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

[bartlanz]

Will a Body lift fix the problems being described (rubbing on sway bars)? I thought only a suspension lift would fix that, and apon further thinking I'm questioning whether it realy would?

[Pick]

You would need to get new rims and probably spacers to offset the wheels and keep them from rubbing. But I can do furhter research to make sure.

[Pick]

The tahoe does have leaf springs in the back? Correct me if I'm wrong somebody.

[JD68]

pick: yeah leaf springs
bartlanz: if your back is sagging a lift is not the anwser to the problem, you need to fix what is making it sag, unless you mean to replace the leafs then get the "lift" while your at it.

lifts will help with rubbing on the wheel well where the fender is, but the spacers are needed for rubbing when turning, inside the wheel wells.

as andjh123 said...

yeah if you dont know much about alignment stay away from your torsion bars, moving those will change your camber, and may requirme a professional allignment, but the amount of adjustment is minimal without changing the keys (octigonal mounts for the torsion bars).


as for spacers I think any increase in stress on an arm/bearing is a bad thing and the need for wider tires does not out wiegh the possibility of damage. 'course I still have not installed a lift yet, it really comes down to what you are going to use the tahoe for and what your willing to pay to keep it that way....

[sweebs]

nobody has mentioned that if/when you change tire size (tread width) and don't compensate by reducing the aspect ratio (sidewall) so as to maintain the same tire diameter, you are going to render your speedometer useless (or at least render it innaccurate)

say you have stock tire size of 245/75-16 and you move up to a wider 265 tire, in order to maintain the same (very close to same) tire diameter, your aspect ratio needs to fall to a 70 versus the 75 of the 245 tire

basically, when you go to a wider tire, you need a shorter sidewall to maintain the diameter of the tire - this way you won't screw up your speedo calibration and you avoid the clearance problems of a bigger diameter tire, although you obviously need to be cognizant of how wide the tire is as far as clearance issues go

I know this is basic stuff, I just found it curious nothing was mentioned about this

[Pick]

If you had a 245-75-16 before and changed to a 285-75-16, it wouldn't matter. Am I correct in saying that?

[sweebs]

Originally Posted by Pick

If you had a 245-75-16 before and changed to a 285-75-16, it wouldn't matter. Am I correct in saying that?

no. it would matter.

in the 245/75-16, the sidewall height is 75% of the width of the tire

if you have a 285/75-16 size tire, then your sidewall will be 75% of 285 mm or exactly 30mm more than 75% of 245mm (although my calculator-less math may be off at this time of day, so you can double check

therefore you will have a larger diameter tire and your speedometer will not be accurate

[bartlanz]

Ok, another thing I just noticed as I was looking at BFG's web site is that they say the 285's are for 7.5-8.5in rims, I only have 7in rims. will this be an issue?

[sweebs]

I would bet the tire WILL fit onto your wheels, though they may appear slightly "fat" (for lack of a better term) due to the bead being pinched to a 7.0" wheel as opposed to the 7.5-8.0 recommended

[andjh123]

So I submit that one could figure out exactly how much the speedometer is off based on the size of the tire (relative to the stock tires that it came with). Calculate change in circumference and then do something with that. It's too early in the a.m. and I'm still recovering from this weekend, so I'm not going to think about that for now.

[andjh123]

And one more thing, could Bart's tahoe be considered a firetahoe? Or how about firehoe?

[bartlanz]

LOL, I was wondering how long it would be before that name was brough out.

My former vehicle was a Jeep Grand Cherokee, and it was well known localy, and around the Jeep comunity because of how decked out it was. It was commonly refered to as either the "Fire Jeep", or "a lightbar with a Jeep under it".

On the Tahoe I desceided to go just a bit more under cover, the only thing I need to finish it is a brush guard and two speakers for the siren. As time progresses you will see that picture change.



For more pictures of the Jeep: CLICK HERE

[JD68]

Originally Posted by andjh123

So I submit that one could figure out exactly how much the speedometer is off based on the size of the tire (relative to the stock tires that it came with). Calculate change in circumference and then do something with that. It's too early in the a.m. and I'm still recovering from this weekend, so I'm not going to think about that for now.

I did the math a while back for this and I found that the differential when you upgrade from 245/75/16 to 285/75/16 the gauge is off by 4mph each 50mph, so when it read 100mph, I was actually traveling at 108mph. I'll look for the formula but i think there are a couple online.

JD68

[andjh123]

Yeah I get [a little] satisfaction out of figuring (or at least trying to) that sort of stuff out. After over-analyzing the problem (like I do for most things) I came up with a bunch of formulas and other various chicken scratch. Then I went on the internet calculators because I don't trust myself....

Bottom line: it looks as though you get about +/- 1.8-2 mph error in speedometer per inch of tire diameter change.

So I could see some significant change to bigger tires (with no speedo adjustment) causing problems with the cops. However, if you speed like a madman in the first place then don't even worry about it!

[bartlanz]

LOL, I tend to "speed like a mad man". But I don't get pulled over too often. I'm just guessing here, but I think it has to do with the square red thing ontop of my Tahoe