Wheel backspacing?

[LaOutbackTrail]

I'm trying to figure out which wheel to get for my Xterra... I am unsure abot backspacing though. The Xterr has a 5.5" backspaced wheel, but I do want to set the wheels/tires out more, but no more than an inch out. So, would I want to find a wheel that is 4.5" backspacing??? I dont get how backspacing works... Any help would be appreciated.

Thanks,
Scott

 

[slooowr6]

Quick answer, yes, if you want to push the wheel out 1" then you need a 4.5" BS.
Take a look at this site, https://www.rsracing.com/tech-wheel.html, it has info on BS, offset.

 

[granitex1]

What size tire do you want to run? and do you have a body lift? Without a body lift and extended bump stops in the back, when your rear end articulates fully there is a really good chance that you will make contact with the fenderwell. I have seen it happen to many times on the trail.

 

[LaOutbackTrail]

What size tire do you want to run? and do you have a body lift? Without a body lift and extended bump stops in the back, when your rear end articulates fully there is a really good chance that you will make contact with the fenderwell. I have seen it happen to many times on the trail.

I will be doing a 3" suspension lift using a 235 85R16 tire (31.7" OD). I wont be doin much articulatin'.... Using Scott's trail rating guide, I dont do anything more than 1.0-3.0 rated tracks.

Whenever I get lockers, I will work on adjusting the bumpstops and stuff.

 

[IggyB]

You don't need 3" lift for 32" tires. I've had 32/11.50-15's for a long time with lift as below.

1/2" torsion bar crank up front and add a leaf or new springs in the back will let you run 235's.

This way you won't need a steering fix, upper A arms or anything else. Idler arm brace would be nice though.

All that on stock wheels. If you go to aftermarket, check your measurements before buying.

 

[Martyn]

Quick answer, yes, if you want to push the wheel out 1" then you need a 4.5" BS.
Take a look at this site, https://www.rsracing.com/tech-wheel.html, it has info on BS, offset.

We are in agreement with you that backspacing is as covered in the web page you referenced. However the terms backspacing and offset are used differently by people in the trade, so it's always good to reconfirm exactly what you are measuring.

 

[slooowr6]

Did not know that people use "back spacing" and "offset" differently.
My understanding is:
Offset: the distance between wheel mounting surface from the wheel center line, + means mounting surface is further from center of the truck, - means the mounting surface is closer to the center of the truck.
Back spacing: the distance from the inside edge of the rim to the mounting surface. The less the back spacing means the further the outer edge of the rim is from the center of the truck.

Please let me know what is the different way BS and offset is used. Thanks!

 

[Martyn]

Did not know that people use "back spacing" and "offset" differently.
My understanding is:
Offset: the distance between wheel mounting surface from the wheel center line, + means mounting surface is further from center of the truck, - means the mounting surface is closer to the center of the truck.
Back spacing: the distance from the inside edge of the rim to the mounting surface. The less the back spacing means the further the outer edge of the rim is from the center of the truck.

Please let me know what is the different way BS and offset is used. Thanks!

It would be nice to use the definition as provided by rsracing as an industry standard. Some companies use the terms to mean different things, the most common being referring to offset when they are really talking about backspacing.

My advice to avoid confusion when purchasing rims, especially if it's sight unseen, would be to confirm that the measurements taken and described used rsracing definitions as a reference.

 

[Martyn]

Positive and negative offset is also one of those things that has various interpretations to it.

 

[IggyB]

Some measure backspacing from the outer edge (wheel weight) of the wheel, others measure it from the inside edge (tire sidewall) of the wheel.

Steel and aluminum wheels sometimes have different thickness at the wheel edge. I think that's where 2 different people will measure backspacing different.

 

[R_Lefebvre]

Positive and negative offset is also one of those things that has various interpretations to it.

Yes, I know a few suspension engineers who argue about which direction is which. There does not appear to be an industry standard here.

 

[LaOutbackTrail]

IggyBYou don't need 3" lift for 32" tires. I've had 32/11.50-15's for a long time with lift as below.

1/2" torsion bar crank up front and add a leaf or new springs in the back will let you run 235's.

This way you won't need a steering fix, upper A arms or anything else. Idler arm brace would be nice though.

All that on stock wheels. If you go to aftermarket, check your measurements before buying.

My Xterra already has the "Poormans lift" with torsion crank and rear shackles.
I know I dont need a suspension lift to run the tires. But I already have the front UCAs and want the lift. I do need to get the other stuff though.

My thing is that I have 15" stock wheels... and there arent really any other tires that I am interested in. I dont think the BFG 33"x9.5 R15 will fit even with the suspension lift. But, according to Scott's research, it may because of them being narrower. But I do not want to cut anything or really loose my mudflaps.

Thoughts?

 

[IggyB]

OK, if you already have the lift.

You can rebuild the insides of the idler arm. New bushings and seals are available from Nissan. Just ask for 95 Pathfinder parts. Remove and replace, very easy.