Offset and backspace questions

[jblues1969]

I am having the hardest time figuring out what I need for my LJ.

I got the 7 inch flares, which was a mistake:

Current status is that it's got 255/75/R17's on stock JKU rims with 1.5 inch adapters.

I want to get new rims that push the wheels out about 2-3 inches while getting rid of the adapters.

Trying to figure out the offset and backspace values that I'll need in a 17 x 8, 5 x 4.5 rim.

Nobody told me there would be math involved in owning a jeep.

If I figure correctly, the JKU rims are +6.5 inch backspaced (wrong direction), and getting rid of the adapters adds 1.5 inches in the wrong direction, so I'm 8 inches in the hole. To move outward, I need -1.5 to compensate for the adapters, then another -4 to get where I need to go. That leaves me at -1 inch.

To combo that with offset, would that be -40mm offset and 0 backspacing?

 

[Jerry Bransford]

FORGET you ever heard the 'offset' term, it's a different measurement that is far more useful for car wheels. For Jeeps and trucks it's the backspacing dimension that is most useful as it shows the amount of clearance the wheel's inner-most edge and the tire's inside sidewall clearance away from the suspension and frame.

The yellow tape measure in this photo is measuring the wheel's backspace dimension which is the distance between the inner-most edge/rim and its mounting surface.

Are your current tires on 17" wheels? What diameter tires are you planning to mount? Typically 3.75" to 4" of backspacing is ideal for 12.5" wide tires, 4.5" is ideal for 11.5" wide tires.

And I hear you on regretting 7" wide flares which I ran when I was far younger and even stupider than I am today. This is when I almost slid sideways off a trail in Death Valley. I was apparently not paying close enough attention to where I was going.

 

[Chilidawg]

FORGET you ever heard the 'offset' term, it's a different measurement that is far more useful for car wheels. For Jeeps and trucks it's the backspacing dimension that is most useful as it shows the amount of clearance the wheel's inner-most edge and the tire's inside sidewall clearance away from the suspension and frame.

The yellow tape measure in this photo is measuring the wheel's backspace dimension which is the distance between the inner-most edge/rim and its mounting surface.

View attachment 395589

Are your current tires on 17" wheels? What diameter tires are you planning to mount? Typically 3.75" to 4" of backspacing is ideal for 12.5" wide tires, 4.5" is ideal for 11.5" wide tires.

And I hear you on regretting 7" wide flares which I ran when I was far younger and even stupider than I am today. This is when I almost slid sideways off a trail in Death Valley. I was apparently not paying close enough attention to where I was going.

View attachment 395590

I see you have the Gambler wheels with a nice tire. What was the setup you had here and how did you keep the tires from rubbing.

 

[jblues1969]

FORGET you ever heard the 'offset' term, it's a different measurement that is far more useful for car wheels. For Jeeps and trucks it's the backspacing dimension that is most useful as it shows the amount of clearance the wheel's inner-most edge and the tire's inside sidewall clearance away from the suspension and frame.

The yellow tape measure in this photo is measuring the wheel's backspace dimension which is the distance between the inner-most edge/rim and its mounting surface.

View attachment 395589

Are your current tires on 17" wheels? What diameter tires are you planning to mount? Typically 3.75" to 4" of backspacing is ideal for 12.5" wide tires, 4.5" is ideal for 11.5" wide tires.

And I hear you on regretting 7" wide flares which I ran when I was far younger and even stupider than I am today lol.

Hey, Jerry! I was hoping you'd be the first to respond.

I'm keeping the tires I have - they are new 255/75/R17's, so I'm shopping for 17 x 8 rims in the 5 x 4.5 bolt pattern. I just want to replace the rims to get the stance I'm looking for - maybe 1 inch inside those flappy ears - and ditch the adapters.

What is frustrating is the online shops often don't even mention backspacing or allow you to filter on it, so you never see that value until you've selected a wheel and then have to back out.

 

[Jerry Bransford]

I see you have the Gambler wheels with a nice tire. What was the setup you had here and how did you keep the tires from rubbing.

Those weren't Gamblers, they were made by American Eagle which only had 3.25" of backspacing. They stuck out too far so I later switched to the American Racing AR23 which had a more appropriate 3.75". Neither even came close to rubbing.

This shows the AR23 wheels on my previous TJ...

 

[Chilidawg]

Those weren't Gamblers, they were made by American Eagle which only had 3.25" of backspacing. They stuck out too far so I later switched to the American Racing AR23 which had a more appropriate 3.75". Neither even came close to rubbing.

This shows my later AR23...
View attachment 395600

Thanks I was just going off the spare you had on in the pic.