Torque sensor BB DIY mid drive questions

Joined
Feb 17, 2016
Messages
19
I may be asking a silly question, but I can't find any builds that answer it, does running a cyclone/gng/LR style mid drive reduction kit apply torque to the sensor of a sempu BB and render it useless, or does it not? I want to have my cake and eat it with a 2000-3000 watt mid drive that also has torque sensing without breaking more than one bank? Links to any builds would be amazing, or even just some advice!
 
I'm running a Sempu torque sensing BB with Cyclone 3000w on my M5 recumbent. Not sure how you'd go about it on a 'regular' bike. I've split the drivetrain into two via the Cyclone double freewheel. That's allowed me to retain the original triple chainring setup. I'm using a rear derailleur as chain tensioner for the triple chainrings. Cycle Analyst V3 handles the torque sensing PAS brilliantly. I've also got throttle, which overrides PAS for when you need an extra boost. It's hooked up to a 52v 17ah battery. So far I've limited max power to 2000 watts. Max speed on the flat at WOT is 40mph - faster than I can pedal! I've done around 600 miles. So far the Sempu torque sensing BB has been working perfectly. It took some experimentation to configure in the CA, but once I got it dialled in, the torque sensing/PAS function works superbly.

m5_shock_proof.jpg
 
In most builds using Cyclone / GNG etc motors, the motor does not drive the bottom bracket itself.. it drives a chainring that rotates around the bottom bracket but does not apply torque to the bottom bracket.
So yes, in a "normal" setup the only torque the bottom bracket will see is the torque applied through the pedals, and the system will work fine.

Good on you for thinking about using Torque Sensing: for off-road riding it is far superior to "Normal" PAS / cadence sensing control, and gives a very natural, instinctive riding feel and a safer, more rewarding riding experience (assuming it is well set up, of course).

Although not commonly advertised, Sempu can make a T3 model torque sensing bottom bracket which works with ISIS crank arms instead of Square Taper. Electrically and dimensionally it is said to be identical to the T4. If you would prefer the ISIS version and cannot find it for sale, PM me and I will send the link to a supplier willing to get one (on Aliexpress).

Good luck with your build.
Dave
 
Drum said:
Although not commonly advertised, Sempu can make a T3 model torque sensing bottom bracket which works with ISIS crank arms instead of Square Taper. Electrically and dimensionally it is said to be identical to the T4. If you would prefer the ISIS version and cannot find it for sale, PM me and I will send the link to a supplier willing to get one (on Aliexpress).

I have 4 of the ISIS T3 sensors if anyone is interested. I am selling them because I am using T4s only now. PM me if you're interested.
 
Back
Top