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Largest tire on stock JK? Here's your answer!

2M views 2K replies 811 participants last post by  Old Dogger 
#1 · (Edited by Moderator)
One of the most frequently asked questions on this forum is “What's the largest tire I can fit on my stock/unlifted 07+ JK?”. So, I put this post together that can either be made a sticky, or something that we can link to whenever this question arises.

Have to give thanks to kbwwolf for proof-reading and making a few tweaks here and there. Thanks bro! :thumb:

First things first. Jeeps come stock with 3 different tire sizes:
1. 225/75/16 (29”x9”)
2. 255/75/17 (32”x10”)
3. 255/70/18 (32”x10”).

The backspacing on stock JK wheels is 6.25". That means that the mounting surface of the wheel is 6.25” from the rear lip of the wheel. The larger the backspace number, the further under the fender (and closer to suspension components and airdam) the wheel will be. (see below image)


I see posts all the time saying that a 33” tire will fit the stock JK just fine, and that is semi-true. In reality, this question requires a 2 part answer. The first part deals with tire diameter. The second part deals with width.

It is true that the largest diameter tire you can fit on a stock JK without issue (read on) is 33” in diameter. With this diameter, you shouldn’t have any issues on the street. However, you could get some contact with your fenders if you flex offroad. Disconnecting your front sway bar will cause contact with your fenders.

Now let’s take a look at tire width. People often overlook this aspect when choosing a tire. The width on most 33's range from 10” – 12.5”+.

On Stock Wheels
The largest tire you can fit without a chance of problems on road is a 33x10 tire (also called a “pizza cutter”). An example is the 255/80/17 BFG KM2. Because this tire is the same width as most stock JK tires, there is no issue on road, despite the larger diameter. You can run this size without issue.

Now, let’s consider some tires that could potentially cause slight issues on road; the 33x11s. The common sizes of these would be 285/75/16, 285/70/17, and 275/70/18.

The 275/70/18 measures slightly under 11” wide, while the other two measure a little over. Many folks have reported running these sizes without issue. However, others have experienced contact with the airdam or front suspension components. Simple fixes are to add washers to the steering stops, trim the airdam, or install wheel spacers.

Any tire larger than 11” in width, you are almost guaranteed to have to do one of the above mentioned mods. In fact, if you go too much wider than the 11” tire on stock wheels, you stand a good chance of making contact with your rear swaybar end link. If that is the case, wheel spacers can correct this issue. Common sizes are 295/70/17 (33x11.6), 305/60/17 (33x12), 305/70/16 (33x12), 295/65/18 (33x11.6).

On Aftermarket Wheels
As I mentioned initially, the stock wheels have a backspacing of 6.25”. This is too deep of a backspace to allow proper clearance for a decently wide tire. The general consensus is that the “magic number” for backspacing for the JK is 4.5” or less. It does not mean you can't run a wheel with 4.6”+. But 4.5” and under is the safest bet.

Many 15” wheels have less (sometimes a lot less) than 4.5”. That's so the wheel clears the brake calipers. Most 15” wheels come with 3.75” of backspacing (MB72, MB TKO, etc). There are a few that come with more (such as the Black Rock 909 – 4”) and some that come with less (such as the Level 8 Tracker – 3.32”). Just remember, the lower the backspace number, the further out the wheel will sit from the Jeep body. One of the most common wheel/tire combos on this site is the 15x8 MB 72 wheel with 33x12.5x15 Duratrac tires. Dozens of people run this setup without a single issue on the street. However, just like most of the other 33” combinations, you can get some fender contact when offroad.

Also, be aware that, while many 15" alloy wheels will fit over the Wrangler's brake calipers, most 15" steel wheels will not.

Once you get into 16”+ wheels, it's pretty easy to select a wheel with a backspace near 4.5”. The most common 33” tire to run with 16” aftermarket wheel is the 285/75/16. A common tire size for the 17” wheel is the 285/70/17.

Links of interest:
Utility to compare tire sizes
Adding washers to the steering stops

4500274
 
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#459 ·
JHR1985 said:
I currently have 255/75/x17 tires.

If I got 17x8 rims, would those tires fit on that in the meantime while I save up to get the bigger tires?

Thanks
Yep.
 
#461 ·
Hello All !! I pulled the trigger on a new 2013 Rubi Unlimited yesterday. It's still in transit .. I hope to have it within the week. I should have a better idea tomorow. Since then I have been total engrossed with this and other jeep forums. Great Info... I'm getting it.. but my head is spinning !!

Initially I thought that I would keep it stock for a while and slowly work my way to a 3" lift w/35's. But now I'm considering some initial upgrades.. I would appreciate your thoughts.

My main reason for phase 1 is winter driving considerations.. Snow/ICE/RAIN and I like the beefier tire.

Phase 1 (from the dealer)
1. Keep the stock rims (there growing on me).
2. Upgrade to Duratrack LT285/70R17
.. I might need spacers
or
upgrade to LT315/70R17
in which case I would need spacers and probably go with the
Rubicon Express economy 2" lift.

** From all that I have read I think the LT315 should work.. with some minor rubbing only if I really push it.

Any thoughts on if I would be better off just paying the up charge at the dealer vs driving to tire shop?

Phase 2 (next few months)
1. Ace Rock Sliders (look great with the Rubi RR's and function as a step)
2. Front and Rear Bumbers

Phase 3 would be a full lift with some true 35" tires... once I save up some money !!

Thanx !!
 
#462 ·
I read this thread twice. The combo being looked it is strictly for on-road use, never off-road.

Looking at 17" MB Chaos 18mm offset wheels (5.5" backspacing) with either the 275/70 or 285/70 tire to keep the tire even or under the car (thus no 4.5" backspacing). The 275/70 is exactly the same height as the stock 255/75 (no speedo errors or calibration with gearing) while the 285/70 is essentially a 33" tire.

No thread I read talks about a 5.5" backspacing, everthing is either 285/70 on stock rim and no off-road use or aftermarket wheel with 4.5" backspacing. Does anyone know if the 285/70 on the 5.5" backspacing causes any rubbing issues for non-off road use? I would think not since the interior side of the tire is actually further from the suspension compared to the stock rim.

Sorry if the question has been asked, but I couldn't find the answer. Thanks in advance for the help.
 
#464 ·
Wheel and Tire combo - recommendations

Awesome thread thanks to everyone for all the information on tire and wheel sizes. I think I just about narrowed down my decision to replace the stock tires on my 2011 sport unlimited
I am looking at the American Outlaw Hollywood wheels to replace my stock 17inch. Looking at the 17x8.5 -10 offset ( about 4.36 inch backspace from what I can calculate).
I am looking at the DuraTrac tires just trying to determine which size I should get the 285/75-17 or 285/70-17. Have heard the DuraTrac tend to mount smaller than the printed size and looking for some recommendations on which size to marry up with the new wheels and not have to do any other mods to the jeep at this time.
I use the jeep as a DD so gas millage would be nice to keep from decreasing too much and do some off-road not much right now but could change as the addiction grows
Thanks for the help
 
#465 ·
Hello everyone. I hope you're having great holiday of Christmas.

I've one question about tire and wheel.

I'm planning to purchase wheel and tire for 2011, JK Unlimited, Sahara.
And I have Old man Emu 2" suspension kit.

Here are my plannedd purchase:

1. Black Rock Series 900 Viper Alloy Wheel in Matte Black
Black Rock Wheels 900B785045 - Black Rock Series 900 Viper Alloy Wheel in Matte Black for 99-12 Jeep® Vehicles with 5x5 Bolt Pattern - Quadratec

2. Cooper Discoverer ST Maxx 285/70/17
285/70-17 Cooper Discoverer ST Maxx Tires

So my question is as following:

1. Does it have any rub to body without any spacer?
2. Did anyone purchased like this before?
3. What is your experience with Black Rock Series wheel?

Thank you, I appreciate your kind comments, advice and blames also

Cheers,
have a nice holiday.
 
#466 ·
I have those wheels and really like them so far. The finish is nice and they're original looking.

You'll be fine with that 285/70/17 tire. It is about 32.5" tall (give or take) and will be a little narrower than the traditional 33x12.5 tire. You'll likely measure around 11.25" wide.

Post up some pictures when you get them mounted.
 
#467 ·
I'm getting a 4" lift put on my new jeep and I ordered tires and wheels for it. I got a 35" tire ( nitto trail grapplers) and 17" wheels. The dealership suggested a -24 offset on the XD Strikes. how much are these going to stick out? I want them to stick out some but not overkill. what do you think?
 
#469 ·
I'm another tire ignoramus who has 7.5x18 stock Sahara wheels which I want to keep. From what I've gleaned from the thread I'll need spacers (1.25 or 1.5?) to put wider tires on with no lift. I'm going with Duratracs because they seem best in snow and ice with occasional off road use. I don't want to go taller just wider to avoid gearing issues. My question is; can I put 295/65R18's on a 7.5" wheel?
 
#471 ·
Thanks for the quick reply, I'm heading to the tire dealer shortly. One question, how do I find out what springs I have? I've got a 2013 JKUS, I would think the springs are already a little beefier than the 2-door, but not as much as a Rubi. Does Jeep have an online spec sheet of everything on our particular JKs that we can access?
 
#472 ·
Hey, New Jeep owner. I just got a 2 door 2007 Sahara. It has stock tires and rims with no lift. I want to get a 2" Rancho lift and keep the 17" stock rims. What would be a good size tire to put on the rims without having to buy spacers? Of course I want as big as possible. Should I just go ahead and get new 16" rims?
 
#473 ·
I just ordered 275/65R18 Duratracs because they're practically the same Dia(32.05vs32.1) as the 255/70s. My tire dealer informed me that the 295s on a 7.5" wheel would crown up even higher than the 33.1" stated Dia. Being in a hilly area I don't want to alter my shift points much because I got 3.21 axles for lo rev @highway speeds and I'm just getting used to shifting with the 32s over the 28.4" 225s on my XJs that I've been driving for the last 25 yrs. Old habits die hard! Although those 295s look sweet on your JK!
 
#474 ·
If I put 285/75/16 Falken's on my stock 16" steelies with 1.5" spacers, should I expect any rubbing issues?
 
#500 ·
Lee,

I have a friend of thinking of 35 x 12.5 on stock wheels with a 2.5" lift. He wants it to look good to take to Moab but also uses it mostly as a daily driver. What would you recommend? If he goes 35" will he need to change rear tire bracket and other stuff? He likes my Jeep but I run 285x75x17s with a 2.5" Tereflex. Can you give some advice?
 
#479 ·
So right now I am currently running 275/65/18 duratracs on Ultra Gauntlet 18x9 wheels. I bought that setup without having a lift. Since then I installed a 2.5 lift. I am looking to move up to 35's and trying to decide on a size. I also want the tires to stick out a little from the fenders. Right now they do a little bit. I was thinking 325/65/18. Would those work or do you guys suggest another size?
 
#508 ·
I'm not going to guarantee it because I'm not running it, but if you have spacers, the guys at Metal Cloak claim you can run 37's on an unlifted JK if you are running their fenders. Of course by the time you buy those, you could have a lift and/or new wheels or both :rofl:
 
#484 ·
I have a quick question about tire and rim selection. I'm looking at Level 8 Strike 5's 17x9. Looks like a 4.25" backspacing. Looking to run Duratracs in LT285/70R17. I need to keep the tire under the fender due to local laws but want a 33" tire. Does anyone know if this setup would have them sticking out past the fender? If I did the numbers correctly they are 32.71" Diameter and 11.2" width. Not too much bigger than stock but the 4.25" backspacing is throwing me off. Thanks for the help.
 
#487 ·
Hey,Quick question I just bought a new 2013 JKU Sport S..I'm new with jeeps and want 2 buy wheels/tires..I have been lookin everywhere on this forum and called a couple of dealers and still can't really get a straight answer...would anyone kno if the 18"x9" XD Rockstars w/ with 5.00 backspacing and 0 offset w/ 275/65/18 Goodyear Duratrac tires fit my Jeep? With no rubbing or issues..I do not plan on lifting because my dealer i guess has told me it will void my warranty...some people have said I will be ok with this setup but then others say the backspacing is too much..idk..thanks for any help
 
#488 ·
This thread is great!

My preferred tire to use is a 275 70 18. Based on this thread it looks like I might be able to run that on my stock wheels with no trouble, or minimal trouble. When I wear out my original tires I'll plan on rolling with 275 70 18s and hope I won't have any issues. By that time, I should have a leveling kit on as well.
 
#489 ·
Quick question, what is the widest tire that will still work with the stock 17" alloy rims? I want to keep them 32" or possibly go up to 33". I want to get spacers either way. I would like to go up to a 12.5",but I don't know if the rim is wide enough.

Thanks M
 
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