štvrtok 23. marca 2017

How to Determine When a Car Brake Service is Needed



Since brake pads (and shoes) are actually wear items and not maintenance items, they don’t need to be replaced at a specific mileage or time interval. However continues driving on brake pads that are worn out could result in additional component failure, resulting in additional repair expense. How much additional expense depends on how long the car owner takes to replace worn out pads, as well as the type of vehicle.

The Pitfalls of Worn Out Brakes

When the brake pedal is applied, the brake pads are hydraulically applied to the metal rotor. The pads have a material that wears as they are applied to the rotor. If the pads go unchecked, the wear material will eventually disappear and the pad will become bare metal. The bare metal on metal reaction can damage the rotor to the point they need to be replaced.

Due to the added heat caused by the metal-to-metal friction, other brake components could also be damaged. Some of the additional components that may be determinately affected include
  • rotors
  • drums
  • calipers
  • cylinders
  • bearings
Routine Maintenance and Brake Inspection

Naturally one of the best methods to determine if your pads need to be replaced is to have an automotive technician inspect them. The best time for a tech to inspect your brakes is when the tires need to be rotated during a routine maintenance visit. Most auto shops will inspect the pad thickness for free since they already have the wheels/tires removed for the rotation.

During an inspection, the pad thickness is measured (in inches or millimeters) and should be replaced if they fall below a specific measurement. The measurement can vary but usually should be replaced if they fall roughly below 3/32nds of an inch or 3 millimeters. If the measurement is greater than this amount the technician should give a rough estimated of how many miles are left on the pads.

Tell Tale Signs of Worn Out Brake Pads

Some (not all) vehicles have a wear indicator that will give an audible sound when the pads wear to the point they need replacement. More sophisticated vehicles may have a ‘visual indictor. The owner’s manual should indicate if a specific vehicle has brake wear sensors.

If the pads or shoes are worn down to the metal, a metallic grinding sound will usually result when applying the brake pedal. If this type of noise is apparent when the pedal is applied, the vehicle should be inspected immediately. A metal-to-metal condition will also result in less effective braking condition. This condition can often be felt when applying the brake pedal.

nedeľa 19. marca 2017

How to Choose Good Car Tires: The Technology Behind Tires is More Complcated than Most Think



So, a tire is a device to keep alloy wheels from being scraped on the ground? Guess again, because tires are by far the most important thing on a car. The four hand sized contact patches of rubber are the only things between a car and a crash, so it is advisable to always purchase the best tires that can be afforded.

Unfortunately the usual route taken by people wanting to dress up a car is to buy the best alloy wheels and then opt for the cheapest possible tires.

Construction of a Car Tire

A tire isn’t just a big hoop of rubber that keeps the air in. Each tire is constructed from many layers, and it is a laborious process to make a tire. First there is the basic carcass, which is the underlying structure of the tyre and the sidewalls. Over that is laid a sequence of belts, usually made of steel, to give the tyre strength and allow it to withstand punctures without blowing out.

It is the number and layout of these layers that gives the tire most of its flexing qualities. On top of these belts is laid the outer rubber of the tire, which is then stamped in a huge press with the tread pattern.

Why are There Patterns in Car Tires?

The best gripping tire is a racing slick, with no tread at all, but when the road gets wet the rubber will not grip anymore. The primary reason for the tread is to allow the water to run onto the grooves so it doesn’t get trapped between the tyre and the road, which can lead to aquaplaning.

What is Aquaplaning?

Aquaplaning is just like taking a boogie board to the beach and sliding along in the wash between waves. It slides along on a thin layer of water and while it’s fun on a boogie board it is to be avoided in a car.

When the front tires are aquaplaning the driver cannot steer at all, even to the point of spinning the steering wheel to full lock either side – the car will continue in a straight line. That’s why tires have grooves, most of which actively pump the water out from between them.

Directional Car Tires

Many tires these days are directional, which means they have to rotate in one direction in order to effectively work. This is largely due to the water clearing ability, because the curved tread patterns channel water away from the centre of the tyre to the outside. Directional tires usually have big arrows on the side, so ensure that the tires on a car are always turning in the correct direction.

Making Car Tires Less Noisy

Tread design goes further than that. As air is trapped between the grooves and the tread blocks, it makes noise as it compresses and then expands. This is tyre roar, and all tyres do it.

Most designs these days apart from very high performance applications are designed to be quieter than older generation tires, all through the shaping and pattern of the grooves and tread blocks. Staggered tread blocks help by breaking up the frequencies of the air passing between the tyre and the road.

Car Tire Pressure is Very Important

And finally, tire pressure is important. Always follow the manufacturer’s instructions on what pressure to run the tires at. Not only will grip be maximized, fuel efficiency will increase as one of the largest causes of excessive fuel consumption are underinflated tires.