Category Archives for "tyre regulations"

Heavy Vehicle Tyres

The 14 Reasons Why Your Heavy Vehicle Tyre Is Dangerous

Ensure Your Vehicle Is Safe and Legal on Australia’s Roads

The tyre inspection is one of the most important jobs that a driver, operator or inspector does. If your heavy vehicle’s tyres are below the required standard, you are putting yourself and other road users at risk. How do you know what the tyre standards are for heavy vehicles? Do your drivers know the 14 reasons to reject a tyre?

National Standards for Heavy Vehicle Tyres

Since February 2014, the National Heavy Vehicle Regulator (NHVR) has been Australia’s independent regulator for all vehicles over 4.5 tonnes gross vehicle mass (GVM). Its job is to ensure that heavy vehicles are safe and efficient on Australia’s road network. The regulations that it oversees include the standards laid out in the National Heavy Vehicle Inspection Manual (NHVIM). It is in here that you will find the standards for heavy vehicle tyre checks.

Do Your Inspectors and Drivers Know the Heavy Vehicle Tyre Standards?

The NHVIM has been composed to provide a consistent approach to heavy vehicle standards across Australia. Its aim is to ensure compliance with standards, to improve safety, and to reduce vehicle downtime.

It wasn’t written by people with no experience, either. The regulator consulted with the industry and developed the NHVIM to provide inspectors and operators with standards that actually achieve what they set out to achieve.

For fleet managers, the NHVIM provides the criteria for heavy vehicle inspections. This includes all the reasons a heavy vehicle tyre should be rejected when inspected.

Here are all 14 of these reasons to reject a heavy vehicle tyre, with explanations where needed.

1.    Insufficient Tread

The law states that a tyre must have a minimum of 1.5mm of tread in a continuous band around the whole tyre. This tread depth must extend at least 75% of the width of the tyre.

Most tyres have tread wear indicators built into them, though these aren’t included when assessing a tyre’s tread depth around its circumference.

Good operators will replace heavy vehicle tyres sometime before they reach legal minimum tread depth.

2.    Tyres Don’t Match the Tyre Placard

Most vehicles have a tyre placard fitted to the door jamb. This shows the dimensions and air pressure levels that must be maintained. If there is no tyre placard, these details will be in the owner’s manual. A tyre that does not match these standards should be rejected.

3.    Tyre Damage

Deep cuts, bumps, bulges, exposed cords, chunking, and other signs of carcass failure.

4.    Regrooved Tyres

Only if it is stipulated on the sidewall of the tyre that it can be regrooved is regrooving permitted.

5.    Wider Than Mudguards

If the heavy vehicle tyre’s sidewall projects beyond the width of the mudguard when in the straight-ahead position.

6.    Non-Approved Modifications

If the tyre has been fitted with a non-OEM front wheel (i.e. rim and tyre) that has not been approved as a modification.

7.    Not Constructed for Unrestricted Road Use

8.    Illegal Retreads and Remoulds

Only tyres that are marked with ‘Retread’ or ‘Remould’ are capable of being retreaded or remoulded. The tyre should also be marked with its maximum speed (e.g. Speed Limited to 125 km/h).

9.    Illegal Speed Rating

The speed rating of all tyres must be no less than 100km/h or the vehicle’s top speed, whichever is the smaller. The exception to this is if the manufacturer has specified a lower speed rating.

10. Manufacturer’s Tyre Load Ratings Are Less Than the Vehicle’s Ratings

Any tyre fitted to a vehicle with a GVM of more than 4.5 tonnes is not suitable for road use if the tyre load ratings are less than the minimum ratings specified originally by the vehicle manufacturer.

11. Tyres Are in Contact

If dual tyres are fitted, there must be space between them. If they are touching, they must be removed and replaced.

12. A Tyre That Is in Contact with the Vehicle

If the tyre is in contact with any part of the vehicle – the body, chassis, braking, steering, frame, suspension – at any point of travel must be rejected.

13. A Tyre That Could Damage Roads

If cleats or other gripping devices could damage the road on which the vehicle is travelling.

14. Incompatible Tyres

A tyre that is not compatible to the rim to which it is fitted.

In Summary

When your drivers or maintenance staff check the tyres on heavy vehicles, it is essential that they check for all 14 reasons to reject a tyre. If you asked your drivers to write the list of 14 heavy vehicle tyre rejections now, do you think they could do so?

A simple tyre test will help your fleet’s vehicles to be safe and legal on Australia’s roads. When these tests show up heavy vehicle tyre frailties, contact Darra Tyres in Brisbane for the professional assistance you need.

Keeping your family and fleet safe on the road,

Dean Wood

how-do-you-know-how-old-tyres-are-and-if-they-need-changing

How do you know how old your tyres are and if they need changing?

Is it time for new tyres?

I’ve had a question sent into us, asking “How do you know how old your tyres are?”

The questioner isn’t sure about the age of his tyres and is concerned in case they should be changed. There’s no real wear and tear on them – no bubbling, chipping, or other sidewall damages – nor are there any other signs that the tyres need changing, as we explain in our article “How do Australia’s drivers know they need new tyres?” However, the questioner knows that manufacturers recommend changing tyres every five years, regardless of wear – but he bought the car second-hand a couple of years ago, and isn’t sure how old the tyres are.

In this article, you’ll learn how to tell the age of your tyres. This one piece of knowledge could help save your life, and it could help you drive a better bargain when buying a second-hand vehicle – if the tyres need changing because of their age, you could negotiate a fair few dollars’ discounts.

Why should you buy new tyres every five years?

The older a tyre is, the less safe it is. This is irrespective of use or wear and tear. This rule also applies to your spare tyre. As tyres age, they become age-damaged – even in storage! Often, the damage caused by ageing will show as small cracks in the rubber, which is oxidised by the UV rays in the sun.

Tyres contain anti-ageing waxes which slow down the effect of ageing, but these are only released when the tyre is in motion. Thus, tyres stored poorly – and your spare – may age faster than the tyres on your wheels.

Ageing tyres are more likely to puncture or suffer a blow-out at speed. Older vehicles that have a low mileage are more likely to have prematurely aged tyres. If you are not sure about the condition of your tyres, please do get them checked by a professional. Just because they have plenty of tread left, they may not be safe for driving.

Manufacturers mostly recommend that you renew your tyres every five or six years if you haven’t done so sooner. This isn’t an exact science. Your tyre specialist will be able to tell you if they are good for another few months or more.

How do you tell the age of a tyre?

If you buy a used vehicle, the chances are that it won’t come with a set of new tyres. It’s also unlikely that the seller will know or remember when the existing tyres were purchased – and even then, it is the year of manufacture that’s important.

Fortunately, all tyres are marked with the month and year of manufacture. If you look around the sidewall, you’ll come across a four-digit number in an oval border. This tells you the week and year of manufacture. For example, if the number is 1116:

  • The first two digits are the week (e.g. 11 means the 11th week)
  • The second two digits are the year (e.g. 16 mean 2016)
  • Therefore, this tyre was manufactured in the 11th week of 2016

Some tyres only have a three-digit number. These were made before 2000. They should be changed immediately.

If you are buying a used vehicle, always check the date of manufacture of the tyres. The older they are, the more likely they are to need replacing, and this is a bargaining chip in price negotiation.

Help your tyres last longer

Though they are a valuable investment in your safety and driving experience, whatever your vehicle, tyres are not a cheap purchase. The longer you can help them last, the more value you will get from every dollar you spend on new tyres. These five quick tips will help your tyres last longer:

  1. Keep them out of direct sunlight.
  2. If they are on stationary vehicles, move the vehicle backwards and forward every week to help prevent flat spots.
  3. Avoid parking on or driving through grease, oil, petrol or diesel. Always clean them if this happens.
  4. Don’t brake hard, especially into and through corners.
  5. Keep them inflated to the correct pressure, and avoid ‘kerbing’.

In summary

Aged tyres are more at risk of failure, and it is recommended that you change them every five to six years. You’ll find the year of manufacture of your tyre embossed as a four-digit number on the tyre’s sidewall. If your tyre is approaching five years old, take it to your nearest tyre specialist to have it checked. A five-minute check could save your life.

If you live in Brisbane, don’t hesitate to call into Darra Tyres. We’re here to answer your questions and keep you safe.

Keeping your family and fleet safe,

Kevin Wood

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Read this warning before you go large on new tyres

New tyre tips to stay legal when you modify your vehicle

In my last article, “Should you check your speedo when you fit new tyres?”, I explained how fitting the wrong-sized new tyres on your vehicle could lead you to break the speed limit even though your speedometer tells you otherwise. This isn’t the only problem you may have if you want to supersize your tyres.

Why you might want larger tyres

If you want extra power, there are many things you can do to your vehicle. You might decide to refit the engine and have it tuned especially for the job your vehicle needs to do. You might fit a supercharger, upgrade the suspension, or replace the turbo.

None of these upgrades will help your vehicles grip on the road. All the power in the world will add up to nothing if you can’t get traction. So, naturally, you’ll look to new tyres. Bigger is better, right? Especially when it comes to grip on the road. A tyre with a wider diameter will give you that grip. It could also void your insurance.

Stay legal with larger tyres

Whatever new tyres you have fitted, they must comply with the law. If you are modifying your vehicle in any way, you must do so in line with the National Code of Practice for Light Vehicle Construction and Modification (NCOP) Vehicle Standards. Regarding new tyres, this code is clear that:

  • New tyres fitted to 4WD passenger vehicles must not be more than 50mm wider in diameter than the tyre size designated by the vehicle’s manufacturer
  • New tyres fitted to off-road passenger vehicles must not be more than 50% wider than the vehicle manufacturer’s recommended widest tyre

You’ll find the manufacturer’s recommendations on the tyre placard on the door jamb, or in the owner’s manual.

Whatever modification you make, you must also ensure that no part of the wheel or tyre touches:

  • Any part of the body of the vehicle
  • The chassis
  • The steering mechanisms
  • The braking system
  • The suspension

Also, when aligned straight, the wheels must be housed within the bodywork – they cannot stick out from the side of your vehicle.

Modify your vehicle legally

If you are modifying your vehicle, and there are many reasons why you might wish to do so, the chances are that you’ll need to consider what to do with your wheels and which new tyres to fit.

A larger-diameter tyre will improve clearance if you do a lot of off-road driving. Increasing the diameter of your tyre will give you the added traction you need to benefit from increased power and retain safe braking distances.

However, by modifying your wheels incorrectly you run the risk of the modification being illegal. If you get into an accident and this is the case, your insurance will be void. You could find yourself with a huge cost to pay.

Modifying your vehicle and fitting new tyres without the technical know-how and legal knowledge is not a smart thing to do. Instead, bring your vehicle into our tyre shop in Darra. We’ll help you decide on the best modification and the best tyres to get the most from your vehicle while staying legal and ensuring your insurance covers what you believe it does.

For a professional and personal tyre service that you can trust, contact Darra Tyres today.

Keeping your family and fleet safe,

Kevin Wood

The perils of over or underinflating agricultural tyres

How to work with the optimum footprint in all conditions

Agricultural tyre pressure is one of the most important factors in getting the best from your tractor and other farming vehicles. Many operators run their agricultural tyres with the wrong inflation. In this blog post, I’ll examine the consequences of getting the air pressure wrong on your agricultural tyres, and how to ensure you run your tyres at the optimum footprint.

Be prepared for expensive field work with the wrong tyre pressure

Your tyres are hugely important in the field. The wrong tyre pressure will affect vehicle performance. Soil will be compacted and crop production affected. And poorly inflated tyres wear faster and damage more easily. Many operators ballast their tyres in attempts to increase performance.

Manufacturers’ studies have shown that incorrect tyre inflation can mean as much as a 40% loss of engine power. It is caused by slipping and poor rolling resistance. Add this to power loss from the transmission and additional equipment, and you’re looking at up to a 50% reduction in power. This amount of power loss puts an incredible strain on a tractor’s engine. It must work harder and uses more fuel. Repair and maintenance issues will increase. All this adds up to a big hit on your pocket.

Functionality depends on footprint

Increased traction depends upon its footprint – the amount of tyre surface area in contact with the ground. The greater the footprint, the greater the traction. So, you would think that running agricultural tyres at the lowest possible inflation would increase efficiency because a larger footprint gives less wheel slipping, and results in longer tyre life and less soil compaction. Wins all round. But it’s not quite this easy.

Agricultural tyres must also carry loads without causing damage to their construction. When this happens, all bets are off. Damage to tyres increases, power is harmed, and costs increased. So, it’s imperative that you run your tyres at the optimum pressure for optimum results.

Agricultural tyre footprint – a constantly changing factor

The optimum tyre footprint doesn’t simply depend on tyre pressure. It also depends upon the load being supported and the tyre size, and ground being driven on. The optimum footprint will constantly change, as the load being carried changes. So, you need to reach a happy medium.

How you do this is to stick within the tyre manufacturer’s guidelines – the tables they produce on tyre sizes, maximum loads, tyre pressures, and speeds. Operate a tyre at 10% below its stated optimum pressure, and you’ll decrease its life by 15%.

The perils of overinflation of agricultural tyres

It’s not only underinflation that can affect tyre life and performance in the field. Over-inflation will increase the likelihood of tyre damage and more. For a start, driving on overinflated tyres will hit your driver hard. Every bump reverberates up the spine. Comfort reduces, and performance isn’t far behind. It is indicative of what over inflation does to tractor performance – wear and tear on tyre and vehicle increases. You’ll use more fuel, increase soil compaction, and reduce tyre life.

What’s worse – overinflation or underinflation?

There isn’t much difference between the effects of overinflation and underinflation. A 20% overinflated tyre causes 30% loss in performance, while a 20% underinflated tyre will cost you 26% of your performance.

However, if you drive your tractor on the road with underinflated tyres, the lugs will start to wear faster. Your rear lugs will be more severely damaged. It could cause bead slip – and leads to rapid destruction of the tyre.

Check your tyre pressure regularly

Neglecting your tyre pressures on your agricultural vehicles will impact your bottom line.

An underinflated tyre will increase fuel consumption, lead to sidewall damage, uneven wear and bead slip, which eventually destroys the tyre.

An overinflated tyre will increase fuel consumption, increase wear on the vehicle and tyre, increase soil compaction, and result in reduced tyre life.

When it comes to your tyres, check tyre pressures regularly. Keep them within the manufacturer’s guidelines for load, size and speed. One final tip: make sure your tyres have a valve cap. It keeps dust and dirt out of your tyre, but, equally as important, it prevents the natural air loss through tyre valves.

For all your agricultural and other tyre needs here in Brisbane, contact Darra Tyres today.

Keeping your family and fleet safely on the road,

Kevin Wood

The Dangers of Driving on Part Worn Poor Quality Tyres

What risk are you taking behind the wheel of poor quality tyres?

No matter how good a driver you are, if your tyres aren’t up to scratch you’re putting your life in danger. More importantly, you’re putting other people’s lives at risk. Poor quality tyres includes partly worn tyres, even if they were once high quality.

A survey in Australia last year found that almost half of all drivers did not know if their tyres were legal or not. Nearly a third of drivers quizzed in the survey admitted that they drove on worn tyres they thought were illegal.

In this post, I’ll look at some of the dangers of driving on part worn tyres that are, in fact, illegal. You’ll also discover how to ensure easily that your worn tyres meet the legal requirements.

Women are more at risk than men

The Canstar Blue survey questioned 1,600 drivers in early 2015. It found that:

  • 40% of Australian drivers don’t know the law on tyre safety standards
  • 29% believe they have driven on illegal tyres
  • 25% don’t know what the correct air pressure for their tyres is, or where to find their tyre pressure guide
  • 20% don’t know how to check their tyres for wear

Perhaps most disturbingly, female drivers are:

  • two times more likely to not know about tyre safety standards; and
  • three times less likely to know how to check their tyres are safe and legal.

What job do tyres do?

Your tyres are an essential part of your car. They help you stick to the road in all conditions. A good tyre properly inflated will reduce fuel consumption and improve the driving experience. In wet weather, they push water away and stop you from aquaplaning.

If you’re driving at 100 kilometres per hour, each of your tyres might have to expel as much as nine litres of water every second in wet conditions. If they didn’t do this, you’d feel like you were driving on ice.

It’s the tread and tread depth which enables the tyre to cope with this amount of water on the road. If you drive on a worn tyre, the grip is destroyed. You might as well be driving in the Arctic. You can imagine the devastation a 100 kilometre-per-hour crash causes. And all because you didn’t know how to check your tyres.

What is a legal tyre, and how do you check on wear?

Under Australian law, you must have at least 1.5mm of the tread where the tyre contacts the road. We used to check this with coin edges. Not very scientific, and not very accurate. Fortunately, most tyres now have tread wear indicator bars. When the tread has worn down to the limit, the tread bar will be level with the tread.

Tyre wear is caused by a range of factors. The roads on which you drive and the weather conditions in which you drive are two of the things that you have little to no control over. But excessive speed, late and violent braking, and driving corners too fast all add to tyre wear. Driving poorly not only increases the possibility that you’ll have an accident, but it also increases the cost of driving.

Don’t stop at checking tread

Tyres have a limited life irrespective of how you drive. Excessive heat or sunlight will deteriorate the rubber. Every time you rub the sidewall against the kerb when parking, a little bit more damage is caused to your tyre.

Tread wear is easier to spot than sidewall wear or other damage. Don’t forget that a spare tyre might not be roadworthy, even if it has never been used before.

Whenever you have your tyres replaced, get the spare checked. And if you’re not sure how to check your tyres to see if they are part worn, bring your car to us, and we’ll show you how.

Don’t be embarrassed that you don’t know the legal limits or how to check your tyre for wear – you’re in the company of almost half of all Australia’s drivers. Getting your tyres checked regularly will put you into the elite driver category – those who make sure their tyres are legal and that road safety is a priority.

Contact Darra Tyres today on (07) 3333 5510. We’re here to serve.

Cheers,

Kevin Wood

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