Jeep JK people...thoughts on tire size etc.

[Autism Family Travels]

Ok,

I have been bouncing around in my head the idea of going 35s on annie. Now, I know annie has 3.21 gears in her. I had 3.73s on my 2011 with the 3.8 motor, and pulled around 33's perfectly fine. I now have an extra 70hp or something? i know the gearing is lower, but the HP should more than make up the difference. would 35's be close to what the previous JK was running with 33's on 3.73s? If you get what I am saying?

 

[Tupenny]

Short answer: You can run 35's, but you might not like it.

I can't say if the drive would be similar, there's others that will share more technical knowledge I'm sure.

If it's an automatic trans, you'll feel the extra weight for sure. A manual will be more forgiving as you can control the power.

The issue is larger tires = extra weight = extra stress on just about everything. My friend has run 35" KO2's for years on a '16 Wrangler sport JKU (manual) , hard, with the only issue of breaking a tie rod; he says that was more his fault than the tires though.

 

[jeep670]

If it's an automatic trans, you'll feel the extra weight for sure. A manual will be more forgiving as you can control the power.

You can manual shift with the auto as well. People tend to forget that.

 

[MidOH]

Miserable. Regear, do it right the first time. If your rear axle is a d35, swap it out for a locked 60 or 8.8 while regearing. No point in dumping good money into a d35.

Otherwise stick with 33's or less.

 

[Autism Family Travels]

Miserable. Regear, do it right the first time. If your rear axle is a d35, swap it out for a locked 60 or 8.8 while regearing. No point in dumping good money into a d35.

Otherwise stick with 33's or less.

I’m not building a heavy duty rock crawler man. No need for a locked d60. And there’s no need for that for a set of 35s anyways. 40s maybe.

 

[MazeVX]

If you are keeping it light, you won't have a problem, just drive smart.
The outer C on the front is the same on the 44 as on the 30 axle tube also and depending on the build year your u joints on the front are also the same.
The gearing isn't ideal for sure.
But I also say I wouldn't spend the money regearing a dana30 front.

 

[jeep670]

Everyone's opinion is subjective. You won't know until you try the 35s on your rig, but if you don't like it it's $$$ thrown out the window.
Ideally, you'd look for someone locally willing to swap his 35s with your for say an afternoon. Enough for you to get a feeling.

 

[4wheelspulling]

Ok,

I have been bouncing around in my head the idea of going 35s on annie. Now, I know annie has 3.21 gears in her. I had 3.73s on my 2011 with the 3.8 motor, and pulled around 33's perfectly fine. I now have an extra 70hp or something? i know the gearing is lower, but the HP should more than make up the difference. would 35's be close to what the previous JK was running with 33's on 3.73s? If you get what I am saying?

kojack,
Here are my thoughts! Not sure what year “annie” is, but it sounds like it is a 2012 or later model JK, with automatic? With the extra horse power and the 6 speed auto, you might get by with 33”s, but still is not forgiving on the long term life of your auto transmission. The rear axle is a D44, so no worries there. Might even work as a daily driver, but off-road, Hills, Mountains, and with any Overland gear or even a few others riding with you, you’re Jeep will be a dawg, and that trans working extra hard! If you are going to stay with your stock gears, 3.21s, I personally would not go over 265/75/17s or 31” tires. Think of it this way; the OEM put in many test miles for mileage and longevity numbers on the power train. What size tires does your door tag say? You can usually go 2 tire sizes up, but that’s about it, to keep drive train parts happy for the long term. If you are going to change out your gears to say 4.10s like what a Rubicon comes with ( at least the few years older ones did ), then 33”-35” would work. Many do run larger tires than they should with the gears they have, then say Jeeps are junk because everything kept breaking and could not keep the automatic transmission alive for long. So, there you go. Just my thoughts. Vance.

 

[MidOH]

If you have a d44 rear, get 4.56-4.88 gears, two lockers, and rock on. No worries. Correct axle gears for large tires are pretty critical, with marginal engines and transmissions.

I've got around 400hp, 450tq, and can notice the difference between stock tires and 35's big time. With 3.73 gears.

 

[tjZ06]

You can manual shift with the auto as well. People tend to forget that.

Also, a torque converter helps mask not having deep enough gears. Not having enough gear is most apparent when getting moving from a stop, since the TC lets the engine rev more as you get moving than a clutch would (without horrrrrribly slipping the clutch) it can make up for too tall gearing too an extent. IMHO 35"s with 3.21 gears is past that point where it's still reasonable. If it was a JL it would get away with a little bit more since the newer 8 speed has very low gearing in the first few gears, and smaller gaps between gears. Still, 3.21s and 35"s are just not a good combo, IMHO.

-TJ

 

[tjZ06]

kojack,
...the 6 speed auto, you might get by with 33”s...

Correct me if I'm wrong, but I thought US-JKs had the W5A580 (5 speed) from '12-17 and the '07-11 had the 42RLE (4 speed). In other markets there were WJs with the 545RFE like my WJ has, which is still considered a 5 speed even though it has 6 forward ratios (it uses a different ratio for 2nd gear when upshifting to 2nd vs. downshifting to 2nd).

-TJ

 

[OutdoorsBen]

What weight of tires are we taking about. Are you going 12.5 wide from a stock 10” wide. That will considerable weight. Now you can run a pizza cutter 34x10.5 ko2 and the weight is not far off from 32 ko2. I personally wouldn’t go 35 on 3.21. I have a ‘15 JKU with 3.21 and I would try and stick as close to stock weight as possible.

 

[tjZ06]

I’m not building a heavy duty rock crawler man. No need for a locked d60. And there’s no need for that for a set of 35s anyways. 40s maybe.

I agree, 35"s don't need a D60, but 35"s are also pushing it for your D30. At least you have a D44 rear. For 35"s I'd look for a take-out JK Rubicon front Dana 44 (which has factory 4.10s and an E-locker), then gear/lock the rear to match. Otherwise, I'd stay 33" but I'd still guesset, sleeve and chromo the D30. That's more or less my plan (my WJ also has a D30 front, D44 rear though I have the aluminum center section D44A) if I stick to 33"s: build the D30. That said, I haaaaaaate putting money into a D30, they're just so dinky.

That said, there are tons of mall-crawlers on D30s and 35"s that are "fine" and you'd probably be fine too for light Overlanding if you haven't made your rig overly heavy. Also, if you don't add a locker, you'll get away with a lot more. But, again I hate putting $ in the D30 and I think you should gear either way... so you're spending on the 30...

-TJ

 

[tjZ06]

What weight of tires are we taking about. Are you going 12.5 wide from a stock 10” wide. That will considerable weight. Now you can run a pizza cutter 34x10.5 ko2 and the weight is not far off from 32 ko2. I personally wouldn’t go 35 on 3.21. I have a ‘15 JKU with 3.21 and I would try and stick as close to stock weight as possible.

Very good point. Too many people focus on tire height, but weight. Height is indeed crucial when it comes to getting the gearing right, but weight is key for strength. Weight will dictate a lot as far as wear and tear, as well as wheel offset. I made almost this same post in another thread: 35" vs 37" tires for Jeep Rubicon Unlimited w/ Turtleback Trailer but a heavy, wide 33" on a heavy beadlock wheel that has a negative offset would be harder on drivetrain components than a light, narrow 35" on a very light non-beadlock wheel with zero offset or a little positive offset.

-TJ

 

[Autism Family Travels]

I am going with one of the lightest 285 possible if I stick to 33s. the c load BFG. I had the e loads on my last jeep and put 296,000 on that one before a leaky main seal jinked me to trade it in. In heinsight, I would have kept it and fixed the main seal. I am very aware of tire weight's effect on performance too. I have built race cars in the past etc. I am just thinking out loud here. My 2011 JKU was used ALOT in the backcountry and never had an issue on 2" of lift and 33's. SO maybe I will just build Annie the same. I keep the stock bumpers because I live in a huge rust belt. The plastics always look good. I will be adding a light mount and VDP high clearance (wide ones) corners on the bumper. I think I will stick to the 33's instead of messing around with the gearing.

 

[Autism Family Travels]

This was our 2011 JKU. Everything we needed nothing we didn't besides a few little odds and ends. I am getting a roof rack this time. and some better cargo management out back. It had a 2" teraflex lift, lower control arms and monroe reflex shocks. It was a great handing riding jeep. I am going to do the same suspension setup on Annie, but I am going with the falcon shocks this time around. I am also adding the JKS flex connect swaybar links, and the griffin attenuator to the steering link. SHould make for a great on road and off road rig!

 

[12C20]

I ran 35s on my ‘08 JKU, and when I regeared to 4.88, it was perfect.

Before that, it was a dog.

 

[9Mike2]

I spent too much time on the fwys here in Low-Cal, so I am going with 4.55 gears in my diffs. I am not much of a rock crawler but do like to get up those hills.....

 

[Autism Family Travels]

We do, do alot of highway driving. I have decided to keep the tire size the same as our old jeep. it worked perfect for our needs, why change a proven combo. Thanks for the advice everyone!