I've searched a ton on this topic, but found conflicting information and non-useful data at best.

This is what I would like to know: How much wheel backspacing do I need to run 315/75R16 tires on 8" wide rims to clear the stock upper A-arm?

I would like real world data from people actually doing this. Please don't post if you are just guessing or estimating. Third gen 4Runners only, Please! This is data to clear the stock upper A-arm only, not for clearing pinchwelds, fenders, etc.

The specific information needed from each example:
1. How much front suspension lift do you have?
2. What brand of 315/75R16 tires are you running?
3. What wheels, size, and backspacing are you running?
4. Are you running wheel spacers, if so, what thickness?
5. How much clearance do you have between the tire and upper A-arm?
(measurements and/or pictures would be helpful too!)

If done correctly, I think this could be a really helpful thread to others in the future as well.

Thanks,

 

1. I have a sonoran steel system 1.2 which equates to 2.5" of front lift and 3 inches in the rear once the coils have settled.
2. I do not run 315/75/R16's. I run the equivalent size in non-metric terms. 35X12.50X17 Interco Trxus M/T's. they rock.
3. I run moto metal 909's. They are 17X9 and have 4.5" backspace with a negative -12mm offset.

I have no rubbing on my upper A-arms. Anything with a higher backspace number will rub.

I wish I would have bought the Mickey Thompson Classic II wheels and powdercoated them black like Vermejo.

They are a 16X8 and have 3.5" backspace with a negative -22mm offset. This is the wheel of choice by Steve of Sonoran Steel. It gives the best clearance to upper A-arm and frame.

4. I am not currently running wheel spacers. I tried 1.25" from WabFab and they made the rubbing on the inner fender worse. So I ditched them.

I may go with some Spidertrax 1.25" (only thickness they make) spacers once I decide to cut out my inner fenders and patch in steel plates.

Do I need wheel spacers? No, not really. It would just be nice to increase the track width since I have a 3" body lift and my tires rub the frame at full lock.

5. I have around 1/2" clearance with my current Moto Metal 909 4.5" backspaced wheels. YMMV and good luck.

 

The specific information needed from each example:
1. How much front suspension lift do you have?
about 3" - Sonoran Steel 1.1 lift (now the 1.2?). Lift shouldnt matter too much. A-arm stays pretty well in the same position when at full compression.
2. What brand of 315/75R16 tires are you running?
BFG KM2 315/75/16
3. What wheels, size, and backspacing are you running?
Stock 5 spoke, star style, 4Runner wheels. 7" wide.
4. Are you running wheel spacers, if so, what thickness?
1" spacers
5. How much clearance do you have between the tire and upper A-arm?
(measurements and/or pictures would be helpful too!)
Plenty. I would guess about 1/2" at the closest point in the suspension travel range, possibly a bit more.

 

just my two cents....a 35x12.50 on a 8" wheel is pushing it. You'll be lucky is the bead seats correctly, air it way up when getting it installed, then air it back down to what you want psi you want to run in the tire.

 

I ran 35x12.50x15s on a 15x8 wheel as well as 37x12.50x15s over an 18 month period on the street as well as off-road and never lost a bead once.

You will be fine with a 15x8 wheel. I have 39.5x13.50x15 Iroks on a 15x8 wheel now and it never sees the pavement...but they are beadlocks too.

If you want to run 35" tires on a 3rd gen 4Runner then check out Steve at Sonoran Steel.

 

subscribed

 

1. Sonoran Steel 1.2 plus 2" Body lift
2. Nitto Mud Grapelers 35x12.50x16 (run 35x13.50x16)
3. Pro Comp 1079 16x8's 4" backspacing
4. Running a 1/4" spacer right now
5. Have minimal clearance, I rub on the frame at full turn

 

to those that are saying an 8 inch wheel is to narrow...here some food for thought.

on our ranger we have ran 35x12.5r15 for 2 years. 4 flats later and not one of them caused by losing a bead. they seal better and when we head to the sand, the flotation from airing down is that much better. goes the same for rocks, mud, etc.

- chris

 

if i was going to run 35's on mine, i'd crank the toytech coilovers a littler more and start trimming.

You don't need a bl to run 35's, just tub your firewall and keep it nice and low

 

35Process

 

ME

1.5" Body lift
Mickey Classic II" with the corresponding 3.5 back space
Sonoran steel Front Lift verson ~7.0
Toyo Open country MT tires 315/75/16
Custom Triagulated rear with 14" of travel (Krawltex Custom Fabricated)

Draw back--wish i had taken the "road less traveled" (do a search on this also) and not done the BL and my Toyos rub the frame at full lock--thinking (as posted earlier) to fab some 1/4" spacers to solve the problem.

The 12.5 on 16x8's do really well when aired down. I run 8 psi with no problems at all

 

No rub in the rear at full flex??

 

Thanks for the responses so far. I have read the Sonoran Steel and Trails Less Traveled sites numerous times. Great info there too.

So from what I gather so far, it seems that a 16 x 8 wheel with about 3.5" backspacing will clear the upper A-arm, but could still rub on the frame at full turn.

Keep the responses coming!

 

Running 6" of suspension lift, American Racing 767's with 315/75R16 Goodyear MTR's with a 1.25" bolt on spacer. Still needed to do trimming on the front and rear to fit the tires....not that big of a deal. (Took off my body lift BTW... yayer)

The rear end still needs more trimming. I am always rubbing when wheeling. I even have dropped down bumpstops.

 

Im completely new with 4runners, I currently have an Integra and am looking to get a 98 or so 4runner. Im trying to figure out how to do this 4x4 stuff right, and have no idea what back spacing and wheel spacers are. any help?

 

Backspacing is the distance from the back of the wheel, where the lug holes are, to the lip of the rim.

Place wheel, face down on the ground. Take a measuring device and measure from the lugnut hole surface to the lip of the wheel. Vertical distance that is...

Less backspacing means the wheel itself will stick further out of the car. Most wheels come in the 3.5 to 4.5 range. 3.5 will stick out an inch further than the 4.5

 

No rub--but the shock hoop/brace was mounted through the bed floor about 4". I think i put pictures up. It took some work--but most of the travel comes from Droop.

 

And i had to relocate the gas tank and spare tire

 

Alright, so after tons of investigating different wheels and wheel spacer combinations here is what I came up with.

I want to run Eagle Alloy Series 1378 16 x 8" wheels. They have a back spacing of 4.625". In addition I will run SpiderTrax 1.25" thick wheel spacers. This would give me a combined back spacing of 3.375". This should give me clearance to the stock upper A-arm, correct?

FYI, here is a pic of the wheels:

Anyone else run these, or heard anything good/bad about them?

Thanks,

 

I have to ask. Why buy new wheels knowing that you have to use a spacer to make them work? I would think you could find some with the proper backspacing.