When I was researching scooters I frequently checked out JustGottaScoot (lots of scooter reviews but no TGBs -- Bill, you gotta find a Minneapolis-area dealer who will lend Dave, the site's administrator, scooters to review). Dave, as part of his scooter reviews, compares the displayed speedo values with a GPS and has found that virtually all of them overstate true speed, sometimes by a substantial amount (10-20%).
Well, sure enough, in my preliminary runs through the neighborhood in my new R50X I discovered that the displayed mph on the gauge significantly overstated what was showing up on the street-pole mounted radars as my speed. I went back with my car and confirmed the accuracy of the radars. The R50X display will go as high as 37 on a consistent basis (I've hit 39 a couple of times and 40 once briefly), but I'm pretty sure I'm not going more than 30 (remember, this is a restricted engine). Keep that in mind when you think you're doing 25 to keep within the posted speed limit -- you're probably only doing 20 (and the cagers know that).
I'll be receiving a "dashboard-style" mounting bracket for my scoot today, allowing me to hook up my Garmin Nuvi GPS. I can then do more extensive testing of the speedo accuracy and report my findings here.
Bill: Is there any way to switch out a part in the speedo chain to make the display more accurate?
Rod