Schlumpf Speed Drive

CptPalmer

Member
Has anyone giving any serious thought to replacing their crank with a Schlumpf. I really wish I could try one of these out as a trial. My questions center around will I get more speed, how hard would it be to pedal in the higher gear, will it even work on the Stromer etc. The ATS model is priced $300+ so the price point is not to bad. Does anyone have any experience with these cranks?
 

bluecat

Well-Known Member
Stromer ceased selling their high speed model after a few months in 2010. Therefore, the need for larger gear declined. Nevertheless, I met a Schlumpf SpeedDrive rider. He told me, riding at high speed was easier (reduced rpm) and shifting gear no problem. As he was a bike mechanic, installation was no issue. Another Stromer rider describes his experience at Stromerforum.ch
 

CptPalmer

Member
I am still sitting on the fence with this one. I want to make sure the higher top end can be utilized by the motor. The other day was I traveling down hill and I was going 44 and the motor felt like it was in regenative mode. The display also had the >>> on the left side as well and I was pedaling. I need to experiment a bit more to find out what was happening.
 

MarcD

Active Member
IIRC, motor assist will cut around 28mph or 30mph on an ST1 Platinum, so higher gears will only help you increase speed on human power alone (since a 50/11 on 26"x2" wheels will top out around 32mph @ a cadence of 90rpm. To exceed 45mph you would have to be pedaling a 60/11 gear at 110 rpm+. I would guess that the resistance you felt was mostly aerodynamic drag. Once you exceed about 18mph, aero becomes a huge factor in the amount of effort/power required to maintain that speed. It is a major reason why real world experience on my Turbo S shows that I get almost 75% more range @ 18-20mph than at 28mph.