bigger tires, factory ride height

[Glendias583]

Anybody know what the largest size tire you can run on a 98 k1500 without lifting it? I'm running factory size right now (245/75R16 I belive) and want a little more "aggressive" stance. I know I'm limited to tire height, but how wide can I go without tire rub?

 

[Shiny]

I have ran 285/75/16 on my 98 Z71 with stock height and stock rims with no issues at all.
If you try to run wheels with offset greater than factory you may run into rub issues.

 

[df2x4]

Yup, 285/75/16 is about as big as you're going to get on a 4x4 without a lift or trimming. Ran them on my Suburban for a couple years, no issues at all with that size.

 

[MDR-97-Z71]

305/70/16 can be done, may need slight cranking


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[Jorge6.5]

Agreed. 285 is what you want. Huge difference over the 245s and no rubbing at least from my experience

 

[Glendias583]

Awesome guys. Thanks for the input! It's been kind of a hobby truck since I've owned it. I got it from my grandfather and it's still in immaculate condition, even with 260k miles. Now that I've got most of the routine stuff done, I want to look more into customization. I contemplated a body lift to put a taller tire on it, but I saw a guy with a 96 Z71 at work one day with the wider tire and some slick flares and decided I liked that better than a taller look.

 

[shovelbill]

seeing as you truck is a hobby truck it shouldn't matter much, BUT.......going to a 33" tall tire will affect your overall gear ratio. it may be of concern depending on how you actually use the truck......gas mileage will almost certainly suffer and your speedo will be off by the corresponding percentage to height increase. "off the line" performance will require more pedal.

i was considering bumping my truck to 285's as well.....i stayed at my stock height of 265's when i switched my rims to newer 17"(265/70-17).....i have 3.42 gears and for the way i use my truck i saw no reason to go bigger, especially when i looked at the downsides v. the benefits....the <1" height, increase cost per tire and needed speedometer calibration issue(mine's a '98 too)convinced me it wasn't worth the trade off.....if i ever decide to go bigger it will be to a 34 or 35 inch tires and a proper SAC with 4" of lift......then i'd change my gearing to 4.10's.....with 2 selectable lockers.....blablabla

it's a domino effect.....some folks don't care or don't know.....others want their trucks to perform to certain expectations and the only way to do that is to come up with a complete RECIPE to suite your particular needs.........hope this helps a bit.

 

[df2x4]

^ I switched my Suburban back to stock 245/75/16s for exactly those reasons. The 285s I had came on a different set of wheels that I was using for a while. Speedometer ran a little bit slow, but only by a few MPH. I'd imagine it threw my odometer off a little bit, too. I will say though, it handled the extra rubber just fine as far as power with the stock 3.73 gears.

Worth mentioning that if you care about this stuff, you can always have your PCM tuned by someone like Black Bear Performance. They can correct your speedometer/odometer for non-factory size tires. If you ask me we Vortec guys are lucky, I'd much rather swap a PCM out than mess with soldering on a DRAC personally. To be fair the DRAC solution for TBI trucks is a lot cheaper than a tune, though.

 

[shovelbill]

^ I switched my Suburban back to stock 245/75/16s for exactly those reasons. The 285s I had came on a different set of wheels that I was using for a while. Speedometer ran a little bit slow, but only by a few MPH. I'd imagine it threw my odometer off a little bit, too. I will say though, it handled the extra rubber just fine as far as power with the stock 3.73 gears.

Worth mentioning that if you care about this stuff, you can always have your PCM tuned by someone like Black Bear Performance. They can correct your speedometer/odometer for non-factory size tires. If you ask me we Vortec guys are lucky, I'd much rather swap a PCM out than mess with soldering on a DRAC personally. To be fair the DRAC solution for TBI trucks is a lot cheaper than a tune, though.

and changing a gear on a carbed truck is easier and cheaper yet.......

as some know i live in NYC and when i'm stuck driving in the stead of riding it's usually bumper to bumper traffic....so getting the rig moving is important.....as is passing all the alien monkeys that "drive" around here. if my stock L31 didn't **** the bed i would have wanted 3.73's for the bottom end torque........the flip side of this is my long trips with the truck......fuel economy (did i just actually type that?) is somewhat a factor.....considering i'd rather get 15 as opposed to 12.

after the stocker blew i swapped in a GM HT383E....there were no more power issues to consider...so 73 mph rpm's were then a consideration.......have to trade something to get something.......i decided that the 3.42's she had was a perfect(and cheap) compromise for how i use the truck with the tire size i have..........fuel economy actually went up after the swap and i have all the power i'll ever need..........yea, i'm still going to have it dyno tuned with all the other modifications i did, but this setup is perfect for ME.

in the past all i've ever had was 2nd gen K/5's....and 33" with 4.10's or 35" with 4.56's were perfect....especially on the overdrive trucks. my '85 Jimmy with the 305 consistently got 21 mpg with 35's on the road......i never lifted them over 3" either.......the lower they are the less drag they make and remain stable. articulation was never an issue with strategic trimming of the front fenders either.

as to the author of this thread, i concur.......go with the 285's. i don't see it affecting things too much if it's not your daily driver.

 

[Glendias583]

seeing as you truck is a hobby truck it shouldn't matter much, BUT.......going to a 33" tall tire will affect your overall gear ratio. it may be of concern depending on how you actually use the truck......gas mileage will almost certainly suffer and your speedo will be off by the corresponding percentage to height increase. "off the line" performance will require more pedal.

i was considering bumping my truck to 285's as well.....i stayed at my stock height of 265's when i switched my rims to newer 17"(265/70-17).....i have 3.42 gears and for the way i use my truck i saw no reason to go bigger, especially when i looked at the downsides v. the benefits....the <1" height, increase cost per tire and needed speedometer calibration issue(mine's a '98 too)convinced me it wasn't worth the trade off.....if i ever decide to go bigger it will be to a 34 or 35 inch tires and a proper SAC with 4" of lift......then i'd change my gearing to 4.10's.....with 2 selectable lockers.....blablabla

it's a domino effect.....some folks don't care or don't know.....others want their trucks to perform to certain expectations and the only way to do that is to come up with a complete RECIPE to suite your particular needs.........hope this helps a bit.

Well to be honest, it is a "toy truck" to some degree, but it's also a daily driver. But seeing as how my daily drive isn't extreme and I work management for a major part store (unnamed for corporate reasons) I just thought it would be kinda neat to be able to show people different options for truck mods. Plus I just think it would be cool looking if I did a wider tire with some good looking flares. But you guys have given me a lot of info I was looking for! Thanks much!