275/60R20 speedo ?
11-15-2013, 09:19 AM
#11
I think you did it backwards... Larger diameter tire will rotate faster than the truck says. you will be going 72.5 when your truck says 70, if the difference would be 2.5mph like you say.
When I went from the stock 275/55/20 Scorps (approx 32" x 11") to the 33 x 12.5 my mph is dead on with a gps @ 80 mph. I did not compare the gps with the stockers because they were on the truck for 1 hr once I signed the paper.
When I went from the stock 275/55/20 Scorps (approx 32" x 11") to the 33 x 12.5 my mph is dead on with a gps @ 80 mph. I did not compare the gps with the stockers because they were on the truck for 1 hr once I signed the paper.
http://m.discounttire.com/dtcs/infoTireMath.dos. Here is a great link for checking your tire size equations.
Last edited by F150_Feste; 11-15-2013 at 09:21 AM. Reason: Addtn
