jasond
Well-Known Member
Lifetime Member
Your 32" tires have a 12.5% greater diameter over factory 28" tires. That being said, if your ECM isn't reprogrammed for 32" diameter tires, that 70 mph your display reads is actually 78 mph.
Should be easy enough to verify actual speed with GPS ground speed reading at WFO.
So I just got out to check this and there’s a substantial difference between the dash readout and the GPS readout. I’ve got 32x10x15 Carnivores all around.
My dash readout on flat ground, High/Sport Mode WFO, was 72 MPH. The same GPS readout during this run was 77 MPH.
I did some additional cruising to see if the 5 MPH difference was consistent and it does appear to be very repeatable at varying speeds.
Here’s a screenshot of the GPS top speed: