Wheel Offset Help

[Hybryd40]

Hi guys,
Getting ready to do some major upgrades to my truck and I am asking for a little help in the wheel offset dept.

I currently am running a TRD Pro 7in wheels with a +4 mm offset I believe and 1-1/4 SpyderTrax spacers. 265/70/17 Nitto G2 tires. 2in front lift.

Just for reference I am going to
3 in Lift
UCA
1 in Body lift
BMC if need be
285/70/17 Nitto Ridge Tires

Now the wheel I'm looking at is 17x8.5 0mm offset and may run spacer or not. Not sure. This was my choice

The guy at Discount suggested running the 17x9 with a -12mm offset. Then I could pull the spacers off. Not because he is against spacers, fyi

I like the stance of how it looks now. Anybody have wheels on their rigs with these sizes. Please post pics for review. Or anyone that knows more about offset then I do. Please chime in. I just want to do it right the first time.

Thanks in advance

 

[Hybryd40]

Just wanted to add, I'm not a newbie to this site and I can search on my own and I have read the tire and wheel sections. Have also read about offset. Just don't quite understand it.

The way I am thinking right now is the rim lip of the 17x9 -12 will stick out about 41mm farther then pro wheels and spacers and maybe a 9mm inward? Still cant quite grasp it.

 

[mvt4r]

Just wanted to add, I'm not a newbie to this site and I can search on my own and I have read the tire and wheel sections. Have also read about offset. Just don't quite understand it.

The way I am thinking right now is the rim lip of the 17x9 -12 will stick out about 41mm farther then pro wheels and spacers and maybe a 9mm inward? Still cant quite grasp it.

Here is a good, less mathematical way, to think about offset and backspacing. Other threads have the formula which is clear to me but might not work for everyone.

Offset is how far the center of the wheel, and thus center line of the tire, is from the hub. The more negative the offset, the farther out the tire will stick out, regardless of the rim width (as long as the tire is appreciably wider than the rim, which it usually is).

With 285 tires, you have a tire that is nominally 20mm wider than a stock tire which means on a stock wheel the tire will sit 10mm further inboard than a stock 265 tire. It will also sit 10mm farther outboard as well.

In terms of clearances, the farther in-board the tire sits, the more likely it is going to rub the upper control arms. The only real way to fix this is to push the tire out with wheels that have a more negative or smaller positive offset. It doesn't matter if this is done with a wheel offset or spacer, the effect is the same. The stock wheel and stock tire is already pretty close, I have to imagine that you are going to rub if you run the stock wheel with no spacers.

The farther outboard the tire sits, the greater the swing of the tire when you turn the wheel, this makes it more likely to rub the front or rear of the wheel well/fender liner/body mount as the wheel is turned. You can trade rubbing on the rear of the well by getting closer to the front by adjusting the alignment (caster I think).

According to the other threads on this, with aftermarket upper control arms there should be no problem adjusting the alignment to clear the body mount and rear of the wheel well (removing mudflaps if need be).

The problem is that with this alignment, you will rub the front fender liner, hence the fender liner modifications and trimming of the front fender.

My configuration which does not rub is a 285/70r17 Goodyear Duratrac on the stock Off Road wheels and 1.25" spidertrax spacers with the fender liner pushed out and fender trimmed at the bottom. I think the stock wheel offset is +15mm and the spacers add -32mm offset for a net of -17mm of offset. Since 285mm is about 11.25" which is way wider than 9" of the wheel you are considering, the -12mm offset wheel and 285/70r17 tire should fit (caveat emptor, of course).

FWIW, I think the scrub radius is a bit large and annoying with the stock wheels, spacers, and 285s. I would go with a 0mm offset wheel if it were me, assuming that the tire will clear the upper control arms. I believe others are running this configuration with no problems so I imagine it'll work with the right fender modifications and alignment.

I do think the 0mm offset doesn't look as cool but is probably more practical.

 

[wfo9]

Offset is simple

It's just another way of stating backspacing.

Take the advertised rim width... add 1 inch and divide by 2 and that is the 0 offset and backspacing (in inches) for a rim.

-12 means the mounting surface moves 12mm inboard to reduce backspacing from 0 offset (5in) to ~ 4.5 inches. That means about 5.5 inches outboard of the mounting surface.

Your current wheels with spacers would be about 3" BS with 5" outboard of the mounting surface. Net would be -28mm with the spacer,

So the 17x9 would increase your track width by about .5" beyond where it is at with the 1.25" spacer and current rim.

The issue with that much rim outside the mounting surface is the scrub radius increase. The more rim outboard...the more rearward and forward the edge of the tire moves at full lock. It might clear with the mods you described... it might not. Caster alignment will have a significant impact... Lift won't really make much difference at all under flex....

 

[mvt4r]

Offset is simple

It's just another way of stating backspacing....

So, does the backspacing of the rim actually matter, or is it the tire width and offset? Generally, I don't like thinking about backspacing because it does not help reason about where the tire sits independently of the wheel width. Offset tells you exactly that regardless of wheel width (approximately, since the width of the tire changes a bit depending on wheel width). Am I missing something? Why do people like backspacing as a measurement vs offset?

 

[wfo9]

So, does the backspacing of the rim actually matter, or is it the tire width and offset? Generally, I don't like thinking about backspacing because it does not help reason about where the tire sits independently of the wheel width. Offset tells you exactly that regardless of wheel width (approximately, since the width of the tire changes a bit depending on wheel width). Am I missing something? Why do people like backspacing as a measurement vs offset?

You really need the rim width with both to determine if it will clear on both sides. You can easily calculate one from the other as long as you know the rim width. The backspacing just give you the number that matters in terms of inboard clearance with no calc required. Offset always requires a calculation (offset is just more the metric way). On these trucks the backspacing up to 4.75 or less usually works. Any more and you are rubbing on the inside of the UCA or spindle.

The ideal rim for clearance on these trucks from my experience is 8-8.5" width and 4 - 4.75"BS.

There are just too many variables to call it. Each tire design will have impact. Even the same size tires won't all fit, it depends on the shoulder design... and how they measure out. 285s are pretty easy, 315s are much more difficult.

 

[dot_tom]

I am running 17x8.5 +0 Method NV's with Bora 1.75" spacer. Love it. I trimmed my body mount and trimmed the bumper and pushed the fender liner forward.

 

[JohnTheLuck]

Just use this site:

Wheel Offset Calculator | 1010Tires.com Discount Online Tire and Wheel Store

 

[wfo9]

I am running 17x8.5 +0 Method NV's with Bora 1.75" spacer. Love it. I trimmed my body mount and trimmed the bumper and pushed the fender liner forward.

Don't see how that would work in actual off-road use. Possible, but unlikely with the scrub and all the bushing deflection. It seems like any decent sized tire would constantly be in the firewall.

Lifts will help for street use... but once you actually get out there and use the truck off-road... the lift will not help clear the tires.

 

[Hybryd40]

Thank you all for your responses. Looks like I will go with my first choice in size and not the tire guys recommendation. I picked my first choice in a new wheel by reading in this forum. I will also off-road with this truck.

Thanks

 

[dot_tom]

Don't see how that would work in actual off-road use. Possible, but unlikely with the scrub and all the bushing deflection. It seems like any decent sized tire would constantly be in the firewall.

Lifts will help for street use... but once you actually get out there and use the truck off-road... the lift will not help clear the tires.

Spacers can always be removed. I've spent a good bit of time trimming and we will see this weekend how it does.

 

[wfo9]

Spacers can always be removed. I've spent a good bit of time trimming and we will see this weekend how it does.

Yes, let us know how it goes. Hard to trim enough for that scrub radius, but stranger things have happened. Will also depend on the type of offroading you do... Try to get the front tire to fully stuff to the bump stop and turn side to side. Even then it still may rub on deflection while descending (but the stuff test is usually good enough to not destroy a fender/tire/axle). A little rubbing won't really hurt anything.

 

[dot_tom]

Yes, let us know how it goes. Hard to trim enough for that scrub radius, but stranger things have happened. Will also depend on the type of offroading you do... Try to get the front tire to fully stuff to the bump stop and turn side to side. Even then it still may rub on deflection while descending (but the stuff test is usually good enough to not destroy a fender/tire/axle). A little rubbing won't really hurt anything.

Thanks for the advice. I will give it a shot and see how it goes. You're right, a little rubbing never hurt anybody. I also not afraid of adjusting/trimming things as needed to make the setup work. An offroad front bumper will help some clearance also, which is on the list. I'll report back after some trails this weekend.

 

[83Mule]

http://www.toyota-4runner.org/attachment.php?attachmentid=264149&stc=1&d=1502927042 Here are my 17x9 Mamba M-14's with 4.5 offset and -12 BS and a 2.5'' lift/spc uca's.........I think the front tires are a little too far in so I went to the 1.25 spacer and a BMC. not even close to rubbing in front but the spacer required the BMC + I can go to 285's with plenty of clearance in the future from these 275's.

 

[dot_tom]

Yes, let us know how it goes. Hard to trim enough for that scrub radius, but stranger things have happened. Will also depend on the type of offroading you do... Try to get the front tire to fully stuff to the bump stop and turn side to side. Even then it still may rub on deflection while descending (but the stuff test is usually good enough to not destroy a fender/tire/axle). A little rubbing won't really hurt anything.

Just an update. Went to Windrock Park in TN for a 3 day event. Wheel and spacer setup worked perfect. Zero rubbing. Very happy with how it all turned out.

17x8.5 Method NV's 4.25" back spacing with BORA 1.75" wheel spacers on 285s.

 

[Toffees]

You really need the rim width with both to determine if it will clear on both sides. You can easily calculate one from the other as long as you know the rim width. The backspacing just give you the number that matters in terms of inboard clearance with no calc required. Offset always requires a calculation (offset is just more the metric way). On these trucks the backspacing up to 4.75 or less usually works. Any more and you are rubbing on the inside of the UCA or spindle.

The ideal rim for clearance on these trucks from my experience is 8-8.5" width and 4 - 4.75"BS.

There are just too many variables to call it. Each tire design will have impact. Even the same size tires won't all fit, it depends on the shoulder design... and how they measure out. 285s are pretty easy, 315s are much more difficult.

Ok, I'll ask for help because the math confuses me also. I'm looking at replacing my LE wheel/tire combo with some 17x9s and 285s (I read the 275s won't fit on 9" wheels).

The wheels are 17x9 with a 10 offset (doesn't specify +10 or -10). Tires would be BFG 285 70 17 (or similar).

I'm assuming the LE is the same setup as the rest, I've not seen that XREAS do anything else to limit wheel/tire travel.

So using your math above (9" +1) /2 = 5, then 10mm offset is -0.4", so about 4.6", which is in the happy zone.

Unless of course the offset is in the wrong direction, but not like I can figure that out...

And 285s are roughly 11.25" wide, but *should* fit with minor modifications if the offset/backspacing fits.

Is that at all correct?