What is my speed? Got 3 readings!

[Longshot270]

Originally Posted by 88Racing

Bill hits the TS right on most of the time with the custom tunes.
In my case the tires I have are lower profile.
To much squish was taken out.
So instead I opened up custom options and added to the TS.
No big deal.
Your speedo needle will always read 1-2 mph higher»that's the way ford designed it.
Best way to dial in your TS is with adjusting the number in the gryphon using a gps.

An to add to what 88 said, the easiest way to get your tire size correct is just driving for a while after clearing the odometers and using this simple formula.

Truck odometer/GPS odometer x current TS= New TS

Since you are using the odometer you dont have to try matching a number on the GPS with a number on the programmer or truck. To make the calculation more precise drive at least 10 miles. The further you drive the more exact the percentage will be when you multiply by the tire size.