Bafang gear sensor

[Jayfdee]

Just a thumbs up for this bit of kit. Yes I know you do not really need one, you can blip a brake lever or stop pedaling , and some sellers are asking £50, so not worth it, but I bought one from China , on ebay for £19, so not a big investment. My son sometimes uses my bike, and he will just thrash it, so this will protect it.
It was very easy to fit, comes with a wiring harness splitter to pair up with the brake lever switches(just like an extra brake switch), and momentarily stops the motor as you change gear. There is a red flashing status indicator to show it is operational, and this flashes green when you change gear. I have fitted it next to the shifter so I can see it, I have seen images of people fitting them on the rear next to the derailleur , but the wiring will not be suitable for this kit.
Shifting whilst under power is now super easy and quiet, no clunking, you feel the loss of assistance briefly, but you can maintain your cadence.
It can only reduce wear on the drive train, so for me, at £19, I am happy.

 

[vfr400]

I'd recommend one for anybody that fits a crank-drive kit,

 

[awol]

I like the gear cutoff too after I fitted one but could do with it keeping the power off for about another second longer.

 

[Deere John]

I just wish the power return (or rather cadence return) after pedalling would work correctly. It creates a very disturbing rpm loss everytime it activates.

 

[vfr400]

I just wish the power return (or rather cadence return) after pedalling would work correctly. It creates a very disturbing rpm loss everytime it activates.

There are different versions with different cut-off times. I can't remember when and how they changed it. Also it might be a function of your controller software. Is there a delay after using the brake?

 

[Deere John]

There are different versions with different cut-off times. I can't remember when and how they changed it. Also it might be a function of your controller software. Is there a delay after using the brake?

yes a slight delay. And it ramps up from zero again. If I'm pedalling and have good flow and suddenly stop pedalling for a second (or brake short). It kind of starts all over again and I loose flow. Very noticeable if I'm riding with some push bikers, I get several meters behind them

 

[vfr400]

yes a slight delay. And it ramps up from zero again. If I'm pedalling and have good flow and suddenly stop pedalling for a second (or brake short). It kind of starts all over again and I loose flow. Very noticeable if I'm riding with some push bikers, I get several meters behind them

Is there not a setting in the controller to adjust that, like start current?

 

[Deere John]

You can not adjust behaviour. Just the ramp up time. If set too fast you get a very nervous bike. But yes, setting it faster than default makes it slightly better at least. But still it starts from zero.

 

[jarob10]

Rumour has it that bbs00x controllers with a built in gear sensor connector (rather than spliced into the brake sensor) have better motor cut in-out characteristics

I’m not convinced gear sensors are needed on a well setup derailleur. Useful on igh’s though

Bear in mind if the sensor within the gear sensor throws it’s hand in - eg water ingress - it’ll likely take the bbs controller down with it

 

[vfr400]

I’m not convinced gear sensors are needed on a well setup derailleur. Useful on igh’s though

That's a very strange thing to say. Have you tried a gear sensor? Do you have a BBSxx? If so, which one and how much power?

 

[jarob10]

That's a very strange thing to say. Have you tried a gear sensor? Do you have a BBSxx? If so, which one and how much power?

Good point, my previous comment only applies up to 500W, and with a decent quality, correctly setup rear derailleur & shifter - in this context, full power gear changes are fine IME

If any of the derailleur parameters are incorrect (skewed hanger, poorly indexed or with a ‘b’ dimension too large) a gear sensor would definitely guard against the associated gear change clunk

 

[harrys]

I have a bafang 750W install w/o a gear sensor. For street riding, I have no need to be shifting while accelerating, so I'm fine.