Tire and wheel offset help please

[Garemlin]

So my Black Diamond is officially on order. I already plan on going with a different wheel and a little taller tire. Need a little assistance choosing offset.

Tire choices are....
285/70-17 (32.7x11.2)
33x10.5x17
255/80-17 (33.1x10)

The wheels I am going with are 17x8 and offered in a 0 and +18 offset. OEM wheels are 17x7.5 with a +55mm offset. I think that is correct.

So with those choices of tires which would be the better offset to go with. And how exactly would both offsets affect how the wheel/tire sits??

I do plan on eventually replacing the crash bars with the 4wp modified crash bars for added room and adding a 1" level. But that will be a little later down the line.

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[GrandGrady]

The positive offset will give you best chance of clearing. Although, I don't know that it matters either way; I've seen several people in various wheel/tire threads with 33s and aftermarket wheels having no problems with regards to rubbing.

 

[Essmith94]

Really depends how much “poke” you want. All of them should fit without rubbing but the 0 offset wheels will stick out more than the +18. Both will stick out more than the stock wheels.

 

[BroncoTPA]

This may not help much but from left to right:

*OBX 4WP Level with +30 Offset 17x9
*Black Diamond Leveling kit and Sas flares with 0 Offset 17x9
*Black Diamond Stock 55 Offset 17x7.5

 

[Rahkmalla]

The wheels I am going with are 17x8 and offered in a 0 and +18 offset. OEM wheels are 17x7.5 with a +55mm offset. I think that is correct.

a half inch wider wheel means 6.35mm wider in each direction. Going from a +55 to a +18 because of 6.35mm seems like overkill, and with the wider tire will mean your new tire at +18 will stick out 1.7 inches more than stock. Going +0 offset will stick out 2.4 inches more than stock.

I understand the sas package gets rid of crash bars, but they are fitting 35x12.5 inch tires with only a +35 offset. Don't think you need to be that aggressive, unless you love poke.

I'm sure someone will check my math and tell me how wrong I am

 

[Garemlin]

This may not help much but from left to right:

*OBX 4WP Level with +30 Offset 17x9
*Black Diamond Leveling kit and Sas flares with 0 Offset 17x9
*Black Diamond Stock 55 Offset 17x7.5

Guessing stock has stock tire size. What about the other two??

 

[Garemlin]

Really depends how much “poke” you want. All of them should fit without rubbing but the 0 offset wheels will stick out more than the +18. Both will stick out more than the stock wheels.

a half inch wider wheel means 6.35mm wider in each direction. Going from a +55 to a +18 because of 6.35mm seems like overkill, and with the wider tire will mean your new tire at +18 will stick out 1.7 inches more than stock. Going +0 offset will stick out 2.4 inches more than stock.

I understand the sas package gets rid of crash bars, but they are fitting 35x12.5 inch tires with only a +35 offset. Don't think you need to be that aggressive, unless you love poke.

I'm sure someone will check my math and tell me how wrong I am

I don't mind a little poke. I just don't want it looking like this. LOL

And to pass inspection here you have to be less than 1" beyond the fenders. I know there are always workarounds. But I don't want to worry about that.

 

[Rahkmalla]

I don't mind a little poke. I just don't want it looking like this. LOL
And to pass inspection here you have to be less than 1" beyond the fenders. I know there are always workarounds. But I don't want to worry about that.

Honestly, I would just wait until your rig shows up and take some measurements. Take-offs aren't going to be worth any more just because they have 9 miles on them vs 200. Figure out how much poke you want, then work the math backwards from there.

I know it's a little annoying to go inches, mm, inches, mm, but if you want your truck to look perfect measure twice cut (buy) once.

 

[BroncoTPA]

Guessing stock has stock tire size. What about the other two??

Both of the leveled Broncos have 315/70r17. The one on the left has BFG KO2 and the middle one has Nitto Ridge Grapplers.

 

[BroncoTPA]

Here is another comparison picture.

Left: OBX 17x9 +30 315/70r17 4WP level with 4WP crash bars

Right:. Stock Black Diamond

 

[TRMFAM]

So my Black Diamond is officially on order. I already plan on going with a different wheel and a little taller tire. Need a little assistance choosing offset.

Tire choices are....
285/70-17 (32.7x11.2)
33x10.5x17
255/80-17 (33.1x10)

The wheels I am going with are 17x8 and offered in a 0 and +18 offset. OEM wheels are 17x7.5 with a +55mm offset. I think that is correct.

So with those choices of tires which would be the better offset to go with. And how exactly would both offsets affect how the wheel/tire sits??

I do plan on eventually replacing the crash bars with the 4wp modified crash bars for added room and adding a 1" level. But that will be a little later down the line.

Give this a try...it gives you measurement data as well as an image overlaid the stock image:

Tire Size Calc

 

[jorgem31]

This may not help much but from left to right:

*OBX 4WP Level with +30 Offset 17x9
*Black Diamond Leveling kit and Sas flares with 0 Offset 17x9
*Black Diamond Stock 55 Offset 17x7.5

What flares are on the OBX?

 

[Garemlin]

Give this a try...it gives you measurement data as well as an image overlaid the stock image:

Tire Size Calc

All these years, probably close to 20, I've been using Tire Size Calculator. Never realized they had an offset calculator and visualizer. That's pretty nifty. Thanks for the heads up.

 

[TRMFAM]

All these years, probably close to 20, I've been using Tire Size Calculator. Never realized they had an offset calculator and visualizer. That's pretty nifty. Thanks for the heads up.

Yes it is really handy...I think I last had it set to metric...you may want to flip the switch back to Inches...not sure how the link comes across.

Here is another oddity about that site, look up your preferred tire on there and it will show a cost for someone like 4WP and then go directly to 4WP on another tab in your browser and it will show you a higher price. The tires I was looking at linking off the tire size chart were $48 less each on 4WP site vs just going directly to 4WP. Somehow going through tiresize.com you may get a discount. I didn't look up any other tires just the ones I was interested in. YMMV

 

[4avor8ntfair]

Here is another comparison picture.

Left: OBX 17x9 +30 315/70r17 4WP level with 4WP crash bars

Right:. Stock Black Diamond

Kinda nice to see that +35 with base flares has a reasonable amount of poke! I had been curious about using SAS takeoffs with painted OBX flares.

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