Trailer Tires

A very common problem is that customers are uncertain how to interpret the sizing and specifications on the side wall of the tire. To make things even worse the industry uses three different systems for sizing on trailer tires which can confuse buyers.

The three systems are:

• The Metric System - Although currently being phased out by tire manufacturers some still use a format similar to this: ST205 75D 14. This indicates the type of application (ST - Special Trailer) the width of each section (205mm) the aspect ratio (75) the type of construction (D bias ply) and the diameter of each rim (15 inches).
  

• The Alpha Numeric system - (B78 x 13) This system is found most often on trailer tires sized 13-15 in. This system indicates the size of the air chamber (B) the aspect ratio (78) and the diameter of the rim (13 inches)
  

• The Numeric System - Mostly used for smaller tires and trailers, this format basically indicates the width and diameter of the tire section. (4.80 x 8) Where 4.80 is the width and 8 is the diameter.
  

When selecting a rim carefully choose replacements that match your trailer's hardware. The wheel bolt circle pattern must match the hub of the axel. You can determine the bolt circle

The selection for your rim is also an important key component of matching your own trailers equipment with your replacement wheels. Look for the 'bolt circle' pattern and match it to the axle hub.

The load range is the total maximum weight that each tire can support is one of the most crucial parts of selecting the proper size for your needs. The information you need can be found on the side wall of the tire. Load ranges some in three main types:

• B - old 4 Ply Rating
• C - old 6 ply Rating
• D - old 8 ply Rating