[Power Hungry]

Originally Posted by Mark_123

...selected yes on custom tunes, I then went down to load previous settings. When I scroll through to check the settings, all of the shift point speeds are at 0??? Also, the tire size reads 2356 which is way off for 275/55-20 tires. Oddly enough, my speed is accurate with the GPS. If I put in the circumference of tires with 5% squish, my speed is about 2mph faster than GPS at 55mph.

Is there a way to see current settings loaded on the unit with 87 tow mode? I can't seem to get the "load previous settings" to load anything for me to view.

Load Previous Settings is used to load the last custom settings you made. This is so when you change levels you don't have to go back through and re-enter every change you made. If you haven't made any changes to begin with, there's nothing to reload.

As I've mentioned before, the default tire size and gear ratio that is displayed in the custom options HAS NO RELATION TO THE ACTUAL TIRES ON THE TRUCK. They are some made up, arbitrary number. You have to put in the correct size for your your tires and you must also put in the correct gear ratio.

Squish is a relative term used to describe the phenomena that occurs where the tire patch contacts the road. Tire inflation, tread compound, tread pattern and aspect ratio (sidewall height) all have an effect on squish.

For a 55 series tires, I would use a 3% squish value since the deflection of the sidewall is going to be considerably reduced compared to say, a 75 series tire. For the size you specified, you should be around 2517mm.

Take care and Merry Christmas!