OTR Tire Size Markings Explained: 23.5-25, Ply Rating and TT/TL

Ordering OTR tires becomes much easier once you can read the sidewall. The markings look technical, but they follow a simple logic that has been used across the industry for decades.

Reading a Size Like 23.5-25

In the size 23.5-25, the first number (23.5) is the approximate tire section width in inches, and the second number (25) is the rim diameter in inches. The same logic applies to 17.5-25 or 20.5-25. So a 23.5-25 tire fits a 25-inch rim and is about 23.5 inches wide.

Ply Rating (PR)

You will often see markings like 12PR, 16PR or 24PR. Ply rating does not mean there are literally that many layers of fabric; it indicates the strength and load capacity class of the casing. A higher PR means a stronger, heavier-duty tire for rougher applications.

TT and TL

• TT (Tube Type): the tire needs a separate inner tube to hold air. Common for bias OTR tires and motorcycle tires.
• TL (Tubeless): the tire seals directly on the rim, fewer parts and fewer puncture-related downtime events.

When you request a quotation, always confirm size, PR and TT/TL together. If you are replacing an existing tire, the fastest way is to read all markings on the sidewall and send us a photo, and our team will match the correct product.