base2 

May 30th, 2020 I installed a Schlumpf Speed-drive on my 1997 Trek 6500zx. In that time I've racked up about 1300 mountain biking & gravel miles on this bike. When mated to an XT 11-46 cassette & RD-M9000 derailleur it has performed flawlessly through all 700% range this combination of parts has to offer. I have predominantly run in overdrive unless there was a reason to go below 25 gear inches.

Moly Disulfide grease has been injected at regular intervals, but recently it's been weeping out far too easily & far to often. Nearly every ride I find the ooze needs to be wiped off of the seal areas & it started making "whirring" noises within 25-30 miles & now it seems that some part inside is scraping the bell housing. Injecting more MOS2 grease quiets things, but the weeping ooze, the "whirring," & the scraping noises always return in short order.

I grabbed the chainring with both hands & discovered it & everything it attaches to, rocks back & forth in all directions. This obviously explains all the symptoms. The entire planetary assembly needs a rebuild.

It seems weird to me that a Schlumpf drive, or any other bike part would only last 1300 miles before needing a rebuild/replacement.

My question is: What are the experiences of others here on Bike Forums with the Schlumpf Speed-drive? How long has your Schlumpf lasted? Are you using yours with a cassette or with a straight chainline? Do you pump 600, 700, 800 hundred watts through yours in sprints or use yours in high torque situations like would be found on extended 15 percent grades typical on forest service/logging roads or do you just steady state cruise on flatland in a recumbent?

I must say, I'm teetering on being disappointed with my Schlumpf unless the case can be made I was using it in an abusive or extreme manner in some way. How long did yours go between rebuilds? Did you even bother to rebuild yours?

Edit: Based on various online calculators, my sprint power meets or exceeds the 250 newton meter ratiing of the Schlumpf. (800 watts at 80 rpm equals 95.5nm average torque, times that by about 2.4 for peak torque because human delivery is dynamic...) Factoring in chainline angle & the stresses can only be worse from there...I'm officially disappointed in Schlumpf. 🤢

Mods: Can we close this thread?

Dan Burkhart 

I did use a speed drive for a time but I couldn't say how many miles were on it as it was not one of my most used bicycles, so had to be less than 1,000.
The scraping noise is probably the dust cover which is held in place by magnets and sometimes takes a bit of fiddling to get positioned properly.
Did you do the installation yourself, or have it done? The BB shell must be chamfered prior to installation and the correct locating cones installed. (steel for aluminum frames and aluminum for a steel frame.)
Failure to follow any of these steps, along with the correct tightening torque would lead to issues down the road.
The mechanism itself is pretty simple and bomb proof, so I can't see it wearing out that quick.
Note that Schlumpf has outsourced at least some of its production so maybe QC isn't what it was.

base2 

The scraping noise is internal somewhere. Most likely it's a planet scraping by the stamped sheetmetal housing. You can actually feel it with your hand as you rotate the crank arms & touch the housing with your other hand.

g_faq.internal.life.1 by Richard Mozzarella, on Flickr

It's the chainring, the trouserguard, indeed the whole rotating assembly that has become sloppy.

I witnessed the installation at the bike shop to see that it was professionally done with all the proper tools. Which were all readily available, organized & marked. The shop was an authorized installer/retailer for many years until Haberstock bought the brand.

As far as the bottom bracket bearings & spindle, that's all good. Zero slop, smooth as butter. Most likely it's the bearing/bushing at the center of the planet carrier that has worn & is allowing the rotating assembly to slop around.

At this point, I have pulled a spare replacement crankset out of the garage & have some Gevenalle Audax shifters on the way. The Schlumpf is getting replaced.

Dan Burkhart 

Well, if you want to pursue the issue with hopes of resolving it, you could try contacting Cycle Monkey as they are the distributor. https://www.cyclemonkey.com/

tomtomtom123

Have you tried disassembling the covers to take a look inside? I'm curious how the planet carrier and outer ring are held together and spaced to prevent rubbing on the housings, the area that you theorized was the problem. I'm also curious if it's the axle that's connected to the planet carrier and how the heel clutch connects to the planet. I couldn't find detailed photos of the internals.

Oh, I've found detailed photos in the ATS manual.
https://www.ats-speeddrive.com/pdf/WHB.sd.engl.pdf

It looks like the lock nuts on the left side should be tightened with neither play nor preload. According to the photos in the manual, all components are in contact by ball bearings in between them, so in theory, the chainring should not have any axial movement.
There is a clip above the bearing spacer (long cylinder in the middle of the spindle) which helps to hold stuff together as you assemble the main components. Above the clip goes a few pieces of 0.1mm shims that's supposed to adjust the spacing between the 2 cartridge bearings just right so that they fit in the BB housing. And then the locknuts clamp the BB housing to the left cartridge bearing outer race. So if all is adjusted right, there should be no play.

If there is play, maybe the locknut has come loose. I don't see anything else in the photos that can come apart, except maybe the cartridge bearing races, clip, or shims splitting.