33"MTRs for a Rubi w/ a 2"BB Lift

[Schmo]

I just put a 2" Rubicon Express Economy/Budget Boost on my 06 Rubi figuring that would provide enough room for the 33" MTRs (31" MTRs came stock). I wanted to make sure that the 33" MTRs would not pose any problems, rub, etc and if I need anything other than the tires to do it up right. Also wanted to see what would be the best size as I've seen a couple different sizes that looked like they'd fit the 16" stock rim.

These are the sizes I've seen on-line:
LT255/85R16/D 33.3"diameter
LT285/75R16/D 33.1"diameter

[blkTJ]

width???

[Materdaddy]

How much do you want to bumpstop and limit upward travel? You'll probably need new wheels with less backspacing as well. Good luck!

[Schmo]

blkTJ - I'm currently running the 245/75/16 MTRs . . . I'm not sure as to how the sizes work exactly but I thought the first number had something to do with the width . . . that's why I was a bit concerned about the 285/75/16 MTRs rubbing . . . but then again I might have it backwards or just be making things up!

Materdaddy - Please correct me if I'm wrong, as I probably am, but I was thinking that with the 2" boost and the 33's only increasing the heigth 1" in the wheel well that I'd still be gaining about an inch of travel, and be gaining an inch of clearance underneath? Backspacing . . . what's that all about? I think one of the guys at the shop had brought up backspacing . . . is there a kit or something that adds the backspacing or do I have to go with new wheels altogether? I'd been told that 33's (and even bigger) would fit on the stock rim . . . I guess I could throw some 15" steelies on there, but I was hoping to get some use out of the stock ones first . . . they just got their first bit of rock rash last weekend!

[dadasjp]

What does the manufacturer say you can run? Depending on the answer, you might be able to run the tires w/stock wheels, but it might be close, or you might be able to up the spring size slightly to boost up the lift another inch or so. By the way, if you want to buy a set of 4 slightly used (6,000 miles, 3 trail runs) and one never used spare for cheap, send me a PM. I'm upgrading to 35's next month and need to get rid of my 285/75/16 mtr's off my '03 rubi. They'll be up at my brother-in-laws tire shop in Fullerton. You can also ask about the MT rims they go with, I was planning on keeping them, but might upgrade as well.

[Materdaddy]

blkTJ - I'm currently running the 245/75/16 MTRs . . . I'm not sure as to how the sizes work exactly but I thought the first number had something to do with the width . . . that's why I was a bit concerned about the 285/75/16 MTRs rubbing . . . but then again I might have it backwards or just be making things up!

Materdaddy - Please correct me if I'm wrong, as I probably am, but I was thinking that with the 2" boost and the 33's only increasing the heigth 1" in the wheel well that I'd still be gaining about an inch of travel, and be gaining an inch of clearance underneath? Backspacing . . . what's that all about? I think one of the guys at the shop had brought up backspacing . . . is there a kit or something that adds the backspacing or do I have to go with new wheels altogether? I'd been told that 33's (and even bigger) would fit on the stock rim . . . I guess I could throw some 15" steelies on there, but I was hoping to get some use out of the stock ones first . . . they just got their first bit of rock rash last weekend!

Even with increased height, the spring could still compress to a great height, which with a taller tire can still rub which brings me to the whole thing blkTJ brought up. Width makes a huge difference with this as well.

It's not as simple as 2" lift (axle to frame, wheel to wheel well) and 1" tire height change. There's many factors involved.

As far as backspacing, that's the distance from the mounting surface to the inside of the wheel surface. With wider wheels, you'll want less backspacing or your tires will rub when at full turn (and possibly when flexed, hence my other questions/suggestions). If they rub during turn, you can adjust your bumpstops with washers.

[Jerry Bransford]

2" is not enough lift for 33x12.50 tires on a TJ and even 3" is marginal. Even with 3" of lift, you'll get tire rub when your front antiswaybar is disconnected. A good height for that size tire is 4", which can be a combination like 3" suspension plus 1" body lift.

I KNOW there's always a few that will claim 2" is enough or "I run 3" and 33x12.50 without problem" but if you want to do it right for 33" tires, especially since you've got an expensive very capable Rubicon, don't cripple it by not giving it enough lift height for the size tire you want to run.

Really.

[Paul B]

blkTJ - I'm currently running the 245/75/16 MTRs . . . I'm not sure as to how the sizes work exactly but I thought the first number had something to do with the width . . . that's why I was a bit concerned about the 285/75/16 MTRs rubbing . . . but then again I might have it backwards or just be making things up!

Those are metric sizes. The first # is the width in millimeters. The second # is the ratio of height to width. In your example the tire is 75% as tall (on the outside of the rim) as it is wide. The lower the second # the lower the profile of the tire, i.e. if the second # was 50 the tire would be 1/2 as tall as it is wide. Hope this helps.

[KNCJeeper]

my buddy help me put my 2" RE BB on. He has the same thing on his Rubi and runs the JKS 1.25" MML and BL with 285/75/16 Maxxis Bighorns without a problems...its actually the same thing im about to do...look at my picture to the left though...that is the 2" BB with 31" MTRs and im bery close to rubbing right there..thats with sway bar attached and pretty much all flexed out

[Schmo]

Sounds like I might want to just knock the knobs down a bit more on my 31s before making the change to 33s. Perhaps the money would be better spent on a CB and some extra armor? Is installing the CB easy? I've pretty much decided on the Cobra with everything in the handset and the small box that can be hidden but don't know of any places that sell and install what I'm looking for (called Fry's, BestBuy, etc).

[Materdaddy]

Sounds like I might want to just knock the knobs down a bit more on my 31s before making the change to 33s. Perhaps the money would be better spent on a CB and some extra armor? Is installing the CB easy? I've pretty much decided on the Cobra with everything in the handset and the small box that can be hidden but don't know of any places that sell and install what I'm looking for (called Fry's, BestBuy, etc).

ARMOR ARMOR ARMOR!!!

[Schmo]

I figured I'd start by adding some armor to the diffs ... any suggestions on which ones offer the best protection. After the diffs, what would be the next best thing to protect? I just installed some rock rails this week.

[Mike]

If a Rubi doesn't already have a protected oil pan, I'd highly recommend that as a next step.

[Jerry Bransford]

Sounds like I might want to just knock the knobs down a bit more on my 31s before making the change to 33s. Perhaps the money would be better spent on a CB and some extra armor? Is installing the CB easy? I've pretty much decided on the Cobra with everything in the handset and the small box that can be hidden but don't know of any places that sell and install what I'm looking for (called Fry's, BestBuy, etc).

The problem with that particular radio is its very (!) tiny speaker inside the handset. You can't really hear it on the highway in a noisy Wrangler and even on the trail it can be difficult to hear clearly. At the least, you should also make plans to install a small external mobile communications type speaker like you can find at Radio Shack.