Tail shaft should work, just divide the wheel circumference by the diff ratio before putting it in.

Evilsm if you had one of those dual Speedo ones that have cadence as well, the second sender could measure your tail shaft revolutions as well, giving you rpm. But id rather not upset balance of the tail shaft.

unfamilia nice work, I had been trying this for some time using the tailshaft (instead of the wheel), but I am going to change mine to use your method!
:)

Nek Minnut
"Micks Speedo Installations" "For on $29.95" hahahahaah
This is an excellent way to do it though, no time at all to get it going cheap as buggery and even better if you're a broke student or apprentice like me! hahaha

I did this as well a very long time ago, plus you can change the rolling diameter to suit your setup and they work really well as I've checked it with a few GPS units and spot on :) lasts ages

Or you could download a gps speedo app for your smartphone

sikaflex or silicon that dries. Not one that stays flexible

Do you mean smear some sikkaflex on the magnet?

Lol I did this over 10 years ago in my Ute originally. Works great.

Ya tinny bastard, what an ingenious idea! #OOPS#e loads cheaper than a GPS too!