10 Bolt 70 Chevelle- Weld RT-S 18x10 Backspacing

[Shiner]

I am looking to put Weld RT-S S71 wheels on my 1970 Chevelle (2" drop) and 10 bolt rear end. The car will have Baer SS4 rear calipers.

I do not have a tool but I am wondering what my backspacing will be... I am not mini tubbed. I am wanting to do a 18x10 with a 315 tire but I am thinking of going with a 305/40 ET Street...


ALSO is anyone on here a Weld Dealer that I could get a good price on these wheels and tires?

Any advice?

[Shiner]

modifications in siganture

[Vince@Meanstreets]

It is best to measure for yourself since all cars are different.

From the cars we get in the shop the average is 5 3/4" to 6" back spacing. One was 5 1/2" but that was due to exhaust tailpipe routing.

[Shiner]

If I have 15x8 5.5" BS and I like the way the fill the wheel wells and I then want to put a 10" wheel would I need to get a 7.5" BS(to accommodate for the 2" wider wheel?

[Vince@Meanstreets]

If I have 15x8 5.5" BS and I like the way the fill the wheel wells and I then want to put a 10" wheel would I need to get a 7.5" BS(to accommodate for the 2" wider wheel?

So a 15x8 and a 5.5 BS will actually take more due to tire bulge. Im assuming you are running a 255 tire? 255 on an 8 is 3/8" average. The actual back space available would be 5 3/4" taking the tire bulge into account.

On an 18 or 17 wheel the tire bulge is less.

I would measure what you have then subract an 1" min for articulation room. For a 305 or 315 on a 10" wide you will need 12" of space. Average 70 Chevelle wheel tub is 14-14 1/2" wide. 1/2" to the outer and 1 1/2" to the inner should do.

Jack up the back and pull the wheels. Let see what you have?

[Shiner]

Wish you would just tell me, "Travis get the rears with 6" BS and the fronts with 5""

[Vince@Meanstreets]

Wish you would just tell me, "Travis get the rears with 6" BS and the fronts with 5""

:lol:

Now what fun would that be.

Actually I would if you would let me measure the car first but you are going to have to get dirty to know for sure. You have everything there to get the answer you need.

With the tire on the car, measure distance from the inner well to the inner tire. Closest section to hit.

Now measure the outer tire face to the wheel well lip. Quarter panel lip.

Pull the tire off and measure the current tire width. Sitting on the ground on its side. Measure the width. Ground to the top of the tire. 8" wheel should be around 10-11" wide. This is the section width.

Now take a measurement of the wheel well to the quarter panel lip.

Now use a ruler and tape measure to measure wheel mounting (axle flange to inner wheel well) pictured^

let me know when you get all of that.

[Shiner]

Will try and do it tomorrow, thanks Vince

Can you get me a good deal on some S71s?

[Che70velle]

The limiting factor on Chevelle rears is the lower shock bracket. It sticks way out toward the tire, and as you go with wider tires, your tires will hit the lower shock bracket before they hit the wheel tub. An 11" wide wheel is very doable WITHOUT the lower shock bracket in place, but of course this would require rear suspension mods.
Good info as always Vince!

[JKnight]

That info on the Lower shock bracket should be useful when measuring too, easily overlooked if you're only focusing on the wheel tubs.

[Shiner]

So a 15x8 and a 5.5 BS will actually take more due to tire bulge. Im assuming you are running a 255 tire? 255 on an 8 is 3/8" average. The actual back space available would be 5 3/4" taking the tire bulge into account.

On an 18 or 17 wheel the tire bulge is less.

I would measure what you have then subract an 1" min for articulation room. For a 305 or 315 on a 10" wide you will need 12" of space. Average 70 Chevelle wheel tub is 14-14 1/2" wide. 1/2" to the outer and 1 1/2" to the inner should do.

Jack up the back and pull the wheels. Let see what you have?

Outer: 1"
Inner: 2"

Section Width 11"

Weld recommended I go with a 6.1 and run .25" spacers if I need to.

[Vince@Meanstreets]

need one more bit of information. The backspace including the tire.
Im guessing you will be 5 7/8"

[Vince@Meanstreets]

Outer: 1"
Inner: 2"

Section Width 11"

Weld recommended I go with a 6.1 and run .25" spacers if I need to.

How many inches to that shock bracket to your current tire?

I am measuring 4 7/8" from the wheel mounting flange to the edge of the mounting stud and a radius of 7" so a 14" circumference. The inside of an 18" wheel is 17 3/4 so I believe you should be good. Also depending on lower shock mounting type. I can see that reducing the gap by an additional inch. Another good reason to got to a DSE OR Ridetech rear coil over system.

good catch guys.

[Shiner]

Lower shock mount to wheel is 1"

[Vince@Meanstreets]

Lower shock mount to wheel is 1"

Looking at what I have in the shop will go into the wheel ok. Don't forget about that Coil over conversion. Best thing you can do for a-bodies.

How much does the tire stick out over the wheel? If you are getting an 11" section width that would be 7/8" -1" , should be since you have an 8" wheel, edge to edge is 9". 11" section width minus the 9" gives us 2" of total tire bulge so 1" on each side is tire bulge. Just have to confirm.

[Shiner]

Looking at what I have in the shop will go into the wheel ok. Don't forget about that Coil over conversion. Best thing you can do for a-bodies.

How much does the tire stick out over the wheel?

Thanks I have coil overs on all 4 corners. The tire is about .25" maybe over the bead.

What are yalls thoughts on the Black Weld S71 vs S77 on a Black/Red Striped Chevelle SS?

[Vince@Meanstreets]

Thanks I have coil overs on all 4 corners. The tire is about .25" maybe over the bead.

What are yalls thoughts on the Black Weld S71 vs S77 on a Black/Red Striped Chevelle SS?

What size tire is on the wheel now? that doesn't make mathematical sense. should be more than that.

Right now its looking like 6" backspace, you will have to trim the quarter lip up to the spot welds. And gives you 1 1/2" to the well and 1/2" to the shock mounts.

I can't believe you haven't started an intro page with some pictures. Lets see some pictures.

adjusted for new currect BS

[Shiner]

What size tire is on the wheel now? that doesn't make mathematical sense. should be more than that.

Right now its looking like 7" backspace, you will have to trim the quarter lip up to the spot welds. And gives you 1 1/2" to the well and 1/2" to the shock mounts.

I can't believe you haven't started an intro page with some pictures. Lets see some pictures.

Honestly I dont know how much the tire is overhanging the wheel.

I have 15x8 4.5" BS on all four corners now.

https://content-na.drive.amazonaws.com/cdproxy/templink/87oVStSJEaDOtAGpvywhzXIC8zS0y2W8nzR4BIx9GyILAYspN/alt/thumb?viewBox=2560

[Vince@Meanstreets]

Honestly I dont know how much the tire is overhanging the wheel.

I have 15x8 4.5" BS on all four corners now.

https://content-na.drive.amazonaws.com/cdproxy/templink/87oVStSJEaDOtAGpvywhzXIC8zS0y2W8nzR4BIx9GyILAYspN/alt/thumb?viewBox=2560

Oh ok, you had it listed as 15x8 5.5 earlier.

[Che70velle]

Great looking ride! BUT...we need more pics!
We love pics!!!

[Shiner]

Oh ok, you had it listed as 15x8 5.5 earlier.

I did say that, sorry.

Its actually 15x8 4.5" BS.

So what size and what wheel?! I left a picture of my car

[Vince@Meanstreets]

I did say that, sorry.

Its actually 15x8 4.5" BS.

So what size and what wheel?! I left a picture of my car

im not seeing any pictures. :EmoteClueless:

[Vince@Meanstreets]

Outer: 1"
Inner: 2"

Section Width 11"

Weld recommended I go with a 6.1 and run .25" spacers if I need to.

I agree...they also list a 6.20" back space