how to figure backspacing?

[mckeddie]

trying to figure out what backspacing i'm going to need for my new wheels. i want the hub to be protected and be up inside the wheel instead of sticking out past it. picking up my krawlers on sunday, so i'm hoping to get my wheels ordered this week.

i'm wanting to run a 17x8 or 17x9 wheel, most likely the 17x8, as i'm doing weld on beadlocks. i've got 5.25'' from the wheel mounting surface to the tip of the hub. how do i figure this out? i've never tried to before, always just ran 4.5'' backspaced wheels. i want this as narrow as possible though, so i'm actually going to properly figure it for once.

thanks,
greg

[bgwyllys61]

i think yu would need a 3.25" backspacing? but, 3.75" might do what you want it to do, that would be with the 8 inch wide rim, the 9 inch width, you could probably go an inch less in backspacing.....im not 100% sure on this, but it sounds right to me

[Nuts]

When you figure it out let me know! I'm using 7" wide wheels with 4.5" BS,weldons and drive flanges. Hoping for tall skinny and narrow.

[Hope Springs Hauler]

I'll try this. Let me know if it sounds way off base.

Backspacing is the measurement from the inside of the rim to the interior WMS.

You are asking about the measurement from WMS to the outer part of the rim.

So, take the wheel width and subtract the backspace and that should give you the measurement that you are looking for.

If we work this backward, an 8 inch wheel width - 5.25 inch desired outer measurement yields 2.75-inch backspace. You could probably get by with a fuzz more backspacing since you are welding on a beadlock kit.

[yota85red]

This may help--> https://www.rsracing.com/tech-wheel.html

[KennyTJ]

Add 1" to the rim width for the weld on beadlock. This is what I have gotten with both TSL "SX" and IROKs on weldon's. So an 8" rim becomes 9", a 9" becomes a 10" well you get the picture.

So just subtract the amount of space you need on the front side (the hub length) in your case 5.25 inches. So 8" rim + 1" for weld on beadlock - 5.25 font space required = 3.75" BS
If you start with a 9" rim you can do 4.75" BS

I would take off an extra 1/4" so the hub is inside and protected from rocks, so 3.5"BS for an 8" rim.
I have 8" eaton steelies with 3.25" BS that I did weld on beadlocks and the hubs are nice and protected.

:beers:

[blazerbrad]

The above information is correct. Subtract the BS from the total wheel width and that gives you the measurement from the WMS (where the lugs are) to the other lip of the rim.

However, unless you buy custom wheels at a premium price you don't have much of a choice when it comes to off the shelf wheels. I went through this a couple of years ago when thinking about going to 17" wheels but there was only one BS available that I could find on 17x8 wheels and that was 4.5" which would definitely make a locking hub or flange on a D60 stick out. I could special order a set of wheels from Summit that only had 3.5" BS but it almost doubled the price, and other than that it was going with some other company for even more money. Just couldn't bring myself to pay the extra money.

[mckeddie]

i'm willing to pay a little extra, the 3.5'' backspaced aren't too much more, like $25 or so i think. i've figured i'm going to narrow this thing up close to a foot with the new wheels and tires, so i'm pretty excited to finally be able to fit down the trails again. picking my krawlers up sunday, it's like christmas all over to me again.