Stupid question - speed sensor on front or rear wheel?

[pn_day]

Hi all
Random question for you. I have a speed sensor to fit to an S12S controller.

How close to the magnet does the sensor need to be? I'd like to fit to the rear to reduce cable runs to the front, but there is a fair distance between the rear stays and the wheel.

So I guess the real question is has anyone fitted a speed sensor onto the rear wheel, or should I just put it on the front and run another cable?

Cheers
Phil

 

[trex]

I always keep it at the rear wheel. It will work up to an inch apart.

 

[Alan Quay]

Mines on the rear. You always have to find a piece of thing to pad it out with, and I 've always fitted them with about 6mm gap.

 

[pn_day]

Splendid. Thanks chaps. I'm very glad there are people like you who have done if before!

 

[Deleted member 4366]

It doesn't matter a hoot which one you put it on.You get an extra wire running back if you put it on the front, but at least you can get it close to the magnet. You normally need a spacer on the back, and it does have to be fairly close. You can also add an extra strong magnet to the spoke one to increase the chance of it being detected. These are always useful anyway:
http://www.ebay.co.uk/itm/10-Very-Strong-Neodymium-Disc-Magnets-10x2-mm-N52-craft-reborn-10mm-dia-x-2mm-/161284891361?pt=LH_DefaultDomain_3&hash=item258d5422e1

 

[pn_day]

Thanks again - the combination of a spacer and having the sensor facing towards the wheel instead of the frame (!) now mean I have speed reported on the LCD-3.

Now does anyone know what P1 value to use for the CST 500 at 36V?

 

[Deleted member 4366]

I don't think you need to set P1. I think it's used for the speed signal if you set P2 to zero, but you''ll have P2 set to 1 for the single magnet wheel-speed sensor.
P4 is for the throttle. Should be set to zero if you want to throttle without pedalling.
As far as I can figure out P5 is some sort of damping for the battery display so that it doesn't go up and down with changing load.

 

[pn_day]

Excellent. I'm glad as P1 seems to be guess work, so I'm glad it's not needed if you have a speed sensor. I got roughly 27 mph reported on the stand from the 36V battery (700c wheel).
Now to get brake and PAS sensors fitted then onto the wiring of lights. Great fun.