Tire Size Help

[ZoSo]

I need help from the experts and i have been coming to this site for awhile now to get info but haven't run across my issue so here it goes.

i bought a sr5 1999 4runner a couple of years ago and i am going to replace the tires.

the 4 runner is stock no lift kit and has unfortunately 18" rims on it with toyo open country at size 285/60/18

they are down on tread but fit snugly. i would much rather have a 16 or 17 inch rim but as said bought them with the rig. the wheels are nice just not the right size and they are as follows

Center-line Wilderness Tracker

product # 635 8907 655 size 18.0 x 9.0 hi-polish forged wheel 5.25" backspace.

ok here is the question perhaps someone can answer.

i am looking to replace the old tires with a slightly narrower tire with a higher side wall to a

275/65/18 made by bfgoodrich called the all Terrain T/A KO

les schwab would sell me the same dimension only in a toyo and said it would fit and sears said it would fit as well both saying if the 285/60/18 worked then the 275/65/18 will work because it is narrower and the height increase won't be an issue.

the only catch is at sears i can use a card and pay it off over 6 months however if the tires don't work because they have to order them i will have to pay a 15% restocking fee.

any ideas or thoughts if these will work is appreciated and thanks in advance for all the help this site has already provided me.

 

[cj80cruiser]

I don't know for sure. You're kinda in that grey area with those tires. Here is some helpful info though

265/75r16.....biggest tire to fit stock...31.6 x 10.43 in
285/75r16....rubs on stock suspension...32.8 x 11.22 in
275/65r18....in between these 2 sizes...32.1 x 10.82 in

So looking at these numbers the one thing you have going for you is the 275s are narrower than 285s...some have trouble with the 285s rubbing the upper A-arms slightly but you should be ok since your tire is thinner like the 265. This is all said with stock backspacing on a stock rim. Now why did you have to throw another wrench in there with an aftermarket wheel, :jk: Honestly I don't know what stock backspacing is. I don't know if it's different between year models either. The reason I say this is because I have stock rims with 285 duratracs (no upper a-arm rub) and I see people with the same stock rims with duratracs and they have the rub...I dont have wheel spacers either so that's not the reason. This could be one of 2 things. Either my 96 a-arms are different or my wheels have a different backspacing. I don't know which it is...I could solve this rather easily with a straight edge and a tape measure but haven't done it yet.


1 other thing is I would order the tires from where ever you want. I'd tell sears if they want my business then they would waive that restocking fee because they are the ones saying the tires will fit and if they don't that is their fault not yours. If they won't do it then tell them you're going elsewhere. Too many tire places around that want your business to be haggled over a restocking fee IMO.

 

[Nelsonmd]

This is all said with stock backspacing on a stock rim. Now why did you have to throw another wrench in there with an aftermarket wheel, :jk: Honestly I don't know what stock backspacing is. I don't know if it's different between year models either. The reason I say this is because I have stock rims with 285 duratracs (no upper a-arm rub) and I see people with the same stock rims with duratracs and they have the rub...I dont have wheel spacers either so that's not the reason. This could be one of 2 things. Either my 96 a-arms are different or my wheels have a different backspacing. I don't know which it is...I could solve this rather easily with a straight edge and a tape measure but haven't done it yet.

I have read that stock backspacing is 15-25mm positive offset. It could make a big difference what your current rim's offset is. If you have the model of wheel, you can look it up, or measure it yourself, but I think that is a little tricky.

Rims swing pretty far to either side, so you should definitely figure this out if you are going to be close on rubbing.

 

[cj80cruiser]

or measure it yourself, but I think that is a little tricky.

What do you mean tricky?

 

[Nelsonmd]

What do you mean tricky?

Well, look up the procedure (a bit hard to describe in text). You are measuring the distance between two separate offset faces (one of which is imaginary, the wheel centerline). It is always a bit tricky to do this accurately, not as easy as putting a ruler up and measuring.

 

[cj80cruiser]

Well, look up the procedure (a bit hard to describe in text). You are measuring the distance between two separate offset faces (one of which is imaginary, the wheel centerline). It is always a bit tricky to do this accurately, not as easy as putting a ruler up and measuring.

Are you trying to warn me that offset is different than backspacing? In that offset is a measurement of how far off the imaginary centerline the wheel mount is and backspacing is simply the measurement from the backside of the wheel to the wheel mount.

 

[Nelsonmd]

Are you trying to warn me that offset is different than backspacing? In that offset is a measurement of how far off the imaginary centerline the wheel mount is and backspacing is simply the measurement from the backside of the wheel to the wheel mount.

No, they are essentially the same thing (when the wheel width is accounted for of course), just measured from different places. I have used them interchangeably.

If the aftermarket wheel has a different backspacing than the stock wheel, then the recommendations of max tire size are off (which was your original point). I was just trying to provide what I have found for stock backspacing (since your wheel recommendations are for stock backspacing), and letting him know he can measure it himself, and doesn't need to find the specs on his specific wheel.

The measurement procedure is not totally straightforward though, which is all I was trying to say (for the mechanically inclined, sure, it's pretty easy, but I don't want to make any assumptions). This is a pretty good guide:
https://www.rsracing.com/tech-wheel.html

Offset is just one calculation away from backspacing, and is what I found info on for stock 4runners.

 

[cj80cruiser]

No, they are essentially the same thing (when the wheel width is accounted for of course), just measured from different places. I have used them interchangeably.

If the aftermarket wheel has a different backspacing than the stock wheel, then the recommendations of max tire size are off (which was your original point). I was just trying to provide what I have found for stock backspacing (since your wheel recommendations are for stock backspacing), and letting him know he can measure it himself, and doesn't need to find the specs on his specific wheel.

The measurement procedure is not totally straightforward though, which is all I was trying to say (for the mechanically inclined, sure, it's pretty easy, but I don't want to make any assumptions). This is a pretty good guide:
https://www.rsracing.com/tech-wheel.html

Offset is just one calculation away from backspacing, and is what I found info on for stock 4runners.

All I can say is that I know the difference and understand the two and I can get a precise measurement....I guarantee it.

 

[ZoSo]

thanks

thanks for the info, i am taking it in to sears on saturday and if the dude and his manager say it will fit and they don't i'm in no way paying a 15% restocking fee.

take care and thanks again, hj

THEY FIT!

i picked up a set of goodyear wrangler duratrac in a 275/65/18 and they work great!