Wheel Offsets Explained

I've been drooling over wheels, but I was still fuzzy on the whole offset thing and what it meant. Thank god there's Google! Sorry if this has been addressed ad nauseam.



Offset-Definition

The offset of a wheel is the distance from its hub mounting surface to the centerline of the wheel. The offset can be one of three types (measured in millimeters).*






Zero Offset
The hub mounting surface is even with the centerline of the wheel.


Positive
The hub mounting surface is toward the front or wheel side of the wheel. Positive offset wheels are generally found on front wheel drive cars and newer rear drive cars.


Negative
The hub mounting surface is toward the back or brake side of the wheels centerline. "Deep dish" wheels are typically a negative offset.

If the offset of the wheel is not correct for the car, the handling can be adversely affected. When the width of the wheel changes, the offset also changes numerically. If the offset were to stay the same while you added width, the additional width would be split evenly between the inside and outside. For most cars, this won't work correctly.


*Backspacing, similar to offset, is the distance from the hub mounting surface to the inside lip of the wheel (measured in inches).

Wheel Tech - Offset



Regarding the Ford Raptor specifically, please see this expertly written Forum Sticky.

http://www.fordraptorforum.com/f25/stock-raptor-wheel-specs-frp-raptor-wheels-55/

To summarize said Sticky:

"The stock Raptor wheels are charcoal grey painted + clear coated. 17" x 8.5", 6 lug x 135mm, with 34mm offset( 3.41 front space, 6.08 back space) The frontspace and backspace measurements are based off the rim's full section width edge to edge(9.5" approx.) where the 8.5" width rating refers to inside edge to inside edge(tire mounting surface). The wheels are hub-centric which means the weight of the rim is supported by the hub bore(the hole in the middle) rather than lug-centric which would use 60* conical lug nuts to center the wheel and support the weight."



Regarding acceptable offsets for our Raptor, it is commonly agreed upon that a 0 offset is the maximum you can leverage before creating trouble for yourself. Greater offsets, like -12, can cause rubbing of the fenders at full suspension compression, and can cause issues with the CV joins on 2012+ model when placed at Full Perch (to avoid fender rubbing).

http://www.fordraptorforum.com/f25/12-offset-doable-19225/



So in short a 17" x 8.5", 6 lug x 135mm with 0 offset and you're in the money!

I made this a sticky, thank you sir!

WOW! I'm blushing! I've never posted anything Sticky worthy.

Nice hopefully this helps the wheel newbs.

Thanks for making this thread and thanks for for making it a sticky

Sent from my DROID RAZR using Tapatalk 2

shooterAMG said:

WOW! I'm blushing! I've never posted anything Sticky worthy.

Click to expand...

Can you add some language about the stock wheel being +34mm and it's generally accepted anecdotally that 0mm is as low you want to go on a Raptor, and for any other questions to PM Greg McManus

Excuse the ricer page, but, Online Wheel & Tyre Fitment calculator. Offset, Tyre stretch and Rolling Radius calculator will give you a visual of how X wheel compares to Y wheel as far as fitting in relation to the hub and eachother.

Here is the best I can do the difference between 0 offset and positive 18mm offset. The variable, and how it came to be.
I ordered wheels from my local tire shop. After delivery and installation I noticed that I had a rub going in and out of my driveway. So I asked what offset the wheels installed were and they said 0. I said well we got a problem they rub. The tire guy assured me well its not the wheels offset. I said well lets try +18mm to get a look see. So today they got installed and my rub is gone. SO on to the pictures to see the visual difference...

Correct me if I'm wrong (and I probably am), but aren't we just looking to stay as close to the 4.5" backspace number as possible? A 17x8 +0 wheel (Method wheels) have a 4.5" backspace. If you go up to a 17x9 -12 wheel, the backspace is still 4.5". But according to everything I've read here, a -12 offset spells doom for 2012-13 Raptors. Is this still the case even though the backspacing is identical?

But then when I went and messed around with this calculator/visual aid (Custom rims, wheel tire packages for your ride - RIMSnTIRES.com) and input Method wheels as "stock" and then specs for a Fuel Wheel that was 17x9 +1 the specs ended up being the same.

Sorry if this is confusing, just trying to get a little clarification before I purchase a set of wheels.

For the Raptor and the places where it rubs when you use a negative offset, the number we really need is the front spacing.
The analog of backspacing, Front spacing is the distance from the mounting surface to the outer (front) lip of the wheel. Front spacing usually isn't mentioned in wheel fitting though, so we have to calculate it and that is where the confusion comes in.
No matter the wheel width (within reason) if the front edge of the wheel sticks out past a certain point, the tire will rub on our trucks. For a 17x8.5 wheel, that safe spot happens with a 0 offset. For a 17x9 you are looking at a +6 max. Since the wheel is wider, we need a little bit of positive offset to keep the outer edge of the wheel in the same place relative to the vehicle body. i.e for every 1/2" wider wheel, you would need +6 more offset in the wheel.
If you start going crazy wide wheels, all this is out the window because you will rub in more places than just the outside of the wheel.
Link

Exactly what I needed to know. Thank you for explaining that to me, Chayse!