305/65R17 Tire Size Guide: Everything About Tire Code

Are you looking for a replacement tire or want to upgrade to another one? 305 65r17 tires can be your choice. This tire has many applications, and most are designed for all-terrain use. But what do the numbers mean?

Understanding the tire size is a challenge to many people, both new and veteran drivers. This particular tire – 305 65r17 – measures 12 inches wide and has an overall diameter of 7.8 inches. It is designed to make 619 revolutions per mile or 385 revolutions per kilometer.

Let’s dive deep into what 305 65r17 tires are and some of their applications. We will also list some of its replacement tire sizes if this is unavailable in your region.

What Do Numbers on 305 65r17 Tire Mean?

From our topic, 305 65r17 is specified by what can be referred to as a mix of characters. These are not just random numbers but are carefully chosen to reveal the technical details of the tire.

A full tire specification reveals the tire type, load index, speeding rating, rim diameter on which the tire is mounted, tire width, and profile. Unfortunately, you cannot get all these from a tire represented as 305 65r17.

The above representation reveals the tire’s width, aspect ratio (profile), and the rim size on which it should be mounted. Let’s make sense of these numbers.

How Wide is 305/65r17 Tire?

The first three letters – 305- represent the tire’s width in millimeters. Through conversion, the 305 65r17 tire is 12 inches wide. A tire width is the distance from the inner sidewall to the outer sidewall.

You should choose the tire’s width carefully and as recommended by professionals. A wider tire means more contact with the ground, which improves grip and handling. However, it can also mean a greater rolling distance. This can lead to poor fuel economy.

305/65r17 Tire Aspect Ratio (Profile)

The aspect ratio or profile is the tire’s height from the rim to the outer edge of the treads. It is typically represented as a percentage of the tire’s width.

In this case, it is the two-digit number after the forward slash. The aspect ratio of 305/65r17 is 65, which means the tire measures 198mm or 7.8 inches from the rim to the top of the tread.

A low-profile tire – 30 or 35 series – provides better handling but causes your ride to be harsher. That is why some people prefer high-profile tires – 65 0r 70 series. These offer you a smoother ride. However, you trade that with precise handling.

What Size of Rim Fits a 305/65R17 Tire?

The last two digits represent the rim size on which the tire should be mounted. It’s the rim’s diameter in inches, meaning the 305/65R17 tire should only be fitted on 17-inch (432mm) rims.

Always fit tires on the appropriate rim size for better handling and ride quality.

It is easy to derive other technical specifications from a tire represented as 305/65R17. These include the tire’s circumference and revolutions per kilometer or mile, as illustrated in the chart below.

	Metric	Inches
Overall Diameter (Tire Height)	828 mm	32.6″
Tread Width	305 mm	12″
Rim Diameter	432 mm	17″
Sidewall Height	198 mm	7.8″
Circumference	2600 mm	102.4″
Revolutions	385 per km	619 per mile

 

Other Tire Technical Specifications

You can deduce the tire’s loading index, speeding rating, and construction type. Let’s briefly discuss how each of these is represented.

Tire Construction Type

Tires are of two main construction types: radial and diagonal or bias ply. These are represented on the sidewall by letters R and D or B. In this case, the 305/65R17 tire is radial. This means its internal ply cords bear radial orientation, and you can guess what diagonal or bias ply means!

Load Index

These are the two or three digits after the digits representing the rim diameter on which the tire should be mounted. It shows the maximum load the tire can bear when fully inflated.

For example, the figure can be 94. This means the tire is rated for 1,477 pounds. There is always a look-up chart to help you decipher this information.

Speed Rating

The last letter on the tire’s sidewall represents the rated speed. It is the top speed at which it is still safe to travel for a sustained duration.

The speed rating ranges from A1 to (Y) from the look-up chart. For example, the letter P represents a top speed rating of 93 miles per hour.

Tire Type or Application

The first letter in the code represents the tire type or its application. A typical code may include P for passengers, LT for light trucks, or ST for special trailers.

P-class tires are fitted on cars, SUVs, crossovers, minivans, and smaller pickup trucks used as passenger vehicles. On the other hand, LT-class tires are designed for vehicles that carry heavy loads or tow trailers. You often find these on ¾ or 1-ton trucks and SUVs. ST tires are designed for heavy-duty trailers, boats, and utility trailers.

A full tire specification can be given as LT 305/65R17 94 M. This information can be decoded as follows:

LT – the tire is used on light trucks

305 – tire’s width is 305mm or 12 inches

65 – aspect ratio or profile, which is 198 mm or 7.8 inches

R – the internal ply cords are radially oriented

17 – the diameter of the rim of the tire to be mounted is 17 inches or 432mm

94 – the loading index, which should be 1,477 pounds

M – rated top speed, which should be 81 miles per hour

305/65R17 Replacement Tire Sizes

A replacement tire should be within 3% of the tire’s overall diameter. This means you can choose a tire with the width or profile you prefer, provided it fits the rim it is to be mounted. So, what can be the best alternatives to 305/65R17 tires?

You can use the following tires as the best replacement for 305/65R17:

• 295/65 R17
• 345/55 R17
• 275/70 R17
• 275/70 R17
• 305/65 R17
• 305/65 R17
• 265/75 R17
• 285/70 R17
• 235/85 R17
• 225/90 R17
• 255/80 R17
• 215/95 R17

Final Thoughts

305/65R17 tires have many applications. It can be fitted on most cars with rim diameters of 17 inches. By dimensions, the tire is 12 inches wide and has a profile of 7.8 inches. It is crucial to note these parameters if you are looking for a replacement tire.

Alternatives to 305/65R17 tires exist. These can be fitted on the same rim size but vary in width, profile, and overall diameter. Choose them wisely to get the best out of the tire while on the road.