Wheel Backspacing and Offset Info

The truck in your avatar is a 16x7 ET30; 5.18" backspacing

 

Awesome, thanks! They're just stock wheels with a powder coat.

 

I have the Alloy TRD wheels right now that come stock on my Baja that have offset of 10, wanted to get different TRD wheels that have an offset of 15. Is there a fitment problem with this or would it work just fine without having to buy anything?

 

As long as the rims are the same width, you will only lose 5mm of backspace. This will move your wheel/tire 5mm to the inside.

 

Do you think that i would have rubbing problems if i moved to a negative offset wheel? Thats with the stock suspension that comes with the baja, the bilstein suspension

 

What size tire are you going with?

 

Was looking at going with a 0 off set or a -12, thats really all i can find. That from my 10mm offsets

 

What rim width?
What tire size?

 

Looking at something like a 18x10 or 18x9 with 275/65r18

 

Found this comparison tool. Very useful. I posted it the wheels and tires forum, but I think it should be in this thread to.

https://www.rimsntires.com/specspro.jsp

 

A 9" with -12 offset will have 4.5" of backspace; a 10" with -12 offset will have 5" of backspace. Your current rims have 4.5" of backspace. If you go with a 10", you would need -36 offset to get 4.5" of backspace.

So, if you go with a 9" wide/-12 offset and 275/65/18s, the rim will sit 41mm/1.61" further out the tire will sit 27mm/1.06" further out. Tire diameter increases 2", increasing tire radius 1". Between the tire sticking out and clearance radius increase, you might run into interference on the cabmount.
Scrub will increase by 16mm/0.63".

For that tire size, I'd recommend a 8" wide/0 offset/4.5" backspace. Compared to stock, it would only sit about a 5/8"" further out. It may or may not make a difference on the cabmount. The increase in positive scrub would be significantly reduced to only 4mm/0.16".

I'd recommend the 9" wide/-12 offset/4.5" backspace if you went to a 275/70/18.
Compared to stock; your scrub radius would be unchanged, tire radius goes up another 1/2" and only protrudes about 5/8" outward.
It may or may not make a difference on the cabmount.


Couple more calculators you can play with.

 

@splitbolt whats your breakdown on these?
I'm running 17x8 4.5 B/S 265/70/17
Going to a 17x8.5 -10 offset
Thinking of either 255/80/17 or
265/70/17 tire size

 

Are you lifted?
Do you need more backspace clearance.
A 17x8.5 -10 is 4.25" backspace.

My approach is from the stock suspension and wheel/tire dimensions; paying attention to large changes in scrub radius.

Both tire choices, with that wheel width, will add about 1-3/8"" of positive scrub over stock.
But...you can afford to add .25" of positive scrub for every 1" of suspension and/or tire lift.

Now, if you had a 3" lift and 255/80s that would allow you to run with 1" of added positive scrub over stock. Then being 1-3/8"" over stock is no big deal. You're actually only have 3/8" of added positive scrub.

A 17x8.5 0 offset would be ideal then...but then that's 4.75" BS...

 

Yes I'm lifted close to 3"
Light racing UCAs
Found a great deal on the SCS SR8 17x8.5 -10 offset 4.3 back space
Was just debating tire size between the 255/80or265/70

Thanks

 

The 265/70 scrub is 1.5" over stock suspension or about 3/4" more than your lifted suspension.
Of the two, based on scrub alone, I'd lean towards the 255/80. Being 33s, high protrusion, and having used ucas to regain castor, it will probably put you into cabmount territory.

 

Will 17x9 -38 3.5 back space offset fit the third gen Tacoma's? Planning on running 295/70/17

 

Throw your specs or here and see what you get. Very helpful tools.

 

I'm not sure what the stock sport rim size is but want to go with 17x9's with -12mm offset and 4.527" back spacing....Tires will be 265/70's and will have a 1.75" or 2.75" lift....Will these fit without wheel spacers?

 

Need some help with these rims guys. Never been good at math lol.

https://www.tirerack.com/wheels/Whe...coma+Double+Cab&autoYear=2011&autoModClar=4wd

01mm offset?? no backspace information. Anyone know how these would work/look on a 2nd gen with a 2.5" lift on 285/70/17's. Eventually wanna go over to a full icon kit, they recommend a rim with 5" backspacing. I can't even find a rim with a 5" backspace, even the icon rims only have 4.5". I'm scratching my head, don't wanna buy rims flat as pancakes lol. Any help would be appreciated. thanks

 

Those are 8.5" wide/+01mm offset.
To find backspace, add 1" to the rim width. This accounts for flange thickness and gets you the outside wheel width, which backspace is determined.
So, 9.5"...
Offset is the measurement from center of the wheel to hub flange.
Positive offset is outward of center.
Negative offset is inward of center.
Moving inward yields less backspace.
Moving it outward yields more backspace.

So...
Center of (8.5+1)/2=4.75

4.75"+1mm=4.79" backspace.

When a suspension requires a certain backspace, it's the maximum.
You should be good to go if they're calling for 5".