Hello all.
I posted some pics and info on how to install a cheap bike speedo on a quad on my profile page.
See Ya.

 

That is neat. How accurate is it? how long do you think it will last untill it brakes off?

 

Hello.
Calibrating it as per the instructions I got it within one MPH of my GPS. It will only read up to about 58mph. A better unit will do better.(Cheap magnet and pick-up.)
I have knocked the display off twice. It has a snap-in type base. A good branch could wipe out the pick-up but so far so good.
It quit once when I got it very wet but started working again the next day. I've had it out at 30 degrees and it still worked. When it dies I'll buy a $15~$25 from a bike shop.

 

thanks