I am thinking about changing the rear tires size to 15. Now I have 14 inch rims all around w/ 225 X 60. What would be the preferred size rims and tires? 15 x 6? 15 x 7? 15 x 8? what size back spacing????
15x7 for the rims to be on the safe side but 15x8 should fit, to be on the safe side 4 1/4 bs but it would be best if you could try a couple different sizes as some cars will fit a 4 1/2 bs. There seems to be no real set in stone size for all cars and it depends on the stance of your car as well
15x7 all the way around, or 15x7 front and 15x8 rear. A 4-inch backspace is about ideal with the stock rearend width I'd go 215 to 225/60 up front, and 225 to 245/60 rear.
I'm running 255/60/15s on an 8" rim with a 4 1/4" back spacing. Everything fits nicely. A wheel with 4 1/4" back spacing has limited availability. Mine are steel wheels from Summit Racing.
I am running Magnums .... 15x7 front and 15x8.5 rear both have 4.25 backspacing. The fronts are factory Ford Mustang wheels. The rears were made by Wheel Vintiques. A better back spacing for the rear would be 3 7/8, and that can be had in some Shelby wheels, but I have not seen that in Magnums. With the 4.25 bs, these are close to the rear springs with plenty of room outboard. You could easily fit a 245 and most 255s with that better backspace if you can find it. I am also running 1/4 inch spacers on the rear. If going to aftermarket wheels, a little less backspace might be an option, too, maybe another 1/4 less. I would switch all the wheels to 15s. The selection of sizing for 14 inch tires is shrinking. Personally, I like the same diameter wheels front and rear. You can stagger the height with the tires.
I know there are others running that same combination on their Mavericks with no problems, but on my car with 235/60-14s, the inner sidewalls would scrub the upper part of the wheel house right above the frame rail when turning into driveways and the car would lean to one side a little. They were also only about a finger-width away from the leaf springs. I suggest that a 4-inch backspace is about ideal for an 8-inch wheel on the back, and 4" to 4-1/4" on the front with a 7-inch wheel.
This is another example of when really filling a car with a lot of tire, you need to look at the actual section width of tire instead of the labelled size. Different brands can run fat or skinny. If Hotrock is running 255 Cooper tires, it is very likely that the actual section width would be very close to 235 BFGs. It is also why I did not post that I have 265/50/15s on mine. They are Coopers and only 1/4 wider than 245/60/15 BFGs. I don't want anyone else to try using my size in another brand ... bound to be trouble. Actual section size is typically posted online in a brands tire specs. Something else to think about too is that if you go to a wheel at either end of the recommended range, it will change the dimension a little too. To demonstrate this ... take the bare tire and pull the beads to the rim widths you have in mind. It moves the sidewalls in and out.
I'm running 255/60/15 M/T Drag Radials which have a 10.10 section width. I also run 255/60/15 BFG Radial T/As with a 10.20 section width. The measurement between the tire and springs is about 3/4 inch. The distance between the tire and the upper wheel house is almost 2 inches. Where I run into a close encounter is the outside wheel well lip which has not been turned. I have about 1/4" of clearance at my tires widest point which is down somewhat on the tire. Therefore, no rubbing. I would say all Mavericks and Comets were not created equal.
The rear axle width supposedly is the same throughout, but a couple of questionable sources on the internet seem to indicate more than one width.
