Bafang BBSHD Vibration Problem

[adcockj]

I have a 100mm BBSHD installed on a Surly Pugsley fat bike, and I'm getting a motor vibration at the point where the motor assist cuts off. For example, when my Assist Level is set to help me up to 16 mph, I get a vibration slightly above that point. It's smooth acceleration up to that point. It does this at all assist levels, so it's not specific to a particular speed.

I have a little over 2400 miles on the bike/motor since I installed the new BBSHD at the first of this year. I ride almost exclusively on paved multi-use trails, so the motor has never been banged on or over-worked. I didn't have the vibration for the first 1000 miles or so. At first, I thought it was perhaps related to the chain or cassette. I changed both of those, with no effect. Then I thought it might be caused by a worn rear hub, so I had a new rear hub (DT Swiss 350) installed, again with no effect.

I've greased both sides of the gearing with Mobil 28...no help. Recently, I replaced the nylon gear (figuring it was the most obvious wear point)...no help.

I don't think it's a programming issue, since I also have a Trek DS8.4 with a BBSHD (with 3800 miles on it over the last year) with the same programming and it doesn't have the problem.

I've now spent almost as much as buying a new motor, and I still have the vibration issue.

Any recommendations? Change other/all gears or bearings?

 

[furcifer]

I have a 100mm BBSHD installed on a Surly Pugsley fat bike, and I'm getting a motor vibration at the point where the motor assist cuts off. For example, when my Assist Level is set to help me up to 16 mph, I get a vibration slightly above that point. It's smooth acceleration up to that point. It does this at all assist levels, so it's not specific to a particular speed.

I have a little over 2400 miles on the bike/motor since I installed the new BBSHD at the first of this year. I ride almost exclusively on paved multi-use trails, so the motor has never been banged on or over-worked. I didn't have the vibration for the first 1000 miles or so. At first, I thought it was perhaps related to the chain or cassette. I changed both of those, with no effect. Then I thought it might be caused by a worn rear hub, so I had a new rear hub (DT Swiss 350) installed, again with no effect.

I've greased both sides of the gearing with Mobil 28...no help. Recently, I replaced the nylon gear (figuring it was the most obvious wear point)...no help.

I don't think it's a programming issue, since I also have a Trek DS8.4 with a BBSHD (with 3800 miles on it over the last year) with the same programming and it doesn't have the problem.

I've now spent almost as much as buying a new motor, and I still have the vibration issue.

Any recommendations? Change other/all gears or bearings?

What's you chainline like? I get a harmonic vibration occasionally. It depends on the gear, but it starts at about 80% and goes away around 90% (of max rpm). Tension in the chain, some rpm, a bit of torque and the chain offset causes the vibration as it meshes with the front sprocket. The chain basically vibrates like a guitar string. There's probably also some flex in the wheel stays that contributes.

Tighten the bottom bracket and isolate the motor from the frame. I glued a piece of nylon webbing where it was making contact to act as padding. Rubber might work better but I wanted something durable and thin. I don't know if this helped, but it used to happen a few times every ride, now it's like every 10th ride. I changed my chain and cassette at about the same time. It's always a good idea to change your cassette and chain together so they mate. This has more to do with slip, but the better the rollers go into the sprocket the smoother it will work. Cyclists don't do this as often as motorcyclists, probably because of the power. Or maybe it's because just the thought of chain slip on a 1000cc is terrifying.

Hope this helps.

 

[adcockj]

I think my chainline is OK. It looks exactly straight in 5th gear (of my 9-speed). Also, the vibration is at the max of each assist level, regardless of whether it's Level 4 or Level 8, so the gear/chainline is in a different position for each one. As I mentioned, I've tried changing the chain several times, along with a new cassette...and a new rear hub.

As an aside, I've programmed the assist levels so that each assist level takes me up to a speed of 10+that number (so Level 5 takes me to 15mph). So it's consistent as I go up the levels from 11mph to 19mph. But the vibration happens at slightly above that speed for each.

I can try isolating the motor from the BB...I may try that if I can't nail down the cause.

Thanx.

 

[Muramura]

I think my chainline is OK. It looks exactly straight in 5th gear (of my 9-speed). Also, the vibration is at the max of each assist level, regardless of whether it's Level 4 or Level 8, so the gear/chainline is in a different position for each one. As I mentioned, I've tried changing the chain several times, along with a new cassette...and a new rear hub.

As an aside, I've programmed the assist levels so that each assist level takes me up to a speed of 10+that number (so Level 5 takes me to 15mph). So it's consistent as I go up the levels from 11mph to 19mph. But the vibration happens at slightly above that speed for each.

I can try isolating the motor from the BB...I may try that if I can't nail down the cause.

Thanx.

Hey was wondering if you fixed this problem, im having the same issue on gear 5 with my bbs02b motor and it vibrates on high stress or hills or speed. it feels like could be the pinion or a bearing? :L happened when I regreased it with mobil.

 

[fabieville]

I also have a problem with my cyclone 24v-72v geared 3000watt motor.
It vibrates a lot at high rpm even without load. Can someone tell me whats the cause of this please?
Please see video link below to see the problem i am facing. Running it at 0-50% rev is no issue but once the rev reaches around 80%-100% then it starts to vibrate real bad.
Please tell me what to do.

 

[Diggs]

I get a harmonic vibration occasionally.

Same here on my BBHSD or at least that is what I assume it is. Noticeable but not distracting.