Going Bigger - 5th Gen Tire Fitment Guide

[feltonian]

hello, great article. I just bought theRR5-S 17X8.5 relations race wheels with -12 offset and 4.28" backspace. Also getting the icon stage 2 lift, 2.5" in the front and 2" in the back. Do you think I can fit 285/70/17 KO2's with only trimming and not a body mount chop? the guy installed them was recommending 275/70/17 because of the offset

 

[SpeedyKevin]

Just mounted Wildpeak M/T 285/70s in stock trail rims. Caster at 3.9 and no rub on road and in reverse. Still need to test on trail.

 

[Ogre75]

The problem is that every 4Runner is a bit different, so even if you had measured before, you wouldn't necessarily know for sure if your adjustments for caster would have enough left to help. So it really is one of those situations where you kinda have to just try and see if it fits.

To add another wrinkle - the higher you lift, the less caster you have. It's just the way the geometry of the A-arms work where the upper control arm pivots at an angle compared to the lower one. So... the lift height will have an effect on the measured caster angle even if the lower control arms is all the way forward. For example at stock height the same LCA settings for 4* of caster would only result in about 1.5-2* of caster at 3" lift. What that means for this situation is that you can't necessarily just assume that if you're set at 2* of caster now, you can go to 4. There might not be enough adjustment left. And the caster angle doesn't really directly translate to whether the spindle is adjusted forward. It can be all the way forward at 2* of caster in some cases and in others that would give 5* of caster.

That's why most lifts end up with replace upper control arms. They move the upper ball joint to get back the lost caster from the lift. BUT... they do it by moving the upper joint to the rear - effectively removing some of your clearance at the body mount area. So the need for upper control arms to have a good allignment can end up reducing your body clearance where you want it.

All of those factors plus a very close fit result in a lot of confusion over whether a certain tire size fits or not. And that's kinda why we always end up with the answer being - maybe, maybe not - depends on your vehicle. How much lift, what control arms, what wheel offset, what tire size, and even what tire tread pattern - some are just a bit wider than others.

I think you can pretty safely assume on most 4Runners that 285/70/17's will fit with trimming the front bumper and removing the mud flaps as long as your wheels are stock offset. Wider offset causes problems and so do larger tires. You can pretty safely also assume that 285/75/17 being 1.3" taller than 285/70/17's will not fit in almost any instance without cutting the body mount. On mine it was not close to fitting. Other sizes like 255/80/17 being narrow tend to fit better than wider ones, so you could have a bit wider stance on the wheels.

And - finally, I think we all dream of a day when we can just slap 35's on without a lift or rubbing like the JL wranglers. Come on Mr. T - give us some tire clearance in the next edition!

I've read and tried to digest your points on Castor angles and moving forward away from the rear flap/body mount. You seem to know quite a bit about alignment.
I just recently had a Dobinson 3" lift installed including UCA's, and 285/70's. No rubbing, othere than the occasional in reverse on the left front against the back liner. My question is on my alignment numbers. I have a 1.3 on LF and 1.1 on RF. I know they are out of spec due to the lift, but would you have them go back to the drawing board on it to bring them foward it little and possibly mitigate any more rubbing?

 

[2016 4Runner SR5]

I've read and tried to digest your points on Castor angles and moving forward away from the rear flap/body mount. You seem to know quite a bit about alignment.
I just recently had a Dobinson 3" lift installed including UCA's, and 285/70's. No rubbing, othere than the occasional in reverse on the left front against the back liner. My question is on my alignment numbers. I have a 1.3 on LF and 1.1 on RF. I know they are out of spec due to the lift, but would you have them go back to the drawing board on it to bring them foward it little and possibly mitigate any more rubbing?

With aftermarket upper control arms, you should be able to get to the 4* mark for caster. Whoever did your alignment didn't know how to properly align a lifted 4Runner.

 

[Jetboy]

I've read and tried to digest your points on Castor angles and moving forward away from the rear flap/body mount. You seem to know quite a bit about alignment.
I just recently had a Dobinson 3" lift installed including UCA's, and 285/70's. No rubbing, othere than the occasional in reverse on the left front against the back liner. My question is on my alignment numbers. I have a 1.3 on LF and 1.1 on RF. I know they are out of spec due to the lift, but would you have them go back to the drawing board on it to bring them foward it little and possibly mitigate any more rubbing?

There's a lot going on with alignment and lift. The lower control arm is where the alignment adjustments are made. It has two cam bolts that ultimately mean that the lower ball joint out at the end of the arm can move to anywhere in an elliptical shape area. Within that area is a range of available caster that will also be within spec on camber.

Some alignment shops will effectively cut corners by only adjusting the rear cams on each side. Generally you can get camber within spec by adjusting only the rear cam bolts, and not the front. That will usually not get the best alignment overall. If you can take a photo of the cam bolts position on both cam bolts on each side, I can probably tell you whether you should go back for a fix at the alignment shop or if you have something else to fix.

 

[Ogre75]

There's a lot going on with alignment and lift. The lower control arm is where the alignment adjustments are made. It has two cam bolts that ultimately mean that the lower ball joint out at the end of the arm can move to anywhere in an elliptical shape area. Within that area is a range of available caster that will also be within spec on camber.

Some alignment shops will effectively cut corners by only adjusting the rear cams on each side. Generally you can get camber within spec by adjusting only the rear cam bolts, and not the front. That will usually not get the best alignment overall. If you can take a photo of the cam bolts position on both cam bolts on each side, I can probably tell you whether you should go back for a fix at the alignment shop or if you have something else to fix.

Does abnormal tire wear occur with increasing castor up towards the 4 end?

 

[Jetboy]

Does abnormal tire wear occur with increasing castor up towards the 4 end?

No. Many cars are as high as 8* of caster stock. 4* is still in factory spec range. If camber and toe are correct, camber should have no meaningful effect on tire wear. (I'm ignoring some extreme circumstances like having 30* of caster and doing short track racing or something)

 

[2016 4Runner SR5]

With higher caster you'll also greatly improve steering responsiveness especially on a crowned road.

 

[Jetboy]

Did you mean caster?

Yes. Caster. :dammit:

 

[SilverSR5-2018]

New to the tire game

Ok, I have read this whole post, clicked the links, and read some more. From what I am reading, I am about to do a 3” lift on my 2018 SR5 4x4 and I am looking at 285/70R17 Nitto Terra Grappler G2 on the stock rim ( will upgrade this later ). From what I read I can fit this with little to no rub, I understand that there isn’t a definite answer. I understand that not every T4R is the same. All I’m looking for is some reassurance that I’m not going crazy after reading this for the past 2 hrs with all these numbers.

 

[2016 4Runner SR5]

Ok, I have read this whole post, clicked the links, and read some more. From what I am reading, I am about to do a 3” lift on my 2018 SR5 4x4 and I am looking at 285/70R17 Nitto Terra Grappler G2 on the stock rim ( will upgrade this later ). From what I read I can fit this with little to no rub, I understand that there isn’t a definite answer. I understand that not every T4R is the same. All I’m looking for is some reassurance that I’m not going crazy after reading this for the past 2 hrs with all these numbers.

You should be fine with nothing more than the fender liner mod and bumper trim.

 

[blackened_offroad]

ok who's running 35's and has them fitting with full articulation? Is there a thread on it? forum users known to have made it work with build threads? I'm about to do a lift and wheels etc, and I'm thinking I may go straight to 35's, as I'm pretty sure I'll go that way eventually and I'd rather not have to do it twice.

 

[Uni1brow]

ok who's running 35's and has them fitting with full articulation? Is there a thread on it? forum users known to have made it work with build threads? I'm about to do a lift and wheels etc, and I'm thinking I may go straight to 35's, as I'm pretty sure I'll go that way eventually and I'd rather not have to do it twice.

I just put 35x12.50x17 on, suspension jba uppers, kings coil over, dirt king lowers, scs 17x8.5 4.30 -12 back space. Needed spacers cause tires were rubbing on uppers, went with bora .75 spacers.
All the gray area in the pic needed to be touched, pound back the firewall, as you can see body mount chop is cut back past half of what it originally was. Pinch weld folded over and flattened, plastics trimmed fender trimmed on the inside. I used gray primer as I was testing so you can easily see where its rubbing.
Any questions PM me.

 

[blackened_offroad]

I just put 35x12.50x17 on, suspension jba uppers, kings coil over, dirt king lowers, scs 17x8.5 4.30 -12 back space. Needed spacers cause tires were rubbing on uppers, went with bora .75 spacers.
All the gray area in the pic needed to be touched, pound back the firewall, as you can see body mount chop is cut back past half of what it originally was. Pinch weld folded over and flattened, plastics trimmed fender trimmed on the inside. I used gray primer as I was testing so you can easily see where its rubbing.
Any questions PM me.

sweet thanks. how much lift are you running?

 

[Uni1brow]

I dont have exact measurements but came from OME heavy 3 inch to kings 2.5 coil over with 700# coil
So I want to say 2.5-3
Also I have a shrockworks front bumper no issues upfront

 

[yota275]

exactly the info i was looking for.

 

[drewcon]

I went through this whole thread and didn’t see an answer.

I have a stock 2018 TRD Pro. Tires need replacing. 80% of the time the car is on roads, 20% sand/ basic overland. Mix between daily driving and fun weekending.

Whats the biggest tire I can put on the stock Pro rims/suspension with no cutting, lifting, etc. and no rubbing? I’m assuming the extra 1in on the Pro means a different answer than other models (which is why I ask).

Just a pure swap. Nothing fancy.

 

[TRD PANTHER]

I went through this whole thread and didn’t see an answer.

I have a stock 2018 TRD Pro. Tires need replacing. 80% of the time the car is on roads, 20% sand/ basic overland. Mix between daily driving and fun weekending.

Whats the biggest tire I can put on the stock Pro rims/suspension with no cutting, lifting, etc. and no rubbing? I’m assuming the extra 1in on the Pro means a different answer than other models (which is why I ask).

Just a pure swap. Nothing fancy.

275/70-17’s

 

[2016 4Runner SR5]

I went through this whole thread and didn’t see an answer.

I have a stock 2018 TRD Pro. Tires need replacing. 80% of the time the car is on roads, 20% sand/ basic overland. Mix between daily driving and fun weekending.

Whats the biggest tire I can put on the stock Pro rims/suspension with no cutting, lifting, etc. and no rubbing? I’m assuming the extra 1in on the Pro means a different answer than other models (which is why I ask).

Just a pure swap. Nothing fancy.

More often that not, the Pro bumper is already cut. The OEM 265 tires rub and the port mechanics trim the bumper. They don't generally do a great job of it either. The reason you can't find a concrete answer is because there isn't one. You might rub with a 265, you might not. You might rub with a 275, you might not. Why are you against doing the fender liner mod and bumper trim? If done right, and kept clean, you'll never know it was done.

 

[83Mule]

275's and minor to no plastic inner wheelwell trimming.