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VESC 6, astroflight 3215, loosing sync with freewheel

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Last seen: 6 months 4 days ago
Joined: 2018-08-28 13:44
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VESC 6, astroflight 3215, loosing sync with freewheel



  • I have a mountainbike with a astroflight 3215 connected to the rear wheel with a 2 stage reduction. On the intermediate shaft I have a freewheel, the ratio from the motor to this shaft is 4:1.
  • Battery is 12s.
  • motor kv is 169
  • Phase current set to 60 A
  • throttle controls duty cycle


The motor wizard did a good job and the combination works great, except for one big problem. 


  • When I reapply throttle after coasting (wheel spinning at 10 - 30 kph. motor stopped, freewheel working.), it happens that the motor starts making a squeezing sound and doesn't move anymore. 
  • I think the controller looses sync
  • seems only to happen at certain throttle position while reapplying it. low throttle or full throttle seems to work ok. Half throttle seems to give the problem.
  • squeezing sound continues until I disconnect the battery

What I think happens:

  • The motor spins up
  • when the motor speed matches the wheel speed, the freewheel engages abruptly and causes a big torque ripple.
  • controller looses sync


Is this a known issue? 

Can I tweak some parameters to solve this problem?


thank you!