Perfect Wheel Backspacing for 37's on 2" Lift - Rubi Diesel Axles / Fenders

[Lunentucker]

I thought offset was millimeters.

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[Andy29847]

I don't really understand how these measurements work and every time I look into it just ends up making my head hurt. Mind posting pics of your setup?

I'm with you. Makes my head spin. It seems to me like different ways to say the same thing.

 

[Rahkmalla]

I thought offset was millimeters.

It is I brain farted

 

[Jefe1018]

0 offset means the wheel connects to the hub at exactly the centerline of the wheel. So for a 9inch wide wheel, 0 offset means backspace is 4.5 (half the width of the wheel). Offset is measured in millimeters. So +6 offset means the point where the wheel connects is 6mm towards the outward face of the wheel (moving the tire inward). 25.4mm to an inch, so 6mm is roughly a quarter inch.

So why do people prefer one measure over another?

If you're trying to stuff as much wheel/tire as possible in as tight a package as possible measuring directly for the limited amount of space you have just makes sense. Too little backspace you can rub suspension components!

If you're trying to match poke between different wheels, offset is preferable. Because offset is a centimeter measurement off the mid line and wheels and tires share their midline, they also share their offset. So a 12.5 tire on a +6 17x7.5 wheel will poke out a tire the exact same amount as a 12.5 tire on a +6 17x9.5 wheel.

But in reality, most people just feel the most comfortable with whichever measurement they learned first. I'm an offset guy personally. Mechanics tend to be offset guys. Wheelers and truck guys tend to be backspacers. I think tuners tend towards offset but wouldn't bet the house on it.

Haha I'm pretty handy around a garage but for wheels I saw a guy running these and I said hey, what are you running and how do you like it, does it rub? Guess what? It worked out that way too, ha!

 

[CrazyCooter]

If you're trying to match poke between different wheels, offset is preferable. Because offset is a centimeter measurement off the mid line and wheels and tires share their midline, they also share their offset. So a 12.5 tire on a +6 17x7.5 wheel will poke out a tire the exact same amount as a 12.5 tire on a +6 17x9.5 wheel.

I think your math is off on that comparison? The 9.5" wheel would be away from the center of the axle by 1" since the 9.5" wheel is 2" wider than the equal offset 7.5" wheel? 9.5" wide +25 would be more of an equivalent?

You are right about sticking with what you leaned first! It makes no good sense to me in converting metric offset to an imperial wheel diameter and width? the math is so much more natural to just subtract BS from the overall width? I can however remember that 25.4mm=1".

 

[Rahkmalla]

I'm with you. Makes my head spin. It seems to me like different ways to say the same thing.

It is... except asking "how much backspace equals how much poke?" requires more information. You need to know backspace AND wheel width to determine poke. Offset is independent of wheel width. Wheels and tires share a centerline, so 6mm off the centerline of a 17x7.5 is exactly the same position as 6mm off the centerline of a 17x10.

 

[Rahkmalla]

I think your math is off on that comparison? The 9.5" wheel would be away from the center of the axle by 1" since the 9.5" wheel is 2" wider than the equal offset 7.5" wheel? 9.5" wide +25 would be more of an equivalent?

Wheel width doesnt matter when using offset if your only concern is final tire position. The WHEEL will stick out an inch more, but the tire will not.

 

[BuyHold]

I knew I didn't want it like my YJ where 40% of the tire is outside the fender!

This is exactly the look that comes to mind whenever I see Jeeps with unecessarily "excessive" poke! Many people think that the extra width translates to aggressive-cool looks. I mostly think low rider vibes on purpose built off-road vehicle. (I actually appreciate low riders, but not for a Jeep!). Other times I think "someone just liked those rims and didn't really think about the vehicle and fitment."

To each their own. I only own my Jeep and no others.

 

[CrazyCooter]

This is exactly the look that comes to mind whenever I see Jeeps with unecessarily "excessive" poke! Many people think that the extra width translates to aggressive-cool looks. I mostly think low rider vibes on purpose built off-road vehicle. (I actually appreciate low riders, but not for a Jeep!). Other times I think "someone just liked those rims and didn't really think about the vehicle and fitment."

To each their own. I only own my Jeep and no others.

Lol!

I might step up to 37s one of these days, but it will require 17" wheels and probably wheel adapter spacers to get it right......

 

[Rahkmalla]

This is exactly the look that comes to mind whenever I see Jeeps with unecessarily "excessive" poke! Many people think that the extra width translates to aggressive-cool looks.

I get I'm not the sole arbiter of taste and decorum, but I have an internal disgust towards people who try too hard to give their vehicles a 'badass' vibe. Certain things like angry eyes, windshield surround armor that looks like a helmet, overly aggressive poke, everything apocalypse 6x6 stands for. It's all a big no from me dog.

It all just screams to me "I'm replacing a personality with attitude"

 

[BuyHold]

Lol!

I think that your YJ doesn't look half bad.

My recollection is that Jeep created the YJ with a roughly CJ width body but widened the axles to guard against rollovers that older CJs were known for. The combination gave first gen Wranglers all the ingredients to give more than mere tire bulge "poke" when changing to other rims or wider tires.

But yeah, too much poke conjures up those 1990s memories for me.

 

[Andy29847]

Wheel width doesnt matter when using offset if your only concern is final tire position. The WHEEL will stick out an inch more, but the tire will not.

Youse guys are assuming the same size tire on both wheels. The OP says he is going from pizza cutters to 12.5" tires. A 12.5" tire will need more of something so that it doesn't poke out too far. Notice too that more back space or more offset both accomplish the goal. I'm guessing the best solution would be a combination of the 2.

Also, a wider wheel with the same offset as a narrow wheel nets more backspace, but doesn't necessarily help the OP make decisions. A narrow wheel with the same offset as a wide wheel does not poke out as far.

Like I said, it is confusing. That is why there are so many threads asking about wheel and tire combinations.

 

[Tommyd]

0 offset is spot on!!!

 

[Camaroboi13]

Level 8 Punch in 17x8.5” with -6 offset on 37x12.5 tires. Seemed like just the right amount to me on a 2.5” level

 

[Mac]

Thanks for all the feedback! Looks like factory wheels with a 1.5" spacer would be +6 offset, correct? I'll likely go this route for now.

@Rahkmalla do the XR flares seem to cover the poke at +6? I want to keep as much debris off the front doors as possible.

If you want to keep the sides clean put on running boards or really long front mud flaps.

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