Tire Sizes for your Truck - Page 2

2004duramaxLB7 · 11-13-2008, 02:45 PM

yeah that what i got, its from peterson's off-road mag.

AMB · 11-13-2008, 03:05 PM

How about explaining wheel offset and how it relates to backspacing.
For example, I am looking to run 285/70/17s or 295/70/17s on my 08
2500 4x4 with 17x9 wheels. Wheel backspacing is 4.50 and offset is
-12. What exactly does the -12 mean?

omcvay · 11-13-2008, 04:09 PM

I have an 08 2500 that came with the Z71 17" wheels. The tires look like pizza cutters and I would like to get much wider and a little taller tires. Anyone know the largest tire size to run with a leveling kit, stock wheels and a little trimming? It seems that the tire genius may be a part of this thread...

**KKami361** · 11-13-2008, 04:35 PM

Quote:

Originally Posted by AMB

How about explaining wheel offset and how it relates to backspacing.
For example, I am looking to run 285/70/17s or 295/70/17s on my 08
2500 4x4 with 17x9 wheels. Wheel backspacing is 4.50 and offset is
-12. What exactly does the -12 mean?

the -12 means that the hub of the wheel is 12(units) behind the centerline of the wheel. It's usually measured in millimeters.

**Duramaximos** · 11-13-2008, 05:17 PM

Yes offset is measured in mm.
It is the distance of the hub mounting surface in relation to the center line.

Therefore, a 0 offset wheel has the hub mounting surface exactly at the centre line of the wheel.
For example, a 9" wide wheel, with 0 offset, will have 4.5" back space.

Negative offset implys that the hub mounting surface is set back further resulting in a deep dish wheel.
For example, a 9" wide wheel, with -25mm offset, will have 3.5" back space.

Positive offset implys that the hub mounting suraface is closer to the font surface of the wheel resulting in a flush appearance at the face of the wheel.
For example, a 9" wide wheel, with +25mm offset, wil have 5.5" back space.

In my experience, you should aim to buy a set of wheels with the offset as close to stock as possible.

AMB · 11-13-2008, 06:01 PM

Ok, then I'm confused. If the wheels I'm looking at are 9" wide and have 4.5" backspace, how can the offset be -12? Shouldn't it be zero?

**Duramaximos** · 11-13-2008, 06:06 PM

Quote:

Originally Posted by AMB

Ok, then I'm confused. If the wheels I'm looking at are 9" wide and have 4.5" backspace, how can the offset be -12? Shouldn't it be zero?

I'll try to find an article that explains it more clearly, but yes, I assume those wheels will have a 4.25" backspace.

Hopefully someone else will jump in here if my logic is flawed.

**Duramaximos** · 11-13-2008, 06:22 PM

Here is a clear article explaining offset:
Wheel Offsets - Discount Tire Direct

It seems I misinterpreted the meaning of backspacing and confused it with "rearspace".
Here is an image indicating rearspace:
http://images.fourwheeler.com/techar...et+diagram.jpg

Backspacing is in fact measured from the outboard bolting surface to the plane of the outboard flange, pictured here:
http://tbn0.google.com/images?q=tbn:..._backspace.jpg

This is overly confusing and unnecessary information, IMO. The important factor is Offset. Knowing the wheel's offset, you can easily calculate exactly how much of the wheel will hang behind, and in front of the center line.

Murrow · 11-13-2008, 06:44 PM

You said anything over nine inches wide should have spacers so if i want to throw on 265 75 r16's i should space? or am i not quite at nine?

**TYREBOYZ_DEMAXIN** · 11-14-2008, 05:21 AM

the duallys are the only ones that need spacers when running a tire over 9"'s wide,to keep the tires from touching each other,so a non DRW truck doesn't need spacers.

omcvay,the biggest tire you can clear on your truck with the Torsion bars raised and minor trimming is a LT285-70R17 which is roughly 33" tall so that will fill in your wheel well very nicely.

BS/Offset,from my experience with wheels if you have a 8" wide wheel you want a 4.0-4.5" BP for the best look but with that BS you can clear a taller tire without any problems other then the usual trimming and such
if you have a 9"-10" wide wheel you want to stay with a 4.5-5.0"BP and even then you will need a leveling kit to run a larger tire(32" or taller)or the tires will rub the frame or innerfender(or both)when turning even with the Torsion bars raised plus with the wide wheels your tires will stick out the side a bit so you don't want to travel gravel roads.to be honest the whole BS/Offset is still new to me also so those numbers are just from our experience selling wheels.
BS=Back Spacing