BBSHD - rotational knocking sound under higher load with PAS and throttle

[Peddlin' Pedro]

My newly installed BBSHD running at 52V has developed a rotational knocking noise under high loads and occurring under both PAS and throttle.

Drive is a BBSHD with Lekkie BBSHD final drive cover V2, well greased with Aeroshell grease 22.

@wheeliepete in answer to your question (deleted?), it occurs under PAS and throttle. On closer inspection it seems to come from the final drive and is a louder initial knock followed immediately, and at a consistent interval, by a slightly quieter one. Wondering if it's the final drive bearing or something else in that area.

Linked vid shows issue in a static context (turn audio up) but will try and video it in action. Excuse the wheezing background noise: something's been sprayed on local fields and feels like hay fever season's back!

Obvious stuff I've already checked is:

- Drive securely fitted and heavily torqued with no free-play or rotation in BB
- Cranks torqued to spec with no play
- Pedals correctly installed with no freeplay or bearing issues
- New 42t Lekkie clone ring: tightened to spec torque
- New 9-spd chain and 11-42t cassette: correctly fitted, lockring torqued to spec and no play at cassette-to-freehub body interface
- Rear hub is Hope Pro 4 with steel freehub body with pawls and engagement ring in good condition and no play at freehub body to hub interface

Thoughts appreciated. Cheers!

 

[peter.c]

Try it without the chain on will get speed sensor error but before it shows up this will reduce the amount of items in play at the same time
Does it still occur under human power only

 

[Peddlin' Pedro]

Try it without the chain on will get speed sensor error but before it shows up this will reduce the amount of items in play at the same time
Does it still occur under human power only

Only does it under load with the motor pulling, i.e. hard acceleration or steep climbs. Power setting doesn’t make any difference. I turned it down to zero and ground up a few climbs to check and definitely only happens with the drive running.

 

[peter.c]

So it has to be in the electrical or clutch of the motor or a flex under load

 

[wheeliepete]

Not sure what happened to my post, anyway, I'm thinking that maybe your final drive gear is not fully pressed into the Lekkie cover bearing and is fouling on the main casing or poss. a duff bearing. I have my drive apart at the moment to replace a broken PAS disc and i don't seem to have the backlash you have.

 

[Peddlin' Pedro]

Thanks both. Was resigned to pulling the drive and opening it again to check so will let you know what I find.

 

[Peddlin' Pedro]

Had the drive cover off this afternoon. Final drive bearing was properly seated and felt fine but the inner thrust bearing race was backwards, no damage to bearings or races though. Final drive gear and pinion both looked fine but didn't scrutinise every tooth. Cleaned everything up, re greased and reassembled. Five miles out all’s fine with mix of throttle and PAS on flat acceleration and steeper climbs.

Stopped briefly to let truck pass and when pulling away up a hill the knock returned

Managed to get a short video but it's not great:

- single, audible knock (once per crank revolution) though seems to be consistently at around 1-2 o'clock on the DS
- without any discernible sensation
- only present under PAS or throttle and at mid-high torque
- previously it was a double knock and occasionally changed position in the revolution

Not familiar enough with these units to know where to go next, other than switching back to the original drive cover to see if it's a duff bearing, though original may have been damaged in the course of driving the final drive gear off it. Ideas?

 

[Karel]

Pedro,

My BBSHD makes a similar noise. I made a video showing the clicking noise. Same sensation as you are explaining. It's only present under PAS or throttle at a mid to high torque. I don't feel confident to keep riding it as I don't want to destroy anything inside. I took the first cover on the drive side off, to inspect the gears, and they are all in good condition. I cleaned it and applied new grease but it's still making the same noise. Anyone has any ideas what could be the issue? I prefer not to take it all apart as I have little engineering knowledge
(366) BBSHD clicling noise - YouTube

 

[Karel]

Pedro,

My BBSHD makes a similar noise. I made a video showing the clicking noise. Same sensation as you are explaining. It's only present under PAS or throttle at a mid to high torque. I don't feel confident to keep riding it as I don't want to destroy anything inside. I took the first cover on the drive side off, to inspect the gears, and they are all in good condition. I cleaned it and applied new grease but it's still making the same noise. Anyone has any ideas what could be the issue? I prefer not to take it all apart as I have little engineering knowledge
(366) BBSHD clicling noise - YouTube

Update: I opened it up once again, added more moly grease to the secondary reduction gear. Then, without the chain installed, i activated the throttle during 2 full minutes, to make sure the grease got to all the right places. Reinstalled the chain afterwards, and it's no longer making the ticking noise.

 

[mr_ed]

I've noticed a click/knock from my recent installed BBSHD but I'm not too worried about it, I think its the clutch engaging/disengaging.

It only does it when the motor is hot (after 20 miles or so) so I think the grease is thinner at this point.
It only does it when pedalling hard and once on the down stroke of a pedal revolution.

I think the force applied by pedal motion is not smooth/continuous and spikes on each downstroke and so I'm momentarily disengaging/re-engaging the clutch on these strokes.

On lower loads, ghost-pedalling, or when the motor is cold it doesn't do it.

I think I'm in a minority in that I don't have a throttle installed!