الموضوع: How to take care of your tires

Tyre Tips - Passenger Vehicles

Good maintenance and care will help maximize the reliability and performance of your tyres. This section provides some guidance about your tyres, as well the common problems that can result if the tyres are not properly maintained.

A. TYRE & TUBE SELECTION
Tyre Selection
Before selecting a tyre, you should know the size, type and use. You should first select the tyre type and size in accordance with the car manufacturers manual. Then, deciding the type of driving conditions for your tyre, you buy the tyre best suited for those conditions.


Tyres user guidelines:
• Use tyres with the same size, type, construction, tread pattern and brand on your vehicle. If using a mix of tyres can not be avoided, you should get professional guidance
• Snow tyres should be put on all wheels during the winter season.
• Avoid using radial and bias tyres on the same vehicle.
• Avoid using tyres with different aspect ratios on the same vehicle. In case it is necessary, the lower aspect ratio tyres should be put on the rear axle.

Tube Selection
A general guide to selecting tubes is as follows:

• Make sure that tube size conforms to the tyre size.
• Make sure that a new tube is paired with a new tyre.
• Make sure that the tube has the same brand as the tyre.
• Choose a tube with a valve which matches with the tyre classification and rim type.
• Use a valve ....... that matches with the valve type. Do not forget to use the valve cap.

A Tube needs to be replaced when:
• Its circumference has inflated up to 92% or more of the tyres inside circumference.
• It has a broken valve.
• It has a flawed valve ....... which has to be immediately changed.
• It is worn-out, or if there is a soft part of the rubber surface.

B. SPEED GUIDELINES
1. It is advisable to know the tyres maximum permissible speed. As a general guideline please refer to the speed symbol table:

Passenger Cars
• Bias Tyres (Standard ) & (Snow)
Rim 12 maximum speed is 140 Km/H
Rim 13 and above maximum speed is 150 Km/H
• Radial Tyres (Standard) All Season
S speed rating maximum speed is 180 Km/H
H speed rating maximum speed is 210 Km/H
• Radial Tyres (Snow)
S speed rating maximum speed is 160 Km/H

2. The maximum recommended speed of a snow tyre is for normal winter road conditions, but not for icy roads.

C. CONVERSION CHART
This chart provides a guide to tyre interchangeability, although there may be some differences due to rim sizes and wheel dimensions. Tyres should not touch the vehicles body when turning or cornering the wheel.

Inch-up Principle
It is recommended in general that as long as the outside diameter remains the same, a 2 inch-up can be accepted. Please see the illustration below on how to inch-up your wheel.

Size:

175/70 R 13

185/60R14

195/50R 15

OD (mm):

575

577

576

Section Width:

176

184

196


D. MAINTENANCE
1. Tyre inflation pressure
2. Tyre rotation
3. Cleaning
4. Loading
5. Balancing
6. Alignment
7. Care while driving

1. Tyre Inflation Pressure
The most important step to maintain good tyres and longer tyre life is to inflate the tyre with proper air pressure. You should check the air pressure periodically and when the tyres are cool, in order to get the precise air pressure

Proper Inflation:

• For correct tyre inflation pressure, please refer to the car service manual or tyre manufacturers air pressure guide.
• Do not check the air pressure when the tyres are hot.
• For high speed driving, add 3 PSI or 0,3 Kg/Cm2
• Valve cores & valve caps should be tightened properly to prevent air leaks.
• For dual tyres, both tyres should have the same air pressure.
• Check the tyre pressure at least once a week.

2. Tyre Rotation (Regular)
Since each tyre wears differently due to road surface, number of passengers, and load, it is advisable to rotate your tyres every 5,000 Km for Bias tyres and 7,500 Km 10,000 Km for Radial tyres, in order to obtain even wear and longer tread life

3. Cleaning
Always clean the tyres with water when the tyre sidewall is dirty, because mud or soil can deteriorate the tyre sidewall compound. Check tyres frequently to remove trapped stones from the grooves. Stones, trapped in the grooves for a long time, can cause the grooves to crack.

4. Loading
Overloading is always unsafe and costly due to abnormal flexing of the tyre. Over loading can cause over-heating, cord breakage and ply or tread separation problems and result in uneven wear and shorter tread life.

5. Wheel balance
Unbalanced tyres or wheels (rims) can cause rough ride and vibration. Both static and dynamic tyre balances for passenger cars are very important for smooth driving. It is necessary to balance your tyres every 10,000 Km.

6. Alignment
Uneven / abnormal tyre wear is not always caused by over or under inflation, as the wheel alignment can also cause problems:

• Incorrect toe in - toe out: can cause abnormal wear, tear, worn groove edge and a feather wear appearance.
• Improper camber: causes irregular wear and will result in one tyre wearing out faster than the others.
• Improper caster: causes irregular wear and worn spots, resulting in one side of the tyre becoming slippery.

7. Care while driving
Rough surfaces will cause tyres to be worn or chipped. Avoid driving over obstructions, sharp objects, and potholes. If there is no way to avoid such obstacles, reduce your driving speed.
Wet roads usually produce hydroplanning between the road surface and tyre tread. In such conditions reduce your speed in order to maintain control over the vehicle.
Avoid sudden starts or stops. Excessive use of the brakes will reduce the lifetime of the tyre tread and the brake shoes.
Avoid sudden fast cornering which usually causes abnormal wear on the tyre shoulder

copied from Tyres 4U

MMamdouh