Gear sensor - about to give up on it..

[egroover]

Hi all,

Bought a gear sensor about a year ago, never bothered to fit it until last weekend, as I was getting increasingly worried about not running one on my Bafang BBS01 and the crunching and clanking on the cassette/chain/chainwheel when up shifting, especially on high assist levels (10 speed setup). I was worried also if there was a risk of damage to the freehub too
The installation was straight forward enough, however, despite tweaking the programming, by reducing 'crank trigger pulses' from 4 to 2, the cut off and subsequent time it takes to pick up power again every time I change gear, is making it a pain to use.
I'm finding that I'm either running a taller or lower gear for longer to avoid shifting, or shifting 2 or 3 gears at the same time. This means when I do shift I lose power and speed/momentum, resulting in a really unnatural riding and up and down cadence.
My start current is set to 30%, I think this is what is causing the delay, it takes 2-3 seconds to get back up to full power again, about 2-3 pedal revolutions, I get bogged down every time. I'm worried about increasing this as I don't want to risk any damage to the controller if I happen to start off in the wrong gear any time

On the plus side, shifting is silent and smooth now with the sensor fitted

Has anyone got any tips to improve things ? Or do I rip it out and go back to clunking gears but enjoy the bike again, and putting a quid a week into a jar for a new gear train every 6 months

Cheers

 

[jarob10]

Gear sensor shouldn’t be needed on a bbs01

A clunking gear change with a BBS01 is a poor derailler setup. A gear sensor is the wrong sticking plaster.

 

[MontyPAS]

Hi all,

Bought a gear sensor about a year ago, never bothered to fit it until last weekend, as I was getting increasingly worried about not running one on my Bafang BBS01 and the crunching and clanking on the cassette/chain/chainwheel when up shifting, especially on high assist levels (10 speed setup). I was worried also if there was a risk of damage to the freehub too
The installation was straight forward enough, however, despite tweaking the programming, by reducing 'crank trigger pulses' from 4 to 2, the cut off and subsequent time it takes to pick up power again every time I change gear, is making it a pain to use.
I'm finding that I'm either running a taller or lower gear for longer to avoid shifting, or shifting 2 or 3 gears at the same time. This means when I do shift I lose power and speed/momentum, resulting in a really unnatural riding and up and down cadence.
My start current is set to 30%, I think this is what is causing the delay, it takes 2-3 seconds to get back up to full power again, about 2-3 pedal revolutions, I get bogged down every time. I'm worried about increasing this as I don't want to risk any damage to the controller if I happen to start off in the wrong gear any time

On the plus side, shifting is silent and smooth now with the sensor fitted

Has anyone got any tips to improve things ? Or do I rip it out and go back to clunking gears but enjoy the bike again, and putting a quid a week into a jar for a new gear train every 6 months

Cheers

Been using gear sensor on both my 500 & 750 BBS02b units, and they work faultlessly. Pick up time seems pretty instantaneous, but then again my 60+ year old legs are not spinning super fast!
Maybe posting screenshots of your Bafang tool configurations might show the problem ?

 

[Fordulike]

I agree with jarob10, there should be minimal clunking when changing gears with a BBS01. Probably no more noise than if you were running unpowered.
I am running a BBS02 with fairly maxed out settings, and even though I use the brake cut-off to cut power when changing gear, on the odd occasion I forget, it doesn't make too much noise.

Also, the start current or crank trigger pulses isn't what is causing the delay. It's inherent in some Bafang controllers that there is a big delay when using the brake cut-offs, and IIRC, the gear sensor taps into the brake cut-off system.

Have you tried momentarily stopping pedalling when changing gear? It tends to allows quicker re-engagement of the motor!

 

[MontyPAS]

I agree with jarob10, there should be minimal to no clunking when changing gears with a BBS01.
I am running a BBS02 with fairly maxed out settings, and even though I use the brake cut-off to cut power when changing gear, on the odd occasion I forget, it doesn't make too much noise.

Also, the start current or crank trigger pulses isn't what is causing the delay. It's inherent in some Bafang controllers that there is a big delay when using the brake cut-offs, and IIRC, the gear sensor taps into the brake cut-off system.

Have you tried momentarily stopping pedalling when changing gear? It tends to allows quicker re-engagement of the motor!

Just out of interest, what makes the BBS01 less prevalent to clunking gear change, compared to the BBS02b.
Thought internals were pretty much the same, just available as both 36v / 48v and greater power options in the 02.

Stand to be corrected????????

 

[Fordulike]

Just out of interest, what makes the BBS01 less prevalent to clunking gear change, compared to the BBS02b.
Thought internals were pretty much the same, just available as both 36v / 48v and greater power options in the 02.

Stand to be corrected????????

Far less outright power through the drivetrain. On PAS 1 on my BBS02, I have it set at approximately the same power as a maxed out BBS01. I can ride using this setting, without the need to use the brake cut-off to change gear. It makes no more drivetrain noise, than riding my bike unpowered.

I am using a 48v BBS02, so it maxes at approximately 1365 watts, with a freshly charged battery in top PAS. Pretty much a drivetrain killer if I don't use the cut-off.

 

[MontyPAS]

Far less outright power through the drivetrain. On PAS 1 on my BBS02, I have it set at approximately the same power as a maxed out BBS01. I can ride using this setting, without the need to use the brake cut-off to change gear. It makes no more drivetrain noise, than riding my bike unpowered.

I am using a 48v BBS02, so it maxes at approximately 1365 watts, with a freshly charged battery in top PAS. Pretty much a drivetrain killer if I don't use the cut-off.

So purely the lower power of the BBS01 at 250w, dictates the use or non use of the gear sensor.
Be interesting to see longevity tests of transmission with and without said sensor?

 

[Fordulike]

So purely the lower power of the BBS01 at 250w, dictates the use or non use of the gear sensor.
Be interesting to see longevity tests of transmission with and without said sensor?

It's not as clear-cut as that. I think it also depends on the other components in the set-up.
The OP might have a derailleur, chain, cassette combo that just happens to be noisy. So no matter how little power they put through the system, it'll still be noisy. As jarob10 states, it might be a poorly adjusted derailleur.

I personally don't use a gear sensor, as I have just learned to blip the brake cut-off when changing gears. This also allows me to not cut the power, when a cut in power would lose momentum. The gear sensor would cut power in all situations when changing gears. Not ideal for me, but I can see why some riders would fit one.

 

[egroover]

Hi all,
Thanks for your valuable feedback and advice.
I think I'm gonna remove the sensor. Although I've enjoyed quiet and silky smooth gear changes this past week or so with it in place, I can't live with the drop off in power on every change.
I have a new cassette and chain, and now with the sensor it's quiet and smooth, so I'm thinking the setup is correct, I guess I've just got a noisy setup under load (600w+ on top assist).
I did think that perhaps I could try and remove a link out of the chain, would a slightly too long chain cause noisier shifting under load ?

cheers

 

[jarob10]

More likely derailler tension. Adjust the ‘b’ screw to minimise the gap between top derailler pulley and the driven gear cluster. Use trial & error to find the closest workable gap