WTF a 1.50 rear end ratio???

[Suicide-D]

Ok i got to wondering why my speedo reads 83 miles an hour and my gps handheld says 65... I just put stock height tires on my truck thinking the tire height was throwing it off...well that didnt solve the problem.

so I jacked up the truck and did the spin the tire thing and count the revolutions of the driveshaft.... and it only turns 1 and a half times with 1 revolution of the tire. whats up with that??

I have never heard of a gear under 2.73 I'm not saying they don't exist just I havent seen them. Is it possible I have such a low gear? The rear end acts fine doesn't pop or anything with no slack...I get outstanding mileage and the truck could get outrun by a bicycle off the line...but once it's up to speed it rolls fine


any thoughts?