Help! Rubbing noise coming from Bafang RM G010.250.D motor under load

[spleenharvester]

Hi everyone

I have a Dawes Falcon 2022 commuter ebike. In January the stock rear rim split and while taking it apart for repair I found the motor, a Bafang rear hub G010.250.D, had the usual issue with the cable starting to tear where it goes into the axle. I replaced the cable myself and then took the motor to be laced into a new WeThePeople 20" rim.

Recently it has started making a rubbing noise per this video:

It only happens when you are sat on the ebike and moving, once per wheel revolution. It happens on both PAS and throttle without pedalling so does not appear to be the drivetrain. If you hold the rear of the bike up in the air and press the throttle it does not make the noise. At first I thought the tyre was rubbing something but I've checked repeatedly and cannot find any evidence of that. There is no loss of power and the bike is otherwise working fine.

I have tried adjusting the clutch bolts at the rear of the motor to ensure they are at the same torque but it hasn't made a difference. Any ideas?

 

[matthewslack]

Too much extraneous noise, and image is just blur, so unable to help.

 

[spleenharvester]

Too much extraneous noise, and image is just blur, so unable to help.

It only happens when sat on the bicycle and moving at speed. Unfortunately I do not have a third arm to hold the camera with so this was the best I could get.

 

[saneagle]

It only happens when sat on the bicycle and moving at speed. Unfortunately I do not have a third arm to hold the camera with so this was the best I could get.

I didn't hear anything other than some rustling noise and a whirring motor. Did you listen to the video yourself?

 

[spleenharvester]

I didn't hear anything other than some rustling noise and a whirring motor. Did you listen to the video yourself?

Yes, it's most prominent in the last two seconds, a plastic rubbing sound on and off
If anyone knows how I can get a clearer video at speed I am open to suggestions.

 

[spleenharvester]

Ok I've pulled the motor off the bike. The noise is definitely coming from the planetary gears - you can kind of feel some intermittent friction when spinning it by hand - but it's an intermittent noise/vibration so I am struggling to track down exactly where it is coming from. The teeth are all present and I see no debris in the shell so I am leaning towards a bearing problem.

The motor is also in generally poor condition and my wiring fix looks messy as all hell so I am going to be redoing that (I had real trouble routing the wires last time), but it still checks out OK on the multimeter so I don't think it is involved.

I think the easiest solution would be to just swap another motor into the existing shell but unfortunately the G010.250.D is out of production.

EDIT - She's scrubbed up nicely with a few hours of wire brush and hammerite actually. I've rerouted that green wire that was scraping the housing, and tomorrow I am going to put some fresh grease on and take a closer look at that planetary gear once I have a bearing puller. If I'm lucky the sticking thing I'm feeling might just be normal (I've never felt this part of the motor before so I'm not sure) and the thick layer of rust may have just been the source of the noise. Will update

 

[Sturmey]

I wonder is the side cover rubbing of the green wire where the insulation has worn away?

 

[matthewslack]

The big green phase wire is worn through, and so able to short to the casing... that might well cause some noise.

Rust particles in the plastic gears also not good, and dry, no grease. If you put right everything that looks wrong that might be all you need to do. Might as well check if any bearings need replacing while you're at it, and remember that the plastic gears need a compatible grease, not any old grease. I don't remember what's OK, but out of date aerospace greases ring a bell.

 

[spleenharvester]

Cheers both, and good spot - I've since rerouted both the green phase wire and the yellow phase wire and it is sitting much nicer now, not sure why I made a mess of it the first time!

I'm leaving hammerite to dry on the sides overnight, then when my bearing puller arrives tomorrow I am going to change all the planetary gears and the two main bearings (both 6001-2RS) and add Super Lube synthetic grease. Will let you all know if it works

 

[matthewslack]

And reinsulated I hope!

 

[Nealh]

Moisture ingress has been an issue so rusty /dry clutch bearings may be an issue.
Repairing the phases will be a good move.
Tbh whilst it is open repalce all bearings one can get at ( they are cheap to buy) LHS casing bearing is one.

One might be able to remove the clutch assembly to get a better look at the nylon gear bearings, one should be able to replace those as well.

 

[spleenharvester]

I've had a bit of a nightmare with getting the planetary gears off. First, the non-drive-side bearing was absolutely jammed on the axle. When I tried to use a bearing puller on it, the outer and middle parts of the bearing just broke off. So I ended up having to hammer an impact socket onto what was left of the bearing, then use an even bigger bearing puller on that. Thankfully it pulled it off.

Then there was the circlips. The god damn circlips. The huge one was a complete pain in the backside even with circlip pliers. Between that and the three on the gears themselves it took over an hour to get all of the damn things off. The amount of force required to open the circlips also permanently deformed them. I did also have to use a bearing puller on the planetary gear platform itself as it was really rammed on too.

Anyway I got the gears off and found one of them was causing the sticking sensation, and it had a small dent in the bearing casing. Fitted all new bearings and greased... then when getting that final M12 circlip back on it shattered into a million pieces when I tried to spread it. So now I am waiting for a new circlip. Fingers crossed that should be the end of it...

 

[spleenharvester]

Circlip arrived today, fitted and reinstalled everything, problem is resolved and motor feels much smoother now.

 

[matthewslack]

And now you know exactly the state of your motor, and how to solve any future issues. Well done!

 

[spleenharvester]

Yep I'm very happy with it! Just need to put some RTV gasket on the drive side I think to stop rust getting in again.

Some random tips for anyone looking to repair this motor in the future, as there doesn't seem to be a lot of info on the G010 series:

• Accessing the motor: If your housing is intact you can do all of the work without unlacing the motor housing. If you are just replacing the cable, you can remove the six small bolts on the drive side and lift the drive side casing off, though you may need to whack it a few times with a hammer to free it up before it will lift off. You do not need to remove the gears to do this (on the freewheel version at least). If you thereafter need to access the planetary gears you will likely need to take a hammer to the non-drive side axle in order to slide the whole motor unit out of the casing. During reassembly I recommend replacing the bolts with new ones as they are quite prone to stripping with corrosion etc. You shouldn't need to remove the six large bolts on the non-drive side but if you do, be careful not to overtorque them back in as they will collide with the planetary gear platform.
• Splayed cable: This motor can encounter the usual issue of the torn motor cable at the point where it enters the axle. Mine lasted about 2 years/probably 1000 miles usage before I noticed the outer insulation was torn and I imagine it would not have lasted much longer than that. You can replace it by getting a standard 9-pin Julet extension cable and just cutting the female side off. The trickiest part (per earlier posts) is getting the replacement cables to sit flat enough that they don't contact the hub, and getting heatshrink on them with the very limited space. Try and put some more strain relief on the cable to stop it happening again (stronger spring etc), and make sure you fit this onto the cable before you thread it through the axle!. Don't forget to silicone seal the entry point and re-mount the wheel to the bike with the axle gap pointing downwards to prevent water getting in.
• Main bearings: These motors use two 16001-2RS sealed ball bearings, one on the drive side and one on the non-drive side. In my case the drive side was easy to hammer out of its housing, but unlike in all the videos where it pops out nicely the non-drive side was absolutely jammed onto the axle and required a bearing puller. When fitting new bearings, hammer them in with a socket or similar round tool that is the same diameter as the outer bearing track and no smaller. If you hammer them in any other way you will damage the casing.
• Circlips: For the love of god get a decent circlip plier, it will make your life a million times easier, tweezers just do not work the same way. The main axle circlips are M14 size. The planetary gear circlips are M8 size so make sure you get some particularly small pliers too. I recommend buying some spare circlips (you can get a huge kit of them for like £6) in case the factory ones get deformed or shatter during the process.
• Planetary gears: This motor uses three standard 38mm x 12mm 36-teeth gears. The gears are fitted with standard 608ZZ bearings. If your gear teeth are OK you can just knock out the bad bearing with a chisel and fit another. These bearings are easy to dent/deform when fitting so I recommend you buy some extras anyway. On my unit there wasn't a detachable key for the planetary gear platform like there is on some larger motors - just one that was part of the axle itself.
• Greasing: I used brake and clutch cleaner to get the existing grease off. I used Super Lube synthetic grease and brushed it onto each of the gear teeth with a hard bristle brush, and then same again onto the teeth of the non-drive side casing. This was the only relatively inexpensive one I can find in the UK - alternatively you need proper aviation grease like Mobil 28. Take care not to over-grease as you will get drag from viscosity effects.
• Rusty housing: If yours has accumulated rust the same way mine did, Hammerite Kurust seems to take it off nicely. I did one pass, used brake cleaner to remove the excess, then did another thin layer as the protective coat.

 

[saneagle]

Yep I'm very happy with it! Just need to put some RTV gasket on the drive side I think to stop rust getting in again.

Some random tips for anyone looking to repair this motor in the future, as there doesn't seem to be a lot of info on the G010 series:

• Accessing the motor: If your housing is intact you can do all of the work without unlacing the motor housing. If you are just replacing the cable, you can remove the six small bolts on the drive side and lift the drive side casing off, though you may need to whack it a few times with a hammer to free it up before it will lift off. You do not need to remove the gears to do this (on the freewheel version at least). If you thereafter need to access the planetary gears you will likely need to take a hammer to the non-drive side axle in order to slide the whole motor unit out of the casing. During reassembly I recommend replacing the bolts with new ones as they are quite prone to stripping with corrosion etc. You shouldn't need to remove the six large bolts on the non-drive side but if you do, be careful not to overtorque them back in as they will collide with the planetary gear platform.
• Splayed cable: This motor can encounter the usual issue of the torn motor cable at the point where it enters the axle. Mine lasted about 2 years/probably 1000 miles usage before I noticed the outer insulation was torn and I imagine it would not have lasted much longer than that. You can replace it by getting a standard 9-pin Julet extension cable and just cutting the female side off. The trickiest part (per earlier posts) is getting the replacement cables to sit flat enough that they don't contact the hub, and getting heatshrink on them with the very limited space. Try and put some more strain relief on the cable to stop it happening again (stronger spring etc), and make sure you fit this onto the cable before you thread it through the axle!. Don't forget to silicone seal the entry point and re-mount the wheel to the bike with the axle gap pointing downwards to prevent water getting in.
• Main bearings: These motors use two 16001-2RS sealed ball bearings, one on the drive side and one on the non-drive side. In my case the drive side was easy to hammer out of its housing, but unlike in all the videos where it pops out nicely the non-drive side was absolutely jammed onto the axle and required a bearing puller. When fitting new bearings, hammer them in with a socket or similar round tool that is the same diameter as the outer bearing track and no smaller. If you hammer them in any other way you will damage the casing.
• Circlips: For the love of god get a decent circlip plier, it will make your life a million times easier, tweezers just do not work the same way. The main axle circlips are M14 size. The planetary gear circlips are M8 size so make sure you get some particularly small pliers too. I recommend buying some spare circlips (you can get a huge kit of them for like £6) in case the factory ones get deformed or shatter during the process.
• Planetary gears: This motor uses three standard 38mm x 12mm 36-teeth gears. The gears are fitted with standard 608ZZ bearings. If your gear teeth are OK you can just knock out the bad bearing with a chisel and fit another. These bearings are easy to dent/deform when fitting so I recommend you buy some extras anyway. On my unit there wasn't a detachable key for the planetary gear platform like there is on some larger motors - just one that was part of the axle itself.
• Greasing: I used brake and clutch cleaner to get the existing grease off. I used Super Lube synthetic grease and brushed it onto each of the gear teeth with a hard bristle brush, and then same again onto the teeth of the non-drive side casing. This was the only relatively inexpensive one I can find in the UK - alternatively you need proper aviation grease like Mobil 28. Take care not to over-grease as you will get drag from viscosity effects.
• Rusty housing: If yours has accumulated rust the same way mine did, Hammerite Kurust seems to take it off nicely. I did one pass, used brake cleaner to remove the excess, then did another thin layer as the protective coat.

You don't have to worry too much about sealing the side-plate. It's quite difficult for water to get in there. I've serviced many waterlogged motors, and the water has always entered along the cable through the axle, in most cases because the wheel had been wrongly fitted with the cable exiting upwards instead of downwards. It's the cable you should seal if you can, but even that probably won't help considering points below.

Water can also get in through the disc holes if the screws are loose or missing and the holes are not blind. I'm pretty sure AKM motors have blind holes, so no problem; however, I know for certain that at least some Bafang motor have holes right through, so it's a good idea to seal them as well.

The biggest problem with motors and water is the change in temperature. When you use the motor, it becomes warm and the air inside expands. When you park up, the motor cools down, the air contracts and socks in any water that's in the path that the air would take, which is why you must have the cable exiting downwards. It's also best to lean your bike with the cable on the lowest side.