Vibration/rumble when Accelerating and Regen braking on Grin All Axle

[LlamaBikes]

Details:

• New build with all new ebike components bought from Grin
• Phase runner v3 control w/super harness
• Grin all axle rear hub motor
• 72v 16.5Ah triangle battery
• 2013 surly karate monkey frame

First test ride was great but unfortunately I got greedy and ended up taking a fall in the parking garage. After that the problem started.

Motor vibrates the whole bike when under hard load from slow roll till faster (20km/h?) Regen sounds grumbly compared to usual. I'm not sure if it's typical but I've also found regen to be somewhat inconsistant in the amount, but maybe that's just a situational thing?

I checked all the cables, checked for shorts, tried removing the brake calipers, checked spoke tension (but I'm definitely not a wheel expert) removed the wheel, brake rotor and torque arm and checked all cables and re-seated everything.

I brought it to Grin and they had a look, they couldn't find anything wrong but they said it does sound unusual but didn't seem willing to want to help?

I'm all out of ideas and this is going to bother me until it's resolved. My instinct tells me it's something to do with the motor cabling being damaged in the fall, but I'm a little hesitant to take the wheel apart just on a hunch?

First video is with the phone strapped directly to the rear rack so the vibrations are much louder than you'd hear while riding:

 

[gromike]

Sounds like a bit of brake rotor rub. I don't know what makes the sound like a playing card rubbing on the spokes.
What did you set your regen level too?

 

[offGridDownUnder]

but didn't seem willing to want to help?

Grin is a DIY supplier, and you DIY.

What happens when you rotate the wheel by hand without power? Explore this for a bit, go as far as you can to get your answer. Disconnect the motor cables, fasten the bike to something so you can spin the wheel by hand and not hold back. Keep at it..

Let us know here.

 

[LlamaBikes]

Sounds like a bit of brake rotor rub. I don't know what makes the sound like a playing card rubbing on the spokes.
What did you set your regen level too?

It's definitely not brake rotor rub because I've tried removing the caliper entirely as a way to rule that out

 

[LlamaBikes]

Grin is a DIY supplier, and you DIY.

What happens when you rotate the wheel by hand without power? Explore this for a bit, go as far as you can to get your answer. Disconnect the motor cables, fasten the bike to something so you can spin the wheel by hand and not hold back. Keep at it..

Let us know here.

Unfortunately this is my first hub motor and the problem started after the first test ride so I don't have the contextual experience to know what sounds/feels typical of a hub motor spinning by hand without power. I do hear/feel some things but it doesn't sound bad or wrong to my inexperienced ears.

I will be picking up the programming cable next week and will do some digging. Right now it's just on the stock grin settings

 

[gromike]

When I installed an All-Axle I progressively adjusted the regen setting in the controller down. I think I went down to 30 from 100 (percent I assume). I'd be afraid of breaking or tweaking something at full regen on a 72v system.

 

[offGridDownUnder]

do hear/feel some things but it doesn't sound bad or wrong to my inexperienced ears.

And do these sounds mimic the sounds you hear when you do ride the bike?

If you coast the bike down a slope without power, do you hear the sounds you hear when powered? The motor can get you up the hill and then you can turn if off while you try the experiment.

 

[offGridDownUnder]

I think I went down to 30 from 100 (percent I assume).

Good thought. I'm not familiar with s SuperHarness and like interface. Does that let you dial the regen to 0? With my CA, there are more than one regen limits I can impose. I don't know what your interface gives you visibility of.

 

[LlamaBikes]

When I installed an All-Axle I progressively adjusted the regen setting in the controller down. I think I went down to 30 from 100 (percent I assume). I'd be afraid of breaking or tweaking something at full regen on a 72v system.

Interesting. I've been enjoying the strong regen, I just went for a long ride and pretty much used it as my only brake for the rear. What are you worried about breaking or tweaking? like the hub in the dropout?

 

[LlamaBikes]

And do these sounds mimic the sounds you hear when you do ride the bike?

If you coast the bike down a slope without power, do you hear the sounds you hear when powered? The motor can get you up the hill and then you can turn if off while you try the experiment.

I think there might be a faint rumble when turning the wheel unpowered by hand, but it's super faint. When i coast without power it does not make the sound. Only on power

 

[offGridDownUnder]

I think there might be a faint rumble when turning the wheel unpowered by hand, but it's super faint.

Of course I can't hear what you hear, but I could expect something from the magnet 'cogging'. I would turn my attention to the regen settings for a possible quick win and proceed hence.

 

[smitty2k1]

I've got a vibration in my all axle and super harness that has manifested over the past two years. A trip back to grin ($400) didn't fix it either. 48v w/ baserunner. I suspect it's a bearing. Happens under load or no load, motor on or off. Sorta ramps up and down with different speeds.

Yours sounds more significant though.

 

[neptronix]

My money is on bearings here.

 

[LlamaBikes]

I'm still waiting on some parts for a Brake upgrade I got myself in the middle of, but while I was working on that I discovered the cassette spacer that was included was incompatible with the cassette I put on. At the back of the cassette there were 3 pins slightly sticking out which had deformed the spacer ring. There are some spacer rings that have notches cut out on them to account for this and I happened to have one on hand. Now the cassette runs true.

I think there's a small chance the warped spacer and wobbling cassette may have caused some weird tension on the motor body? Well have to see later this week when the new brake hose kit arrives

 

[dab]

I'm having a similar issue with a TSM-A5, although there are some differences. 72v TSM-A5 vibrates,throttle cuts off, no regen

 

[gromike]

That TSM-A5 is in failure mode. The bearing boss that the torque arm fits to has probably turned and is cutting/grounding/shorting the wires going into the motor.
My posting on this issue is here:
TSM-A5 failure
I'd suggest you don't ride it and take apart the motor and look inside.

 

[LlamaBikes]

Ok so I finally figured out my brake situation... Mostly enough the ride the bike again. Loaded up the phase runner software, re loaded the defaults from grin... And the vibration has improved! It's still there but a lot more subtle .. more testing to do throughout this week