How do you find the right tire

Determining what size of tire you need is quite simple if you know where to look. The letters and numbers on the side of your tire will tell you everything you need to know. The 3 measurements needed to look up a tire for your vehicle are:

1.Tire Width
2.Aspect Ratio
3.Rim Diameter

Once you have those 3 numbers, click here to search our tire prices.

If you are unable to find the tire size yourself simply call us and we will be more than happy to look up the tire size specified by the manufacturer of you vehicle.

Aspect Ratio (Height of Tire Sidewall)

The second set of numbers in the tire size code represent the tire height (in percent) starting from the rim to the tread. This number identifies the tire’s profile and is a percentage of the tire width.

Ex: The size 205/55/16 has an aspect ratio of 55%. The height of the sidewall is calculated as follows:

205 millimeters x 55% = 112.75 millimeters

The larger the aspect ratio number the taller the sidewall profile (height), and the small the number the lower the sidewall profile.

Tire Width (Width of Tread)

The first set of numbers in the tire size code represent the tire width (in millimeters). This number is measured from the widest point of its outer sidewall to the widest point of its inner sidewall when mounted and inflated.

Tire Construction

R = Radial construction. This classification implies that the tire’s body plies “radiate” out from the imaginary center of the wheel. Radial tires are by far the most popular type of tire today representing virtually all tires installed.

D = Diagonal construction. This classification implies that the tire’s body plies crisscross. Tires of this sort are for light truck and spare tires.

Note: The Tire Construction is always written on the sidewall, but does not have to appear in the tire size code. Ex: You may see 225/50/17 or 225/50/R17 – both of these are the exact same.

Rim Diameter

The final number in the tire size code represents the rim diameter (in inches). The most common personal vehicle rim sizes are: 8”, 10”, 12”, 13”, 14”, 15”, 17”, 18”, 19”, 20”, 22”, 23”, 24”, 26” and 28” and can be found on cars, minivans, vans, sport utility vehicles and light duty light trucks.

In rare cases some vehicles have rim diameter expressed in half-inches (ex: 15.5) or in millimeters (ex: 415). It is absolutely crucial that the correct tire size is installed on rims with these rare diameters.

Other Important Markings

Tire Class

P = When a tire size begins with a “P,” it signifies the tire was designed to be fitted on vehicles that are primarily used as passenger vehicles. The “P-Metric” size applies to cars, minivans, sport utility vehicles and light duty pickup trucks (typically 1/4- and 1/2-ton load capacity).

LT = If a tire size begins with “LT,” it signifies the tire was designed to be used on vehicles that are capable of carrying heavy cargo or towing large trailers. The “Light Truck-Metric” size applies to medium and heavy-duty (typically 3/4- and 1-ton load capacity) pickup trucks, sport utility vehicles and full-size vans. “LT Metric” tires have more heavy-duty internal components designed for heavier vehicles which carry large loads.

The absence of a letter preceding the three-digit numeric portion of a tire size, signifies the tire is a “Euro-Metric”. “Euro-Metric” tire sizes have identical dimensions as “P-Metric” tires but have minor variations in load carrying capabilities.

The first number after the tire size code indicates the tire’s Load Index. Generally, the numbers on passenger cars and light trucks range from 70 to 110. The Load Index specifies the maximum amount of weight a tire can safely carry. It is very important to maintain the proper load index for your vehicle when replacing your tires.

Load IndexLbKgLoad IndexLbKg
717613451112,4031,090
727833551122,4691,120
738053651132,5351,150
748273751142,6011,180
758533871152,6791,215
768824001162,7561,250
779084121172,8331,285
789374251182,9101,320
799634371192,9981,360
809924501203,0861,400
811,0194621213,1971,450
821,0474751223,3071,500
831,0744871233,4171,550
841,1025001243,5271,600
851,1355151253,6381,650
861,1685301263,7481,700
871,2015451273,8581,750
881,2355601283,9681,800
891,2795801294,0791,850
901,3236001304,1891,900
911,3566151314,2891,945
921,3896301324,4092,000
931,4336501334,5412,060
941,4776701344,6742,120
951,5216901354,8062,180
961,5657101364,9382,240
971,6097301375,0712,300
981,6537501385,2032,360
991,7097751395,3572,430
1001,7648001405,5122,500
1011,8198251415,6772,575
1021,8748501425,8422,650
1031,9298751436,0082,725
1041,9849001446,1732,800
1052,0399251456,3932,900
1062,0949501466,6143,000
1072,1499751476,7793,075
1082,2051,0001486,8443,104
1092,2711,0301497,1653,250
1102,3371,0601507,3853,350

 

Ply Rating

Much like a passenger tire has the load rating written after the tire size code, light truck tires specify the load range after the tire size code as well.

LT-metric, LT-flotation and LT-numeric tires are branded with their load range using letters. The further along the letter in the alphabet, the higher the ply rating, and maximum inflation pressure and load.

LT-Metric, LT-Flotation and LT-Numeric Light Truck Tires
Load RangePly RatingAbbreviatedMaximum Load Pressure
B4B35 psi (240 kPa)*
C6C50 psi (350 kPa)*
D8D65 psi (450 kPa)*
E10E80 psi (550 kPa)*
F12F95 psi (650 kPa)*
*Selected large LT sizes are designed with reduced maximum load pressures

Speed Rating

The letter after the number indicates the Speed Index. Tires are issued a speed rating by the federal government for meeting safety standards at a specified speed. In general, a higher speed rating will result in better vehicle handling. The maximum driving speed of a vehicle must be limited to the speed rating of the tires installed.

As advances in technology have increased vehicle top speeds, the tire speed ratings have evolved to better identify the tire’s capability, allowing drivers to match the speed of their tires with the top speed of their vehicle. Despite their high speed capabilities, no vehicle should be driven on public roads in excess of the legal speed limit.

Caution should be used when tires have been damaged, altered, under-inflated or overloaded as the speed rating has been compromised under such circumstances. Additionally, most tire manufacturers state that a tire that has been cut or punctured no longer retains the original speed rating after repair because the tire manufacturer can’t control the quality of the repair.

The most common tire speed rating symbols, maximum speeds and typical applications are shown below:

L75 mph120 km/hOff-Road & Light Truck Tires
M81 mph130 km/hTemporary Spare Tires
N87 mph140km/h
P93 mph150 km/h
Q99 mph160 km/hStudless & Studdable Winter Tires
R106 mph170 km/hH.D. Light Truck Tires
S112 mph180 km/hFamily Sedans & Vans
T118 mph190 km/hFamily Sedans & Vans
U124 mph200 km/hSport Sedans & Coupes
H130 mph210 km/hSport Sedans & Coupes
V149 mph240 km/hSport Sedans, Coupes & Sports Cars
W168 mph270 km/hExotic Sports Cars
Y186 mph300 km/hExotic Sports Cars
Z>149 mph240 km/h(obsolete, replaced by W and Y)