How to Measure for a Spare Tire Cover

How to Measure for a Spare Tire Cover

A spare tire cover is more than simply throwing a piece of canvas over your spare tire. It provides major advantages that will benefit any vehicle owner in the long run. These covers serve as a protection of sorts for the spare tire, most especially from damage caused by UV rays from the sun and extreme weather conditions. Over time, exposure to these elements can cause cracks in the sidewalls of the tire and weaken the rubber. One great thing about these covers is that they do not need any maintenance.

Measuring for a Spare Tire Cover

To find the right size for your tire, the simplest and most logical way is to measure the distance from the top of the tire to the ground.

Reading Tire Sizes

Another way is to refer to the size information branded to the sidewalls of each tire. The tire sizing information may seem overwhelming at first, but they contain invaluable pieces of information, namely, the vehicle type, section width, aspect ratio, tire construction, wheel diameter, load index, and service description.

These tire sizes can be written in three different ways – in metric conventions, numeric conventions, or alphanumeric conventions.

  • Metric. If a tire uses the metric way of writing, you will see the information that may look similar to this – P225/70R16 97H or ST175/80R13 LRD. Let’s break these figures down:
  • Tire Type. The first letters in the code tell you the class of tire. P stands for passenger vehicle tires, ST means special trailer, and there’s the LT, which stands for a light truck tire.
  • Tire Width. The three digits following the tire type indicate the tire’s width in millimeters. This measurement is taken from the inner sidewall to the outer sidewall.
  • Aspect Ratio. The two-digit aspect ratio is separated from the width numbers by the forward slash. The aspect ratio is the relationship between the tire’s width and height. In the sidewalls, it is expressed as a percentage of the tire width. In the first example, P225/70R16 97H, it means that the sidewall is 70 percent as high as the tire is wide. To get the height, take the tire width of 225 mm and multiply by 0.70 to get the tire height.
  • Construction Type. The single letter, either R (Radial) or D (Diagonal) or B (Bias), tells you about the internal construction of the tire.
  • Wheel Diameter. The next two digits following the construction type show how wide the wheel is across the center in inches.
  • Load Index. The two or three-digit number that follows the gap indicates how much weight, in pounds, the tire can support when fully inflated.
  • Speed Rating. The last figure corresponds to the particular speed capability of the tire for a sustained amount of time. The higher the speed rating, the better the tire can handle the heat and provide more control at faster speeds.
  • Numeric. This is the oldest tire sizing system and most commonly used. An example would be 4.80 x 12B. This shows only the cross-section width of the tire, the rim diameter in inches, and the load index.
  • Alpha Numeric. This system was introduced in 1968 and provides the following information: the load rating, the tire construction, aspect ratio, and the wheel diameter. An alphanumeric tire sizing information would look something like this – FR70-14. 

You can see many people utilizing the benefits of spare tire covers, and you may have been hesitant about getting one. This article will not only let you understand the benefits of getting these covers but also how to measure for one.  

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