35s vs 37s on a TJ/LJ

[Rottwheeler]

I want to thank all of you that chimed in on the beadlock discussion... and I will take your advice and opt for the Hutchinson rock monsters (Argent should look good on the red LJ)

Now the question is... should I continue my plan of increasing my tire size from 35" to 37" (second guessing myself...)?

I re-geared from the Rubi 4:10s to 4:88s (sorry Toby, I put 5:13s on my JKU... not the LJ) with the tire upgrade in mind. I am currently reving ~2950 at 70mph on the hwy. A 35" KM2 is 60lbs and a 37" is 74lbs. For any of you that have run both 35 and 37... what are the pros and cons?

Also, 15" vs 17" rim size... I got some feed back that I should run 15s with a load range C tire to get better "expansion" when aired down in the snow. I do more rock crawling than snow wheeling (so far)... so which rim size is better for various types of wheeling and still a good deal of street travel?

I've done a fair amount of reading in this and other forums... but most of those discussions centered around D30/D44 combinations on JKs... I didn't find much related to TJ/LJ D44s front and back.

What say you all??? Thanks!!!

[tobyw]

37's on an LJ would be absolutely fantastic, IF you have enough axle to run them for your driving style. The Rubi D44 front is marginal at best, given that it is essentially a D30 with a larger R&P. Now with that said, I personally would not be afraid to run this setup, but I drive like a grandma and only wheel at the mall, so... To keep it in perspective, Boyscout runs 37" PBR's on Hutchison bead locks on the D30 under his TJ, and does not back away from anything. Granted he's only pushing a 4-banger, but I've seen it survive a lot of things most innerweb bashers swear it shouldn't.

As for gears, I think with your 6-speed the 4.88's will be just fine with 37's. Again, the innerweb will hate you for it, but I'd rock it and not look back. Heck, I had 37's on my first JKU with the stock 3.73's and didn't complain, even at freeway speeds? Downshift here and there, sure. But guess what, I got there at the same time everyone else did, and usually managed to meet/beat them to the top of the trail (at the mall of course ), so...

As discussed, I prefer more sidewall for my driving style. The 17's would probably make for a little nicer road machine, increasing lateral stiffness a bit with the shorter sidewall, but that is a sacrifice I'm more than willing to make. Having more sidewall translates into more "cushion" when you air down, and that is what counts for me. Ask anyone - I'm not a high speed driver

Cliff notes: IMO, 37's on 15" wheels with your 4.88's. Done.

[Rottwheeler]

Cliff notes: IMO, 37's on 15" wheels with your 4.88's. Done.

I am not a high speed driver either. I prefer slow and finesse to fast and loud.

37"s on a 15" rim severely limits my choice of tires though... let me know if you have any suggestions.

[bobracing]

I'm going to disagree with Toby on the 17" rims. I had the same thought when I got 17s by accident but they really seem to work well in snow. Yes, an inch less of sidewall but also an inch more of clearance under the rig too.

Not sure you can go wrong either way.

[OldGreen]

My only real gripe with 17" wheels is that they make tires more expensive. A LOT more. . .The flip side of that is the lack of availability of tires even in the few brands that make them (backorders).

but. . .again. . .if you want the best of the best. . .37" MT/R on 17" Rock Monsters. I'm not mad at my KM2s either. I'd stay away from Toyo's simply because of the weight.

[benw]

You have very few choices for a 37" on 15" rim these days. You are pretty much limited to Interco products, Maxxis Creepy Crawler and the Toyo MT. For that reason only I would say 37" on 17" rim.

[White trash]

You have very few choices for a 37" on 15" rim these days. You are pretty much limited to Interco products, Maxxis Creepy Crawler and the Toyo MT. For that reason only I would say 37" on 17" rim.

Fact. 17's if for nothing more than tire availability. I'm an interco die hard since I'll trade on road manners for offroad prowess any day but even interco is making most tires in 17" wheel sizes these days.


The 15" vs 17" snow debate is a moot point once you are over 33" tires anyway. Just make sure you aren't getting load range D tires meant for a coal rolling, black socks wearing, flat billers tow rig and be happy.

[Rottwheeler]

Just make sure you aren't getting load range D tires meant for a coal rolling, black socks wearing, flat billers tow rig and be happy.

And therein lies the next chore... finding a 37x17 that isn't load range D.

[OldGreen]

D rated tires in flotation sizes are fine. If you can find a C, it is better off road, but only marginally. I ran D's and never had any issue "keeping up".

The trick is to get the right air pressure both on and off road. With the double beadlocks, you don't have an issue off road, you can go as low as you want to as long as you aren't pinching the sidewalls.

[iaccocca]

Being the least experienced of all that have posted up, I'll disagree with everyone. Actually, 37s on an LJ would be cool, but if you are not looking at major axle upgrades you will spend more time under it than in it on the trail. I smoked a stock front shaft on 33s. The rear Rubicon locker is the weak link at that end. 4.88s, 35s x 15 load c, less air pressure than you think is prudent, and don't load the thing like a truck it will work great in the snow and the loose stuff. (Guilty of at least one of these things). And with the weight of 37s, braking will get interesting on the road.
My LJ is on 35s now with stock gears, and I am well pleased, except when towing, but what fool tows with a trail rig? And I haven't had it in the snow yet, so ask my opinion in the spring.
That is my 2 cents, which this time I think is worth even a penny more.

[Nukegumby]

I'll agree with Iaccocca, but my reasoning is different. A D30 will last with 37s if you are careful on the pedal and stick to moderate trails. I'd be more worried if I had a D35 in the rear. What I'd use to decide on tire size is whether or not:

A) Breakover angle has been a problem as your wheeling prowess progresses,

B) Unsprung weight isn't a problem either for your rig or your wheeling style,

C) The cost of your decision, whatever it is, works for you.

I run the smallest wheel that'll fit my brakes within my budget. That's all I use to decide wheel size. I will eventually leave 16" wheels for 17" wheels, but so far, on my JKU, it'll be the cost of wheels and tires that makes the decisions and not the brake size.

I'll run the shortest tire that'll work within my budget and capability. Right now I think 35s would work just fine as far as my capabilities go, but I have some new Creepy Crawlers (38.5x14.5x16LT) in storage that I'd love to run on my JKU. So I'll probably build in that direction anyway. Then, I guess, I'll have to get better at wheeling.

In short, for me, it's not one thing that drives the decision but all of them. My capabilities, my budget, and my equipment. So really, if you adopt my approach, you're the only one who can decide what the right answer is.

-Mikey-

[commando14]

I've ran 35's on the Comanche with 4.88's for the past 14 years and I've rarely had the need or wish for bigger tires (except in the snow). I think 35's are the best overall tire size for most of the trails around here (Rimrock, Naches, Liberty, etc..)

Snow is a different story.. bigger is almost always going to be better. I have 37's on my Cherokee, but I only run them in the snow. Built the Cherokee mainly for snow but I've swapped the 35's on the Cherokee the few times I've taken it on trail runs.

I prefer 15" rim for more sidewall and flotation.. especially in the snow.

[Lurch]

So run 36" tires. Best of both worlds. I've ran as big as 38" tires, ran 37" tires for the last few years and I'm now back where I started at 36" tires bias ply Iroks. Best tire I've ever ran off road. Not the best if you spend much time on the pavement.

[scumby]

on a TJ I'm running 37s, 4.56s, and a 6 speed but have the options of 3:1 or 5.22:1 transfer case so I have plenty of low range off road, not running stock axles though. at 60 I'm running about 2250 rpms on an I-6. at 65 2375 rpms. my speedo is also right on w/o mods. so what's your goal, back to stock rpm? you have a rubi 4:1 transfer case, 6 cyl 4 cyl?

I went through the same thoughts as to 456s or 4.88s, pretty happy with the 4.56s but may have thought I would have liked 4.88 when towing a small trailer but my rpms would probably be a bit high on the highway at speed.

[Rottwheeler]

4.0L I6, 6sp manual trans, Rubicon 4:1 t-case, 4:88s and yes... back to near stock rpm. 60mph is fine... but 70 (I drive my rig to the trail, including Moab) is near 3k rpm. It makes pulling the hills great... but I wonder about wear on the engine.

With all the research I've been doing lately... starting to wonder if I should just stay with 35"s. The difference in weight, cost and potential highway handling may make it impractical... but with the 5.5" RE LA lift, it's certainly got room and would look and wheel great. I love the way this thing flexs...

[scumby]

see if someone will lend you a set of 17s to put those 37s on and give it a shot. or if someone will lend you their 37s already mounted.

[scumby]

17" 5x4.5 wheels

http://kpr.craigslist.org/for/4627230948.html