Hi everyone, I am somewhat new here, been reading and reading for about the past 3 months. I have a 1998 SC400, and I am finally in the position to purchase some new wheels.

I wanted to go 18", and I wanted either 18x10 or 18x10.5 for the rear. The plan as of now is only a 0.5" drop. So I am asking what tire sizes for each width can I use without having to roll fenders. I was planning to stay pretty close to the 50mm offset, just slightly less.

Despite reading around the internet, can someone explain to me perhaps how you know what tire widths you can use on a given wheel width? I thought you would just use a tire the same width, but for a 10.5" wheel, that would still only be around a 265 tire, which I would assume is considered narrow for that width.

Before I get flamed, I read the sticky and tried to compile as much information as I could, but I couldn't find something close to the setup I am wishing to run. Sorry if I missed something.

Thank you in advance for any help.

 

At least a 275 on a 10.5 wheel. Even then it's a bit stretched. If you want the sidewalls to be more square, look at a 295 - 305.

 

ok thanks! is there a formula to figure out the appropriate tire width, or is it typically like a range for a given wheel width?

 

I wouldn't go any smaller than 265's on a 10.5 wheel.

 

General run of thumb if you want to run a fairly square sidewall, look for a tire that is roughly an inch wider than the wheel. This is for lower profile tires, the higher the profile equates to a narrower wheel.

In your case, 10.5 x 25.4 = 266.7mm (roughly a 265 tire). You have to understand this measurement is the sectional width of the tire, not the tread width. This number is the widest width of a tire produced by a given manufacturer.

With that infomation; a 285 equates to an 11.22 inch tire and a 295 equates to an 11.61 inch tire. I currently run a 285/30 on a 10 inch wheel and it is a square tire on the verge of slightly mushrooming. Adding another half inch to the wheel equates to roughly 13mm, so moving from a 285 to a 295 is a 10mm difference; therefore fitment of a 295 on a 10.5 wheel is going to be similar to that of a 285 on a 10 inch wheel. These measurements are with the use of BFG KDW's.

Last thing to note is tires do run narrower or wider from manufacturer to manufacturer. Nothing is guaranteed to fit 100% without knowing all elements involved.