Larger tires. To tune or not?

Crooks · February 11, 2014

Exactly hes going further than what the truck can calculate.

OP, I think getting a tune is a must when changing the tire size. Even if all you do is have it calibrated for tire size. But if you are gonna tune it, might as well get it running better too and get some extra HP out of the motor.

Blackbear Performance has great tuning options.

If I was going to have it tuned it would be by speedinc on a dyno with hptuners. They have been doing Ls motors since 97 and tuned my camaro. There is no way I am paying for a trans or a motor on a new truck. So thats out of the question

Crooks · February 11, 2014

Crooks,

Can you post some pics of your truck with those tires? Also... what lift do you have?

Its to bad the mods moved my thread with my truck pics so no one will see them now. It pisses me off.

I am going to wash the truck this week and get some pics. I think its not going to snow for 3 days finally

Rough country 2.5

BigMikeVA · February 12, 2014

Even just reprogramming is going to leave a log file on the PCM which technically is a warranty voidable offense according to GM. So either way he's gonna have to deal with it. Gotta pay to play.

Ya but if its done at a GM dealership they wouldn't void the warranty because they would be able to pull up all service performed at a dealership and see that one extra flash was from the time it was brought in to adjust the speedometer for larger tires.

fondupot · February 12, 2014

Ya but if its done at a GM dealership they wouldn't void the warranty because they would be able to pull up all service performed at a dealership and see that one extra flash was from the time it was brought in to adjust the speedometer for larger tires.

Yea but the dealership wont reprogram a speedo to a non-stock tire size. So its gonna have to be done elsewhere.

KUUG · February 12, 2014

Yea but the dealership wont reprogram a speedo to a non-stock tire size. So its gonna have to be done elsewhere.

Yes they will, just not for every tire size

fondupot · February 12, 2014

Yes they will, just not for every tire size

Yea...that's what I just said. They will only do like +1 and +2 sizes which come stock on some modles like trucks with 22" wheels.

Crooks · February 13, 2014

I wonder if they do it for brand new trucks with 35s sitting on the lot

I hate that the mods move every post to a section no one looks at

KUUG · February 13, 2014

Yea...that's what I just said. They will only do like +1 and +2 sizes which come stock on some modles like trucks with 22" wheels.

I wonder if they do it for brand new trucks with 35s sitting on the lot

I hate that the mods move every post to a section no one looks at

As I stated in a previous post; I talked to my dealer and they do it for 35/36" Tires. I believe they consider these sizes the same, so its probably just 1 program.

They cant do any thing for 33" yet but they said they will later on

Danthaman69 · February 14, 2014

If you get a tuner to recalibrate your tire size only the dealers won't void your warranty just for doing that. I could understand if you did tune on the engine and tranny

alvincb3 · February 19, 2015

I put 275/65R20 34.1" tires on my truck. I havent tuned it and dont know if I will. How far off is my speedo and the mileage on the DIC? The AFM doesnt come on as much either. I wont do anything that might void my warranty.

I'm a newb here. What is DIC and AFM stand for?

dirtfan21 · February 19, 2015

If I was going to have it tuned it would be by speedinc on a dyno with hptuners. They have been doing Ls motors since 97 and tuned my camaro. There is no way I am paying for a trans or a motor on a new truck. So thats out of the question

Just an FYI, BlackBear Performance tunes by EFI live which is the same as hptuners and Justin has done thousands of LS series motors. With that said, the only way I have ever found to reprogram the speedo on my trucks for a tire size change is by a tune, whether it be a handheld like Hypertech or a custom tune by a tuner.

Crooks · February 19, 2015

I'm a newb here. What is DIC and AFM stand for?

Well you know how to search and I like that because this post was from last year.

DIC= drivers info center (your computer screen in between your gauges on the dash)

AFM= auto fuel management? (its when your truck runs on 4 cylinders instead of 8)

Crooks · February 19, 2015

Just an FYI, BlackBear Performance tunes by EFI live which is the same as hptuners and Justin has done thousands of LS series motors. With that said, the only way I have ever found to reprogram the speedo on my trucks for a tire size change is by a tune, whether it be a handheld like Hypertech or a custom tune by a tuner.

Data logging and remote running is way better then those hypertech style ones. I would still prefer in person on the spot tuning

dirtfan21 · February 19, 2015

Data logging and remote running is way better then those hypertech style ones. I would still prefer in person on the spot tuning

Agreed, over ten years ago I had to use Hypertech and since then BlackBear has tuned three of my trucks. I just wanted to ease your concern with BlackBear, they are a very reputable tuning company.

Crooks · February 19, 2015

Thank you. My truck runs good enough that I dont want to risk my warranty on a tune. I also have a radar detector that shows my speed by gps now so no guessing.