I have an 06 lly crew SB and would like to put bigger tires on it. I have heard that if you go wider than a 265 it voids the Allison warranty so I want to stay at that width but would like a larger diameter tire. Does anyone have any suggestions as to what brand and how big I can go without rubbing? As you can tell I have no idea what I'm talking about when it comes to tire sizes so any help would be appreciated. :o:
Thanks!

Who told you that the Allison warranty would be void? I have never heard that. 285/75/16 Are what I run and seems to be the most popular. Crank your torsion bars and do a little trimmin and your good to go

I'm running a set of 305X70X16 Toyo Open Country MT's. i have a set of offset keys in it, and they are turned up slightly and all is good.

It won't "void" your warranty. The dealer does, however, have the option to not repair a drivetrain related problem that they believe is a result of larger tires. If the tires are not factory size, or a factory option (e.g. NBS 265s), then you may not get certain repairs covered at certain dealers. GM has been cracking down on warranty claims to save money. For OBS trucks, this means only having 245s as an option - for NBS trucks, it leaves 245s or 265s as a factory option.

Here's what my dealer suggested - keep an extra set of 245's on hand in case something goes bad, and put them on before you bring the truck in. My dealer said they will deny certain warranty claims if I bring it in with the 285's on. It sucks, but it's the nature of the beast...

It won't "void" your warranty. The dealer does, however, have the option to not repair a drivetrain related problem that they believe is a result of larger tires. If the tires are not factory size, or a factory option (e.g. NBS 265s), then you may not get certain repairs covered at certain dealers. GM has been cracking down on warranty claims to save money. For OBS trucks, this means only having 245s as an option - for NBS trucks, it leaves 245s or 265s as a factory option.

Here's what my dealer suggested - keep an extra set of 245's on hand in case something goes bad, and put them on before you bring the truck in. My dealer said they will deny certain warranty claims if I bring it in with the 285's on. It sucks, but it's the nature of the beast...
X2, my ECSB has 265's and the RCLB has 285's and i have never had any warranty problems. The techs also know the ECSB has a tuner on it and they have never let that bother. We usually chat about the tuners they run on their trucks as compared to my tuner.

It won't "void" your warranty. The dealer does, however, have the option to not repair a drivetrain related problem that they believe is a result of larger tires. If the tires are not factory size, or a factory option (e.g. NBS 265s), then you may not get certain repairs covered at certain dealers. GM has been cracking down on warranty claims to save money. For OBS trucks, this means only having 245s as an option - for NBS trucks, it leaves 245s or 265s as a factory option.

Here's what my dealer suggested - keep an extra set of 245's on hand in case something goes bad, and put them on before you bring the truck in. My dealer said they will deny certain warranty claims if I bring it in with the 285's on. It sucks, but it's the nature of the beast...

x3. That's the same thing my dealer told me.

Great info, thanks all. I do run a Predator tune also and have always wondered if I should put back the factory tune before taking it in for service.
txboozehound: I read it in another diesel forum. Hard to say where he got that info.
So, with all the info above, what's the largest tire I can safely put on the stock 16' rims? I would like to put new rims on but that will have to wait. I just had a 50 gallon Transfer Flow tank put in (not cheap).

You will not void the warranty by changing tire size...

The absolute best upgrade I've done to my truck was to offload the stock wheels and tires and install the ones at the bottom of signature. The improvement in handling and maneuverability was explosive (my truck is not lifted).

I have 285/75-16's on my truck with my front torsion bars lowered. I had to trim some plastic, but I don't have any rubbing.

As for the warranty, I could really care less, I've done too much to my truck to expect GM to pay for something if it breaks due to my driving style.

moved to tires and wheels

ar007: LT285/60-18 Nittos on 18" x 9" Centerlines. You have no rub at all? Assuming the 06 Sierra wheel well clearance is the exact same as the 06 Silverado, right?

Great info, thanks all. I do run a Predator tune also and have always wondered if I should put back the factory tune before taking it in for service.
txboozehound: I read it in another diesel forum. Hard to say where he got that info.
So, with all the info above, what's the largest tire I can safely put on the stock 16' rims? I would like to put new rims on but that will have to wait. I just had a 50 gallon Transfer Flow tank put in (not cheap).

I may be wrong but that programmer will void the warranty. They can always see what it has gone through on the computer..............

ar007: LT285/60-18 Nittos on 18" x 9" Centerlines. You have no rub at all? Assuming the 06 Sierra wheel well clearance is the exact same as the 06 Silverado, right?

I had to trim a little off the bottom trailing plastic corners of the front bumper on both sides (not noticeable), and the bottom front part of the wheel well liner on the drivers side, up to the bottom of the windshield washer reservoir -- and that's all! A sharp knife made a very clean cuts. I'll take a picture and post it if anyone's interested.

It's critical to get wheels with the correct offset if the truck isn't raised, like mine isn't.

I had to trim a little off the bottom trailing plastic corners of the front bumper on both sides (not noticeable), and the bottom front part of the wheel well liner on the drivers side, up to the bottom of the windshield washer reservoir -- and that's all! A sharp knife made a very clean cuts. I'll take a picture and post it if anyone's interested.

It's critical to get wheels with the correct offset if the truck isn't raised, like mine isn't.

Mine isn't raised either so I would be in the same position. How do you determine the offset you need?
If you wouldn't mind I think pictures of the areas you trimmed would be helpful too.

Mine isn't raised either so I would be in the same position. How do you determine the offset you need?
If you wouldn't mind I think pictures of the areas you trimmed would be helpful too.

For 18" x 9" wheels the offset needs to 5.25" and the diameter of the tires needs to be close to that of the stock 245/75-16s. My LT285/60-18 Nittos are slightly taller (< 1/2") than the stock tires. My Centerline wheels are Part # 626 8907 865. I'll try and get pictures taken and posted this weekend.