Automotive Marketplace

tire safety

Dennis DesRosiers May 28 2001
Automotive Marketplace

tire safety

Dennis DesRosiers May 28 2001

tire safety

Automotive Marketplace


Dennis DesRosiers

The recent Firestone tire tread separation problems have thrust tire safety to the forefront of public attention. To the credit of Firestone and Ford — on whose cars most of the tires were sold — the suspect tires were recalled and replaced free of charge. If any overall good has come of this well-publicized tire failure situation, it is in raising the awareness of the importance of good tires and the very real need for regular inspection and proper maintenance.

Most safety experts believe that tires are the most critical operating component of a vehicle. Let’s face it, without tires, your vehicle doesn’t move an inch. Essentially, the tires are the means through which the driver actually operates the vehicle on the road. Additionally, tires help keep the vehicle upright during cornering, they stop the vehicle, they keep you from sliding off slippery roads, and they determine acceleration, steering, control and braking. All of this is accomplished with only a very small area of the tire actually tracking the road — an area about the size of a small paperback book.

Surveys indicate that tires are the most neglected item on a vehicle. Given this lack of attention to tire safety it is surprising that we don’t hear of many more tire problems.

Yet since the demise of the full-service gas station, few drivers think to regularly check their tires for conditions such as tire pressure, unless of course the tire is almost flat and then it is too late. Tire pressure is important A tire's rotation causes friction, which produces heat. Feel your tires when you stop and see for yourself how hot they can get. This heat is normally dissipated by airflow and tire design. If under-inflated, tires can overheat breaking down the chemical bonds that keep a tire together This is when they fail.

If you over-inflate your tires, you start diminishing the size of the contact patch and the tires’ ability to stick the vehicle to the road. These over-inflated tires also give the vehicle a harsher ride. In fact, an over-inflated tire can explode if it hits a hard object like a curb. In addition, tires also operate in a very harsh environment They rotate hundreds of times a minute, running on uneven roads, hitting potholes, driving through rain and snow and mud and they have to be reliable during the extreme heat of summer and cold of winter

Surveys indicate that tires are the most neglected item on a vehicle. Given this lack of attention to tire safety, it is surprising that we don’t hear of many more tire problems. The tire companies deserve a lot of credit for producing tires that can withstand extreme abuse and still operate reliably. Since our lives depend on them, consumers’ ability to trust the integrity of tire manufacturers is paramount. Tines are complex assemblies, made of multiple layers of

rubber nylon or other fabrics and steel cords. According to Yokohama Tire, there are five key elements to tires:

1 > Treads are designed to pluck water, dirt

and other substances from between the tire and the road and channel them away from the contact patch where the tire meets the asphalt.

2 > The Belts are made of steel cable and are

designed to hold the tires’ round shape.

3> The Body Plies are made of fabric cord or steel cord and are designed to wrap the tire from bead to bead to give it lateral strength.

4> The Bead provides an airtight seal against the wheel.

5> The Side Wall gives the tire flexibility when cornering.

■ ■ ■ irtAA

The tire companies meet their responsibility by producing quality tires. Maintaining tires, ensuring proper tire inflation and checking for wear and tear is the responsibility of consumers. Poor alignment of a vehicle’s steering and suspension creates more heat and wear and tear in the tires. Maintaining proper alignment is the responsibility of the consumer A visual inspection that shows part of a tire’s tread is wearing out faster than others, or that one tire is wearing out faster than the rest, can be an indication of improper inflation or misalignment or even internal tire damage.

There is a simple inspection solution for consumers. Every time you bring your vehicle in for maintenance, ask your mechanic or service adviser to inspect your tires — including the spare tire — for damage and to inflate your tires to the proper level. Your life may depend on it The do-it-yourselfer should carry a portable tire inflator that plugs into the vehicle’s accessory port or lighter socket, a flashing red warning light, gloves, a tire pressure gauge, a ruler to measure tread depth and some clean rags. And then remember to check the tires every month or two. But most consumers should simply ask their local mechanics to do this.

I also believe that for most drivers, it is best to replace

tires with the same class and type that were originally on the vehicle when ft was bought new.Tires are a series of compromises.The various elements of traction, ride comfort, tread life, heat and speed capacity, responsiveness and noise are all interactive. Improving one area usually results in decreased performance in another area. For instance, better traction reduces the tread life.The vehicle companies spend a lot of time matching the various elements of tire design to the specific vehicle. They know which tire is best for your vehicle, so why not use the same ones for replacement? A lot can be said though, for using winter tires instead of all season tires during the winter months. However; this involves buying an extra set of tires and going through the bother of changing them twice a year— something most consumers will not do.

What do all those numbers on the tire’s sidewall mean?

> A tire’s sidewall carries a lot of information including size, load rating, speed rating, maximum inflation pressure and classification for tread wear and heat


> Sidewall height is called the aspect ratio and is measured as a percentage of the tread width. For instance P235/75 R16 is a passenger tire (P) 235 mm wide with an aspect ratio of 75 per cent.

The R stands for radial construction and the 16 is the inside diameter of the tire.

> Temperature ratings are marked A, B or C with A being the best.

> The speed ratings are marked S, T, H and Z with

S the lowest rating then T, H and Z. An S-rated tire is safe up to 190 kms per hour. A Z-rated tire is safe up to 240 kms per hour.

> Traction is rated AA, A, B or C with AA being the best.

Although tire failure is rare, there are some specific things consumers can do to prevent problems.

> Have a tire inspection every time your vehicle is in for service. Have them check for cuts, gouges and bumps in the sidewall that may indicate problems and — of course — proper inflation.

> Rotate them every 10,000 kms.

> Replace them when tread depth falls below a 1/16th to 3/32nd of an inch.

> Immediately fix a tire that is under-inflated.

> If you have a flat, immediately get to the side of the road. Remember that changing a flat at the side of a busy road is extremely dangerous. Call your CAA club for assistance.

> Aerosol flat repair products are only temporary, so be sure to get the tire properly repaired as quickly as possible, and never drive fast if you have used a can of one of these chemical fix-it products.

> The best thing to do when you have a flat is to put the spare on.