Anything to do with the tyres on certain surfaces?
I had exactly that problem with a bike i bought recently
Very disappointing start....
- Thread starter ScottA
- Start date
I had exactly that problem with a bike i bought recently
Oh my god, it gets worse!! Woosh killed Bambi and shot his MumIn the interests of accuracy (and being a pedant) I think it was Bambi's mum that was shot
Jim
I'm inconsolable.
Gaz
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Joking aside, isn't it worth checking the bearings and re-packing them with grease? There's only a limited number of moving parts that'll cause vibration and one ball bearing that's out of true or has a compromised surface can cause all sorts of rumblings. And not get any worse (necessarily) over time.
Gaz
Gaz
To address the balance, I heard rumours that some of the other ebike sellers on here were involved with the construction works at Watership Ship down, evicting many innocent rabbits and leading to their untimely demise
No need for all that....To address the balance, I heard rumours that some of the other ebike sellers on here were involved with the construction works at Watership Ship down, evicting many innocent rabbits and leading to their untimely demise
Just give them a large plate of toasted ham and toasted cheese sandwiches.
Then sit back......
Watch them die....
Of.
mixing ma toasties.
the difficulty is that we can't feel what Scott feels from the pedals, not from his saddle. The vibrations are not obvious enough. Scott described it as something that feels graunchy in the pedals. Like a bad ball bearing. That's why his first suspicion was on the bottom bracket, then when he removed the chain, he can't feel anything graunchy there. So the vibration travels up, through the chain.
I did ask him whether the motor was on or off, he said the motor was on, adding one more variable into the equation.
@ ScottA
Scott, can you do this experiment?
1. try to get the vibrations to come up. Note the gear number and current speed and location. That way, we can try to recreate the conditions.
2. Blip the brakes to cut off the motor while continuing to pedal. Does the vibration cease?
3. try to get the vibrations to come up again. This time, stop pedaling.
Does the vibration cease?
4. try to get the vibrations to come up again. This time, change gear. Does the vibration cease?
5. Turn the preload lever on the left fork about 45 degrees anti-clockwise to reduce the preload (make the fork goes softer) and try to get the vibrations to come up again. Does the vibration cease?
I also wonder if it is linked to the legal speed limiter. When you get around the speed limit (15.5mph), the motor can start and stop, causing that sort of sensation.
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The thread is still here...ok anyway @Woosh - no problem will do - thanks. Just completed 15 mile round trip to Benfleet. No issues. Sensation no better no worse. Recorded on Strava but not sure how to share?
Used assist 2 or 3 depending and v. occasional throttle on return journey to get past some slow cars (!).
Quick question - I assume front wheel bearing are adjustable? Noticed a bit of side to side play when I got home so guessing easy adjustment
Started with full charge half battery left according to gauge.
Anyway a great ride - bike got attention and discovered car drivers don't like being overtaken on inside...
Used assist 2 or 3 depending and v. occasional throttle on return journey to get past some slow cars (!).
Quick question - I assume front wheel bearing are adjustable? Noticed a bit of side to side play when I got home so guessing easy adjustment
Started with full charge half battery left according to gauge.
Anyway a great ride - bike got attention and discovered car drivers don't like being overtaken on inside...
Just thinking out loud but could the effect of taking the chain off hide what's going on if it needs the chain in place to allow enough pressure on the pedals to show it up, rather than it being conclusive that the vibration is being conducted along the chain?
I'm no cycle mechanic though, so I'm going to shut up now and mind my own business
Gaz
Can't say how insane I find overtaking cars on the inside.
It is one of the major causes of serious accidents for cyclists.
Cars and their passengers aren't expecting it ( and nor should they be ).They will pull in towards the kerb without looking to let cars going the other way pass in a tight space, they will open kerbside doors without looking. Sorry but cycling proficiency test fail unless in a totally segregated cycle lane not just a painted stripe on the road.
OK this is the best description I can come up with what’s happening:
What
Best description is a “Grrrr” feeling through the pedals as the crank passes from horizontal to vertical on the power stroke of either leg – in other words at the point of most load from the leg currently pushing the pedal down.
When
Only noticeable from 10mph upward from whence it becomes increasingly more noticeable up to 15mph when it is most noticeable.
Noticable in gears 7 or 8.
Happens with power on
Barely noticeable with power off – you’d have to be standing and powering as hard as you can to feel it.
Summary
It’s load related. It happens when most load is on the pedal from 10mph upward with motor on.
I've been reading up a lot on the Bafang/8fun over the weekend and the engine looks pretty simple - as Gaz says there aren't many bearings to check or regrease. What grease is recommended? Lithium? (not the spray stuff - it's crap)
What
Best description is a “Grrrr” feeling through the pedals as the crank passes from horizontal to vertical on the power stroke of either leg – in other words at the point of most load from the leg currently pushing the pedal down.
When
Only noticeable from 10mph upward from whence it becomes increasingly more noticeable up to 15mph when it is most noticeable.
Noticable in gears 7 or 8.
Happens with power on
Barely noticeable with power off – you’d have to be standing and powering as hard as you can to feel it.
Summary
It’s load related. It happens when most load is on the pedal from 10mph upward with motor on.
I've been reading up a lot on the Bafang/8fun over the weekend and the engine looks pretty simple - as Gaz says there aren't many bearings to check or regrease. What grease is recommended? Lithium? (not the spray stuff - it's crap)
D
Deleted member 4366
Guest
It's most likely a chainline issue. Look at it from the front when in top gear. See how the chain is out of line with the chainwheel. You often get that grinding when new, but it'll go away when things wear in.
You don't need to worry about greasing your Bafang motor. It should go for about 30,000 miles before needing a regrease unless you can find a clever way to fill it up with water, like putting your wheel on upside down.
D
Deleted member 4366
Guest
In fact I might know what the op means. I do feel a very, very slight vibration on the power stroke at all times. On mine its the left pedal causing it, it's just a little less smooth and spins less freely than the right pedal, I might clean and regrease at some point
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