Knocking sound from BB area

Rik08

Member
Jan 9, 2021
68
22
Leamington
So my E150rs has started to make an occasional knock/tap sound from bottom bracket area, I know there is no BB, Amy ideas ? Only when pedalling, motor on or off, not all the time and more when loaded then spinning freely (so it wouldn’t do it on bike stand), 550 miles in
 

kenevo Nige

Member
Jul 28, 2019
18
28
Clitheroe
So my E150rs has started to make an occasional knock/tap sound from bottom bracket area, I know there is no BB, Amy ideas ? Only when pedalling, motor on or off, not all the time and more when loaded then spinning freely (so it wouldn’t do it on bike stand), 550 miles in
Check to see if the chain ring locking nut is tight , the bosch gen 4 is known for it. Just grab the ring and give it a jiggle, if there's movement there's your problem
 

Rik08

Member
Jan 9, 2021
68
22
Leamington
Check to see if the chain ring locking nut is tight , the bosch gen 4 is known for it. Just grab the ring and give it a jiggle, if there's movement there's your problem
That’s all tight ! I’ve ordered a lock nut removal tool so I can take chainring off to get to bottom swingarm bolt to check torque of it !
 
Last edited:

N9VNS

Active member
Jun 26, 2020
101
143
South Wales
I’ve seen a few people on facebook have a knocking noise which they thought was their BB but it turned out to be a loose bolt that holds the rear shock in place. Worth checking this.
 

Clubby

Active member
Oct 3, 2020
159
132
Tayside
Few different threads in Bosch section. Try this one see if it sounds familiar.

 

Rik08

Member
Jan 9, 2021
68
22
Leamington
So checked all the linkages are still at 24nm, removed and greased seat, bars removed and cleaned, so making the noise, sometimes it’s a creaking noise, some times just a metallic feel, only when pedalling so driveline related surely? Wd40’d the linkages earlier, Next up remove pedals and fit so cheapo clip less I have, after that I’m running out of ideas, it’s not the clutch or the downhill rattle in freewheel, I’m worried bearings in motor are on way out after 600 miles !?
 

Tribey

Active member
Jan 1, 2019
313
225
South Devon, UK
Without hearing it, it's hard to judge. Have you tried riding and pulling a control cable taut at the bar, in case its rubbing inside the frame.
 

Rik08

Member
Jan 9, 2021
68
22
Leamington
Ok so after much investigation! Chainring found to be loose (but only just happened as I’d checked it before !), cranks removed, cleaned, motor mounts checked - lower 2 behind plastic cover on non drive side moved about half a turn each, rest were tight. Cranks regreased and refitted, tested and still the random knocking sound ! Front QR removed, cleaned, greased refitted, rear axle tightened (was tight), most likely candidate was the seat post, pulled this out as far as I could, a lot of dust, cleaned up as best as I could. Took bike out tonight, nice and quiet !! How do I get seat post out ?
 

duncbrad

New Member
Mar 18, 2021
2
2
Sheffield
had this on my e150rs, turned out it was a faulty bearing on the pivot of the swingarm by the rear mech
bearing felt really rough considering it was only a couple of months old, quite difficult to trace. No noise downhill orwhen freewheeling or bouncing but bad under load climbing. sounded really creaky /clonky like the frame had a weld broken of something. got it replaced under warranty and cured everything.
 

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