2nd Gen Non-Engine/Transmission Using Smarty to change tire size in ECM???

[DirtyDodge]

Anyone ever reprogram their ECM/PCM for oversized tires? I did this on mine, but am guessing if I did it right or not. I used the Smarty to do this. My tires are 285/75-16. If you do the math, the height says it should be 32. 83", but if you take a tape measure to it, it is more like 31. 5". The tires have roughly 70% tread on them.



What number should I use when enetering it into my ECM?



Thanks,

Derek

 

[Gary - K7GLD]

I did mine with the TOYO 285 M55's I recently had installed - several down the road checks against mileposts ended up with a setting of 32. 25 for mine.

 

[DixonL]

Another way to check your speed is to use a GPS. If you have a laptop you can put on a GPS for around $129. Or if you have a friend who has one... . borrow theirs. :-laf



Thad (Ohio)