2005 Porsche 911 Tire Size
Your Porsche was manufactured with different tire sizes. To determine the best tire size for your specific 2005 Porsche 911, we first need to determine your rim size. Please review the information below.
How to Determine Rim Size
Check your existing tires. Your Porsche 911's rim size is the number to the right of the R. In the example pictured here, the tire size fits 16inch rims.
Rim Size Selection
Now that you know your rim size, make a selection below to filter your results.
17Inch Rims
2005 Porsche 911
There are multiple tire sizes for your 2005 Porsche 911 that depend upon the trim level. Look for your trim level below to get a colorcoded explanation of your tire size. Then pick the best tire size for your 2005 Porsche 911.
Trim Options:
Carrera (997)
255/40R17/RF 98(Rear)
Simplified Size: 2055017
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 205/50R17 89V (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
255  This number indicates that your tire has a width of 255 millimeters.  
17  The tire size was designed to fit rims or wheels that are 17 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.  
98  This tire has a load index of 98, which means it's capable of carrying a load of 1650 pounds (750 kg) or less. A higher number means the tire can carry more weight. A lower number means the opposite.  
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 102 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.
 
This tire has a speed rating of V, which means 149 mph (240 km/h) is the maximum speed that can be sustained for 10 minutes. A higher speed becomes dangerous. 
Trim Options:
Carrera (997)
205/50R17 89(Front)
Simplified Size: 2554017
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 205/50R17 89V (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
205  This number indicates that your tire has a width of 205 millimeters.  
17  The tire size was designed to fit rims or wheels that are 17 inches in diameter.  
89  This tire has a load index of 89, which means it's capable of carrying a load of 1276 pounds (580 kg) or less. A higher number means the tire can carry more weight. A lower number means the opposite.  
50  This number means that your tire has an aspect ratio of 50%. In other words, your tire's sidewall height (from the edge of the rim to the tire's tread) is 50% of the width. In this case, the sidewall height works out to be 102 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.
 
This tire has a speed rating of V, which means 149 mph (240 km/h) is the maximum speed that can be sustained for 10 minutes. A higher speed becomes dangerous. 
Trim Options:
Carrera (996)
255/40R17(Rear)
Simplified Size: 2055017
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 205/50ZR17 (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
255  This number indicates that your tire has a width of 255 millimeters.  
17  The tire size was designed to fit rims or wheels that are 17 inches in diameter.  
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 102 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.

Trim Options:
Carrera (996)
205/50ZR17(Front)
Simplified Size: 2554017
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 205/50ZR17 (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
205  This number indicates that your tire has a width of 205 millimeters.  
17  The tire size was designed to fit rims or wheels that are 17 inches in diameter.  
Z  This tire has a speed class of Z, which means it's part of an elite speed class of 149 mph or more (240 km/h). A tire's speed class is less specific than the speed rating.  
50  This number means that your tire has an aspect ratio of 50%. In other words, your tire's sidewall height (from the edge of the rim to the tire's tread) is 50% of the width. In this case, the sidewall height works out to be 102 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.

Trim Options:
Targa
255/40ZR17(Rear)
Simplified Size: 2055017
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 205/50ZR17 (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
255  This number indicates that your tire has a width of 255 millimeters.  
17  The tire size was designed to fit rims or wheels that are 17 inches in diameter.  
Z  This tire has a speed class of Z, which means it's part of an elite speed class of 149 mph or more (240 km/h). A tire's speed class is less specific than the speed rating.  
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 102 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.

Trim Options:
Targa
205/50ZR17(Front)
Simplified Size: 2554017
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 205/50ZR17 (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
205  This number indicates that your tire has a width of 205 millimeters.  
17  The tire size was designed to fit rims or wheels that are 17 inches in diameter.  
Z  This tire has a speed class of Z, which means it's part of an elite speed class of 149 mph or more (240 km/h). A tire's speed class is less specific than the speed rating.  
50  This number means that your tire has an aspect ratio of 50%. In other words, your tire's sidewall height (from the edge of the rim to the tire's tread) is 50% of the width. In this case, the sidewall height works out to be 102 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.

18Inch Rims
2005 Porsche 911
There are multiple tire sizes for your 2005 Porsche 911 that depend upon the trim level. Look for your trim level below to get a colorcoded explanation of your tire size. Then pick the best tire size for your 2005 Porsche 911.
Trim Options:
GT2 (Winter Tires)Turbo (Winter Tires)Turbo S (Winter Tires)
265/35R18 93(Rear)
Simplified Size: 2254018
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 225/40R18 88H (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
265  This number indicates that your tire has a width of 265 millimeters.  
18  The tire size was designed to fit rims or wheels that are 18 inches in diameter.  
93  This tire has a load index of 93, which means it's capable of carrying a load of 1430 pounds (650 kg) or less. A higher number means the tire can carry more weight. A lower number means the opposite.  
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 92 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.
 
This tire has a speed rating of H, which means 130 mph (210 km/h) is the maximum speed that can be sustained for 10 minutes. A higher speed becomes dangerous. 
Trim Options:
GT2 (Winter Tires)Turbo (Winter Tires)Turbo S (Winter Tires)
225/40R18 88(Front)
Simplified Size: 2653518
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 225/40R18 88H (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
225  This number indicates that your tire has a width of 225 millimeters.  
18  The tire size was designed to fit rims or wheels that are 18 inches in diameter.  
88  This tire has a load index of 88, which means it's capable of carrying a load of 1232 pounds (560 kg) or less. A higher number means the tire can carry more weight. A lower number means the opposite.  
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 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.
 
This tire has a speed rating of H, which means 130 mph (210 km/h) is the maximum speed that can be sustained for 10 minutes. A higher speed becomes dangerous. 
Trim Options:
Carrera 4S (Winter Tires)GT3 (Winter Tires)
265/35R18/RF 97(Rear)
Simplified Size: 2254018
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 225/40R18/RF 92V (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
265  This number indicates that your tire has a width of 265 millimeters.  
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.  
97  This tire has a load index of 97, which means it's capable of carrying a load of 1606 pounds (730 kg) or less. A higher number means the tire can carry more weight. A lower number means the opposite.  
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 92 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.
 
This tire has a speed rating of V, which means 149 mph (240 km/h) is the maximum speed that can be sustained for 10 minutes. A higher speed becomes dangerous. 
Trim Options:
Carrera 4S (Winter Tires)GT3 (Winter Tires)
225/40R18/RF 92(Front)
Simplified Size: 2653518
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 225/40R18/RF 92V (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
225  This number indicates that your tire has a width of 225 millimeters.  
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.  
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 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.
 
This tire has a speed rating of V, which means 149 mph (240 km/h) is the maximum speed that can be sustained for 10 minutes. A higher speed becomes dangerous. 
Trim Options:
Carrera (996)
285/30ZR18(Rear)
Simplified Size: 2254018
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 225/40ZR18 (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
285  This number indicates that your tire has a width of 285 millimeters.  
18  The tire size was designed to fit rims or wheels that are 18 inches in diameter.  
Z  This tire has a speed class of Z, which means it's part of an elite speed class of 149 mph or more (240 km/h). A tire's speed class is less specific than the speed rating.  
30  This number means that your tire has an aspect ratio of 30%. In other words, your tire's sidewall height (from the edge of the rim to the tire's tread) is 30% of the width. In this case, the sidewall height works out to be 85 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.

Trim Options:
Carrera (996)
225/40ZR18(Front)
Simplified Size: 2853018
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 225/40ZR18 (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
225  This number indicates that your tire has a width of 225 millimeters.  
18  The tire size was designed to fit rims or wheels that are 18 inches in diameter.  
Z  This tire has a speed class of Z, which means it's part of an elite speed class of 149 mph or more (240 km/h). A tire's speed class is less specific than the speed rating.  
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 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.

Trim Options:
Carrera (996)Carrera 4STurboTurbo S
295/30ZR18(Rear)
Simplified Size: 2254018
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 225/40ZR18 (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
295  This number indicates that your tire has a width of 295 millimeters.  
18  The tire size was designed to fit rims or wheels that are 18 inches in diameter.  
Z  This tire has a speed class of Z, which means it's part of an elite speed class of 149 mph or more (240 km/h). A tire's speed class is less specific than the speed rating.  
30  This number means that your tire has an aspect ratio of 30%. In other words, your tire's sidewall height (from the edge of the rim to the tire's tread) is 30% of the width. In this case, the sidewall height works out to be 88 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.

Trim Options:
Carrera (996)Carrera 4STurboTurbo S
225/40ZR18(Front)
Simplified Size: 2953018
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 225/40ZR18 (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
225  This number indicates that your tire has a width of 225 millimeters.  
18  The tire size was designed to fit rims or wheels that are 18 inches in diameter.  
Z  This tire has a speed class of Z, which means it's part of an elite speed class of 149 mph or more (240 km/h). A tire's speed class is less specific than the speed rating.  
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 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.

Trim Options:
Carrera (997)
265/40R18 97(Rear)
Simplified Size: 2354018
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 235/40R18 91V (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
265  This number indicates that your tire has a width of 265 millimeters.  
18  The tire size was designed to fit rims or wheels that are 18 inches in diameter.  
97  This tire has a load index of 97, which means it's capable of carrying a load of 1606 pounds (730 kg) or less. A higher number means the tire can carry more weight. A lower number means the opposite.  
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 106 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.
 
This tire has a speed rating of V, which means 149 mph (240 km/h) is the maximum speed that can be sustained for 10 minutes. A higher speed becomes dangerous. 
Trim Options:
Carrera (997)
235/40R18 91(Front)
Simplified Size: 2654018
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 235/40R18 91V (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
235  This number indicates that your tire has a width of 235 millimeters.  
18  The tire size was designed to fit rims or wheels that are 18 inches in diameter.  
91  This tire has a load index of 91, which means it's capable of carrying a load of 1353 pounds (615 kg) or less. A higher number means the tire can carry more weight. A lower number means the opposite.  
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 94 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.
 
This tire has a speed rating of V, which means 149 mph (240 km/h) is the maximum speed that can be sustained for 10 minutes. A higher speed becomes dangerous. 
Trim Options:
GT2
315/30ZR18(Rear)
Simplified Size: 2354018
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 235/40ZR18 (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
315  This number indicates that your tire has a width of 315 millimeters.  
18  The tire size was designed to fit rims or wheels that are 18 inches in diameter.  
Z  This tire has a speed class of Z, which means it's part of an elite speed class of 149 mph or more (240 km/h). A tire's speed class is less specific than the speed rating.  
30  This number means that your tire has an aspect ratio of 30%. In other words, your tire's sidewall height (from the edge of the rim to the tire's tread) is 30% of the width. In this case, the sidewall height works out to be 94 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.

Trim Options:
GT2
235/40ZR18(Front)
Simplified Size: 3153018
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 235/40ZR18 (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
235  This number indicates that your tire has a width of 235 millimeters.  
18  The tire size was designed to fit rims or wheels that are 18 inches in diameter.  
Z  This tire has a speed class of Z, which means it's part of an elite speed class of 149 mph or more (240 km/h). A tire's speed class is less specific than the speed rating.  
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 94 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.

Trim Options:
Carrera (997)
265/40ZR18/XL (101 )(Rear)
Simplified Size: 2354018
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 235/40ZR18 91(Y) (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
265  This number indicates that your tire has a width of 265 millimeters.  
18  The tire size was designed to fit rims or wheels that are 18 inches in diameter.  
XL  The mark of XL means extra load. A tire with this designation can handle higher inflation pressures than a regular tire, which increases its maximum load.  
101  This tire has a load index of 101, which means it's capable of carrying a load of 1815 pounds (825 kg) or less. A higher number means the tire can carry more weight. A lower number means the opposite.  
Z  This tire has a speed class of Z, which means it's part of an elite speed class of 149 mph or more (240 km/h). A tire's speed class is less specific than the speed rating.  
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 106 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.
 
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. 
Trim Options:
Carrera (997)
235/40ZR18 (91 )(Front)
Simplified Size: 2654018
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 235/40ZR18 91(Y) (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
235  This number indicates that your tire has a width of 235 millimeters.  
18  The tire size was designed to fit rims or wheels that are 18 inches in diameter.  
91  This tire has a load index of 91, which means it's capable of carrying a load of 1353 pounds (615 kg) or less. A higher number means the tire can carry more weight. A lower number means the opposite.  
Z  This tire has a speed class of Z, which means it's part of an elite speed class of 149 mph or more (240 km/h). A tire's speed class is less specific than the speed rating.  
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 94 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.
 
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. 
Trim Options:
GT3
295/30ZR18/RF (98 )(Rear)
Simplified Size: 2354018
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 235/40ZR18 91(Y) (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
295  This number indicates that your tire has a width of 295 millimeters.  
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.  
98  This tire has a load index of 98, which means it's capable of carrying a load of 1650 pounds (750 kg) or less. A higher number means the tire can carry more weight. A lower number means the opposite.  
Z  This tire has a speed class of Z, which means it's part of an elite speed class of 149 mph or more (240 km/h). A tire's speed class is less specific than the speed rating.  
30  This number means that your tire has an aspect ratio of 30%. In other words, your tire's sidewall height (from the edge of the rim to the tire's tread) is 30% of the width. In this case, the sidewall height works out to be 88 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.
 
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. 
Trim Options:
GT3
235/40ZR18 (91 )(Front)
Simplified Size: 2953018
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 235/40ZR18 91(Y) (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
235  This number indicates that your tire has a width of 235 millimeters.  
18  The tire size was designed to fit rims or wheels that are 18 inches in diameter.  
91  This tire has a load index of 91, which means it's capable of carrying a load of 1353 pounds (615 kg) or less. A higher number means the tire can carry more weight. A lower number means the opposite.  
Z  This tire has a speed class of Z, which means it's part of an elite speed class of 149 mph or more (240 km/h). A tire's speed class is less specific than the speed rating.  
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 94 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.
 
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. 
19Inch Rims
2005 Porsche 911
The original tire size for your 2005 Porsche 911 is listed below. Tap on the box to view a colorcoded explanation of your Porsche 911's' tire size.
Trim Options:
Carrera (997)Carrera SCarrera S (Full Load)
295/30ZR19/RF (100 )(Rear)
Simplified Size: 2353519
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 235/35ZR19 87(Y) (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
295  This number indicates that your tire has a width of 295 millimeters.  
19  The tire size was designed to fit rims or wheels that are 19 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.  
100  This tire has a load index of 100, which means it's capable of carrying a load of 1760 pounds (800 kg) or less. A higher number means the tire can carry more weight. A lower number means the opposite.  
Z  This tire has a speed class of Z, which means it's part of an elite speed class of 149 mph or more (240 km/h). A tire's speed class is less specific than the speed rating.  
30  This number means that your tire has an aspect ratio of 30%. In other words, your tire's sidewall height (from the edge of the rim to the tire's tread) is 30% of the width. In this case, the sidewall height works out to be 88 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.
 
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. 
Trim Options:
Carrera (997)Carrera SCarrera S (Full Load)
235/35ZR19 (87 )(Front)
Simplified Size: 2953019
Simplified size is useful for shopping and buying tires.
The original tire size for your 2005 Porsche 911 is 235/35ZR19 87(Y) (Front). A colorcoded explanation of the 2005 Porsche 911's tire size is shown below.
235  This number indicates that your tire has a width of 235 millimeters.  
19  The tire size was designed to fit rims or wheels that are 19 inches in diameter.  
87  This tire has a load index of 87, which means it's capable of carrying a load of 1199 pounds (545 kg) or less. A higher number means the tire can carry more weight. A lower number means the opposite.  
Z  This tire has a speed class of Z, which means it's part of an elite speed class of 149 mph or more (240 km/h). A tire's speed class is less specific than the speed rating.  
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 82 millimeters.  
R  This letter denotes how your tire was constructed. Radial is the standard construction method for about 99% of all tires sold today.
 
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. 