I just found out my grandson replaced the stock tires on his new 2006 Ram 2500 4X4 (auto transmission). I don't know what size tires came on his truck, but he had new rims and 35X12.50 R18LT/D tires installed. The first problem was the tires rubbed thefront bumper. My grandson went to a 4-wheel drive performance center and they said he could lift the front 2" and solve the problem...this would also level the truck. Well, he had that done also--now my questions:

Will the 2" lift change the front-end alignment, or affect the performance of the shocks?

What will this do to thegear ratio?

Can the dealer change the tire size in the computer so the speedometer is accurate?

Thanks for any help.

 

Ok The lift of 2 inches might need new shocks, 2nd the lift will change the alignment angles but I dont know how much. The gear ratio will stay the same but the Speedomight be off a little, being its a 2500 maybe the stock tires are close enough to the 35's that it wont change the speed reading much at all. Dodge can calibrate the computer for the different tires but sometimes it wont work. I had a 2000 Ram Lift 5.5 inch Fab Tech lift with 35's it was off 5 mph. The bigger the tires the harder they are to balance, which will cause the truck to shake if they are not weighted to 0.

 

The lift will affect the shock performance and the alignment if it's a suspension lift. If it's a body lift, then stock geometry is maintained.

The tire size does affect the perceived gear ratio, because as you increase the diameter of the tire, you are also increasing the length of the "lever arm" from the center point of your axle to the ground. Longer lever arm has the same effect as ataller gear ratio, which means less torque to the ground.

The speedohas anelectronic pick-up, so it is possible to change it. I know Hypertech and Superchip programmers can do it. If you don't want to spend the $$$, there are also tire formula's on the web that can compare tire sizes and let you know what speed you're actually running with the different tire sizes. www.discounttire.com has one on it's information page.

 

HellaciousHemi & crcarch,

Thanks for the responses...this helps. I'll need to find out if it was just a body lift. "Perceived" axle ratio was what I was concerned with. Thank you again.