33" vs 34" - Weight vs Inches

[XyloSesame]

TLDR: Is it worth it to go from OE 31" to 33" or should I jump to 34"? Does the added weight of a 34" justify it over a 33" on a 2dr Sport for mostly on-road with some forest trails?

I'd like to replace my OE Goodyears with either 33" or 34", but I'm not sure about the possible performance hit from the added weight. I've been reading too much about tires and I feel like I'm overthinking it - but a +$2k mod doesn't come easy for me. This is my DD, 90% on-road, and I drive it like a sports car. However, I'd like to take easy to moderate trails and forest/service roads at some point soon. I'm looking for on-road handling, wet traction and trail capability and am leaning toward Falkens.

• 2 door 3.6 manual, standard 3.45 gearing.
• Rubicon takeoff suspension and Mopar lift LCA.
• Front bumper, winch, and sliders added 164 lbs total.

SL-rated 33" (32.8 measured) don't add any weight, but also only gain 1" overall height and 1.5" width. Being a noob, I don't know why I'd spend the money on this other than tread depth. Since I don't see myself doing any difficult rock crawling, I don't see a point in the added weight from a C or E rated 33". But then I jump to 34" which add (to me) significant total weight at either 92 or 125(!) lbs.

How do you tell what the tipping point is for weight vs performance?

Tire	Size	Load	Dia	Width	Tread	lbs x1	Total lbs x5
Goodyear Wrangler AT (OEM)	LT245/75R17	SL	30.6	9.8	11.9	47	N/A
Mickey Thompson Baja Boss AT	285/70R17	SL	32.8	11.6	18.5	48	5
Falken Wildpeak A/T3W	P285/70R17	SL	32.8	11.3	13	50.5	17.5
Falken Wildpeak A/T3W	LT285/70R17	E	33	11.6	18	58.9	59.5
Mickey Thompson Baja Boss AT	LT285/70R17	E	33	11.5	18.5	63	80
Falken Wildpeak A/T3W	LT285/70R17	C	32.8	11.1	18	63.7	83.5
Falken Wildpeak A/T3W	LT285/75R17	E	33.9	11.1	18	65.5	92.5
Mickey Thompson Baja Boss AT	LT295/70R17	E	33.7	12.1	18.5	72	125

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[dchemphill1]

With the gearing you have....your sports car feel may disappear some? You have room with the Rubicon suspension. Are you wanting it for looks over function function over look or would you prefer both? BFG KO2's are some of the lighter weight tires and don't see them in your list? Good luck...I am pondering the move to 35s when my 33's need replacing...money money money!

 

[azwjowner]

Tire diameter kills your performance, not weight (weight just wears out ball joints, etc.). With 3.45 gearing and the manual transmission I wouldn't go to even a 33 if you care about performance. I have the same configuration and stuck with 32s (255/75/17) for precisely this reason. Your best mod would be to remove the Rubicon suspension (unless it's merely preventing sagging from your winch/bumper/sliders, or put a half inch spacer instead) and put on 32s.

I have spent a lot of time on rocky trails, forest roads, and remote mining roads and for your uses, you don't need even 32s to be honest, particularly not with the shorter wheelbase of the 2 door.

I argue that nothing is wrong with the looks of a 2 door on 32s, and you save the cost of a regear. You're otherwise going to regret 33s/34s without a regear, in my opinion. The 3.45 gearing with the manual is mediocre enough on 32s.

 

[XyloSesame]

Tire diameter kills your performance, not weight (weight just wears out ball joints, etc.). With 3.45 gearing and the manual transmission I wouldn't go to even a 33 if you care about performance.

As I understand it, and I'm no physicist, diameter relates to torque and weight to inertia. Both play a deciding factor in performance, but diameter (torque) may cause more of a practical loss in performance unless the wheel/tire is ridiculously heavy - in which case, you may be SOL.

I agree, keeping stock size or near stock (the 3% rule) would result in optimal performance, I'm looking for the unicorn balance of compromise.

 

[bjm00se]

It sounds like you're a really good use-case for buying someone's factory Rubicon takeoffs:

1. They're usually a very affordable option, around 1000/1200 for all five.
2. They're factory wheels/tires, so they're the lightest available at that size point.
3. The jump from 31 to 33 subjectively looks and feels bigger than the "only one inch higher" on paper number might suggest.

So my suggestion would be to do that first, and see if you get the results you want. If not, you can sell those for not much less than you paid for them (depending on how many miles you added), and move on to a larger choice.

 

[bjm00se]

This is my DD, 90% on-road, and I drive it like a sports car. However, I'd like to take easy to moderate trails and forest/service roads at some point soon.

...(actually, it sounds like you're a lot more than 90% on road at this point)

Follow on thought:

Don't undersell the Jeep's stock capability out of the box as you have it right now with no changes at all. Forest service roads are totally within its capability right now with no changes at all.

I'm assuming you're about due for tire replacement anyway. In that case, Michelin LTX tires, either in M/S2 or A/T2 might be all you really need. You might be surprised at some of the roads I drove in my old F150 on Michelin LTX tires. They're tougher than you might think.

 

[XyloSesame]

It sounds like you're a really good use-case for buying someone's factory Rubicon takeoffs

I don't disagree with that. So far the takeoffs in my area included wheels and they aren't willing to separate - the prices have been pretty close to new tires, then I'd have the hassle of selling wheels afterward to recoup cost. I've checked out how others have fit 5 tires in a 2 door and have been searching within a 3 hour drive from me. Also, I don't really want KO2s and most Gladiator takeoffs I've seen nearby have been MT.

...(actually, it sounds like you're a lot more than 90% on road at this point)

Don't undersell the Jeep's stock capability out of the box as you have it right now with no changes at all. Forest service roads are totally within its capability right now with no changes at all.

You aren't wrong there, I'm 99.999% on-road having taken exactly one 5 mile jaunt on a well kept service road. The stock Wrangler AT are serving me well, but I'd like to be prepared for my next trip to Colorado, my first in a Jeep, that I haven't even started to plan yet.

 

[Steph1]

34 were the tipping point for me. All was totally fine and fealth stock from the 32 oem to Rubi 285/70-17 take-offs.

Then I pushed my luck and tried 34s in the form of 305/70-17 Toyo OC AT3. Darn.... I suddenly fealth all that weight and regretted it immediately. I installed a hikeit X9 throttle controller and it helped quite a bit around town, but highway was a frustrating experience. The 8sp auto tranny kept down and upshifting, always looking for the proper gear to be in... I totally hated the Jeep at that point. It looked good, but I couldn't stand a shitty ride to get ''the look'' given what Jeeps are worth nowadays.

So I bit the bullit, moved up to 35s and regeared to 4.56.... Now my friend my Jeep drives even better than it looks. Been driving Jeeps for 35 years and always stopped modding to avoid going over the famous 4% tire upsize old school rule of thumb.

First Jeep I regear and it is by far the best money spent to driving enjoyment ratio ever.

 

[roaniecowpony]

As I understand it, and I'm no physicist, diameter relates to torque and weight to inertia. Both play a deciding factor in performance, but diameter (torque) may cause more of a practical loss in performance unless the wheel/tire is ridiculously heavy - in which case, you may be SOL.

I agree, keeping stock size or near stock (the 3% rule) would result in optimal performance, I'm looking for the unicorn balance of compromise.

azwjowner gave you accurate information on diameter vs weight. Yes, there's a penalty for weight, but it's much smaller than increased diameter, in the scheme of tires. Diameter, or more accurately, the increased radius of the moment arm (axis of the tire to the road surface), requires more horsepower to cause the vehicle to move a specified distance in the specified amount of time. Also, an aggressive tread increases rolling resistance and has a significant effect on fuel economy. Mud tires are worse than A/T tires, A/T tires are worse than street tread tires.

For what you stated your intended use is, I like your choice of the Falken. On tire size, you can go a lot of places with a 32" tire and it will be a lot better on road with smaller tires.

 

[AcesandEights]

..., I'm looking for the unicorn balance of compromise.

Have you thought about taller tires that are lighter weight, provide significantly better traction and last an incredibly long time?

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