I have been pondering the synergy of tires size and gearing for my as-yet theoretical 93 Trooper RS. I want to make the right choices the first time, not waste time and money trying this and that. And even if it is silly to get into such details for a vehicle I donÆt even have, I think this discussion will be useful to the community in general. Which brings me to my first question:

I know 33s can fit OK. Assuming a 3ö lift, can anything bigger than 33ö tires be stuffed under a 93 Trooper with no more than mild rubbing and correction using a BFH?

Related question: am I risking frequent driveline breakage going to 35s? (Near as I can tell, nobody makes a 34ö MT tire, so 35s are the next step up.)

This is important, because it impacts my choice for gearingàmaybe. 33s are an 11.9% differential from 29.5ö stock 245/70/16 tires. With a diameter typically around 34.6 according to a generic tire size calculator, 35s are a 17.3% differential from stock.

Which brings me to gearing, I have already decided to install ARB lockers so I might as well re-gear at the same time (like how I said that without flinching, budgetwise? <img src="/forums/images/graemlins/evil.gif" alt="" /> ) so the gears only have to be set up once. The stock gears are 4.56s, with the rare coveted 4.77s, Matt's hypothetical 4.88s, and Tera 5.38s as more-or-less available choices.

Departure from stock 4.56:
4.77 = 4.6%
4.88 = 7.0%
5.38 = 17.9%

Note that even 33s, the smallest tire size I am considering, are a bigger departure from stock ratio than the 4.77 or 4.88 gears compensate. Even the 4.88s and 33s are still 4.9% shy of stock ratioàwhich makes me look hard at the 5.38s. Obviously, with 35s the 5.38s are a no-brainer. But even with 33s, the 5.38s are only 6% over. This is slightly less than the differential I was living with (on the minus side) with 32s on my former 99 Trooper.

So I am thinking that the 6% deeper ratio would be a good thing, what with the much heavier tires, and increased aerodynamic drag due to the lift. It even helps the crawl ratio slightly <img src="/forums/images/graemlins/notooth.gif" alt="" /> .

So what do you guys think of running 5.38s with 33s? Opinions and real world experience welcomeà

just FYI swamper makes a 34x10.50 in the LTB and a 34x12.50 trxus M/T. Mickey Thompson makes a 34x11.50/16 baja belted as well.

If you live in mountains/hills, get the 5.38's. It's pretty flat around here, so I'd rather have the 4.88's.

Thanks, I'll check into those...I have looked at BFG MTs and ATs and Goodyear MT/Rs as well as others and never found any 34s.


Nothin' but flat around here after the glaciers got done! Highest point in the state: 2,301 feet <img src="/forums/images/graemlins/lol.gif" alt="" />

Gave us lots of lakes, though! <img src="/forums/images/graemlins/cheers.gif" alt="" />

I'm running 34x10.50 LTBs on my 94 Trooper. I have 4.77s and I wish that I had lower gears. It is fine at 65mph or 45mph, but at 55 it shifts in and out of OD. 4.88s might be just right. With my 33x10.50 SSRs I didn't have a complaint.

If I was doing it again I'd stay with 33s and 4.77s - so 4.88s should do very nicely for you. My next set of tires will probably be 255x85R16 Dunlop Mud Rovers - although I'm not set on the brand/tread yet.

-Tad

Hmmm, 4.88s and 33s are about a 4.2% taller final drive ratio than stock 4.56s and 29.5" tires. If I go to the expense of regearing, I am still tempted to go the other way, and go 6% shorter with the 5.38s.

Hey Tad, did those 34s fit OK? How much lift were you running?

I have no body lift, so the front does rub a little bit. I have 15x6 1986 Trooper rims. I run 1.5" wheel spacers in the back. With the spacers in the front I rubbed on every corner. I'll be hammering the back of the front fender a bit once I get some free time (I'm in the process of moving) but I've been driving it on the street and over curbs and the like without an issue.

I have OME springs and 1.5" spacers, but with IFS, the lift doesn't matter for tire clearance. I haven't extended the bump stops, which would make a difference as far as rubbing is concerned.

-Tad

I ran 33s with the 5.38s for a few months. My opinion = GREAT!! The Amigo never felt as peppy around town. Up till about 65 (GPS speed) on the freeway was painless. After that you notice a bit to much RPM for extended driving. But there was even acceleration after 65! With the 2.6 I4!!

Now with the 35s and the 5.38s (and 190,000 niles), I think it is beter than stock gearing as far as acceleration and feel go.

MPG increased with the 5.38/35 combo in comparison to 4.55/33s.

My opinion is that for the cost, you will not be satisfied with 33s and 4.88s. If you are going to regear and/or go to 35s, 5.38s are the only way to go.

Bear in mind, that my opinion has no knowledge of a V6 or automatic transmission.

Steve G

Steve G

Thanks for the report, Steve...yeah, the 3.2 obviously has more power to handle the load...but I would still rather go with a few extra rpms to pull around the extra tire weight and such, steel wheels, maybe a winch and bumper eventually, sliders etc. That all adds up. I guess I am more comfortable with an engine at higher rpm than one that is straining to pull at lower rpm.

Steve, a couple things to keep in mind.

1) this is supposed to be a trail only truck, the 5.38's will be nice on the trail, but you may not be able to run down the freeway at 75mph for extended periods. My Amigo is still geared stock (4.30), it goes alot faster with the bigger tires, even though it really shouldn't be going as fast as it can go <img src="/forums/images/graemlins/zombie.gif" alt="" /> Other wise its bearable. If the 5.38's are decent for 65, how much faster do you need to go for sustained driving? Passing will be much better too.

2) The 93 3.2L V6 didn't have quite the power your old 99 3.5L had. I don't remeber exact numbers but it think its close to 50 less hp. Admittedly in a slightly lighter vehicle. Lower gears will help.

3) IF you ever want to tow your camper trailer, the 5.38's will be much more enjoyable.

4) if you stick with 33's you can steal a spare 285/75/16 off your Tahoe (It'll just have to go on the back end).

I say go 5.38's and 33's. But thats just my opinion <img src="/forums/images/graemlins/kewl.gif" alt="" />

Mike W