On the tire you should see a set of numbers like 285/35/18ZR
The 285 is the width of the tire in millimeters, divide this by 25.4mm and you should get 11.22" wide. The 35 is the ratio of the width to height. Take the 285 and multply by the .35 and then this will give you the height of your tire in millimeters so again divide by 25.4 and this will give you 3.92" from the rim to the floor or basically from the rim to the end of the tire. The ZR or YR or whatever you have is a speed rating. I know that the ZR os for speeds of 149+ mph. You figure the rest.
Dude got your calculations, but what if I have a tire for example like 255/40ZR17 and want to upgrade to a 285/40/ZR17. I dont know if the 255s were the exact size for the rim. How will I know if the rim is big enough for my 285s and is there some way to measure it. I have a Racing Hart Type-C ,17".
See this? This is what I love, everyone helping everyone out. If someone has a problem, someone jumps at the opportunity to help them out. Steve, great job and taking over, thanks for your help because I wouldn't know how to answer that.