Last month the Bionx back wheel of my Dahon Mu SL fell out of the drop out when I hit a rut on the bicycle path. The wheel locked up and the bicycle skidded to a stop. Luckily I was on the flats so no injuries. The consol turned off and battery stopped working. I remounted the wheel and installed a spare battery that I usually carry in a backpack on longer trips. I rode the bike at assist level 4 for a mile and then the motor started making a harsh grinding sound and would not spin freely under power. It still freewheeled and pedaled fine with the power switched off, so I just pedaled to my intended destination without the Bionx motor assist.
I started this topic to warn all Bionx owners that reads this forum to make sure the Bionx wheel motor nuts on their bicycle are tight before each ride to avoid this fate.
On the positive side, when I was shopping to replace the broken motor, I found the new high speed Bionx 500W system. Bionx does not make a 20" rim high speed 500W wheel, so I purchased the 26" kit and respoked it with the rim and spokes from the broken Bionx 350W wheel. So far so good with the new system.
Did this happen to anyone else?