As mentioned in this
topic, I lost 2 weeks ago one of the shift buttons of my Schlumpf Speed Drive.
I ordered a new one and received it. When I mounted it yesterday I understood why I am loosing it: I am unable to apply sufficient torque to it.
The figure below shows what is the issue:
For one or another reason, the threaded shifting shaft does not protrude enough out of the crank shaft, and the M3 Allen screw sits then quite deep in the shift button.
The 1.5 mm Allen bit being too short to engage properly in the Allen screw, it slips in the screw head so the applied torque is not high enough.
I see that the torque wrench Schlumpf/Haberstock is selling does have a longer head, which makes it possible to tighten the screw properly, I guess
The only solution I have now is to use a common L-shaped Allen key to tighten the screw or to buy the torque wrench (60Eur!
Has anybody encountered the same issue?
might it be possible that the small Allen screw is of the wrong length?
It should be 5 mm.
(Maybe you could use a longer screw i.e. M3x6 or M3x8 mm)
Are you sure that the button is adjusted correct?
The surface of the button should be (when engaged) plain with the surface of the cranks.
The right one is a little bit too much outboard.
(The installing instructions were moved from the above mentioned topic to here.)
(From the Manual-Sclumpf-Speed-Drive.pdf (17,7Mb), Chapter B-5, found here:
One of the most important adjustments is the correct positioning of the gear
Please spend a few moments reading this to understand why this is so important:
If a gear shift push button is screwed on too much, the clutch, which has
to transmit the high torques from the axle to the sunwheel or planet carrier,
can´t engage correctly. The load on the teeth of the clutch increases and the
clutch can be damaged by excessive pressure.
It is most important, that there is still some inward play on the button, even
when it is in its depressed position! It isn´t important how much travel the
button still has.
If using our original crankarms, the position of the button is correct, when the
push button is flush with the surface of the crank.
If using your own crankarms, please check the cranks before of assembling
them. Hold the crankarm in your hand and put an axle bolt and gearshift
button in the hole of the crank. Now you can see, whether the button is
too high. Its surface should be below the surface of the crankarm.
[b]- The gear shift button must be tightened with a torque of 110 cNm. It may
be difficult to find such a low-torque torque wrench. That´s why we include a
high-quality 1.5 mm Allen wrench for tightening the gear shift button.
Hold the gear-shift button with [a pair of pliers*] while tightening very firmly.
Finally attempt to unscrew them by hand. If you can, you will lose the button
soon. Tighten it again!
Never use thread-locking compounds. If the button is tightened correctly, you´ll
never lose it.
The new designed gear shift buttons allow easier tightening.
The button must be approximately flush with the surface of the crank, when
being pushed. It can protrude up to 1mm (especially in combination with
easy-shift kick plates).
Then tighten the small Allen screw M3x5 within the button by holding the
button with the special wrench, that comes with every tool set.
Use a 1.5mm Allen wrench or the 1.5mm bit of our tool sets.[/b]
*[a pair of pliers]
That’s meant for the old non-slotted version of gear shift buttons (before October 2004).
Instead of the pair of pliers please use the special wrench (tool B of