are the datums from which the entire interface
standard is derived
[I]http://www.isisdrive.com/isisdrive/ISIS_Drive_Standard_Document_revD.pdf[/I]
Anyway that is my take on it. The milled cranks did the trick, and I’m loving GUni!
Pete, thanks very much - that’s interesting.
Hey nathan, I was having this problem too at RTL. I mentioned to florian that it seemed due to excessive pressure on the cranks, causing the aluminum to deform. New cranks fixed the problem, and this is one of the reasons I don’t go quite as high as the spec recommended.
But, having said that, I can mill your cranks for you 
corbin
I ended up wondering if I’d inadvertently created a vicious circle of crank problems by significantly over tightening the cranks excessively damaging/deforming the ISIS fittings in the cranks - pic attached of one of the cranks.
I had a fairly average torque wrench at the time. It may or may not have been the root cause of the problem but I decided to replace it with two much better torque wrenches (one for the cranks, one for the lower torque bearing caps etc) before the replacement hub from Florian arrived last September.
Since then no such problems. I use 45Nm on the cranks and check them once a month - they’ve hardly moved at all (weren’t new when fitted) since September. Add in the extra width of the new hub and the milled cranks and frame clearance is all good.
So to clarify. When I get my Schlumph, should I buy new cranks from Florian? I cannot use the cranks I already have? I have several KH Moments now. If the hub has problems and I need to send it in, will I have to use different cranks on my spare (non-GUni) wheel set-up?
The Isis hub is meant to be used with KH cranks. The Schlumpf cranks are all square taper as far as I know. So your Moments should be fine (assuming your getting the muni isis hub).
Thanks. That’s what I thought, but some of the above problems have me wondering.
I will denfinately consider getting one when I have the $$. What was this about a new broken hub, they are pretty expensive and that would be the last thing I would want. Also, how new are these, because lately there have been many threads about them.
The brand new broken Schlumpf story was a bearing problem that affected lots if not all of the previous generation of KH/Schlumpf hubs after only a few kilometers of riding. Schlumpf is still in the process of replacing all the broken hubs. I’m still waiting for my second one. So far it seems the newer model with beefed up bearings is much more reliable than its predecessor. I haven’t had any problems with mine since I got it end of last year. You will probably have to wait a while for yours.
I have some good tech questions regarding Schlumpf Hubs and a disk brake mounted to the AXLE. I have no experience with the hubs as of yet and wonder if anyone here could clarify on this thread or on the thread below:
One suggestion on geared hubs. If you brake through(attached to crank) the gearing, it puts a lot of stress on the gears,you would be using the gears to take up all the braking weight. If you brake at the hub it stops the wheel no gearing involved, and at the price of a geared hub, more undue stress through the gearing could have expensive/catastrophic results.
-Lobbybopster
im just wondering with the disc mounted to the Schlumpf axle wouldn’t there be a little bit of backlash when using the brakes?
if you stop the axle the hub would still have play within the gears and would cause a slight slipping feel,with a HS33 you wouldn’t feel this as bad,because the rim is slowed down.
any input to this?
-filotr14lsdude
If you use a drag brake, what additional strain does it place on the gears that your legs don’t when slowing down?
-KB1JKI
In my opinion it won´t stress the hub more than you can do by your leg power. the hubs are designed to withstand drops up to 5 feet, and even droping 2 or three feet with landing power on back leg will put more energie into the hub than any brake can do.
http://blog.ridetriton.com/__oneclick_uploads/2010/02/arne-schlumpf-3.jpg
I am not quite sure but for example, rolling down stairs with or without using magura brake I feel not the play within the gears
I guess smooth downhill braking is much better for the hub than changing leg brake power at each revolution.
Thank you Jogi, I am very reassured by your comments. They seem very reasoned, and insightful coming from someone with so much experience with the Schlumpf and other similar hubs!
“Hard spots” on the knurled bearing => NORMAL with brand new hubs
Hi guys!
As a follow-up to this message from me which I probably hosted in the “not-exactly-right” thread.
Good news!
I just received the following reply from Florian regarding the “rocky” feeling of the knurled bearing:
I hope Florian will forgive me for quoting his words without his upfront approval. This is not something I like to do much - but in this case I thought it would be worth, rather than uselessly trying to rephrase his words.
Cheers, MadC.
I have a question for those using the KH Schlumpf hub with the KH frame. The problem I have is that even after torquing the bearing bolts to 6Nm I still experience slipping. For example, while riding in high gear trying to slow down on a steep downhill I applied a heavy amount of back pressure and it broke loose. I took a look at the inside of the bearing cap and saw that a small amount of the paint had stripped off. I was wondering if anyone has had this problem. I’m thinking of striping the paint off the inside of the bearing to see if it will hold at the required spec of 5-6Nm. What I’m looking for here is some feedback.
By the way you that ride these things are in great shape. I have had my hub for just one week and I find riding in high gear is taking me into a whole new level of fitness.
I hear you about fitness - it is great. The other day I rode 12 miles on an ungeared 36 - first time in months and months. It felt so slow and easy and like I couldn’t push anywhere near hard enough to get any exercise.
On the 6nM - that’s what I use and it has been working with no slipping. Less on the other side. Not sure what to try. You don’t want to go much tighter or you risk premature bearing death. Maybe 7nM would be ok? Maybe shoot Florian an email. And post about what happens.
Good luck!
I used 5nM on both sides and it has not slipped so far (about 100km). But a small amount of paint has been stripped off too.
