Many drivers don’t seem to realize that tyres are the only point of contact cars have with the road, at any given time. Vuyi Mpofu shares 7-basic tips all motorists should get into the habit of practicing.
Some motorists don’t appreciate how dangerous it is to drive on worn or damaged tyres. Granted, tyre are expensive to replace, but what all road-users should be aware of is that in the event of an accident, your insurance claim could be repudiated if accident investigators discover that the tyres were in poor condition and as a result, were the cause of the collision.
Here are some basic tyre maintenance tips all motorists should get into the habit of following:
Some tips on tyre maintenance:
Check all tyres (including the spare) whenever you refuel your tank.
When parking your car, turn the front tyres so that they are at a slight angle. This will make it easier for you to check the tread of your tyres.
Check the tyre pressure indicator in your owner’s manual or in your car, and inflate your tyres according to the load they will carry. Don’t over, or underinflate, your tyres,
Attend to tyre related problems immediately regardless of how insignificant they might appear to be. Bear in mind that tyres can be quite expensive to replace and as the saying goes – prevention is better than cure.
Replace your tyres as soon as is necessary but NEVER buy your tyres at the side of the road. Buy tyres only from credible tyre outlets.
Ensure that your tyres are Only buy tyres from reputable tyre dealers, not from the side of the road. Remember, a good deal now may cost you more later on,
Ensure your tyres are correctly aligned and balanced, particularly before and after a long-distance trip.
The practice of filling our tyres with nitrogen is not yet as common as it could be, even though it has many safety benefits. Vuyi Mpofu explores the reasons why more motorists should switch to using nitrogen in their tyres
Nitrogen gas is environmentally friendly, non-flammable and non-corrosive . It is a pure gas and does not attack or oxidise the rubber of the tyre from the inside like air does. Nitrogen in tyres is also known to prolong tyre life and improve road handling. For these reasons, nitrogen tyre inflation is mostly preferable to air inflation
Nitrogen gas in tyres does not hold heat thereby allowing the tyres run cooler. Filling your tyres with nitrogen reduces tyre pressure variation which is normally caused by changes in tyre temperature. As the biggest molecule gas, nitrogen is slow to migrate through a tyre, causing very little loss of pressure.
There is a direct correlation between tyres filled with nitrogen gas and road safety. In South Africa, the top-three reasons for tyre related accidents are:
Poor tyre condition
Vehicle overloading
Incorrect inflation
The above conditions are all within our control and require a decent measure of diligence on the part of all drivers. Correctly maintaining one’s tyres is a long term process while it’s not every day that drivers overload their vehicles. On the other hand however, filling tyres with nitrogen gas is an easy habit to get into and one which has many benefits. These include:
Slower rate of pressure loss
Cooler running temperature of tyres
Improved road handling
Reduced corrosion
1. Slower Rate of Pressure Loss
The molecular structure of nitrogen differs from that of air, in such a way that it escapes through the tyre’s inner liner or tube at a slower rate than regular compressed air. The result is a dramatically slower rate of pressure loss in a tyre filled with nitrogen. For example, it might take up to six months to lose 0.14kpa with nitrogen, compared to just one month with compressed air.
2. Cooler Running Temperature of Tyres
Tyres inflated with nitrogen run cooler than those inflated with air, resulting in an improvement in tyre life of up to 20%. By reducing the tyre’s running temperature, you increase its tread life thereby increasing its overall lifespan.
3. Improved Road Handling
As tyres heat up, their inflation pressure increases, which in turn reduces the size of the tyre’s footprint – the area that has contact with the road. Subsequently, the tyre grip is reduced as a result of the tyre’s diminished footprint. So the cooler the tyres run the better their ability to grip the road.
4. Reduced Corrosion
Unlike air there’s no moisture in pure nitrogen, thereby drastically reducing the possibility of corrosion in tyres.
In Conclusion…
Filling one’s tyres with nitrogen gas should be the norm for South African road users as it is safer than filling up with air. It is also cost effective as it leads to better maintenance of tyres.
Nitrogen gas is the ultimate tyre inflation gas and is available at reputable tyre fitment centres across the country at a nominal cost.
It is important to be alert to the warning signs that your wheels might be out of alignment.
Uneven tread wear is a sign of a car which has been driven over a long period of time on misaligned tyres. Often, the inner tyre tread wears down quicker and more smoothly than that of the outer section of the tyre, which usually has plenty of outer tread left on it. Of course, the opposite of this is true and it could be the outer section which wears out sooner than the inner section of the tyre. The result, however remains the same in that the tyres would need to be replaced sooner rather than later.
Your driving behaviour will decide how often your vehicle requires wheel alignment. In order to preserve the wheel alignment on a vehicle, avoid potholes, climbing curbs, and parking up against curbs. If you have to climb a curb, do it very slowly and at a slight angle.
When Do I Need To Consider Wheel Alignment?
Alignment should be checked every 10,000 km or 6 months, whichever occurs first unless you know that you have hit a pothole, or some other object; in which case it should be done immediately as a precaution.
Other facts drivers should know about wheel alignment:
A proper wheel alignment should best start and end with a test drive.
The front end and steering linkage should be checked for wear before performing an alignment.
The tyres should all be in good shape with even wear patterns.
If you have a tyre with excessive camber wear and you correct the alignment problem, the tyre will only make partial contact with the road.
Pulling problems are not always related to wheel alignment. Problems with tyres (especially unequal air pressure), brakes and power steering can also be responsible.
How is Wheel Alignment Performed?
A camera unit (sometimes called a “head”) is usually attached to a specially designed clamp which holds on to a wheel. There are usually four camera units in a wheel alignment system (a camera unit for each wheel). The camera units communicate their physical positioning with respect to other camera units to a central computer which calculates and displays how much the camber, toe and caster are misaligned.
Often with alignment equipment, these “heads” can be a large precision reflector. In this case, the alignment “tower” contains the cameras as well as arrays of LEDs. The system flashes one array of LEDs for each reflector whilst a camera centrally located in the LED array “looks for” an image of the reflectors patterned face. These cameras perform the same function as the other style of alignment equipment, yet alleviate numerous issues prone to relocating a heavy precision camera assembly on each vehicle serviced.
In conclusion – More attention should be given to wheels and tyres as requirements for safe driving. Tyres allow you to start, stop and change direction and are the only components which keep your vehicle in contact with the road’s surface.
If we compromise their ability to perform these basic functions we put ourselves and other road users at risk. Have your wheel alignment checked periodically byt a professional from a tyre specialist.
All motorists need to prioritize regular tyre checks in order to be assured of their safety when driving. The importance of reducing stress and strain on the vehicle’s suspension components to improve the handling of the vehicle, should not be underestimated.
What is Wheel Alignment?
Wheel alignment is the process whereby the wheels are aligned to point in line with the direction of rotation. This is done to ensure that the tyres are calibrated to ‘point’ straight ahead. Proper wheel alignment makes a vehicle steer easily and allows tyres to wear evenly.
Deteriorating roads contribute to a greater need for regular wheel alignment. Tyres can be nudged out of alignment when they accidentally hit objects such as curbs and potholes, or by catching a centre cement divider while making a miscalculated turn.
During wheel alignment, there are three major considerations. These are:
camber (vertical angle)
caster (rearward inclination)
toe (front of wheels pointing inwards or outwards).
Wheel alignment usually requires that adjustments are made to various parts of the suspension. Alignment angles can also be altered beyond the maker’s specifications to obtain a specific handling characteristic.
Here is a brief explanation of the settings used in alignment; it is a bit technical but it will provide some insight into the expertise required from tyre experts when aligning your wheels:
Toe Settings– this is the inward or outward pointing of the wheels in relation to the centre line of the vehicle and is set to take up any slack in suspension joints so that the tyres will in fact run parallel with one another when the vehicle is travelling in a straight line.
Camber– This is the tilt away from the vertical of the wheel and is designed to place the wheel loading on the larger inner wheel bearing of the front wheel on rear-wheel-drive vehicles. Too much camber will cause a tyre to wear off on the shoulder and differing camber angles from one side to another will cause the vehicle to pull to one side.
Caster– the backward tilt of the steering axis, which is designed to give feel on the steering as well as provide steering self-centring, so the steering comes back to the straight-ahead position following a corner. Too little caster will cause the vehicle to wander and too much will cause heavy steering.
Steering Set Back– this is when one wheel is ‘set back’ from the other. If a vehicle has high steering set back, the vehicle will pull toward the side where the wheel is ‘set back’. This can often occur when a vehicle has been involved in an accident.
Steering Axis Inclination– this is the tilt from the vertical of the steering axis and is designed to create a vertical load through the axis, in order to reduce stress and bending moments on suspension components.
Thrust Angle– this is when the rear wheels are out of line with those on the front, causing the vehicle ‘crab’, (steer sideways). This can occur when a vehicle has been involved in an accident.
Scrub Radius– this is the radius created between the centre line of the wheel in contact with the road surface and the line drawn through the steering axis. This can either be positive where the wheel positioning is on the outside of the steering axis line or negative where the wheel positioning is inside the steering axis. Scrub radius may also be referred to as Roll Radius. Changing the offset of the wheels on the vehicle will change the scrub radius and could severely affect suspension component life, due to increased stresses being placed on them.
Once a tyre is knocked out of alignment, its orientation on the vehicle is slightly off-centre. The degree of misalignment is not obvious to the human eye, but the effects will be noticeable in your ability to steer the vehicle. It is critical that motorists schedule regular tyre checks with at a specialist tyre service.
In most instances, drivers of bakkies don’t even realise the spare is gone until they need it.
– Manuel Reis, Managing Director, Grip-Tech
Statistics from the short-term insurance industry suggests that petty theft of various kinds is on the up.
One of the perceived easy targets is the faithful spare, a high-value item which can be liberated in seconds if not fitted with a proper anti-theft device. With a 17- or 18-inch tyre an alloy rim the default size and with a replacement value sometimes in the five-digit territory, leaving it unprotected is unwise
Manuel Reis, Managing Director of mechanical anti-theft specialists, Grip-Tech, says the problem doesn’t end with the financial loss however: “In most instances, drivers of bakkies don’t even realize the spare is gone until they need it. That occasion will in most instances already be an emergency – or at the very least an inconvenience, along with the loss of a no-claim bonus.”
Underslung spares are normally secured with a cable or chain arrangement, a crank handle is then used to lower it to the ground. Thieves simply cut the cable or break the chain and the wheel drops free. Few manufacturers fit a suitably robust locking device as standard and an aftermarket product is a must-have rather than a nice-to-have, says Reis, a mechanical engineer who has specialised in wheel protection solutions for more than two decades.
“We’ve recently added to our Auto-Grip Anti-Theft range and now offer products for virtually every light commercial vehicle manufactured in South Africa and many of their SUV derivatives. We’re always keen to work with OEMs and distributors to come up with the answer to a specific problem. For example, we’ve recently added a device for the Mahindra Pik-Up, and made changes to the locks for Isuzu and Nissan.”
Reis says the reason for Grip-Tech’s ongoing success in the marketplace is a combination of sound engineering principals, quality materials, tight production control and simplicity. This is combined with design innovation in coming up with the largest possible number of “key” combinations.
The tyre safety motto is simple: look after your tyres and they’ll look after you. Keeping a close eye on the checklist above and visiting a tyre specialist to balance, align and rotate your wheels at least every 10,000km will keep your tyres in shipshape.
Also, if you hit a pothole or an obstacle in the road, it’s always a good idea to have a technician inspect your tyres for any damage. Although they might look and feel normal to you, an expert will be able to spot any problems that could put the integrity of your tyres – and your safety – at risk.
It is as important that you maintain the tyres that are attached to your car as you maintain the tyre that isn’t. If anything goes wrong, it’s your spare that will take you from the side of the road to the nearest middle-of-nowhere town.
All of the checks you perform on your tyres apply to your spare too. It’s also necessary to replace your spare occasionally, even if it’s only rarely used, as spare tyres are especially susceptible to losing their structural integrity over time.
Having your tyres regularly inspected by a tyre specialist not only keeps you safe, it can also increase your tyres’ longevity and saves you money.
Tyre damage can happen for a variety of reasons and without the driver being immediately aware there’s a problem.
The most common types of damage are punctures, cuts, impacts, cracks, bulges and irregular wear. Here are some common signs and symptoms aimed at helping you diagnose the issue as well as some useful tips on how to prevent them.
Identifying irregular wear
There are several types of irregular wear, the most typical variations being heel and toe wear, one-sided wear, and centre wear. Here we explain how and why they occur.
a. Heel and toe wear – Heel and toe wear is a pattern caused by normal usage and suspension settings. It’s the outwardly visible (and audible) manifestation of various distortional forces at work on the tread. To explain further, let’s dive a little deeper into the design of the tread.
Tread grooves are essential in ensuring safety on wet and flooded roads. With low-profile tyres in particular, a higher percentage of tread void is necessary to displace the water and to improve protection against aquaplaning. Cross-grooves for water drainage take the form of freestanding blocks in the shoulder area. These shoulder blocks can wear into a heel and toe pattern as a result of a rolling movement under certain operating conditions. These operating conditions include:
Long journeys at a steady speed on straight roads
A moderate driving style
The alignment and camber of the suspension geometry
As the tyre rolls along the road, the freestanding blocks deform as they get closer to the contact patch of the tyre, and they compress as they touch the tarmac. After they lose road contact, however, the blocks snap back into their original shape, rubbing the surface of the road as they do so. The result is wear on the block run-out edge and is more likely to appear on non-driven wheels.
A minor amount of heel and toe wear is reasonable and has no discernible effect on driving comfort. But if the wear is more extensive, more specific issues could be to blame, including improper inflation, excessive toe-in and low-wear applications.
b. Centre wear – You will find this wear pattern on the driven wheels of high-power cars. High torque levels generated during strong acceleration, in stop-start urban traffic or when accelerating away from traffic lights can quickly increase wear of the tread in the centre of the tyre. Even today’s mid-range vehicles have modern engines that can generate high levels of torque and are capable of producing high degrees of slip.
c. One-sided wear – The biggest cause of one-sided wear is incorrect axle geometry. Deviations from the standard specification can develop over time and are the result of, for example, mounting a kerb.
Lowering the height of a vehicle in conjunction with low-profile tyres can also negatively affect wheel alignment. During driving, modified suspension arms tend to cause the alignment of the wheels to deviate from the specified position. The problem can catch drivers unaware, because wheel alignment values can still be found to be within tolerance limits when measured in a static position on an axle measurement bench. But the manufacturer’s alignment data applies to vehicles as delivered and may not necessarily apply to customised cars. Thus, the result may be an increase in non-uniform tread wear.
If a vehicle’s wheels are misaligned, a qualified specialist can correct the deviation by realigning them.
Identifying an impact break or bulge
An impact break is damage inflicted on the carcass (the casing of the tyre) after the tyre comes into contact with certain obstacles. A pronounced external bulge on the sidewall of the tyre indicates destroyed cords inside the carcass.
Damage of this kind is usually caused by driving over objects – like kerbs or speed bumps – at excessive speed or at the wrong angle, overstressing the carcass and causing individual cords to break. The exact extent of the damage will depend on the speed and angle of impact, and the size of the obstacle. Careful motorists are usually able to avoid this type of damage, unless an obstacle suddenly appears in front of them and they can’t steer around it.
Ignoring such damage increases the risk of tyre failure at some point in the future, either delamination of the tread and plies or disintegration of the tyre sidewall.
An impact break is sometimes confused with a sidewall indentation, but they are not the same thing. As we explain below, dimples or indentations in the sidewall are not cause for alarm.
Identifying a sidewall indentation
A tyre sidewall is not always perfectly even; sometimes there will be dimples and indentations that may require a more detailed inspection to determine their cause. The essential thing to know is that indentations are harmless and aren’t detrimental to either driving or safety characteristics. The dimples are superficial.
Indentations in the tyre are best illustrated if you imagine tying a string around an inflated balloon and then gently pulling the string tighter. If the balloon is the tyre, the string is the embedded carcass cords, which are concealed by the rubber. These cords provide the tyre with its strength and stability, and transfer steering and braking forces while driving.
During manufacture of a tyre – or rather when constructing the carcass, to which the steel belt and the tread are attached – there are often one or two overlaps in the carcass. It’s this overlap that is sometimes visible as an indentation after the tyre is fitted and inflated.
But if you’re in any doubt, have the sidewall indentations checked by a qualified tyre specialist.
Identifying a cut
Cuts are the result of external influences like bad road conditions, protruding bodywork parts or sharp, foreign objects such as stones or glass. If you discover damage in the form of a cut on the tyre surface, you should visit your local tyre retailer and have your tyres immediately checked by a professional.
Punctures explained
Punctures are the consequence of sharp objects on the road – for example, nails, screws or broken glass – that pierce through the surface of the tyre. If the puncture is deep enough, the tyre could begin to lose air pressure. If you find that one or more of your tyres are continuously losing pressure, or if you discover a nail or screw embedded in the tread, then visit your local tyre specialist as soon as possible to have them repaired.
How to prevent damages
Change the position of the tyres on the car at regular intervals (unless otherwise recommended by the vehicle manufacturer) to promote even tyre wear. The position of the tyres should be rotated, for example, when making the seasonal transition between summer and winter tyres.
By swapping the wheels from the driven to the non-driven axle on a regular basis, drivers can expect to have a uniform pattern of wear on all tyres. But as always, please observe the recommendations provided by the vehicle manufacturer.
If you find yourself in a situation where you have to drive over an obstacle in the road, approach it slowly and as close to perpendicular as possible. Afterwards, check your tyres for exterior damage such as cuts, cracks or bulges. Also, avoid driving aggressively on unpaved roads.
Article and images courtesy of Continental Tyres South Africa
Alignment should be checked every 10,000 km or 6 months, whichever occurs first unless you know that you have hit a pothole, or some other object, in which case it should be done immediately as a precaution.
Other facts drivers should know about wheel alignments:
A proper wheel alignment should best start and end with a test drive.
The front end and steering linkage should be checked for wear before performing an alignment.
The tyres should all be in good shape with even wear patterns.
If you have a tyre with excessive camber wear, for instance, and you correct the alignment problem that caused that wear, the tyre will now be making only partial contact with the road
Pulling problems are not always related to wheel alignment.
Problems with tyres (especially unequal air pressure), brakes and power steering can also be responsible.
The choice between an illegal, worn out tyre and a safe tyre could be a matter of life and death especially when you consider the various terrains and conditions we drive on.
This is especially relevant when we get flash rains that make the road surface slippery or drive over spillings. Although second hand, worn out tyres appear to be a more cost effective solution, they reduce the performance of a vehicle by increasing stopping distances, raising the risk of skidding and increasing the risk of blow outs.
At the launch of Transport Month in October 2019, President Cyril Ramaphosa said, “It pains me that our country continues to experience around 14,000 road deaths each year.”
“With over 60% of second hand tyres in South Africa deemed illegal, road users need to understand the dangers of driving using unsafe, worn out tyres. “Unsafe second hand tyres as well as worn out tyres are one of the major culprits that cause fatal consequences for road users, especially when one considers that the only component of the vehicle which, at any given point, makes contact with the surface of the road, is the tyre,” stated Darren Hayes-Powell, Group Managing Director at Goodyear South Africa.
Transport plays a critical role in sustaining our economy and commuting people to various destinations, therefore it is of utmost importance that we focus on the condition of tyres, the critical component that keeps the vehicle moving.
“It pains me that our country continues to experience around 14,000 road deaths each year.”
– President Cyril Ramaphosa
A simple tyre check at the end of each week will ensure you keep on top of the safety and wear performance of your tyres. As you park, move the steering wheel to the left or right to expose the front tyres when you exit the vehicle. This will give you easy access and view of your front tyres. It is also important you look at your rear tyres as they may also wear differently depending on how you drive.
These simple checks can ensure that you keep yourself, your passengers as well as the pedestrians around you safe as you drive.
Darren Hayes-Powell, concluded by saying, “Always make sure that your tyres are in good condition, that they are not worn out and if you are buying a second hand tyre, make sure that the tread wear indicator is visible, and it is below the tread across the whole tyre and there is no bulging on the side of the tyres. Adopt the habit of parking your car with the front tyres at an angle to make it easier to check their tread depth. This simple exercise, combined with a stringent quality check, can be the thin line between life and death.”
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