BoxTurtle

Hello Folks,

My new handcycle has a Schlumpf Mountain Drive pedal crank. Something is loose and getting looser. At first it would only occasionally slip. The problem progressed, and now the crank will not engage low range unless I push on the button while slowly turning the crank. Otherwise it turns without moving the chain, and I can hear the cogs grinding (which makes my skin crawl!). High range works fine.

Can you help me understand this mechanism sufficiently to make an adjustment that will realign the gear selector properly?

Thank you.

Take care, Tom

steve0257

Not familiar with that but these might help.

mountain drive

https://www.schlumpf.ch/hp/handbuecher/WHB.md.engl.pdf

BoxTurtle

Thanks, I had seen them, but am having difficulty figuring out what to do.

fietsbob

gear selector is a shuttle through the BB, there is a Cap where the crank's Dust cover for the crank Extractor would Be

there are 2 simple tools involved 1 a little sheet metal L shaped wrench to engage the slots in the cap,

and a Small Hex 1.5mm allen wrench to tighten a setscrew in the cap , the adhustment is looosening the set screw so the cap turns on the shaft that goes thru the BB

then you Re-Tighten the set screw to hold the adjustment. 1 cap sticks out Proud , the other is more flush,

you push the one that sticks Out, in and the other side stucks Up , Thats about all the adjustments , you adjust how far the cap sticks Up..

Do you Own those 2 tools? PG B6 is showing them in that PDF mentioned above?

In the US https://www.cyclemonkey.com/ in Cal, will have the tools to sell .

BoxTurtle

No, I don't own the two tools. The Schlumpf web site says they are shipped with the drive, so I hope the guy who built the bike has a box full of them and will send me a set. We shall see.

BoxTurtle

The builder is sending the tools to me today. I'll have them by the weekend I'm sure. If we can't fix the problem by adjusting the mechanism, he said he will send me another Mountain Drive and ship this one back to Germany. I hope it doesn't come to that.

I'll let you fellows know what I find, and ask for help again if needed.

Thanks, Tom

fietsbob

Afaik there is just an in/out; encage the low range, letting the gears work, cranks turn faster than the chainring,

or block them, to turn the cranks the same rate as the chainring..

Adjustment is just How far out the button Protrudes from the center of the crank arm..