A tire upgrade is one of the first things many off-roaders do, since the stock tires may be good, but not always ideal for off-road tracks. Manufacturers always ensure the tires they fit are best suited for highway driving first and then some light off-road work after. Factory tires will always be more on-road biased. However, if you are a serious off-roader or intend on getting into wheeling or Overlanding, then a decent set of rubber should be high up on your list of vehicle upgrades. Besides, it adds a lot to the aesthetics of your off-road weapon.
The largest tire you can fit without any modifications to panels, fender liners, and mud flaps is 275/70/17. The largest tire you can fit with a small modification to the front fender liner is a 33-inch (285/70/17)
Now that we know, let’s look at the fitment and modification procedures in more detail. We’ll cover exactly what needs to be done to make the 33” fit on your 5th Gen Toyota 4-Runner.
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Biggest Tire on Stock 4Runner 5th Gen
As mentioned from the outset, there are basically two answers to the above question. And that depends on whether you are prepared to do a few small modifications, requiring a few basic tools, or if you want a no-mess no-fuss, hassle-free tire fitment.
Let’s look at the first option in more detail, the no modification size of 275/70/17.
Biggest Tire on a Stock 4Runner (No Lift)
So the 275/70/17 tire is a good middle-ground tire upgrade. These are slightly bigger than the stock rubber and have a nice tall sidewall for off-road use. A taller sidewall comes in handy when you air down for sand or rock crawling. Also, when driving off-road tracks, the taller the tire, the more ground clearance you have, meaning clearing obstacles with more ease. There is no need for a BMC (Body Mount Chop) with the 275 profile on a 17-inch rim.
The 275/70/17 is not as wide as a 285 profile tire and the risk of body scrub is minimal to none.
Remember the first 3 numbers are the width of the tire. i.e 285. The second 2 numbers are sidewall height profiles, i.e. 70. The last two numbers are the wheel diameter. i.e. 17-inch rim.
So a 275-width tire should be a straight bolt-on upgrade, even on the stock rims. The rim offset won’t be an issue and you won’t need any spacers to increase backspacing.
Your gas mileage will not be impacted and your speedo will still read true. If you opt for a nice aggressive-looking AT or MT tire, you’ll get a nice upgrade in the aesthetics department too. Remember, in most cases, the more aggressive the tread pattern is, the higher the road noise will be.
- Bigger than stock (Good for over-landing and off-road tracks)
- Slight increased Ground Clearance
- No BMC (Body Mount Chop) is needed to make it fit
- Fits fine on Stock Rims
- Backspacing is sufficient (No spacers needed)
- Gas Mileage won’t be affected
- Speedo still reads accurately
Next, let’s look at going slightly bigger in the form of a 285/70/17
WATCH – RUNNING 33s Pros and Cons (VIDEO)
5th Gen 4Runner on 33s – 285/70r17
So you’ve decided to take the plunge and fit 285/70/17 tires on your 5th-generation 4-Runner. This tire size definitely makes the tires stand out nicely which adds a nice aggressive look to the vehicle. It’s basically a 33-inch tire.
There are, however, a few minor modifications necessary to make these work. If you decide not to opt for a complete suspension upgrade like this Full 3″ suspension upgrade(Amazon) then a small 2-3” body lift will help a lot, depending on the brand of tire, since all tire molds are not built identically. You definitely will need to do a BMC or at least a relocation of the fender liner in the front wheel well. It’s not a major modification and only requires a few basic tools. For this job, you will need a decent heat gun and Dremel Cutting tool. If you don’t already own one then I would recommend you check out this Top-Selling Infrared Thermo gun on Amazon with almost 17000 good ratings. Also, for trimming fender liners I would recommend investing in this Dremel Variable Speed Cutting Tool (Amazon) It will give you better control than an aggressive grinder leaving your trimming looking a lot more professional and neat.
Your gas mileage will be slightly affected but it won’t be drastic at all. Your rolling diameter is still within the manufacturer’s specification. The 285 is roughly a 32.7-inch or most just round it off to a 33”. The 285 is 1.6% larger in diameter than the 275. Your speedometer will be slightly out. Your speedometer will read 60mph however your actual speed will be 60.9 mph. Not even 1mph out, which isn’t even noticeable.
The below video is a clear explanation and demonstration as to what is required to make the 285/70/17 tires fit nicely without scrubbing.
Have a look:
- Aesthetically pleasing (More aggressive stance)
- No suspension upgrade is needed but there would be advantages
- BMC (Body mount chop needed)
- The front fender liner relocated
- Speedo is marginally out (Nothing noticeable)
- Gas mileage won’t be noticeably affected
NB: when you are upgrading from the stock 265 tires to the 285 you will notice a slight decrease in power when pulling off. Once you get going you won’t feel anything. It’s very minimal, but with only 278 lb-ft (375nm) of torque, if you look out for it, you’ll feel it.
Next, let’s look at the biggest tire you can fit on a 3” lifted 5th Gen 4-Runner
Biggest Tire on Lifted 4Runner (5th Gen)
When you make the jump up to a 33″ tire, you will require a leveling kit or a lift kit. With a leveling or lift kit, a BMC or relocation of fender liners will not be necessary. There will be no need for wheel spacers with a 3” lift either, assuming you are running stock rims with limited backspacing. There is light scrub in reverse at full lock, however, that can be easily rectified. Get something similar to this 2.5″ Lift kit (Amazon)
NB: remember with any IFS, once you do a suspension lift combined with body lift/leveling kits, you throw out the front CV joint angle. This might never be a problem when you are driving on-road, however, it’s the quickest way to destroy your CVs off-road. If the angle is too extreme, your risk of eating CVs on the trail is high, especially when the front wheel becomes airborne and suddenly makes contact with the ground while spinning. To remedy this, you’ll need a front diff-drop to bring the angle back to a safe specification and more in line with factory settings again.
Always keep in mind that these rules/recommendations stipulated here will not be 100% accurate for every 5th Gen 4-Runner application. That is simply because there are always other variables that need to be accounted for.
Tire manufacturers, for example, don’t all use the same specification, tread pattern, and design when manufacturing tires and some might be slightly wider/taller than others. Certain brands of 33″ tires will result in rubbing, even with a 3″ lift, while others won’t. Get a 3″ similar to this 3″ Full Lift Kit (Amazon)
Have a look at this:
- The spare wheel just about fits
- No scrubbing on arch liners
- No to little BMC (depending on the tire brand)
- No relocation of fender liners needed
- Speedo is marginally out (Nothing noticeable)
- A combination of 3” lift and tires will see a slight drop in MPG
Let’s look at going bigger than 33” by running 35s on your 5th Gen
5th Gen 4Runner on 35s (Is Bigger Always Better?)
If you want to run 35s, there are quite a few factors you need to keep in mind.
- Wheel space is limited on the 4-Runners. You will need to chop the cab extensively to make it fit, so get that angle grinder out! A lot of plastic needs to be cut away. That 1 extra inch tall plus the extra width makes for a very tight squeeze.
- You will definitely need a body lift, especially if you intend to venture off-road.
- You need to lower your rear bump-stop rubbers too. This is needed to prevent the rear tire from scrubbing and damaging the fender well.
- You might want to think about re-gearing since she will run like a lazy dog on-road and even worse off-road.
- Your gas mileage is highly affected!!!
- Fitting 34” is a challenge, even with trimming and relocating, imagine the drama with a 35”
- There will be extensive panel-beating so whip out your 5# hammer.
- You will need to fold over the pinch seam as well
- The lugs rub on the bolts that hold the fender flare on at full flex
- The 35” can They can stress out the steering box after a while. These things are super heavy
- Alignment shops won’t like you since they often struggle to align them properly
- 35s are pretty darn expensive just to go bash them about in the bush or have them sliced up by wheel fenders.
- Due to their pure weight and size, they strain your transmission internals.
- Don’t forget your poor brakes that get chewed up in no time trying to stop these oversized monstrosities.
- Last but not least, your spare wheel won’t fit, so you’ll need to fork out even more cash for a rear-mounted tire carrier.
If you are venturing off-road, don’t go bigger than 33”. If your intention is to stay on the tarmac with the odd gravel road you could attempt the 18” in a /65/18 profile.
I would not recommend the 35s for either on-road or off-road applications. The FJ is thirsty enough with stock rubber, imagine the 34s or 35’s? Remember the unsprung weight massively impacts your MPG.
My recommendation is a 33-inch in the form 287/70/17 or a 275/70/17. You’ll get the best of both worlds.