Stiff rear wheel

[cer]

Hi,

I recently bought a cheap electric bike (Hitway BK15) which I haven't yet used. After assembling it I was away for a week, so left it in the shed with the plan of using it for the first time this week.

However, I've now found that the rear wheel is stiff (doesn't spin freely), which I'm sure wasn't the case when assembling the bike. I think I may have over-tightened the axle nuts and caused the hub to tighten somehow (maybe by pushing the anti-rotation washers inwards?).

Anyway, I don't know how to loosen it. I have in the past adjusted the hub on a standard quick release rear wheel, but I'm a total newbie to e-bikes and basically don't know what to do. I haven't found any instructional videos on Youtube that have helped. I'm not sure if I need to remove the freewheel or what tools to use.

Could anyone tell me how to fix this?

Thanks for any help.

 

[saneagle]

It's impossible to say what you did wrong without seeing photos. Either you had the washers in the wrong sequence or your disc out of line with the caliper. Put the wheel back on with the caliper removed from its adapter and see what happens.

 

[cer]

Hi,

Thanks for the reply. It's nothing to do with the brakes as I've already tested it with the caliper removed. The washers were in the correct position (verified this with an online video from the bike company). The wheel doesn't spin freely even when removed the bike.

Here is a short video of how the wheel spins (note: no brakes):

http://imgur.com/a/RjJXSyh

So how do I fix this?

 

[Sparksandbangs]

Does it spin freely when out of the frame?

 

[cer]

Does it spin freely when out of the frame?

No, it doesn't. It did initally though. Something has happened, which I thought may have been due to the axle nuts being over-tightened. I haven't actually ridden the bike yet.

Regardless of what has caused it though, how do I make the wheel spin freely again? That's the main thing I'd like to know.

 

[Cadence]

Have you tried removing the brake disc and spinning it? Perhaps the disc bolts are too long and catching the motor inside?

 

[cer]

Have you tried removing the brake disc and spinning it? Perhaps the disc bolts are too long and catching the motor inside?

I haven't tried that, but I did actually replace the original disc brake rotor because it was slightly warped and I decided to get a new one rather than trying to true it. However, I'm fairly sure the bolts were exactly the same as the original ones so I don't think that's what's happened. It doesn't feel like anything catching the motor, it's just stiff. I'll check it tomorrow though just in case, thanks.

 

[Benjahmin]

Disc bolts would be my first thought. Second would be the smallest cog of the gear cluster rubbing on the frame. It's not possible to see in your video if the wheel is centred in the frame. Is the tyre rubbing anywhere?

 

[saneagle]

I haven't tried that, but I did actually replace the original disc brake rotor because it was slightly warped and I decided to get a new one rather than trying to true it. However, I'm fairly sure the bolts were exactly the same as the original ones so I don't think that's what's happened. It doesn't feel like anything catching the motor, it's just stiff. I'll check it tomorrow though just in case, thanks.

If you changed the screws at the same time of the disc, that's probably it, though they look like the correct ones in the photo. The only other thing I've seen is when a batch of Bafang motors were over-shimmed on the inside, which made them tight to turn and knackered the bearings in no time. I guess you could get the same with under-shimming. Did you attempt to tighten any inner axle nut/s. I can't see any in the photo. The only other thing to cause stiffness is when the gears rub on the motor at the back, which you fix with a spacer, but that would be stiff off the bike.

Please confirm that the motor is still stiff when you hold one axle in a vice and try to turn it.

 

[cer]

Thanks everyone for the replies. I can now confirm it was actually the disc brake rotor that was causing it! After removing it, the wheel spins fine again. I had no idea that could be the cause of the issue. When I replaced the disc I was going to use the bolts from the the original one, but one of them stripped so I used the new bolts instead. I'll be buying some better quality (and correctly sized ones) now. Cheers for the help.

 

[saneagle]

Thanks everyone for the replies. I can now confirm it was actually the disc brake rotor that was causing it! After removing it, the wheel spins fine again. I had no idea that could be the cause of the issue. When I replaced the disc I was going to use the bolts from the the original one, but one of them stripped so I used the new bolts instead. I'll be buying some better quality (and correctly sized ones) now. Cheers for the help.

Standard bike disc brake screws are too long. You should use the ones that come with the motor, otherwise get replacements that are exactly the same length.