2007 MercedesBenz CLK63 AMG Tire Size
Listed below is the tire size for your 2007 MercedesBenz CLK63 AMG with a detailed explanation of the tire code. Make sure to compare the size with the information in your driver side door or owner's manual to confirm accuracy.
Front Tire 225/40ZR18/RF 92 


225 
This number indicates that your tire has a width of 225 millimeters. 

40 
This number means that your tire has an aspect ratio of 40%. In other words, your tire's sidewall height (from the edge of the rim to the tire's tread) is 40% of the width. In this case, the sidewall height works out to be 90.00 millimeters. 

Z 
This tire has a speed class of Z, which means it's part of an elite speed class of 149 mph or more (over 240 km/h). tire's speed class is less specific than the speed rating. 

R 
This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.


18 
The tire size was designed to fit rims or wheels that are 18 inches in diameter. 

RF 
The mark of RF indicates that the tire is reinforced. This means it can handle a higher inflation pressure than a standard tire, which increases its maximum load. 

92 
This tire has a load index of 92, which means it's capable of carrying a load of 1386 pounds (630 kg) or less. A higher number means the tire can carry more weight. A lower number means the opposite. 

This tire has a speed rating of Y, which means 186 mph (300 km/h) is the maximum speed that can be sustained for 10 minutes. A higher speed becomes dangerous. 
Rear Tire 255/35ZR18/RF 94 


255 
This number indicates that your tire has a width of 255 millimeters. 

35 
This number means that your tire has an aspect ratio of 35%. In other words, your tire's sidewall height (from the edge of the rim to the tire's tread) is 35% of the width. In this case, the sidewall height works out to be 89.25 millimeters. 

Z 
This tire has a speed class of Z, which means it's part of an elite speed class of 149 mph or more (over 240 km/h). tire's speed class is less specific than the speed rating. 

R 
This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.


18 
The tire size was designed to fit rims or wheels that are 18 inches in diameter. 

RF 
The mark of RF indicates that the tire is reinforced. This means it can handle a higher inflation pressure than a standard tire, which increases its maximum load. 

94 
This tire has a load index of 94, which means it's capable of carrying a load of 1474 pounds (670 kg) or less. A higher number means the tire can carry more weight. A lower number means the opposite. 

This tire has a speed rating of Y, which means 186 mph (300 km/h) is the maximum speed that can be sustained for 10 minutes. A higher speed becomes dangerous. 