Tyres

This could be the only reason why you like to go to tyre workshop.

Time for some honesty: when you're looking for a new set of tyres, you buy the cheapest set you can get away with, right? Most drivers are savvy enough to know that dirt cheap tyres probably aren't worth the risk, but how many of us can honestly say we really consider much more than cost?

Defective and badly worn tyres, a contributory factor in road accidents

Tyres are the ultimate forgettable products and their importance overlooked and yet they are a major contributory factor in many road accident. It is only a small surface contact on the ground which make a quality tyres inportant.

WHEN TO CHANGE

A Michelin Man/ triangle figure on the shoulder of Michelin tyres shows the location of the tread wear indicators situated in each of the main grooves of the tread.

Michelin Man/ Triangle Indicator

Small Raised Area

These indicators are small raised areas at the bottom of the grooves of the tread patterns

If the surface of the rubber is at the level of these raised areas, the tyre is most likely very close to the safe limit of 1.6 mm, or could even be below it! Use of worn-out tyres increase the probability of tyre failure, and in wet conditions can cause the tyre to lose traction suddenly. In most countries, it is illegal to drive with less than 1.6mm of remaining tread depth.

Fuel consumption
According to Michelin, up to 20% of your car's fuel consumption can be attributed directly to the tyres - that's one whole tank of fuel in every five.

Low rolling resistance tyres are becoming standard fit on eco-cars now, because the less an engine has to work against the friction of the tyres, the less fuel it uses. Michelin claims that since the launch of its Energy Saver tyre in 1992, it has been responsible for saving 184 million litres of fuel.

Rolling resistance on a road is largely the result of a tyre 'deforming' and springing back into shape, generating heat and dispersing it as lost energy. Avoiding this as much as possible, without compromising a tyre's grip, is key.

Safety
Tyres made of steel would roll on for miles on a flat, smooth road, but wouldn't be much good around corners. That principle applies to rubber: if the rubber compound of your tyres is very hard, rolling resistance is lowered, but so is grip, making braking distances longer.

All tyre makers face the same issue. The trick to getting the right balance of grip and fuel economy is in the rubber mixture itself. Michelin's mix is a secret, like the recipe for Coke, but it involves adding a substance called carbon black - which dissipates heat from the tyre - and silica, a hardening substance found in glass.

Wet weather
Braking distances and cornering grip are massively affected by wet weather, which is why the tread pattern of a tyre is so vital. The actual contact patch between a tyre and a road surface is only about the size of your hand - a fact that makes it easier to understand why it's so easy to skid in wet weather.
Therefore, it's vital that a tyre is able to clear water from the road as it turns, so that the contact patch effectively hits a dry area. This is possible with a good tread design, which in Michelin's case shapes the contact patch like the pointed bow of a ship, directing water away from the tyre to the sides.

Longevity
Cheap tyres are a false economy because they simply don't last, says Michelin. Tyres are no longer legal when any of the tread blocks are worn down to 1.6mm.

A host of different factors affect wear, but tyre pressure, suspension geometry and a car's weight do so most obviously. You can't do much about the latter, but it's imperative that you check pressure regularly - too much and the middle of the contact patch will wear quickly, too little and the outer edges will.

Tyre ratings
The way tyres will be rated and ranked in 2012 isn't finalised yet - discussions are still ongoing - but it will likely grade tyres on an A to G scale, where A is excellent.
Wet weather grip, fuel efficiency and road noise will be graded separately, allowing consumers to find a tyre that best fits their needs.

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Q- Up to 100mph

R- Up to 106mph

S- Up to 112mph

T- Up to 118mph U- Up to 124mph

H- Up to 130mph

V- Up to 149mph W- Up to 168mph

Y- Up to 186mph

Z- 149mph and overTwo important notes when considering speed rating:

• We do not recommend downgrading the speed rating of your tires. This may result in poor handling and unpredictable steering. However, if you want better cornering response, there is no problem installing a higher speed rated tire on your vehicle.

• Never mix and match tires with different speed ratings on your vehicle. This will cause serious problems with the handling of your vehicle.

Above is a list of speed ratings along with the corresponding speeds they represent. Remember, the speeds are test speeds, not recommended speeds.

Take good care of your tyres unless these sweeties are there to help.