Best positioning for rear wheel speed sensor and cadence

[rsmithersfitness]

I was just wondering what the best positioning for the speed sensor on the rear wheel and the cadence sensor so there are no strange readings? Thanks

[Site_Admin]

I usually position mine about 4" (10cm) apart, and keep them both on the chainstay. Some people are having better luck putting the speed sensors on the seatstay. It's kind of a user-preference thing.

[Norm]

The first race of the season was yesterday and I was hoping to trap some good data, but I wound up with some strange spikes that I haven't seen on my training rides.

I had lots of speed spikes where speed goes up 5, 10, or more mph one second and returns to normal the next while cadence remains steady. I know there were a lot of micro-surges in the peloton, but spot checking near these spikes shows speeds that I can't reconcile with my cadence, gearing, and course elevation profile: the ride file shows me going over 53 mph on the flats at one point-- that'd be nice, but I don't think the tailwinds were quite that strong.

I also had some cadence spikes that were 300+ rpm. Likely caused by a brief coast with the magnet resting over the cadence sensor I suppose.

My cadence and speed sensors are mounted on my chain stay, separated by 4 inches. My speed magnet is about 6.5 inches from the hub. I've read somewhere that odd speed readings can be caused by the speed magnet being too close to the hub.

I'm considering sliding my speed sensor a bit closer to my cadence sensor to see if speed settles down a bit. Has anyone else dealt with a similar issue?

[Site_Admin]

Send me your file and we'll have a look.