Hi stock is 265/40R18, what’s the max width I can use with the stock 18 inch rear wheel? searched google but actually couldn’t find anything so far.

 

What are your rim specs. The offset and width will determine what size tire you can fit. You also want to keep total tire circumference within 3% of OEM for your speedo to be somewhat accurate.

315/30-18 will fit though depending on your rim. Although if you have 265 on there now you probably have a 9.5 or 10.5 width rim

9.5 max is 275
10.5 max is 295

This site will help.
https://www.1010tires.com/Tools/Tire...ismetric=False

 

Thanks for the reply, the rear is 18x10 +58mm. Fronts 18x8 +57mm with 235/40R18. I was thinking of doing 295/35R18s that’s the closest % to the tires there now but it’s right at the limit on a 10 inch wheel, should I go for it or try 285s?

 

You will be fine with 295 on the 10 inch.

 

My car has the same size and offset wheels and the previous owner installed Michelins 10mm wider than stock front and rear, so: 245/40-18 and 275/40-18. It works fine but there is a note in the maintenance records that the tire shop didn't want to go any wider (unsure if front or back). Make sure to check for clearance between the tire and the suspension components on the backside.