Tire size correcting

[cplchris]

I brought my 2006 sport in to have the tire size reprogrammed a few days ago....the tech botched the job and my speedometer is about 12% slow and my Odometer is reading about 20% less than actual mileage, (based on a gps odometer on a 6.7 mile trip the jeep odometer read 5.5 miles).

so I went back to the dealer and the service writer spoke with a much more experienced tech who I trust. apparently on the 2006 and up models the abs system has to be programmed while driving, (corrects the speedo, as well as the ESC and abs systems).

My main question is relating to the wrangler duratracs, goodyears website lists the 245-75-16 as being 30.7" tall, and 686 revs per mile...well I found those numbers odd for a few reasons:

1) a standard 245-75-16 is approximately 30.47" tall when the sizes are converted to inches
2) 30.47" tire height translates to 662-663 revs per mile
3) the duratrac is obviously taller than most standard 245-75-16 AT's so I believe the 30.7" height
4)30.7" height = 657 revs per mile

so for those of you running 245-75-16 duratracs that have had the tire size corrected and verified within 1-2%, how many revs per mile did you end up programming for?

Thanks in advance everyone.

 

[tommudd]

Every tire brand, tire model is somewhat different , can't always go with what it " should " translate to
Mine was off 4 MPH when I bought it brand new, now with the gearing and tire size I have I'm 4 MPH off yet. Tech who did my gears said he could play with it and get it closer but wasn't worth it to me
It will be interesting to see what others come up with, but has to be 06-07 since before that they were different when doing this

 

[cplchris]

Yea tom, up through 2005 it was a simple update in the bcm and the abs system for revs per mile.

I just need it to be accurate enough so i dont have to worry about maintenance schedules being thrown way of or trans issues.