Quote:
Originally Posted by Mexico Dan
I just got my custom tunes, took it out for a 250 mile drive this weekend. I don't have a gps, but using the mile markers on the freeway, my odometer flips about 150 feet before each mile marker. I also feel "slow" driving the same roads I'm used to. Decrease tire size a little? I have 285/75/16 Terra Grapplers, max psi 65, and running them about 43. Is this too low?
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Your 150 feet in 5280 feet is about 2.8% in error. You COULD try subtracting 2.8% from the current circumference you are using. The pressure seems all right to me - are you using OEM sized tires and wheels? If so, there should be stickers on the truck recommending the tire pressure. However, since the max pressure is 65, I doubt you'd hurt anything using 50 psi cold.
When I enter your tire size in Bill's Gear Ratio Calculator in Pegasus and use a 7% rubber squish, I get a circumference of 2525 mm. What are you currently using?
- Jack