Tire Size Conversion Calculator: Tire & Wheel Plus Sizing

So, it’s time to buy new tires for your vehicle that are quite damaged due to excessive drive. The best way in this situation is to consult with any retailer of tires but you also should know about the product which you are going to buy. Before buying any tires, you should know what type of tires are appropriate for your vehicle.

The size of tires also matters. This article is composed to make people aware of different sizes of tires and also tire sizes fitting to the rim. It is a requirement of a car and other vehicles to match the tires with the old tires which you are going to replace.


Usually, we never notice about the numbers written on the tires but these numbers are having a bulk of information in them. Let’s read the article further for more information about the tire sizes.

Types of Tire Size Measurement

There are two types of tires measurement sizes.

  1. Metric
  2. flotation

Somehow, it is quite difficult to understand this measurement. Lets try to understand it by starting it with Metric.

1. Metric:

There are five sections of Metric sizing.

First Alphabets

1.1 First Alphabets

First one or two alphabets in tires stand for different categories of tires.

LT : Light Truck:   P : Passenger car tires:   ST : Special Trailer   T : Temporary car tires

1.2 Section width

Section width is about the measurement of tire in millimeters from sidewall to sidewall

1.3 Aspect ratio

The aspect ratio of a tire is about the height of a tire’s sidewall as a percentage of the width of the tire.

1.4 Radial Ply

A radial ply is a particular design of vehicle tires in which cord plies are arranged at 90 degrees to the direction of travel.

1.5 Wheel Size

The wheel size is the size assignment of a wheel given by its distance across, width, and balance.

2. Flotation:

Flotation tire sizing is much easier than Metric. In this sizing criteria, tires are measured by inches instead of millimeters. Mostly both tire sizes are equivalent and only the method of measurement is different.

Here, we have read about the sizing techniques, and now is the time to understand the different tire sizes fitting on different rims according to the needs. For this purpose, we need to understand rim diameters.

What Is Rim Diameter

The diameter of the wheel is about the distance of the tire and tube surface on which tire beads set. These are classified into certain categories.

Overall Tire Diameter:

SW – Section width: AR – Aspect Ratio: RD – Rim diameter: SH – Section height: CI – Tire circumference, RE – Revolutions per mile/km.

What Size Tire Fits a 15×8 Rim


Tire size depends on the size of the rim. When the diameter of the rim is 15 and the width is 8 the best tire size is 33×12.5. Its sidewall is 8 inches that are equal to the width of the rim. It is even connected from bead to the thread. This size has great protection overall for the rim.

What Size Tire Fits a 17×9 Rim

17x9 -rim

So, if you have a 17×9″ size rim you can run any 17″ tire. So you have a 17×9″ size rim you can run any 17″ tire. Space may be changed if you want a lifted tire or a more extensive tire. Other than that as long as they’re both 17″ is fine. This is a hybrent tire and it has a sidewall of 7 inches.

What Size Tire Fits 18×8 Rims

18x8 -rim

The overall diameter specs of this tire are 225/40/18 with an offset of 32. This is basically a stretch tire. 215 is the right tire for this rim size. The sidewall of this tire is small because the rim gets larger and the sidewall gets smaller.

What Size Tire Fits a 15×10 Rim

15x10 -rim

The size of the rim as we know is 15×10 and the tire size that fits this rim is 265/50R15. It’s a a10.5 sized wide tire even an 8″ rim is needed when you air down so the bead is not lost.

What Size Tire Fits a 17×8 Rim

17x8 -rim

235 and 245mm wide tires are fit for 17×8″ rim size. It’s a high performance tire. The sidewall of this tire is small because of its larger rim size.  205/45-17 is the complete measurement of this specific tire with +40 offset. It is an offseason tire that performs well in rain and snowy weather as well. It is also a harder tire with speed performance quality.

What Size Tire Fits a 20×9 Rim

20x9 -rim

255/45/20 tire size is best for the rim of 20×9. Its sidewall is a little stiff because of its small area rather than the area or width of 20×9 rim size. These are also called stretched tires. These are good tires for braking as well.

A Guide to Choose Right Tire Size for the Rim.

For getting the best tire for your rim of different sizes you need to measure the rim and tire sizes. You can see the 3 digital numbers on the tire followed by 2 digital numbers also flowed by the letter “R” OR “ZR” again followed by two digital numbers which are the same size of a tire. You can start this task with a measurement of the width of the tire. Also, measure the rim not from the edges but the point of beads. You also can take help from the tire size calculator for the selection of an appropriate tire.


As you all know, it’s really difficult to select a perfect sized tire on a rim. In this article, we have mentioned the types of tires and the measurement of tire sizes. There are also mentioned some rim sizes and the best selection of tires with a specific rim. This is a useful article that must be read before buying a tire. Different ways of measurements are also described in this article. This is quite a unique article with some aspects.

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