I recently purchased a 05 Durango and it came with 265/70 r17s and when I went to get new tires I found out it took 265/65/r17s. I went back to the stock size and now my gps indicates my speed if off. How do I adjust my Speedometer?
Thank you in advance for any advice

Tim

 

You can buy a tuner such as a Diable Sport that will correct the error,
FF

 

+1

Most performance tuners have that as a self usage setting you can play with.

IndyDurango

 

Thank you very much I will look into getting a tunner or at least access to one.

 

the tuner will allow you to set a parameter in the pcm called the pinion factor. the dealer can also do this for typically a 1/2 hour or so of labor. the setting is "revolutions per mile" and this number can be found at the tire manufacturer's web site or literature. the dealer will have it a shortcut table for the stock, factory tire sizes.

 

Never heard the pinion factor verbiage but probably is right. Most tuners will simply ask you to select what size tire you had and then what size tire you have, it will adjust accordingly. That is how my SuperChips worked IIRC. They may very well use internal charts and factors to auto calc all that. The nice part is as the enduser, it is easy

IndyD

 

yes, the tuner just asks for tire diameter and then calculates out all the rest.
very easy.
when the smoke clears, the pinion factor has been set.

i think? the dealer scanner will allow a direct input of revs per mile.