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1968 Plymouth RoadRunner backspacing question

JonnyBeervo

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Any idea what backspacing I would need for this setup?

I’ve already purchased 275/60/15’s for the rear and 235/70/15’s for the front.

I THINK I want to go with wheel vintiques 54 series magnum 500 wheels. If I did 15x8 for both the front and the back, that wheel only comes in 4.5” backspacing and I’m not sure if that works for the front tires. I could stagger that with 15x6’s in the front, but that backspacing is 4”. Would that work for the front with 235/70/15’s?

Any guidance is appreciated. Thank you!
 
Yes I have 15X6 on the front with 4 inch back space. Have the 275/60/15 rear 4 1/2 back space. Think I could put 10 inch wide on that rim but they would ware funny. Did that on my charger and they wore in the middle. Could have finder strike if not raised in the rear end. I put 2 and 1/2 inch recurve spring's six leaf on the rear of my car. It dose sit a little higher. Did not want to go with air shocks puts a strain on the shock tower. Just my 2 cent's.
 
Yes I have 15X6 on the front with 4 inch back space. Have the 275/60/15 rear 4 1/2 back space. Think I could put 10 inch wide on that rim but they would ware funny. Did that on my charger and they wore in the middle. Could have finder strike if not raised in the rear end. I put 2 and 1/2 inch recurve spring's six leaf on the rear of my car. It dose sit a little higher. Did not want to go with air shocks puts a strain on the shock tower. Just my 2 cent's.
Thanks for the reply! What size tire are you running up front?
 
Think I went with a 7 inch wide rim on front. The tire measures at 7 inch wide so this is the numbers for mine P235/60R15 for the front. I like it. Figure enough rubber to grab the road. Hope this will help.
 
275/60/15 on 15x8 with 4.5" backspacing will be perfect on the rear. I always go with 15x7 4.25 bs with 225/70/15's on the front. This is a nice setup giving a tad of rake. 275/60 = 28" tall, 235/70 = 27.96" tall, 225/70's are 27.4" tall.
 
275/60/15 on 15x8 with 4.5" backspacing will be perfect on the rear. I always go with 15x7 4.25 bs with 225/70/15's on the front. This is a nice setup giving a tad of rake. 275/60 = 28" tall, 235/70 = 27.96" tall, 225/70's are 27.4" tall.
Thanks for your help! So do you think everything will clear with 235/70/15’s with 15x7’s with 4.25 BS in the front?
 
Thanks for your help! So do you think everything will clear with 235/70/15’s with 15x7’s with 4.25 BS in the front?
I've personally have never used 235's, but know that members here are running them with no issues. @Richard Cranium, didn't you put that size on your MM1 Charger?
 
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Thanks for your help! So do you think everything will clear with 235/70/15’s with 15x7’s with 4.25 BS in the front?
I'm running 245's on 8" wide rims with 4" BS and everything clears (69 Charger). You should be fine with just an extra .25".
 
I'm running 245's on 8" wide rims with 4" BS and everything clears (69 Charger). You should be fine with just an extra .25".
Is that 245’s with 4” BS up front? Thanks for your help!
 
I'm running 245's on 8" wide rims with 4" BS and everything clears (69 Charger). You should be fine with just an extra .25".
Just so the op knows that your wheels are not 15" Dev. Don't know how much it matters having less sidewall bulge for flex/clearance? Also your Charger has a bit more room in the rear wheel wells compared to a Road Runner.
 
I've personally never use 235's, but know that members here are running them with no issues. @Richard Cranium, didn't you put that size on your MM1 Charger?


On my '68 Charger, I have 235-70's on the front & on my '69 Road Runner, I have 225-70's on the front. On the rear (both cars) I have 275-60's. All are 15" wheels.
 
On my '68 Charger, I have 235-70's on the front & on my '69 Road Runner, I have 225-70's on the front. On the rear (both cars) I have 275-60's. All are 15" wheels.
Thanks for that. Do you happen to know the wheel width and backspacing for the front?
 
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PXL_20210404_191723192.jpg
 
Just so the op knows that your wheels are not 15" Dev. Don't know how much it matters having less sidewall bulge for flex/clearance? Also your Charger has a bit more room in the rear wheel wells compared to a Road Runner.
My apologies Hunt, I knew he wasn't going anywhere close to the same direction as me so I was only pointing out that if a 12" tire will fit with 5" BS then his 275's on 4.5 should be fine. Wasn't aware of a big difference between the 2 cars? Goon and I were swapping rims and tires back and forth between our cars (his being a 69RR) and I didn't see anything noticeable but I wasn't measuring either. It was actually his 305's that made me confident that I could squeeze them in there lol.
 
Any idea what backspacing I would need for this setup?

I’ve already purchased 275/60/15’s for the rear and 235/70/15’s for the front.

I THINK I want to go with wheel vintiques 54 series magnum 500 wheels. If I did 15x8 for both the front and the back, that wheel only comes in 4.5” backspacing and I’m not sure if that works for the front tires. I could stagger that with 15x6’s in the front, but that backspacing is 4”. Would that work for the front with 235/70/15’s?

Any guidance is appreciated. Thank you!
 
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