how to figure backspacing?

mckeddie · 12-29-2009, 04:53 PM

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 · 12-29-2009, 06:35 PM

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 · 12-29-2009, 07:54 PM

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 · 12-29-2009, 08:37 PM

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 · 12-30-2009, 08:52 AM

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

KennyTJ · 12-31-2009, 03:21 AM

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.

12-29-2009, 04:53 PM	#1
mckeddie Join Date: Apr 2007 Location: van wert oh Posts: 583	how to figure backspacing? 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 __________________ zuk buggy.....it'll be a jeep eventually.

12-29-2009, 08:37 PM	#4
Hope Springs Hauler Join Date: Jul 2008 Location: Hamilton, OH Posts: 431 Images: 16	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. Attached Images __________________ 1988 Suzuki Samurai on propane FJ 40 axles (4.10) 5.14 tcase 36" TSL SX

12-29-2009, 06:35 PM	#2
bgwyllys61 fullwidthxj Join Date: Feb 2008 Location: lex Posts: 15	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

12-29-2009, 07:54 PM	#3
Nuts Join Date: Feb 2008 Location: middletown,oh Posts: 508	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.

12-30-2009, 08:52 AM	#5
yota85red Join Date: Sep 2008 Location: McArthur OH, Posts: 7	This may help--> https://www.rsracing.com/tech-wheel.html

12-31-2009, 03:21 AM	#6
KennyTJ The Pirate Join Date: Oct 2007 Location: Lebanon, Oh. Posts: 297	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.