What Size Tyre Do I Need ?

I'm buying new wheels for my 70 Satellite, for the rears i'm a bit unsure what tyres to fit

I'm getting 15 x 8 for the rear but they have a 3.75" backspace, ideally I would like 275/60/15 but do you think that size would rub ?

The fronts i'm going with 15 x 7 with 225/70/15 I think, also 3.75" backspace, think that should be ok ?

Many thanks.

the rears will probably rub
you need a 15x8.0" wheel with closer to 4.50" backspace - 245/60/15s would probably clear with the 3.75" backspace

your 275 tire will rub with 3.75 backspace. WRONG WHEEL. Get 4.50 backspace.

They don't come in 4.50 backspace

what wheels are you using? I have the same problem with these - I WANT TO USE THEM
- 15x8.0" Motor Wheel Spyders, but they are 50 years & 3.50" or 3.75" backspace

I'm thinking B-body rear axle & moved springs in a '73 Challenger

https://www.summitracing.com/int/parts/are-ar615865/overview/make/american-ironhorse/model/outlaw

3 & 3/4 " back space is really hanging them out there.
Take a tape measure to the car and see just what will fit in there.
Tell the tire store what you want instead of buying what they want to sell.
We used to jack up the car to make a big tire fit,
Think long ugly shackles, and air shocks.
Tires protruded out side the fender.
Looked kool, didn't werk the best .
This is the 21st century man.

use 'em ! get the biggest, widest tire you can find that fits, then cut the quarters for clearance [clarence]!
day 2 all the way........ [JK ]

This is my current wheels, 18 x 9.5 with 265/40/18's on the rear, not sure on the backspace though, their website lists them as available in 6.75" , 5.75" or 5.25" so i'll have to take one off and check

With the current wheel off any idea what measurements I need to do in the arch to see if they will fit ? So just to clarify I want the 15 x 8 with 275/60/15 tyres and 3.75" backspace, I assume I should just measure from the hub to the wheel arch lip then find out the exact width of the tyre ? Thanks

I think the bottom line is that you're going to have to answer this for yourself. Remove both rear wheels, using a carpenters square, measure (BOTH SIDES) how much room you have to work with. The rim you've chosen has 4.25 front space, add tire width + about 5/8" (15 millimeters) for sidewall flex. The 275/60/15 tires you inquired about are 10.8 inches wide. So if my calculations are correct, you'll need 6.25 inches from the face of your brake drums to the wheel well lip for that tire to safely fit. If my numbers are jacked up, someone will soon chime in...

I took a measurement and there seems to be 6.5" from the hub to the wheel arch lip

The current wheels on the rear are 18 x 9.5 with 5.75" backspace with 265/40/18 tyres

With the current tyre on there is about 1.5" between the edge of the tyre and the wheel arch

6.5" should give you 3/4" for sidewall flex. Double check my math (and maybe yours as well) before you spring for those new wheels.