tire size and speedometer

[NOBrakes86]

my truck hasa 6 inch lift with 35s how much am i off any one have an idea and what a abotuthe odometer hows is that affected


my truck is a 2001 extended cab 4x4

 

[jagtoes]

my truck hasa 6 inch lift with 35s how much am i off any one have an idea and what a abotuthe odometer hows is that affected


my truck is a 2001 extended cab 4x4

Go to the tire rack web site and look at the circumference of the OEM tires/wheels and then the same for the larger tires. I believe they have a chart which will tell you the difference. If not just calculate the % different in size and that will be the difference in the odometer. The 6" lift doesn't have anything to do with it. As to how do you correct the difference I would check with the dealer. I don't know what year it was done but with newer models the dealer can change the odometer electronically based on tire size.

 

[NOBrakes86]

any ides how to find out what gears i have with out ripping it apart ?

 

[jagtoes]

any ides how to find out what gears i have with out ripping it apart ?

Lift the rear wheels and put a mark on the pinion flange at the rear end. Have someone rotate the wheel (1 revolution) and count the number of times the pinion goes around. That's the gear ratio also check in the OM what optional rears there were and see what is nearest to the pinion number. So if the tire goes around once and the pinion flange goes around 3 1/2 turns and the owners manual says there is a 3:54 to 1 gear ratio then that is what you have.

 

[Z15]

I don't know what year it was done but with newer models the dealer can change the odometer electronically based on tire size.

ONLY for tires that were originally installed on that particular vehicle or available thru GM as a accessory. They cannot do it for anything else because those calibrations do not exist.

Inside the glove box is a label of all originally installed equipment (RPO's). Look for all codes that start with a G and list them here. They will tell you what axle options came on the vehicle.