My 75 DT250 rat bike project is constantly evolving and I would like to put a GPS speedometer on it, has anyone ever seen or tried this. A google search seems to always bring me back to the offshore Amazon products. My 12 volt power supply would be a M12 Milwaukee battery.

Something like this? www.trailtech.net/en-us/shop/accessories...fWdPqqRoCnLcQAvD_BwE

Has anyone had any luck installing a Trail Tech Vapor on an old Enduro/MX bike? I am building a RT3 and I have installed a 73 MX360 front tire/rim and that eliminates the option of using an original speedometer. I called Trail Tech and they said nothing they have will fit our old bikes but I am certain someone here has probably tried to install a magnet sensor speedometer of some sort.

Looking forward to any ideas!

Mike

I have, the Trail Tech is not GPS though.  On one I used a tiny super powerful magnet and epoxied it in a little recess I machined between spokes just outside the brake drum.  I attached the sending unit to the fork.  I wish I had pics. 

On another I installed the magnet into a recess I machined in the rear sprocket and attached the sender to the swingarm. 

Perfect Mark, was there any particular model of the Trail Tech you bought?  Do you have the model number?
 

I used a couple different Trail Tech ones.  They are similar with different features...  all the way up to Navigation (which might have GPS speedo capability?  But the nav ones were like $400+ vs. less than a hundred for a basic model that was pretty much just a speedo)

Don, who you might have met, has been using a bicycle speedometer (electronic) on his RT3 for years...  I think it was a Bell brand unit from Walmart for like $20.  That's probably what I would do for just a basic speedometer.