just got back from the states where i had my new 315's put on , drove home to the dealer for a front wheel alinment, new tie rod too, and i asked them to do a flash to the computer to reset the speedo for the larger tires.
they are telling me that they can't do it because the size of tire i went to is too big.
so i am asking for help here as i know they can do it , they just don't know how,or never done it.anyone here reading this, if you know the steps to take, or the buttons to press or whatever, can you walk me through it so i can tell them how to do it, or show them.
i would really like to have this thing running at normal speeds,correct mileage, and abs.
thanks

 

Take the truck to a real tire and speedometer shop. The dealer will get their tit in a wringer with Chrysler if the tire size is outside the parameters of those approved as OEM by Dodge. In fact, too large of tires will invalidate your warranty if the dealer wants to get picky. It is an emission certification thing, and you are now outside the approval limits under which the EPA certifications were granted.

 

thats is my problem, i don't have a real tire and speedo shop here that i know of, i have been to 3 different dealer ships, and they all said they could do it,but all have failed.
they keep telling me that they need to pull the rear diff cover off to count the teeth on the tone ring, i keep telling them that no they don't they just need to learn how to work their scan tool/programmer.

 

with a superchips programer you can do it yourself as lond as your tires are not more than 42" tall.

 

If all else fails, hit one of the 4X4 off road sites and pick up an adaptor that you can adjust yourself for any tire size.

 

If the tire size isn't listed you just change the revolutions per mile, tire rack tells you most tire rpm. Most dealers have idiots working there! Hard to find good help for $10 an hr.

 

Back when I worked for Dodge, I recalibrated several trucks for larger tires. They would not allow you to recalibrate for any size tire, only gave you choices for a few sizes, which were all the OEM possibilities. I had actually spoken to Chrysler engineering about this and the answer was basically that the OEM would never make it possible to recalibrate for any size tire except for those which could be ordered with the truck. They don't condone oversized tires, because the suspension was not designed for them, so why would they design the speedo electronics for their use?

 

I good tech can change tone ring and rpm settings to get the speedo correct, been there. Sometimes easier to just buy a TruSpeed sensor and by pass all the dealer frustration.

torquefan - do you know how to change tone ring and rpm settings? there are no limits! you can get the speedo very close.

 

i read in a couple of talks in here(site)
that to do the speedo recal, you don't do it through the speedo area, but through the ABS / other tab, and from there you input the rev/per mile, which i have.
if this is correct, can some body confirm this , so i can go back to the dealer and let them know how to do it.
i know others have had no problem doing this with the same size tire that i am running(315/70/17)and it took all of 2 mins to do. all i need to know was how they did it, so i can relay the info to the dealer so they can do it for me as well as others.
the dealership around here don't see too many truck like mine with larger tires.

 

Pullin Hard- That's correct, the recalibration is done through the ABS controller.

RickCJ, are you referring to installing an aftermarket tone ring? I didn't know these existed, but if so, I can see how simple that would be. When working with brand-new vehicles, we pretty much stayed within Chrysler parameters.

 

No not replacing the tone ring, just changing the number of teeth and rev per mile!