TranzX ebike crank/pedals slipping

[mikesova]

So I picked up a Raleigh Sprite Ie with the M16 Tranzx mid drive motor. It was a fixer upper. I've got most of the "bike stuff" sorted and when I took it for a test ride today, I discovered that pedaling allows the motor to kick in and move the bike. If you pedal really slow, without much effort, the sensors just motor the bike along no problem, but if you try to pedal hard, it feel like the crank arms just slip and its like the crank isn't really syncing up with the sprocket to move the bike. The way it is, it would be a major struggle to try and ride the bike without any power. This can't be normal. Has anybody else had a situation like this? Please help! This bike is for my wife and I'm bummed it's not working right.

 

[Al P]

We have two bikes with that motor and have not experienced it slipping from within. It sounds more like your chain is slipping. Check the chain tension and the sprocket teeth for wear. If the chain is OK, the gear cable and derailleur may need adjustment. If there is in fact an internal problem I don't think there is a remedy other than replacing the motor.

 

[mikesova]

Thanks for the reply. It's definitely not the chain slipping, there is no noise like a chain skipping on the sprocket. I even went out and double checked this morning. the slippage is definitely happening inside. I started a "build thread" here with more information. This is a low buck project, so replacing the motor is probably out, but I'm not scared of getting inside and trying to fix the mechanical internals. The electric motor part seems to be functioning fine.

 

[Al P]

As was mentioned in your other thread, try calling Raleigh to see if they have parts and a diagram available. If not, check with a Raleigh dealer rather than poke around in the motor. If they can fix it for a reasonable cost you would still be way ahead of the game.