What is the biggest tire I can put on a STOCK 98 Tahoe?

[bartlanz]

What is the biggest tire that I can put on my 100% stock 98 Tahoe?

I was thinking about lifting it, however because I do a huge amount of highway driving, i descided against it.

That being said, what size can I do?

[JD68]

I have had 285 BFG A/T ko's on my stock 99 for 45k miles and I have only seen a little rubbing on the sway bar and no damage to the tire, I drive on the freeway everyday and offroad about every other weekend . I know that 265 and 275 are the stock tires offered with tahoe. hope this helps
JD

[andjh123]

JD's dead on. Any larger than a 285 (which translates to roughly 33 inches) and you'll get into problems rubbing the lower-rear portion of the wheel well during a moderate turns and suspension compression. This part of the wheel well, if you look closely, is of a odd double panel construction with a lip that sticks out. Part of this lip can be ground away very easily for a little extra clearance, and no one will be able to tell the difference. Grind any deeper and you're looking into some serious body work with that double panel--it has to be closed up because crap will slide in between those panels, down the body and rust out.

On the same note, you throw some larger tires on there and smash up that rear, double panel part of the wheel well, you're going to have to pay a body shop big $$ to repair that, and live with some undesired, "custom" tread patterns in your tire.

[bartlanz]

So I can safely say that i could put 275's on there with out any rubbing? rite now my stock tires are 245/75/16's, how much bigger will 275's be?

[andjh123]

You should have no problems with those if you keep the stock rims. You could ask a tire dealer as well, but of course they're going to say yes b/c they want to sell you tires. If you want to figure out how large metric rated light truck tires are (in terms of inches), you can get into some math:

245/75/16 = section width(SW)/aspect ratio(AR)/wheel diameter (WD)

Tire Diameter in inches= 2 x (AR/100) x (SW/25.4) + WD

So your 245's are about 30.5 inches in diameter and the 275's you're looking at (assume same AR) are about 32.2 inches.

[Pick]

If i'm not mistaken 275's are a lot harder to find than 285's. Good luck with your search and really consider BFGoodrich's if you do go any bigger.

[bartlanz]

I have been noticing that, I'm thinking I'll go with the BFGoodrich Alterain AT KO's size 285/75/16's or 275/70/16's. I realy want to do the 285's, bc they are like 1.6in bigger. But I am realy worried about rubbing, because ontop of a large amount of HWY driving, I spend alot of time in the city trying to park. Is there anything other than a lift i could do to my truck to make it so those tires wont rub?

[Pick]

You could crank your Torsion bars about an inch. That shouldn't effect ride much and will give you the clearance you want. I'm almost 100% sure 285's won't rub, however. I know many people with them on their 92-99 Tahoes and Blazers. In fact, I had the same query about a month ago and my research yielded that you could.

[bartlanz]

Ok, so another stupid Newbie Q. What are the torsion bars realy for, or rather what is their intended purpose?

[JD68]

The torsion bars replaced the need for springs in the front of the vehicle so instead of wound metal bar (spring) you have a straight bar that torques under load(torsion). least thats what I think.

JD

[Pick]

Here is a little piece on what a torsion bar is:


Torsion Bars
Torsion bar suspension uses the flexibility of a steel bar or tube, twisting lengthwise to provide spring action. Instead of the flexing action of a leaf spring, or the compressing-and-extending action of a coil spring, the torsion bar twists to exert resistance against up-and-down movement. Two rods of spring steel are used in this type of suspension. One end of the bar is fixed solidly to a part of the frame behind the wheel; the other is attached to the lower control arm. As the arm rises and falls with wheel movement, the bar twists and absorbs more of the road shocks before they can reach the body of the car. The bar untwists when the pressure is released, just like a spring rebounding after being compressed. Adjusting the torsion bars controls the height of the front end of the vehicle. The adjusting bolts are located at the torsion bar anchors in the front crossmember. The inner ends of the lower control arms are bolted to the crossmember and pivot through a bushing.

[andjh123]

You crank that front torsion bar you're going to have a little rougher ride not to mention a "hot rod" setup with the front end up high (might look sort of cool, actually). Not to mention the bar sags back down over time and you have to keep cranking the bolts to raise it back up.

[Pick]

You can put new shackles in the back if need be, but the "hot rod" setup, as you call it, will not be noticeable.

[bartlanz]

well, given that i already have a bit of a saging rear end, and i meen on my tahoe. i may need to look into mabe a one inch lift or something.

[andjh123]

Nice one, I had to pause for a second, but I got it.

I'm telling you, stay away from the block lift/torsion bar crank combos. It's a cheap/quick fix, but not only are you going to have a rougher ride and strung out shocks, you're going to run into problems with driveshaft geometry (new u-joint every few months, vibration, etc.) because those blocks have to be made perfect, and most aren't unless you get full lift kit from ProComp, Fabtech etc.. ($3k).

Body lift is definitely the way to go here. Doesn't change anything except the body height of the vehicle, adds a few gaps which you can fill, and you can even get it installed and everything for around $500.