MPH off after switching to low pro 22.5s

Set tire revs in ECM. Revs are different between 24.5 and 22.5

 

Any independent shop with a laptop should have the ability. It's a single simple parameter change, takes literally minutes

 

Unfortunately with an e model cat it’s a mathematical equation instead of a quick parameter change
But anyone w/laptop and right model software can do it
I just can’t remember the equation

 

@Diesel Dave went through that a while back I think.

 

11R22.5 tires are the same overall diameter as lopro 24.5 but yeah you already got the lopro 22.5's.

 

I’m surprised you remembered . I did go through a process. I played with the CAT E.T. for awhile then figure I had to play with the “Dip” switches on back of the speedometer head to get it right. There’s a thread on here about it, but it’s been awhile.

 

For just your speedo to read right you just need to change the dip switches on the back of it. Any decent service guy should be able to help with that. It's just a bunch of small switches on the back of speedometer.
Your ecm might read different but does that really matter?
I believe this information to be correct. I did this on my 01 pete with cat

 

I'm not sure guys, but i thought most T2 speedos were ECM driven.

Been a long time since I've messed with one though