Rim BackSpacing Help

[lowroder]

Hi I Have A 51 GMC That Im Going To Bag.. Using MII an 4 Link On Original Chassis. Gonna Run 15" Steel Wheels But Not Sure On Width Or Back Spacing.. Any Help an Pics? Not Sure If Need 15x6 or 7 or What Backspace To Get.. Going To Run Same Size Tires Fnt & Rear

[lowroder]

any ideas guys???

[Speedbumpauto]

You need to have the rear you are going to use before you can talk about backspace. I prefer to have it mocked up or installed with the suspension in place before I measure for backspace but you can do it the "math" way by measuring flange to flange and fender to fender to get pretty close. With the cost and return policy on wheels, I prefer to remove as many variables as I can before ordering.

[lowroder]

i have the rearend in the truck... its on leafsprings now but changing to 4 link to bag it.. going with MII up front.

[wolffcub]

Originally Posted by lowroder

i have the rearend in the truck... its on leafsprings now but changing to 4 link to bag it.. going with MII up front.

What is your axle width? Let me know the dimension from rim mounting face to rim mounting face and i can help you out with a Solidworks image.

[lowroder]

ok wolffcub ill get back to you... gonna get that measurement.

[lazypineapple]

if the rear is in place,
just run a straight edge along the flange face where the wheel goes.
and pull a measurement to the inside bed/frame.
That measurement there is your MAX backspace.
probably 4-6".
now pick your tire.
there is only 12" to work with. fender to bed is 12" wide.

i run 245/ 60/15" its about 10.5" total width. tread with is 9.8" so i have about and 1" or less on each side.
i run, Steel Rallies
8x15 bs4
245/60/15 T/A
1" wheel spacer on rear.
axle wide, 60-1/4"

If you subtract the 1" spacer from my 4" BS. thats a 3" BS
the bed is 50" wide my diff is 60.25" wide, thats 10.25" difference divide by /2
5" each side with diff centered up. for my Total BS.
with my 5" Total BS, subtract my 3" Wheel BS thats 2" of clearance left
8" wheel with a 10" tire, thats 1" overhang of the tire(give or take)each side of wheel. centers up and Tucks real nice
I run 7" front with MII with 3"BS 225/60/15

if you want to run the same on all 4.
7" should do.

*of course all measurement taken at ride height.


(all the data is available in the Google on tire width by size)

[wolffcub]

This is the crude drawings i used to sort mine out in solidworks. My fenders only have a clear dimension of 11.25". My axle width from brake rotor face to rotor face is 59.5". The first drawing shows a 7" wide wheel with a 3.75" BS and 235/60 tire would fit like. The tire width was drawn in from internet info I found on how wide it would be after mounted on a 7" wheel.



The second drawing shows what i would get with a 1/2" spacer installed.



Strange how i get something different lazypineapple after using your setup info. Everything check out ok? it would be interesting to see whats up.

[lazypineapple]

My diff measurement my by off.
I was looking at old notes.
I got 12" of fender clearance or maybe a little more. By pulling the fenders out bare handed
Cool program there. Wish I had that back when.

[lowroder]

I'm looking to go 205/75/15 radials or 215 75 15 radials with 3" WW.
Steel Wheels. I Thought Bout The Coker Bias Cause I Like The look. But Ill drive This quite A Bit Once Drivable. The 205's are just a lil shorter so I can get all the way down on bags.