Car Basics - Tire Basics

Want to know more about tires, especially their history and types? Then look no further and read all about them in this page!

Tire Basics


Table of Contents

  1. Introduction
  2. Four Basic Functions of a Tire
  3. Basic Tire Constructions
  4. Different Tire Tread Patterns
  5. Tire Size Label Description
  6. Important Things to Consider in Choosing the Right Tire for your Vehicle

Introduction

Tires or tyres (can be spelled interchangeably, Tire is from American English while Tyre is from British English.) are pressurized gas enclosures used to protect and enhance the effect of wheels.

Tires can be found on all types of vehicles, from motorcycles to cars to airplanes. Tires allow vehicle performance by providing for traction, braking, steering, and load support. Tires are inflated with air, which provides a flexible cushion between the vehicle and the road that smoothes out shock and provides for a comfortable ride quality.

Knowing more about your tire helps you save more. Having the right inflation pressure, proper wheel alignment, and constant monitoring of tire wear to ensure the lowest tire cost per kilometer is achieved.


Four Basic Functions of a Tire

The pneumatic tire out-performed the solid tire because it is fundamentally a toroidal (doughnut) shaped flexible pressure vessel. It is the contained air - not solid rubber - that carries the load.

Today's tires are high technology products which are manufactured in various constructions and a vast range of sizes but they still have to carry out the same four basic functions. These are:


Basic Tire Constructions

Pneumatic tires are currently made in two fundamentally different constructions - bias ply and radial ply.

BIAS PLY

Bias ply tires have casings made from layers of 'plies' of parallel textile cords which run diagonally from bead to bead. The cords are arranged so that alternate layers are on the opposite hand and cross each other at an angle of between 70 and 80' to form a trellis like structure.

RADIAL PLY

Radial ply tires have the casing cords run directly from bead to bead radiating outwards like the spokes of a wheel.

Because the cords do not cross each other the casing is more flexible. The structure is stabilized by a belt formed of layers of cords laid right around the casing just under the tread rubber. The belt cords are placed at a low angle to the centerline of the tread and alternate layers cross each other at angles ranging from 30 to 45'.


Different Tire Tread Patterns

There are the four basic tire tread patterns:

Type Rib Block Rib-Lug Lug
Pattern
Profile

Grooves flows along the circumference of a tire.

Patterns in which individual blocks are arranged.

Combination of rib and lug patterns.

Grooves flows in a lateral direction.

Feature
  1. Superb driving stability.

  2. Fewer rolling resistance.

  3. Fewer noise generation.

  4. Superior water drainage performance.

  5. Less skidding.

  1. Excellent drive and braking forces.

  2. Superb driving stability on normal paved road.

  1. Rib-type pattern acts to increase driving stability, and to prevent skidding.

  2. Lug-type pattern acts to transfer traction drive and braking forces effectively.

  1. Excellent drive and braking forces.

  2. Stronger traction force.

  3. Better resistance to cut.

Applications

Best for driving on cemented roads and highways.

Good performance when driving on normal cemented roads

Suitable for driving on normal cemented roads and uncemented ones at a middle/low speed.

Suitable for driving on normal cemented roads, and uncemented ones, suitable for work sites such as a building site.


Tire Size Label Description

On the sidewall of a tire, its size, performance, etc. are shown by using numerical symbols.

Passenger Car Type

185 / 65 R 14 86 H
185 Section Width (millimeter)
65 Aspect Ratio (%) = Sidewall Height computed as 65% of 185mm
R Radial Construction
14 Rim Diameter (inch)
86 Load Index
H Speed Symbol

Truck Tyres

10.00 - 20 18PR
10.00 Section Width (inch)
- Bias Construction
20 Rim Diameter (inch)
18PR Ply Rating
86 Load Index

Important Things to Consider in Choosing The Right Tire for your Vehicle

SAFETY FIRST

Make sure that you choose the proper tire based on your application. Understand the Load capacity and speed limit of your tire.

Choose brands that passed the quality standard of the government. (For Philippine residence, check the ICC or PS markings)

COST PER KILOMETER

Cost per kilometer would be a good consideration in choosing your tire. It would make no harm to try different brands as long as they give warranty and has passed government quality standards. Try to make an index card for each tire. Record the life span of the tire in terms of mileage. It would be better if you could have a hub odometer installed on your tire. After obtaining all the data, compute its cost / kilometer.

WORD OF ADVICE

Every fleet is unique. Try to find the most suitable tire for you. Don't hesitate to experiment. Tire technology improves everyday. Many brands are being introduced every now and then. Road condition differs each year. It would be wise to find the right tire for your operation. After finding it, do not stop entertaining new brands. You might find something better. In return, you save more.