I bought 315/17's mounted on pro-comp 6001's for my leveled 08 2500 the other day. I stopped at my local 5 star shop to get the speedo reset and the service manager tells me that he cannot program my new tires into the system. It appears that on the 08 the scanner will not let anything other than the brand specific tire that it rolled off the assembly line be programed into it. I know there are the aftermarket programers out there but I don't really want to spend another $300 just to caliberate the speedometer. Is there such a thing as 'borrowing' an aftermarket to set it or are the programers locked when hooked up to a specific vehicle?

 

it may be that
the the technician does not know
the less used procedure to manually set
the revolutions per mile

see archived post below:
=====
originally posted by grfraz
Augusta GA

Here is the recipe.

1) Have the tech plug his hand held into the OBD port and turn it on. A menu
screen comes up with a bunch of info. Select YES to go to next screen.

2) On this screen select menu item 1, "DRB III Standalone" to go to next
screen.

3) On this screen select menu item 1, "1998-2008" to go to next screen.

4) On this screen select menu item 1, "All" to go to next screen.

5) On this screen select menu item 5, "Antilock Brakes" to go to next screen.

6) On this screen select menu item 9, "Miscellaneous" to go to next screen.

7) On this screen select menu item 2, "Set Pinion Factor" to go to next
screen.

8) On this screen there are a several tire sizes and Other. Select menu item
8,
"Other" to go to next screen.

9) On this screen there are two items, an Axle Size, (9.25" on the 1500's and
10.5" on the 25/3500's) and Other. Select menu item 1, "9.25" Axle" (10.5 in
your case) to go to next screen.

10) You have now arrived at the point in this process where you will enter the
revolutions per mile for your tire size. Select the menu box for RPM. It will
indicate 400. Here is where the tech will change the revs per mile with either
the up or down arrow. It will take a while to go from 400 to 604 (for the BFG
315's) so be patient. As you are waiting on him to finish, take this time to
let
him know that he shouldn't charge you more than say $20.00, especially since
you
trained him on this procedure.

11) The last step is to select "OK" and the changes will be excepted, then the
hand held will display "Reprogramming Successful".

Good luck!

======
There is an online Java calculator to compute revolutions per mile at:

http://pw1.netcom.com/~sgalaba/tiresize.htm

 

WOW..........now there's some greaat information right there.
Nice one Hank.
Al.

 

Wouldn't a larger tire take less RPMs to go a mile?

Rick

 

yes it should, but sadly that doesnt mean better gas mileage =( throwin those huge treaded tires round and round takes alot.

 

I'll print this off and have a chat with my 5 star man. Thanks again for the info.