Ok guys I spend most of my time over in the 2nd gen section but my dad has a 07 ram 2500 cummins maga cab and we just put new tires on it. We went from 265/70r/17 to a 285/70/17 and I was wondering how you change the speedometer to get it back on. I know with my truck all I need to do is change the gear but was told I need to have the dealer do the 07. Is this true? Thanks for the help.

 

You can get a tuner like Superchips or Diablo and input the tire size to recalibrate the speedo

 

I check a tire size calculator and it says that when your speedo is at 60mph your actual speed is 62.1 mph... I don't think is worth it to recalibrate the speedometer, imho!!!

 

The guy a the tire shop told my dad that the abs light might come on. Also what tuner would you guys recommend for a cummins

 

I don't know about that! I went from 16 inch factory rims to an 18 inch after market rim and got no abs lights or nothing wrong going on!!!!

 

Diablo U7131 tuner. IDK if the Trinity is compatible

 

Agreed. Not worth worrying about. Just know it reads about 4.3% low. If you have a GPS unit, it can narrow-down the error.

 

Yeah, and a tree might fall on it, or 12/21/12 might really be the end of the world. BTW, I would have guessed a Mega would have larger stock tires.

 

Cheapest way would have the dealer recal it. The most fun would be throwing a tuner on it.

 

We are going to watch if and see what happens. He wanted to get the tuner anyway so that is probably what he will do.