not sure how it could tell u your speed without gps or wheel sensors. If u want speed and rpm on a hud, u can get a trail tech Vapor. I have one and its fully adjustable to get accurate speed, just dont use the crappy wheel speed sensor mount screw that comes with it. the crew snapped on install, and had to dremel it out and use a better screw. I used my gps to check speed accuracy and its spot on.