HISTORY OF TYRES

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Michelin, Clermont-Ferrand, France

Apollo, Gurgaon, Haryana, India

Bridgestone, Kurume, Fukuoka, Japan
Continental AG, Germany

Cooper, Tyre and Rubber Company, America (motorcycles)

CST Cheng Shin Rubber Ind Co Ltd (bicycle)

Hankook Tire Group, Seoul, South Korea

Gait, Singapore, Inodnesia
Goodyear Tire & Rubber Company, Akron, Ohio, USA

Hankook Tire Group, Seoul, South Korean

Huayi, Shaghai, China

Kumho Tire Co., Gwangju, South Korea

Maxis, Cheng Shin Rubber

MRF Madras Rubber Factory, India

Nexen Tire Corporation

Nokian, Finland
Pirelli, Milan, Italy

Sumitomo Rubber Industries, Japan (Dunlop)

Toyo Tire & Rubber, Toyota, Japan
Yokohama Tire Corporation, Tokyo

THE PLANET NEEDS OUR HELP - If we are to continue our motoring pleasure without destroying our planet and the health of people all over the world, we urgently need international legally binding laws that apply to all members of the United Nations. Humans created this mess, humans should clear it up.

RUBBER & PLASTIC POLLUTION - PHYSCIS.ORG 14 NOVEMBER 2019

Where do these lost centimeters of tire tread "disappear" to as yur tyres wear out? As micro-rubbers, they mainly end up in soil and water and, to a small extent, in the air. And the amount of these particles in our environment is anything but small, as Empa researchers have now calculated.

Everybody is talking about microplastics. But the amount of microplastics in air and water is small compared to another polymer that pollutes our air and water—and therefore our organism: Micro rubber. These are the finest particles from tire abrasion, which enter our soil and air via the road surface or are removed by artificial turf. Empa researchers have now calculated that over the last 30 years, from 1988 to 2018, around 200,000 tonnes of micro rubber have accumulated in our environment in Switzerland. This is an impressive figure that has often been neglected in the discussions on microplastics.

SQUEALING TIRES

Researchers around Bernd Nowack from Empa's "Technology and Society" lab identified car and truck tires as the main source of micro-rubber. "We quantified the abrasion of tires, but also the removal of artificial green areas such as artificial turf," says Nowack. However, this only plays a subordinate role, because only three percent of the rubber particles emitted come from rubber granulate from artificial green areas. Tire abrasion is responsible for the remaining 97 percent. Of the particles released into the environment, almost three-quarters remain on the left and right side of the road in the first five meters, 5 percent in the remaining soils and almost 20 percent in water bodies. The team based its calculations on data on the import and export of tires and then modeled the behavior of rubber on roads and in road waste water. Since the year 2000, the guidelines for the recycling of water and the prevention of soil pollution have been significantly tightened. Through measures such as the construction of road wastewater treatment plants (SABA), part of the microrubber can now be removed from the water.

LOW IMPACT ON HUMANS

A part of the micro rubber is first transported by air into the first five meters left and right of the road, deposited and partly whirled up again. However, Christoph Hüglin from Empa's "Air Pollution / Environmental Technology" lab estimates the impact on humans to be low, as a study from 2009 shows. "The proportion of tire abrasion in inhaled fine dust is also in the low single-digit percentage range at locations close to traffic," says Hüglin.

Researchers emphasize, however, that microplastic and microrubber are not the same. "These are different particles that can hardly be compared with each other," says Nowack. And there are also huge differences in quantity: According to Nowack's calculations, only 7 percent of the polymer-based microparticles released into the environment are made of plastic, while 93 percent are made of tire abrasion. "The amount of microrubber in the environment is huge and therefore highly relevant," says Nowack.

WHAT CAR 29 MAY 2019

Previous research from the USA has estimated that 30% of the microplastics that are polluting Earth's oceans and waterways comes from tyres.

Other research done in Germany in 2018 found that microplastics from tyres and vehicle brake pads made up 89% of the particles taken from the air above motorways. The scientists believe these tiny particles are being blown by the wind and washed by rain into waterways that lead to oceans.

WHAT IS THE GOVERNMENT DOING ABOUT THE PROBLEM ?

In the wake of a number of recent studies of microplastic pollution in the world’s oceans and the air above busy motorways, the UK government commissioned research into the issue in May 2018. The results from this 11-month project, conducted by Plymouth University, are due soon.

The Department for Food and Rural Affairs (DEFRA) pledged £200,000 to pay for the research, which will analyse how tiny plastic particles from tyres and other synthetic materials, such as polyester from fishing nets, ropes and lines, enter our waterways and oceans and the impact they have on marine life.

Environment minister Thérèse Coffey commented on the DEFRA-funded research: “The impact of plastic pollution on our oceans is one of the greatest environmental challenges of our generation. Robust scientific evidence should support our policy proposals, and through this exciting project, we will build on work under way to better understand how microplastics end up in marine environment and what we can do to tackle this in the future.”

WHAT ARE TYRE MANUFACTURERS DOING ABOUT THE PROBLEM ?

Tyre makers refute the claims made from previous research. Eleven of the world’s leading tyre makers formed a global forum in 2005 to look at issues relating to tyre particulates. The Tyre Industry Project (TIP) aims to proactively identify and address the potential human health and environmental impacts associated with tyres.

According to a spokeswoman from Continental Tyres, which is also a member of the TIP, the microplastics from roads consist of 50% of material from tyres and 50% of material from the actual road surface. She stated that contrary to other research, the German company's initial investigations show that only 2% of tyre microplastics have the potential to get into oceans, because they're heavier than water so sink to the bottom of rivers rather than make it to the ocean. TIP is continuing its research and expects to publish findings in 2020.

WHICH ARE THE BEST TYRE BRANDS & HOW CAN YOU SAVE MONEY ON TYRES ?

You probably don’t give your car’s tyres much thought until a garage tells you they need replacing, but they're one of the most important safety items on your car. They provide the only contact between your car and the road and ensure that it makes it around each corner and stops when you want it to.

In fact, every manoeuvre you make in your car relies on the tyres, so it’s vital to ensure they are in first-rate condition and that when you replace them, you do so wisely.

WHEN SHOULD YOU REPLACE TYRES ?

Although the legal limit for tyre tread depth is 1.6mm, many safety organisations and tyre makers recommend replacing tyres when the tread reaches 3mm, because their effectiveness – in particular their ability to stop a car on a wet surface – is reduced once the tread is below this level. They must also have the minimum tread across three-quarters of their width without any gaps.

The other legal requirements for tyres are that they are in physically good condition – they can’t have any gashes or bulges in the sidewalls – and are inflated to the recommended pressures. The tyres also have to be the same size across both axles, although you can fit larger tyres on the back or front axle of your car. 

Break any of these rules and you could get three penalty points on your licence and a £2500 fine. You could lose your licence altogether and be fined £10,000 if all four tyres are below the legal limit.

Although there’s no legal requirement to stick with the brand of tyre fitted to your car when it was new, the car's maker will have worked closely with the tyre company during development, so changing to a different brand or tyre with a different tread pattern could affect the handling and road noise. However, if you stick with a similar tyre from a different premium or mid-range brand, the differences should be minimal. 

One thing you should consider doing, however, is changing the two front or rear tyres at the same time, unless you’re replacing a new tyre that’s been damaged. If you change a single tyre and the new one has 8mm of tread and the one on the other side has 4mm, they won’t provide the same grip. While this isn’t likely to be an issue on dry roads, stopping distances will increase in wet and wintry conditions. 

You might be able to save money by looking for retailers that offer a discount for buying more than one tyre.

SHOULD YOU FIT NEW TYRES ON THE FRONT OR BACK ?

Most modern cars are front-wheel-drive, so the front tyres have to work harder than the rears and are likely to wear out quicker. However, whether your car is front, rear or four-wheel drive, most safety experts advise switching the tyres around when replacing the front pair so that the new ones are on the rear. 

This is because if a car loses grip in a corner, it will either understeer or oversteer. Understeer is when the car’s front tyres lose grip first, making the front end slide outwards. Oversteer is when the rear tyres lose grip first, making the back end of the car swing out. 

It’s easier to get a car that’s understeering back under control than one that’s oversteering – simply slowing down should help to regain grip – and this is why the new tyres should be on the rear wheels to minimise the potential to oversteer and risk a serious accident.

TYRE INFLATION PRESSURES

Although cars are manufactured to give trouble free motoring over long distances, the tyres should still be checked weekly. Tyres expand when they heat up, and this happens when you start driving, so the best time to check your tyre pressures is first thing in the morning before you leave home. If you do check the pressures during a journey, and they read higher than the normal recommended pressure, do not reduce the pressure. It is less dangerous to drive with over-inflated tyres than it is to do so with under inflated ones. However, the best solution is regular checking to establish the correct pressure at all times.

Too much

If the front tyres on a front wheel drive vehicle are over-inflated, the tyre becomes hard, and the area of tyre in contact with the road is reduced. This then means that the grip of the tyre is also reduced. In bad weather, the steering becomes less positive, and the tyre will wear more in the centre, because of the over-inflation. The same applies on the rear tyres of a rear wheel drive vehicle.

Too little

As we mentioned earlier, it is actually most dangerous to drive a car with under-inflated tyres. The main reason for this is that under-inflation causes the tyre to become less rigid, and consequently offers inferior control to the steering functions, and ironically can cause less of the tyre to be in contact with the road surface. It is equally dangerous to both front and rear tyres to have them under-inflated. Continued use under these circumstances increases the likelihood of the tyre casing breaking, as the internal heat of the tyre will increase due to the lack of sufficient air inside the tyre.

Finally, given the increasing environmental concerns facing us all, under-inflated tyres lead to increased fuel consumption.

On the side of your tyre, you will see a code. This is an international code, which shows the type of tyre and the specification. Those numbers and letters tell you exactly about your tyre.

This is what they stand for (from left to right):

155 - is the nominal tyre width in millimetres.

70 - is the height as a percentage of width, the Profile. In this case (from rim flange to tread) it is 70% of 155mm, or 108mm. 

R - means that it is a radial tyre.

13 - is the wheel diameter in inches.

75 - is the code for the carrying capacity per wheel of the car. Code 75 = 387kg.

T - is the maximum speed rating for the tyre. This tyre is rated at 118mph. The full table is below.

Never put two different types of tyres on the same axle. Indeed, fitting a radial and a cross ply tyre on the same axle is illegal. It is possible to have radials on the rear and cross ply on the front axles, but not the other way round, and is not recommended. The only exception to this is in the case of temporary use spare tyres.

WHAT IS THE  'OFFSET'

One of the most asked questions, what's the offset closely followed by what is the biggest wheel that can I fit onto my car? The offset is a gauge of how much a wheel will stick out from the arch of a car or how far it will recess into the arch of the car. If the offset is wrong, the wheels will stick out too far and will almost be a like a beach buggy!

If you take a wheel and cut it in half and draw a line down the centre of the width of a wheel, the offset would be the distance between the back face (mounting face) of the wheel and the centre line that you have just drawn (shown as a dotted line in the diagram below.

It is very important not to deviate too far from the offset of the wheel originally fitted to the vehicle. In this case Vauxhall engineers developed the 'Negative Scrub Geometry". This gave a offset of -49mm (et49). A wheel of radically different offset can cause serious clearance and handling problems along with accelerated tyre and bearing wear.

Negative scrub geometry had the intention that if you got a flat tyre you were still able to control the car (so long as you weren't going motorway speeds). So its best to keep as close to the et49 figure as possible.

However the bigger the alloy wheel goes, the more difficult it becomes to stay close to the et49. The reason being is that as wheel gets bigger in diameter, it also becomes wider, and so does the tyre that fits it. This is when other items in the wheel arch can begin to foul with the alloy wheel or the tyre. Namely the arch lip of the car and the suspension strut. When this happens the offset must change for the bigger wheel and tyre to fit in the arch. Plus if the car has been lowered, this will have to be considered too as the wheel is now tucked further up in the arch.

Tips on keeping safe and being prepared

Changing a tyre can be a daunting prospect. Here are a few hints that can make life easier when changing a tyre.

• Gloves – Keep a pair in the car at all times.

• Bin Liner – Something to put a muddy tyre into. Keeps your car clean.

• Sturdy Board – If the ground is soft the jack may sink. Use as a stand.

• Wheel Nuts – Grease threads lightly to allow easy removal.

• Wheel Nuts – Make sure these are tightened correctly.

• Wheel Nuts – Correct tightening will allow easier removal next time.

• Wheel Balancing – Always have this done after repair.

• Tyre Pressure – Never drive too far or too fast after replacing a tyre until the pressure is checked and at the correct level. Refer to Owners Manual.

• Spare Tyre – Check and examine condition regularly. 

PUNCTURES

It is not always necessary to replace a tyre when punctured. In some cases the tyre can be repaired.  Here are some basic guidelines.

What can be repaired?

(In accordance with British Standards (BSAU 159))
Only certain areas of the tyre can be repaired. This is demonstrated below by Area’T’

Repairable Area - Definition of Area'T' 

 
 
The repairable area 'T' is defined as a percentage of the tyre's nominal section width and this is dependant on the type and size of the tyre.

Radial Ply tyres – Minor Repairs to Radial Tyres for Cars, Vans, and Commercial Vehicles

WHEN CAN A TYRE BE REPAIRED

The following checks are mandatory before repairing any tyre. (General Requirements of BSAU159f.) This ensures whether a tyre is suitable for repair.

• Minimum Tread Depth Requirement. (Cars 1.6mm, Truck & Motorcycle 1.0mm)

• Run-flat Damage

• Contamination

• Ageing/deterioration of the rubber

• Bead/Liner Damage

• Previous repairs not in accordance with BS159

If any of the above is evident it is recommended that tyre is not suitable for repair. Do not repair it. These are only guidelines, and not an exhaustive list. Basic principles of common sense must be adhered to when deciding upon puncture repair.

TYRE SIDEWALL INFORMATION - WHAT DOES IT MEAN

At first glance the lettering on the side of the tyre may look complicated. It is not meant to be that way. The lettering explains the exact specification of the tyre you have. In short it tells you anything that you may need to know about your tyre.

SPEED RATING

It is IMPORTANT that you check your speed rating before buying your tyres - as choosing a lower tyre speed rating could INVALIDATE your INSURANCE.

This is indicated by the speed symbol on the tyre sidewall, and represents the maximum speed that this tyre can sustain at full load. Consult your vehicle manufacturer to check which speed rating your vehicle requires. It is of the utmost importance that you stick to the manufacturer's guidelines. 

The tyre speed rating (i.e. S) is the maximum speed for which the tyre is rated. For example, the S rating identifies speeds up to 112 mph.

Speed ratings are based on scientific tests where the tyre is run at speeds in 6.2 mph steps in 10 minute increments until the required speed has been met.

You will find your speed rating on the side of your tyre at the end of a series of numbers - as follows:

What is a tyre load rating?

The Load capacity of a tyre determines what payload each tyre can carry. It is vital that you check with your manufacturer what capacity should be put on your car. Again in cases insurance can be void if you select the incorrect tyres. The following table shows what Index specification can carry.

How do I know if my tyres are Trading Standards approved?

Check your tyre for an "E" Number. E.g. E4 0213760. This is an ECE type approval mark and number that shows if the tyre has been tested and passed as high quality by the European regulatory authorities.

AIRCRAFT TYRES

The very earliest of tyre designs were called Type I and were referred to only by their outside diameter eg 27" which is a common fitment to aircraft such as Harvards or P51 Mustangs.

General Aviation tyres are generally Type III designs and include the most widely used sizes such as 5.00-5 and 6.00-6. These measurements refer to the section width of a tyre and also the rim ledge diameter (or the hole in the middle) hence a 6.00-6 is 6 inches wide and sits on 6 inch wheel.

Three Part Name Sizes cover most of today’s designs and typically describe the Outside Diameter, Section Width and Rim Ledge Diameter. Eg, 15x6.00-6, the tyre is 15 inches tall, 6 inches wide and sits on a 6 inch wheel. Some tyres in this classification are preceded with an ‘H’ which identifies the tyre as having a higher percentage deflection.

Metric sizes are the same as three part name sizes but the Overall Diameter and Section Width are replaced with millimeters but the rim sizes remains in inches, eg 380x150-5, it’s imperial equivalent is a 15x6.00-5.

Radial tyres are also the same as three part name sizes but the dash preceding the rim diameter is replaced with the letter ‘R’ eg 32x8.8R16

RUN FLAT TECHNOLOGY

Run Flat Tyres Explained
Several Tyre Manufacturers have developed tyres, and tyre systems that allow a vehicle to continue moving despite a loss of pressure. There are two different approaches: 

1.Reinforced Tyre Sidewall manufacturers of this include Bridgestone, Dunlop, Goodyear and Pirelli. 

2.Rubber clip to your rim manufacturers of this include Michelin. All Run flat technology must operate in tandem with tyre pressure warning systems.

1.Reinforced Tyre Sidewall

The Diagram below shows The Dunlop DSST system for run flat. These tyres can be placed on any rim. The sidewall is reinforced allowing the tyre to support the vehicles weight. The tyre is constructed with new rubber compounds that prevent tyre destruction with excessive flexing. Run Flat Tyres allow a vehicle with complete loss of tyre pressure to handle effectively. Braking, acceleration, and steering behaviour remain unchanged. Mobility is maintained even after a puncture, but you must refer to each individual tyre’s guidelines from the Manufacturer.

Dunlop DSST Tyre

Tyres that carry this technology include the Bridgestone RFT series, Dunlop DSST series, Goodyear EMT series, and the Pirelli Euphori @ series.

2. Rubber Clip to your tyre rim

The rubber clip prevents the tyre rim cutting into your tyre when you experience a loss of pressure. This system has been developed by Michelin and is known as the PAX System. Like the reinforced sidewall it operates in tandem with automated tyre pressure monitors.

WHY DO SOME PEOPLE USE NITROGEN instead of AIR ?

Why would you want to do this? The benefits of Nitrogen filling are as follows:

• Improved comfort of ride

• Improved safety

• Increased fuel savings

• Improved life of tyre

Nitrogen has long been the accepted gas medium for filling aircraft tyres, racing tyres and heavy mining and construction vehicle tyres. Nitrogen is used for safety reasons and to ensure that tyres are always at a constant pressure. Compressed air, the traditional medium for inflating car tyres, contains both oxygen (21%) and nitrogen (78%).

The rubber tyre is like a membrane, through which oxygen permeates three times faster than the nitrogen. The result is that the oxygen slowly leaks out through the rubber walls, and the under-inflation leads to higher tyre wear with a consequent decrease in safety and comfort, and higher fuel costs.

MORE ON WHEELS and TYRES

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