The grip of the tyre with the road. The best adhesion occurs on a rough and dry road surface. In rain and/or ice, adhesion is reduced.
Parts of a tyre
1. Pneumatic part: formed by the cover, air and tube (if it has one).
2. Metallic part: rim
Types of tyres:
|With tube: |
|Without tube (tubeless): |
better because they reduce the risk of blowout
|Air under pressure leaks between the inner tube and the tyre||Airtight coating that replaces the inner tube|
When a tyre must be changed, you should try make them all of equal width, size and tread. If you decide to mix tyres, at least use the same ones on the same axle (front or rear).
It is RECOMMENDED to replace a tyre when the tread depth is less than 2 millimetres. When the depth is 1.6 millimetres or every 5 years, it is MANDATORY to change the tyre.
In the picture we can see, how to check tyre wear with a coin.
Keep in mind that wider tyres consume more fuel and have higher adhesion with the road.
Tyre pressure should be checked with cold tyres and the manufacturer’s recommended pressure for either winter or summer must be followed.
You may not install tyres with a speed symbol below the manufacturer’s recommendation.
Spare wheels must have pressure higher than the recommended by the manufacturer. When driving with a spare wheel, it is required to:
|Less air in the tyre (underinflated)||More air in the tyre (overinflated)|
|Wears down on the sides |
Decreases adhesion and consumes more fuel
|Wears down more in the center |
Can damage the suspension
If a wheel is unbalanced (due to blows or bumps), go to the workshop.
In case of a puncture, despite changing the wheel, you should go to the nearest workshop.
In case of a tyre blowout, hold the steering wheel tightly, slowly release the accelerator and apply the brakes.
Lack of brake maintenance is the main reason why cars do not pass the ITV/MOT.
Types of brakes:
Disc brakes are better, since they cool and dry better when uncovered.
Maintenance: Check the brake fluid and replace it when indicated by the manufacturer. The liquid neither heats or consumes.
If you step on the brake and notice it feels light and spongy, this indicates there is air in the brake fluid pipes.
If when you step on the pedal, it brakes, but you have to go almost to the bottom, it means that the brake fluid level is low.
The brake servo makes the brakes smoother.
The ABS prevents wheel locking when braking, which prevents the wheels from skidding, so they don’t lose adhesion. In case of emergency braking with ABS, a constant and regular pressure is applied until the vehicle has stopped.
In case of skidding:
Can be increased by: