Backspacing Help Needed!
Thread Starter
JK Freak
Joined: Mar 2008
Posts: 986
Likes: 0
From: Mandeville, Louisiana
Backspacing Help Needed!
hey guys, just got my 08 jk about 3weeks ago and i'm shopping around for a wheel and tire set......i have a couple ?'s though....i've never understood how backspacing works.....i want my tires to stick out about 1.5in to 2in. from the fenders...does rim backspacing have anything to do with that....or do i just need a pair of wheel spacers and a wide rim........i'm planning on running the tf 2.5in bb w/ 35/12.50 on a 16in rim...........thanks in advance to your feedback
JK Enthusiast
Joined: Apr 2008
Posts: 119
Likes: 0
From: Scottsdale, AZ
With 12.5" tires, if you do anything from 4" backspacing or 3.75" backspacing....they'll definitely stick out about an 1.5 inches. With you're size tire, I would do 3.75 inch backspacing for the look you're describing and it will keep your tires from rubbing against the fender or control arms and coils when turning or offroading
Some wheel brands I like are Cragar and Pro Comp...AEV is getting pretty popular too it seems.
Some wheel brands I like are Cragar and Pro Comp...AEV is getting pretty popular too it seems.
JK Super Freak
Joined: Sep 2007
Posts: 1,623
Likes: 5
From: Lawrenceville, NJ
Backspacing is the amount of room in the brake area...and, its confusing, because it's expressed in what appears to be a backwards fashion, in that more BS = LESS room.
Its because its the distance from where the rim bolts to the hub (The hub face), to the most inboard side of the rim.
If you have ALOT of BS, the rim is mounting so that the inboard side is moved inboard ALOT, as in the rim is covering the brakes.
If you have a LITTLE BS, the rim is mounting so that the brakes are inboard of the rim, and are not fitting inside the rim.
The size of the wheel doesn't matter...5" of BS, etc...on any rim is the same effect....5" of distance from the hub face to the most inboard side of the rim.
OFFSET is what changes with rim size...as OFFSET is measured from the center of the rim, so a wider rim need more offset to have the same effect, etc.
Hope that helps.
PS - in most states (Not all...), its not legal to have the tires protrude out past the fenders, you'd need to add wider flares for example, defeating your aesthetic purpose.
You can of course "Get away with it" depending upon enforcement in your area, etc. Its your call.
Its because its the distance from where the rim bolts to the hub (The hub face), to the most inboard side of the rim.
If you have ALOT of BS, the rim is mounting so that the inboard side is moved inboard ALOT, as in the rim is covering the brakes.
If you have a LITTLE BS, the rim is mounting so that the brakes are inboard of the rim, and are not fitting inside the rim.
The size of the wheel doesn't matter...5" of BS, etc...on any rim is the same effect....5" of distance from the hub face to the most inboard side of the rim.
OFFSET is what changes with rim size...as OFFSET is measured from the center of the rim, so a wider rim need more offset to have the same effect, etc.
Hope that helps.
PS - in most states (Not all...), its not legal to have the tires protrude out past the fenders, you'd need to add wider flares for example, defeating your aesthetic purpose.
You can of course "Get away with it" depending upon enforcement in your area, etc. Its your call.
JK-Forum Founder
Joined: Jul 2006
Posts: 36,534
Likes: 16
From: Laguna Niguel, CA
well, it looks like you've got your answer covered but just in case you have more, please check out the Modified FAQ as I think you will find it helpful 
https://www.jk-forum.com/forums/show...74&postcount=3
https://www.jk-forum.com/forums/show...74&postcount=3