I rencently purchased 33" tires for my truck and have a Edge Evo on the way and i want to have my shift points right so that its not hard on my trasmission or do i just leave it stock. Also if you have the shift points that go with having those larger tires it would be much appreciated. Thank you

 

The "program" the PCM uses to determine part-throttle shift is a function of vehicle speed and throttle position. A higher throttle position delays the shift to a a higher speed.

That said, if your PCM sees your speed correctly, it will command a shift at the right time. To make it see the speed properly, you will "customize" the "canned" tunes in your Edge to account for tire size and gear ratio. You MUST do both. The Edge manual gives a table for tire circumference for various tire sizes and if yours is not listed, just measure the distance traveled during one wheel revolution in inches and multiply that by 25.4 to get millimeters.

Bill Cohron from PHP (who wrote the tunes for the Edge), recommends reducing the distance measured (or read from the table) by 3% to account for "squish". I did this and my speed and odometer are dead on.

Hope this makes sense!

- Jack

 

Yeah i think i understand if i dont i will surely figure it out. Thank you very much.