I'm not sure you can install a 275/60 on a 10, into a Duster/Demon/2nd genBarracuda.
275s are only 275 on a 70% checking rim, which in this case is a 7.5. That 275 number is a section width and corresponds to; 275/25.4=10.827 inches. When you put that 275 tire on a rim wider than 70%, the section grows. On a 10, I would expect the section to grow to say ~310
But it gets worse, the actual section width, on the checking rim, is rounded to the nearest 5mm, on the 5s. So that 275 mightabin 271 to 279
The question then is; will it fit into your tubs?
A 310 is ~12.2 inches of section, and I need a minimum of 3/8" on either side for city corners so that comes to 12.95 from inner tub to the quarter lip....... that's daymtight. And I had to move the springs.
but hang on
a 275/60 is ~28tall, so it's gonna be tight to the front of the opening down by the rocker. If your front spring bushings are soft, you may find the tire-treads getting cut up. You might have to move the axle back, or cut metal. I moved the axle back.
Plus, there is a ledge on the outer side a couple of inches above the fender-lip,that encroaches, so you may have to raise the back of the car.
and the curvature at the front of the inner wall will not allow that 28 to get to a minimum 3/8 clearance without a lot of BFG-work, and if you break thru, well now you gotta fix it.
And then
you get into another issue; What pressure will you have to run to get the tire to run flat on the road? See, that 10"rim will allow or actually force the outer tread on each side, down onto the road, And this will have a tendency to allow the center treads to come up off the road. To counter that,you will need to run more than the usual pressure. Probably in the neighborhood of 30+.... If your "mags" are actually steel, they are pretty heavy. And 275s on steel wheels at 30 plus psi, rides like a dumptruck.
That said;
I run 295/50-15s on 10s at 24psi on alloy wheels, and the treads last forever.
The checking rim for a 295 is 206.6mm or 8inches. On a 10, the section will be around 1 inch more or 320=12.6inches. Adding 3/8 per side, you need a 13.4" tub, still daymtight. But a 295 is only less than 27" tall, so no clearance issues to the front. And you get to run a great 24psi(*). But you still have to deal with the outer ledge and the curvature at the front of the inner wall. If you center the wheel in the tub, it should not be a problem. But you will still have to move the springs.
Finally, 295s on alloys at 24psi, ride like a limo.
(*) Warning; at 24psi, the first time you come into a corner a lil hot, the back of the car is gonna heave over and roll the sidewalls under. This will cause the rear of the car to steer to the outside of the turn, causing the front of the car to be steering further than you expected it to. And so, you will have to correct for that on the steering wheel; be ready. I very quickly adapted to it, and I like it.
As for you, with those skinnys up front, I can't see you cornering hard enough for this to be a problem.
My question is;
if this is a streeter,
how are you planning to stop this car on those tiny front patches?
