My truck is completely stock with Lt 265/75r 17 tires and I think the speedo is reading too fast or in other words I'm going slower than the speedometer says. I don't have a GPS to test it but the few radar trailers I've passed seem to indicate this. I have a 6spd auto with 3.73 gears and stock tires. At 60 mph my tach is reading 1500 rpm. Anybody out there with the same set up that can let me know what rpms they are running at 60 mph and if they know if the speedo is accurate? Thanks!