First of all, this is my first post, as well as my first Dodge truck. My dad's had them for years, and I've had Fords.

My truck came with the factory 20" rims. The door panel says it had 245/70R17's, and the spare is a 265/70R17. I have no idea what the speedo was originally calibrated for. I recently bought some factory 17" rims on Ebay, and just had 265/70 BFG All-Terrains put on.

When I had a Ford and was on the F150 site all the time, they talked about being able to change the sensor in the tranny to one with a different number of teeth on the gear so the speedo would be correct.

So here are my questions:

1. Is changing the sensor also possible with these Dodge trucks?
2. If it is, does anyone have any idea how many teeth the gear should have for the tires I now have on the truck?

Thanks in advance

 

I believe that on all newer vehicles the speedo change is done through the computer. You have to either take it to the dealer who can hook it up to their computer and easily reprogram the correst trans calibration, or have a hand held tuning device such as a diablo sport predator that changes calibrations for you. Either way it should be simple. Maybe someone here can be more help and elaborate more on this. Good luck and welcome to the forum!

 

You're right. The calibration would be done through the computer.

I did just the opposite with my wheels. I went from the 20's to the 17's. I don't know if they ever recalibrated the computer on not. The difference in diameter is right around 1% between the 20 and 17.

 

Thanks guys!! These forums have really been a great source of information!

 

Glad we could out.