New truck tires and truck computer

[Mosby]

I am going to get new truck tires this year and replace the Goodyear Duratrac's that came with my Chevy Colorado. I am thinking about going up a size, getting 3 ply sidewalls and either a C or E rated tire. I have read that getting bigger and heavier tires will throw off my truck computer and impact speedometer, mpg etc;, accuracy. Always had older trucks and this was never an issue for me before but it evidently is now.

Do you guys have your truck computer retuned/calibrated after changing tires size and weight?

 

[Rob5589]

A taller tire will slow your speedometer. It could also affect shift points in the transmission. There are usually easy fixes, however. Some vehicles can have the ECM flashed for the new tires at a dealer or other capable shop. Or there may be a module that you can attach to the OBD2 port that will adjust the speedometer for the new tires.

 

[Mosby]

Thanks for the information. I was planning on calling the dealer and see what they recommend, what they can do and what it will cost me to fix.

The Duractrac's that came on the truck are lightweight, 2 ply tires and I really would prefer going with a heavier tire and thicker side walls. Going up a size would give me an additional inch of ground clearance but I don't want to over engineer this. I guess I can always stay with a stock size, depending on what I learn. My last truck was a 2001 and never had to deal with this stuff. Maybe I should have but didn't.

 

[Rob5589]

Thanks for the information. I was planning on calling the dealer and see what they recommend, what they can do and what it will cost me to fix.

The Duractrac's that came on the truck are lightweight, 2 ply tires and I really would prefer going with a heavier tire and thicker side walls. Going up a size would give me an additional inch of ground clearance but I don't want to over engineer this. I guess I can always stay with a stock size, depending on what I learn. My last truck was a 2001 and never had to deal with this stuff. Maybe I should have but didn't.

Yep, not as simple as a 5 min speedo gear swap in the tcase any longer. Truly, it isn't difficult to diy if there is a module made for your pickup, which is highly likely. A quick G search is likely to turn up at least a couple.
As far as tires; a size up will provide you with half the diameter increase in clearance. So an inch taller tire, 1/2" more ground clearance. Going to a heavier ply tire will increase rolling weight as well which can zap a bit of power. As long as you don't go nuts the difference is negligible

 

[Davidson51]

Not sure if you've already seen this tire comparison calculator. Might be useful.

315/70-R17 vs 35/12.5-R17 Tire Comparison - Tire Size Calculator | Tacoma World

35/12.5-R17 tires are 0.67 inches (16.92 mm) larger in diameter than 315/70-R17 tires and the speedometer difference is 1.9%

www.tacomaworld.com

 

[Justinjs]

I have an app that allows me to adjust things like tire size on my f150, it's $6 + $50 for the dongle. However, it's Ford specific. I'm sure Chevy has something similar, check out the colorado forums.