How to Read Bias Tyre Markings: From Ply Construction to Load Index

The regulatory landscape for operating safe and secure vehicles is becoming increasingly complex. While tyre manufacturers are ensuring efficiency, quality, reliability, and safety, users must know what they are getting with their tyre purchase.

The marking on the tyre sidewall includes different data that might seem difficult to understand at first glance. However, these numbers and markings hold immense significance, describing the tyre’s capability, safety measurements, speed ratings, and so on.

We have crafted a guide to help you understand how to read tyre markings. Go through this article to thoroughly understand how to read the markings on your tyre’s sidewall.

What do the Numbers on Your Sidewall Mean?

It’s critical to understand the meaning behind the tyre sidewall markings. These numbers are indicators of the manufacturer’s instruction, the tyre’s specification, and tyre safety and performance markings. Both drivers and owners of logistics fleets must understand the meaning of sidewall markings to ensure the safety and efficiency of the vehicle’s performance.

Major Components of a Tyre Sidewall Markings

The following are the key components of tyre sidewall marking to familiarize with if you want to learn how to read tyre marking:

Width

The sidewall marking includes the width measurement of the tyre. This measurement is taken from the sidewall to the outer wall of the tyre.

Aspect Ratio

The aspect ratio of the tyre is the height of the sidewall expressed as the percentage of the tyre’s section width.

Tyre Construction

Tyres go through different methods of construction. Many heavy-duty and off-road commercial tyres use bias-ply construction, while radial tyres dominate highway haulage and passenger segments. A tyre with such construction would have “–” (dash) marking instead of an ‘R’ which is the marking for radial tyre construction.

Radial tyre design is common among passenger vehicles. Here, the tyre has the design marking ‘R.’ It’s the most common marking approach for passenger vehicle tyres.

Rim

The rim diameter of the wheel comes in inches. If you’re buying the rim for existing tyres, you’ll need to check the rim diameter. Rim diameters vary widely by application – from 14–20 inches in trucks to 25–61 inches in OTR.

Load Index and Speed Symbol

The load index of a tyre shows how much weight it can bear, while also safely operating at a specific speed. The index also suggests the tyre’s load-bearing capacity, while maintaining the instructed inflation pressure with proper fit.

Other Important Sidewall Details

Manufacturer’s Name: Birla Tyres branding is clearly visible on the tyre’s sidewall. The sidewall shows manufacturer branding, such as Birla Tyres and Country of make.

DOT Code: It’s a sequence of letters or numbers starting with “DOT”, including the manufacturing date and location. This code outlines the tyre’s size, location of manufacture, and its unique identifier for the manufacturers to find out the year and month of the tyre’s production.

Tread Pattern Name: The tyre’s sidewall marking might as well include the tread pattern design. The pattern names are typically rib, lug, mixed, or herringbone/traction for agricultural tyres.

M+S indicator: This indicator shows if the tyre is designed for muddy, snowy, or standard conditions in summer.

3PMSF (Three-Peak Mountain Snowflake): This marking suggests that the tyre has passed the objective testing for winter conditions. A 3PMSF marking indicates winter performance capabilities in off-the-road-tyres common in passenger/LT tyres. But, it’s a rare marking to spot on an off the road tyre.

Tubeless (TL): This marking is the indicator of a tyre being tubeless. It suggests that the tyre requires no tubes.

Run-flat: This marking is indicative of a feature. It means that the tyre can run flat after driving for a limited distance.

P-Metric: Passenger car tyres have this marking on the sidewall.

LT (Light Truck): Pickup trucks, SUVs, and minivans can have these truck sidewall markings.

How to Read Birla Tyre Markings? With Examplex

The tyre sidewall markings are printed in contrasting colours and clear fonts. A typical example of the tyre’s sidewall marking would look something like this: BIRLA 10.00-20 14PR BIAS PLY 160/157K. It’s an example of Birla Bias Ply tyre marking. The marking stands for:

BIRLA – This stands for the name of the Birla Tyres brand.

10.00-20 – This number denotes the tyre size, consisting of the approximate width of the tyre (10.00), and the diameter of the wheel rim in inches (20.00), designed to fit.

14PR: This mark denotes the Ply Rating, which is a measure of the tyre’s strength and its capacity to carry weight. The term 14PR means that the strength of the tyre is similar to that of 14 plies of fabric, as in the older tyre construction process.

BIAS PLY: This describes the construction of the tyre “Bias ply”. It means that the layers of fabric within the tyre run diagonally from one bead to another. It helps form a criss-cross pattern.

160/157: The load-bearing capacity of the tyre is also included on the tyre mark engraved on the tyre sidewall design. The marking 160 stands for single tyre load index, while the 157 marking stands for dual tyre load index.

J = 100 km/h: This marking suggests the maximum speed at which the tyre can deliver its optimum performance.

Having a proper understanding of the tyre’s sizes and features helps maintain vehicle performance at intended road conditions and drive safely.

How to Read Tyre Markings: Guide for Reading Different Components

You can expect the following measurements on different Birla Tyres products. Here’s a list of different parameters of the sidewall marks for Birla Tyres. Understanding these elements will help decode what a specific tyre’s sidewall marking means:

Disclaimer: The load index shown here is indicative and it varies by size.

Visual Inspection of a Bias Tyre Sidewall

Whether purchasing a bias tyre or simply trying to understand “how to read tyre markings,” the instructions in this article must help. Look for BIAS PLY or BIAS marking on the tyre's sidewall to confirm if it has a bias construction or radial construction.

Additionally, check out the load index, speed rating, and DOT serial number. Here’s a simple, yet useful way of inspecting bias tyre sidewalls for your understanding:

Knowing these terms to check the tyre's design would greatly help in identifying its capacity and safety parameters. Let us know if you have any other queries about tyre sidewall markings. Check out our other blogs about ‘what tyre sidewall markings mean’ to have a more detailed understanding of the terms engraved on your tyre’s sidewall. Thank you for reading.

FAQs

How to identify bias tyres?

A: When trying to identify a bias tyre, observe if the sidewall runs diagonally from one bead to another bead. Additionally, it features different rubber-coated fabric plies running at angles to each other and to the tyre's centre line.

What does LT mean on a tyre?

A: The word LT stands for Light Truck. It's used on the sidewall of the tyre. When a tyre has this marking, it means that the tyre is specifically engineered to work with light trucks, full-size SUVs, and vans. It also includes a load capacity marking of 1/2 ton, 3/4 ton, or 1 ton.

What does "-" mean in Bias Tyres?

A: “The dash (–) indicates bias construction, unlike ‘R’ for radial.” The internal layers get arranged in a straight line from one bead to the other under such constructions.