32's on an unlifted TJ for a while?

Hey Jeff, I'll offer opinion on both posts (31 vs.32's and BFG vs MTR)

Regearing to 4.10 is more conducive to 31's... from my reading I've concluded 4.10=31", 4.56=32", 4.88=33". That's not to say 32's on 4.10 will suck... depends mostly on your driving style and usage.

The 35c won't give you much trouble up to 33" unless you're locked or you're pounding on it. If you bounce on a spinning wheel, even a stock D44 will break.

BFG vs. MT/R... I just bought 31" MT/R's for my XJ and can't give you much first hand info other than they look great. From the research I have done, I'll give you my impressions:

MUD: Most people seem to favour BFG MT. SNOW: Most say BFG MT are not nearly as good as the AT... MT/R's are good but not great. RAIN: Don't recall a clear winner here. ROCKS: Most say MT/R hands down. NOISE: Most favour MT/R but not by a land slide. WEAR: Both perform well considering their intended use.

What would I do? I'd go with 31's if you're not ready for a lift. The extra inch will likely just piss you off more than it will help you. I was leaning to BFG because it is a good tire and met my needs enough that I couldn't justify paying so much more for the MT/Rs... until I found them on sale. Got the MT/Rs cheaper than BFGs - that was the decision maker for me.

-Brian

I have just been through the same decision making process in the last 2/3 weeks. I finally went with 265/75R16 BFG Muds primarily because of two reasons (1) my TJ came with 16 inch rims, which allowed me narrower but taller tyres (2) MT/R availability is somewhat limited in our part of the world, so if I had blown a tyre it would have taken some time and big $$$ to find a replacement. In the end I actually got a very good deal on my Muds with previous 225/70R16 BFG ATs thrown in as trade-in. Road noise with Muds is not really than much more compared to ATs. I do have a hardtop and this is middle of the winter (in the Southern hemisphere), perhaps it is filtering the noise a little.

Now the question about rubbing, I think BFG Muds in 15 inch size come in

We tend to have more mud on our trails than rocks and snow. Therefore, almost everybody runs BFGs or Simex Muds.

Also keep in mind, changing tyre sizes significantly will change your speedo calibration. You'll have to calculate by how much it is off. In my case, my speedo is reading about 10 percent slower than my actual speed (speedo says 90 kms/h, but I am actually doing 100 kms/h). Also with 32 inch and onwards, spare tyre is not likely to fit on the stock tailgate mount (it doesn't in my case). You will also have to raise the third brake light by a couple of inches, if it exists, for 32+ sizes.

Hope this helps. TW

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If you are not going to lift at all for a while I would probably stick with the 31's. I rode with 31" BFG AT's for a while and the car drove great.

I would probably not go with 32's on an unlifted Jeep, especially if you plan on installing sway bar disconnects. If you go with a

'and the car drove great'? Car? Ugh.

Anyway, other than the fact that you seem to be doing this in complete reverse order (i.e. gears first, then tires, then lift?)... you probably won't even find a tire shop that will mount 32's on a stock height Jeep. How high were you planning to lift in the future (you didn't mention)? And what wheels? If you don't 'do that kind o wheeling', the 35c isn't going to be a concern anyway.

Stick with 31's IMO if it's go>If you are not going to lift at all for a while I would probably stick

Yeah, I've been hit on that one before !

It's because I have a manual tranny and when I bought the vehicle, it was geared 3.07 and that just SUCKED. SO the regearing had utility to me, while a lift and 33's would have been basically almost unusable with the 3.07's, and I can't afford to just dump thousands upon thousands into the Jeep all at once... I've sworn off credit cards, you see !

Besides, i think I did it in the RIGHT order. I don't mind being low-geared, and let's face it, there's a whole bunch of lifted street queens out there. Lifted just for looks. I felt I was "getting the foundation right", a lesson I've leaned before in building buildings on my property.

jeff

Brian,

I just want to take issue with you on the gearing/tire combos. I think you're being a little more aggressive than necessary. My own reading into this and figuring ratios and such actually puts 4.56 w/a

4.10 gears for 31" or 32" tires is perfectly fine; a little better than stock (except when compared to a stock rubicon with 31" tires).

Of course if you don't care if your top street speed would be 55MPH, then by all means, get 4.88 gears for 33" tires. It's just that, with my 4.56 gears, my engine is revving at 3000 RPMs when I'm going only 75MPH or so.

Just my take on it.

/Bob

I'm gonna chime in with Bob here. If the objective is to get back to stock gearing for a daily driver, for example in the case of 215/75R15 (27.7") on 3.07 ratio, here's what ratios you would need:

Granted, bigger tires and steel wheels will add rolling resistance, wind resistance, unsprung weight, etc. so simply matching stock gearing will yield a relative drop in power. Going up to the next gear size to compensate gives the following conventional recommendation:

If you're hauling heavy bumpers, skids, rack, winch, welder, hilift, spares, tools, etc. then next ratio may be desired. If you primarily rally in high range on dirt, one or two up would help. For low range crawling ability on a daily driver, the ideal solution is to gear slightly hotter than stock and upgrade to a 4:1 transfer case.

Steve

Bob wrote:

Hi Bob,

Personal preference and intended use is obviously the deciding factor. My experience is mostly with auto-XJ's as well and that would probably account for the difference our opinions.

My 4.0HO(fresh)/AW4/3.55 on new 31's seems a little sluggish now compared to stock form and while I have yet to get offroad, I know in advance my crawl ratio is going to suffer with the 2.72 t-case.

Having driven a friends auto-XJ with 31's and 4.56, I quite enjoyed it on/off road but I would tend to think that would be overkill for most users. He's since installed 33's... says it's liveable but misses the crawl ratio.

Two things I know we can agree on:

1. there is no absolute standard for gearing - everybody needs are different.
2. wouldn't it be nice if retailers/installers had a free trial period?

-Brian

Bill, it looks to me in that picture like your rear tires are larger than your front tires. Is it just some kind of optical illusion or are the rear tires actually larger than the front ones? If so were you running different gear ratios in the front and rear to compensate?

lighten up.

lighten up.

lighten up.