Thin w/ Display takes off by itself!


New Member
This has happened more than three times so far: I'm off the bike and holding the bars and it suddenly goes full throttle!

The first time it happened I just assumed I accidentally hit the throttle, but when it happened again I realized it was doing it on its own. I'm getting used to always having my hand on the brake to cut the motor when it wheelies.

Any ideas what to check? Throttle? Display?


(stock Thin w/ Sondors display)

NOTE: I've also posted this in the Sondors Owners Forum. I've found no similar thread.

Al P

Well-Known Member
It sounds like an intermittent short, which could be difficult to locate. Start by looking for pinched wires. With the battery turned on and one hand ready to brake, squeeze along all the wires with the other hand, particularly where they enter the frame or other components. If the bike jumps you may have found the short. If it is inside the throttle or motor you will most likely be unable to find it. If this doesn't work I would call Sondors and ask if they have had any other similar reports, which they will most likely deny. Good luck.


Well-Known Member
Set the rear wheel off the ground, using a stand, rack, or whatever. Tap on the throttle with a screwdriver, to see if it starts up. Tap on the controller box too. Wiggle the main harness.

Also look at the magnet disk on the crank and see if it's mounted tight. Long shot, but if it's spinning freely, that could start the motor too.


New Member
I finally figured out what happened... The original grease in the rear freewheel was not allowing the bearings to spin freely, so whenever the bike was moved forward, even slightly, the chain and crank would turn too. Once the crank sensor crosses enough magnets the controller thinks someone is pedaling, so it assists by turning on power to the motor.

The fix was to put in some lighter weight oil into the freewheel so it would ratchet freely and not turn the front chainring.