Car maintenance diy 1: Tyre facts that will help you avoid burst tyres and road accident

Car maintenance diy: Know your Tyres to avoid burst tyres or road accident
I am on a mission to educate you on the dangers of driving vehicles of not road worthy tyres: Operation Know your Tyre (KYT)
The sudden increase in road accidents has been attributed so many times by the federal road safety commission (FRSC) to expired or burst tyres. Yes! Car tyres, Those black rolling things  beneath your car sure have a lot to play in your vehicle's health. Last  Sunday, on my way to the Lagos Island, I witnessed a fatal accident, involving a BRT bus, a jeep and hilux vehicle, some said it was caused by overspeeding by one of the drivers, others said, the tyres lost traction when the  brakes were applied. Needless to say, some souls were lost. Now this got me wondering, What really causes tyre failure?

My friend, Chris Okafor was able to provide some answers:

Tyre information every driver and Vulcaniser should know 

As a driver, you cannot neglect the fact that you need to learn about car tyres and everything else about cars. When you own a car you will need to learn the basics on how to put your car moving, such as changing a flat tyre and light bulbs. These are the small things you can do as the owner of your car. However, when its time to change your tyres and you are unsure of the types of tyres then pay attention as we try to educate you on how to make the right choice from the different types of tyres and its usage.

Tyres are a very important part of a vehicle, they hold so much to the overall human safety on the road, hence when going to pick a tyre replacement, “shine your eyes” and be sure you pick the right one.

There is a wide range of tyres types and size available from popular brands such as Bridgestone, Dunlop, Goodyear, Michelin, and Pirelli. It pays to know what is currently on your vehicle and to learn about your options. There are three basic types of tyres—car, Light truck and truck, —and each has a few choices in each category. Running a tyre on a rim size not approved by its manufacturer can result in tyre failure and a loss of vehicle control which can as well result in casualties..

Here are a few tips on what to look out for when procuring a tyre.

(1) First and foremost. Don’t buy used tyres otherwise known as tokunbo tyres. They are no good the your vehicle neither are they good for your life. A tokunbo tyre must have been used by someone and discarded for several reasons. One of the reasons could be age, another could be bad pressure balance and other factors like worn threading and so on.

(2) Age
The age of a tyre is very important. Tyres (rubbers as they are) are designed to expire and this is also a factor why you should not buy tokunbo tyres. Tyres are designed to last a maximum of four years from date of manufacture. This means that if you buy a tyre that has spent 2yrs already before you buy it, even as new as it may be the tyre has about 1 or 2 yrs left to serve. The manufacture date of a tyre is usually written on the tyre inside a semi-oval shape. The first two numbers indicate the manufacture week while the last 2 numbers indicate the manufacture year. For example if you find 2310 on inside the semi-oval, it means the tyre was manufactured 23rd week in 2010. 23rd week in 2010 means June 2010 and even if the tyre is brand new right now don’t buy it as it is expired right on the shelf. Buy tyres that have at least 3yrs left to go. If you find out that the number written in the semioval is 3 digits, it means the tyre was made before year 2000 and please don’t go near as it is a death trap.

(3) Size:
Be sure the tyre you’re buying is what is meant for your vehicle. To be sure, check for a sticker by the driver’s side door of your car or the driver’s side seat belt. Manufacturers usually state the tyre size and pressure for your vehicle there. Here are some words and acronyms you might like to know their meanings:
If you ‘re buying a tyre and the word “P” comes before the tyre size, for example P215/55/15. The “P” means “passenger” which in turn means that the tyre is meant for passenger carrying vehicle like cars, minibus and smaller vehicles.
LT means it’s a light truck, this could be bigger busses and pickups.
S means “special trailers”. This are for heavy duty trucks and trailers and for earth moving vehicles.
T means is a temporary tyre. Not to be used for a long time or for long distances neither is it to be used on high speed. Examples of such tyres are the small tyre types that come as spares with some vehicles. They are not to be used beyond 80km/hr max, and not for more than 100km in a stretch.
In the tyre size, the first number indicates the width of the tyre at the widest point, 55 being the height of the side of the tyre is 55% of the width R — this is a radial tyre and 15 indicates that the tyre fits into a 15inch wheel. E.g P195/55R16H210
Sometimes some tyres have an “H” after the wheel size it indicates the speed index, this means the maximum permitted speed, here 210 km/h (130 mph). Please take note of the speed.

(4) Next is weather performance. Tyres are designed to work with different climates and its one of the reasons not to buy tokunbo tyres because some of them were made for snowy weather and will not work in our tropical region here.
many tyres have the mark “M+S” by the side indicating that it could work both in the snow or in the tropics. They’re good tyres and are usually the type that comes with your vehicle from the factory.
Winter tyres (snow tyres) often comes with small metal spikes, they are no good for our roads here and are very dangerous on high speed when the tyres are hot. Don’t buy tyres meant for winter seasons as they’re dangerous to drive on during high temperature.
SFI, or Inner: Side Facing Inwards; inside of asymmetric tyres
SFO, or Outer: Side Facing Outwards; outside of asymmetric tyres
TWI: Tread Wear Indicator; a device, such as a triangle or a small Michelin Man icon, located where the tread meets the sidewall. It indicates the location of the raised wear bars in between the tyre tread channels.
LL: Light Load; tyres for light usage and loads

If you're in the market for new tyres, you need to understand the different types of tyres on the market. Don't take advice from just anybody ---doing a little research yourself generally saves a lot of money. Learn the differences between mud tyres and snow tyres, and which kinds of vehicles need studded tyres. Don't forget the all-important spare tyre, for safety's sake. Car tyres come in several types for a reason: different cars have different needs in different situations.

High-Performance Tyres
If you're shopping for tyres for your sports car or if you do a lot of highway driving, then high-performance tyres are what you're after. High-performance tyres use a softer rubber compound for increased traction, keeping you on the road when you're cornering at high speeds. The softer rubber also makes the tread life shorter. You'll need to replace high-performance tyres more often than other types of tyres. Experts don't recommend using high-performance tyres in inclement weather.

Spare Tyres
Those compact spare tyre isn't designed for long-term use. Experts recommend it for emergency usage only. However, prolonged use of a compact spare tyre can put too much pressure on your other tyres, leading to unnatural wear and tear. You also shouldn't drive at highway speeds using a compact tyre. Use a compact tyre to transport yourself to a tyre shop and repair the flat tyre or blowout that caused it. It is better you use the regular tyre size for your spare tyre so that when you need to have a change on tyre on the highway it won’t be an issue. Driving on a flat, even with run-flat tyres, is never recommended. Have the tyre repaired as soon as possible.

Types of tyres
1. All-season tyres
comes in sizes to fit everything from small cars to full-sized SUVs and pickups. They are for drivers who want year-round traction, long tread wear, and a comfortable ride. But they typically lack the precise handling and grip of performance tyres.

Speed Ratings: None, S (112 mph), T (118 mph)
Tread-wear warranty: None or 40,000 to 100,000 miles
Typical wheel size: 14 to 16 inches

2. Performance all-season tyres

have a higher speed rating than standard all-season tyres. They generally provide better handling and braking, and usually have a lower profile (shorter sidewall height) and a wider footprint for sportier applications.

Speed Ratings: H (130 mph), V (149 mph)
Tread-wear warranty: None or 40,000 to 60,000 miles
Typical wheel size: 15 to 17 inches

3. Ultra performance tyres
are commonly fitted to upscale sedans or sporty vehicles. These tyres are designed to provide good handling and responsive steering in wet and dry conditions, but the tread wear and ride comfort are common compromises. All-season versions tend to provide a compromise of dry and wet grip relative to summer tyres for all weather conditions.

Speed Ratings: Z (more than 149 mph), W (168 mph), Y (186 mph)
Tread-wear warranty: None or 30,000 to 40,000 miles
Typical wheel size: 17 to 22 inches

4. Truck tyres
Because of their size, dynamics and how they are used, trucks and SUVs often require special tyres. Some automakers advise sticking with the tyre type that the vehicle originally came with. Consult the owner's manual to see if a specific type is recommended. You can often improve road handling by switching from an all-terrain tyre to an all-season.

The tread is the part of the tyre that comes in contact with the road surface. The tread is a thick rubber, formulated to provide an appropriate level of traction that does not wear away too quickly. The tread pattern is characterized by the geometrical shape of the grooves, lugs, voids and sipes. Grooves run circumferentially around the tyre, and are needed to channel away water. Lugs are that portion of the tread design that contacts the road surface. Voids are spaces between lugs that allow the lugs to flex and evacuate water.. Sipes are valleys cut across the tyre, usually perpendicular to the grooves, which allow the water from the grooves to escape to the sides in an effort to prevent hydo planning. Specialized tyres will always work better than general/all purpose/all weather tyres when being used in the conditions the specialized tyres are designed for.

When shopping for tyre, be sure you are picking the right size, right age, right purpose tyre so it can server you the right function and keep you safe. Have a safe motoring in the “ember” months.

Tire Pressure
Tire pressure is a measure of the amount of air in a vehicle's tires, measured in pounds per square inch (PSI). it is imperative to check a tires' pressure often with a pressure gauge, at least twice a month, if not more frequently. Having the proper tire pressure is a crucial safety issue. Next to the brakes, the tires are the most important safety devices on your car. Incorrect tire pressure will compromise cornering, braking and stability. And in the worst-case scenario, improper tire pressure can lead to tire failure — and a serious accident. Incorrect tire pressure also will affect your comfort, fuel economy and tire life span.

If tire pressure is too high (over-gauged), then less of the tire touches the ground. As a consequence, your car will bounce around on the road. And when your tires are bouncing instead of firmly planted on the road, traction (grip) suffers and so your braking /stopping distances (this means when you apply your brakes its likely to roll more distances before it eventually stops). You'll also feel a decrease in ride comfort. Tires are designed to absorb contours as they roll (RCO - Rolling contour optimization), this allows tires to fold in when it climbs a bomb or stone instead of bouncing up and down. If your tire is too tightly pumped, it is not likely able to absorb pressure when you hit a pot hole suddenly and is likely to burst.

Now, If your tire pressure is too low, then too much of the tire's surface area touches the ground, which increases friction between the road and the tire. As a result, not only will your tires wear out prematurely, but they also could overheat. Overheating can lead to tread separation — and a nasty accident. One sign of low tire pressure is if your tires squeal when cornering. And you need to check your tire pressure even if your tires aren't leaking. Why? Because tire pressure also changes with the temperature outside. Tire pressure decreases by about 1 pound per square inch for every 10-degree drop in outside air temperature. So if you last had your tire pressure checked in February, when it was 80 degrees outside, and it's now June — and the temperature is 30 — your tires may be under inflated by 10 pounds, which is dangerous.

Now, on very high speed, especially is you are moving above 80km/hr, tire pressure is very important. At that speed, every weight and vehicle balance is important. That is why often when a tire burst, especially if it’s the front tire its important you don’t step on your brakes until the speed is drastically reduced. This is because once you step on the brakes, the weight of the vehicle is pushed to the front (which is what occurs normally) but on high speed its very dangerous, the weight of the vehicle is pushed to the front and with the vehicle imbalance due to one side being down the vehicle swerve (swings over) to the direction of the deflated tire and in trying to bring it back to centre the vehicle is likely to summersault. Disaster that would be!

How do you determine the correct tire pressure for your car's tires?

A lot of people check the pressure listed on the tires themselves, but that's actually the wrong place to look. The number on the tire (i.e what manufactures put there) is the maximum allowable air pressure the tire can take — not the recommended pressure for that tire when used on your vehicle. The recommended tire pressure is almost always lower than the maximum tire pressure. Check your owner's manual to find out where to look on your vehicle to find the recommended measurement and if you did not buy your vehicle new and can’t find the manual, check the driver side door area or the vehicle safe (the safe facing the passenger seat in front).

Once you know the manufacturer's recommended tire pressure, then you need an accurate tire gauge to check the tire pressure. Some tire gauges, such as the popular pencil-style gauge (the type many vulcanizers use), are notoriously inaccurate. Analog, dial-type gauges or digital gauges tend to be fairly accurate.

You should check it when the tire is cold. That doesn't mean you wait for harmatan or when it rains, to check your tire pressure. Cold, in this sense, simply means that your tires are at air temperature. You can check tire pressure any time of the day, as long as the tires have been sitting for a few hours or haven't been driven for more than a few miles. In other words, you can drive to the petrol station a few blocks away and ask them to check the pressure, but don't expect to pull off the highway after driving for an hour and expect to get an accurate reading, no.

When you check your tire pressure, remember to check all four tires. Just because three of your tires are at ok doesn't mean that the fourth tire isn't nearly flat.

Finally, check the spare tire at least once in a while — it would be an unpleasant surprise to find it flat when you need it (that’s if you’re not in the middle of no where). If you have a small, space-saver spare, then the pressure for that tire is probably not the same pressure as your regular tires. The correct tire pressure should be printed right on this particular type of spare. if you have no known problems with your tires, check your vehicle's tire pressure seasonally or before you head off on a road trip. When you bring your car in for service, ask them to check the tire pressure; most garages will do this at no additional cost. Plus, they'll usually have an accurate gauge — which will also give you an idea of whether your gauge is correct.

Check your tire pressure even if your tires look fine. Radial tires can be deceiving (they're sneaky little guys). They may look fine even when they're down 10 pounds of air — or overinflated by 10 pounds. So don't trust your eyes — use your gauge.

To be continued...........
Causes of bursts
Tyre speeds - Maximum and minimum speed
Under inflation and over inflation of tyres
Tyre sizes and effect on fuel consumption


Chris Okafor said…
Great work Christie,,, keep the good work up