BBSxx tachometer?

[WoodlandHills]

I have read a lot about the need to keep a BBSxx from spinning too slowly causing overheating and I have even seen recommended RPM ranges, but I've never seen anything about installing a % rpm gauge or even an actual tach onto the crankshaft. If the BBSHD can sense overspeed during PAS and pull back power causing surging, is there a way to use that sensor to read % RPM? Can anyone help?

 

[docw009]

I've wondered about the same thing. When I've ridden a BBS02, if it accelerates smartly, I figure it's in the right gear and not lugging, but having an rpm indicator would also help in situations where my seat of the pants sensor is less sensitive.

I found a general purpose tach with a remote sensor for $10 on ebay. Kind of ugly though. There might be some kind of motorcycle tach that might work. One could always use a bike computer with magnets on the crank. Just input a wheel circumference and interpret the "speed" as an rpm.

 

[Antenor]

Very interesting...that would be a great way to better understand the motor

Enviado do meu SM-G850F através de Tapatalk

 

[spinningmagnets]

Good idea, this is something that should be cheap and fairly easy to add.

 

[Speady]

You can use a cheap speedometer and glue the sensor fairly easy onto the cover of the second reduction gear. Then make use of two magnets on the chainwheel and set 66" or 167cm as wheel circumference. What you can read on the speedo is rpm instead of kph right away. 8)

 

[WoodlandHills]

Having an actual rpm number isnt very helpful if you do not know the speeds of the torque peak and redline. The display already processes that information as a percent of maximum rpm, 100%=redline. Just having a gauge that indicated from 0 to 11 would do it. As an added bonus you could be like Spinal Tap and "turn it up to 11"!

 

[brucemetras]

I use a cadence sensor .. with the BBS02, you have a max crank speed unloaded of around 110 rpm at full voltage .. keeping my cadence in and around 90 rpm and an eye to the amp reading on the display, I know if I am in an efficient motor rpm window.. more useful info on a display would always be nice.. I have the new Bafang color display, and a good portion of the display's capability is not even available at this time to the end user..

 

[Speady]

So if you want a % rpm gauge, and let's say 110rpm equals 100%rpm equals 10.0kph on the speedometer.
Then you have 10.000meters per hour/( 110rpm*60min per hour). That would be 1.51 meter wheel circumference and a single magnet. Would this work?
Probably I miscalculated some.