All you need to know to make the right tyre choice.
Find out all you need to know to make the right tyre choice with our report and test results. We explain the types of tyres available and provide tips on making your tyres last longer.
Many carmakers offer their vehicles with two or three different wheel sizes within a range, typically increasing the wheel size and decreasing the tyre profile for higher trim-levels. The theory is a wider contact area generally improves roadholding and braking, while a shorter sidewall is stiffer and deforms less during cornering, which in turn sharpens steering response. It’s not just performance though, some people simply prefer the look of low-profile tyres – a larger wheel size can give a sense of sportiness or prestige to a vehicle.
Our roads can be rough. Driving in New Zealand, you are less likely to roll smoothly on tar-sealed Euro-style highways and more likely to rumble over coarse chip-seal roads. Your tyres, an integral part of your car’s suspension system, are on the frontline when dealing with humps, potholes and other road irregularities. As tyre profile reduces, so does the tyre’s ability to absorb and cushion bumps, which results in a less comfortable ride. Additionally, the chance of your tyres, wheels and other components suffering impact damage increases.
Fitting after-market wheels and tyres of a different size to those specified in your owner’s manual may upset your car’s balance and can potentially be dangerous. Altering your tyres’ overall diameter can affect the calibration of your speedometer and odometer. If you want bigger wheels and low-profile tyres, we advise seeing a tyre specialist.
A car fitted with low-rolling-resistance tyres will require less force to roll down the road, so they’ll be more fuel efficient than standard tyres.
Most tyres grip well in the dry. It’s the combination of good wet grip and low rolling resistance that’s more difficult to achieve. The top tyres in our test tend to have better wet grip and lower rolling resistance.
Some tyres have a tread-wear rating on their sidewalls, but local tyre-makers say the ratings often have little relevance to New Zealand conditions.
And long-lasting tyres may not be a good thing. The US consumer organisation Consumer Reports says tyres that last too long may pose a safety risk, because rubber-compounds deteriorate with age.
Some major car manufacturers have recommended throwing away tyres after 6 years, regardless of wear.
Tyres are usually date-coded, so a tyre dealer can work out if a tyre is really old. In New Zealand tyre wear is fairly rapid, so 6-year-old tyres aren’t common – except for imported second-hand tyres.
If long life is your priority, ask your tyre dealer for a model with a good tread life. Just be aware that long tread-life and good grip don’t always go together.
Choosing a tyre with a short stopping distance could avoid accident and injury if your worst nightmare happens. Our “Average stopping distances” tables show the difference in metres between the best and worst in some of our tests.
|Speed||Shortest distance (m)[width=large]||Longest distance (m)[width=medium]||Difference (m)|
|50km/h||10.73 - Bridgestone Ecopia PZ-XC||12.44 - Michelin Energy XM2||1.71|
|80km/h||26.81 - Firestone TZ700||29.63 - Michelin Energy XM2||2.82|
|50km/h||14.55 - Continental ContiPremiumContact 2 E||20.35 - Supercat DT58703-1||5.8|
|80km/h||36.39 - Continental ContiPremiumContact 2 E||48.49 - Supercat DT58703-1||12.1|
|Speed||Shortest distance (m)[width=large]||Longest distance (m)[width=medium]||Difference (m)|
|50km/h||9.54 - Bridgestone Potenza Adrenalin RE002||10.65 - Michelin Energy XM2||1.17|
|80km/h||23.47m - Achilles ATR Sport||27.03 - Nexen Classe Premiere CP661a||3.55|
|50km/h||13.65 - GT Radial Champiro BAX2||17.62m - Kumho KH27||3.98|
|80km/h||34.04 - GT Radial Champiro BAX2||Nexen Classe Premiere CP661a||7.91|
Each tyre has standard markings that allow you to pick the right type for your car. It’s a confusing mix of letters and numbers, and of measurements in mm and inches. Here’s what it all means.
All new tyres are marked with a size and speed rating such as 185/65R14 86H. This means:
|Symbol||What it means|
|P||Passenger tyre (not always shown).|
|185||The tyre width (across the tyre) in millimetres when fitted to the correct rim and inflated. A larger number means a wider tyre.|
|65||The profile or aspect ratio. In this case, the height is 65 percent of the width.|
|14||Rim diameter (inches). This can be metric, but very rarely.|
|86||A load index, which allows you to calculate the maximum load from a table. Tyre dealers have copies. 86 means this tyre can support a maximum load of 530kg. Not always shown on older tyres.|
|H||The speed rating. This is the maximum speed the tyre will withstand at the rated load, in this case 210km/h. Speed ratings are typically from Q (160km/h) to Y (300km/h). Retreads have the speed rating removed, but those made to NZS 5423 are capable of speeds of at least 100km/h.
Older tyres may have the figures and letters in a different order (185 SR13) but they mean the same thing. Use the size and speed ratings when checking prices, to ensure you are comparing like with like. Replacement tyres should always have the same or better ratings.
To keep the tyre grip evenly balanced when cornering, a car must have the same size and type of tyre on the left and right wheels on an axle (and usually the same size all round). Marking the size means WOF inspectors can easily check that your car has the right-sized tyres.
It also helps you. When you’re looking for the best price on a replacement tyre you need to be able to quote the size (and sometimes the load and speed ratings).
The triangle on the sidewall points to a small bar in the tread grooves, which shows the minimum tread depth. The letters “TWI” or the maker’s logo are alternative sidewall markings for the indicator.
Standard markings can reveal the tyre’s origin. All tyres (except some Australian-made ones) should have at least one of these marks.
There may also be information about the construction: number of plies and ply material, tubeless rating and information about suitable uses, or how to correctly mount the tyre (see Directional tyres, above).
Replace a single tyre with the same type and size (a different brand is acceptable in an emergency). Don’t mix an old cross-ply type with a radial, or a steel belt with a fabric-belt tyre on the same vehicle. This can make the vehicle too difficult to handle safely and is against the law.
Put the tyres with the best grip on the rear. If you lose grip, it’s easier to control an understeer than a rear-end oversteer.
WOF rules say you can fit tyres that are no more than 5 percent larger or smaller in diameter (so replacing tyres up to 20” diameter with tyres 1” larger or smaller is fine). If they are wider, the tread must not extend outside the body panels and the vehicle’s track (the distance between the centreline of tyres on an axle) must not vary by more than 25mm. Anything bigger in diameter or width will require a modified certificate.
Our low-mid-high categories are based on each particular tyre size. For example a high-price 165/R14 tyre may be less expensive than a low-price 225/R18 tyre. Most tyres we test are mid-priced ‘Premium’ models suitable for most consumers. However, in most sizes we also list some high-price ‘Performance’ and low-price ‘Budget’ tyres.
When using our results and shopping for tyres, here are a few tips:
If the tyre size you need isn’t covered by our tests, look through the test results and note which brands and models do well in sizes close to the one you need. One of these models would be a sensible choice.
Phone around. During our surveys we find large variations in tyre prices. Retailers running specials were able to sell some models around $100 cheaper per tyre than others. Haggle for the best price using quotes from other fitters.
Consider the total price of your new tyres. Quotes for tyre prices should include fitting and balancing cost, but also ask about wheel alignment – you might get this offered at a discounted rate. If you are shopping for budget tyres, it might be worth paying a little more for Premium tyres that come with a road hazard warranty.
Tyre prices can be difficult to find online – most fitters will only offer a quote in person or over the phone. But check websites such as hyperdrive.co.nz who offer a wide range of tyres with online prices that include local fitting.
Since April 2010 if you need snow tyres, they must be fitted to all wheels of the vehicle. They also must have a minimum tread depth of 4mm – more than twice the 1.5 mm depth for normal tyres.
This change was brought about by the deaths of 4 people in accidents involving cars with snow tyres fitted only to the rear wheels.
Tests later showed this combination was highly unstable in certain conditions. We called in 2008 for the rule to be changed and fortunately there have been no further deaths as far as we know.
We think snow or winter tyres should only be used in the conditions they’re designed for: on snow and ice in winter.
Given good operating conditions, regular rotation and a conservative driving style, a set of new premium steel-belt radials should last for 50,000km or more. Expect less from around-town use with lots of turning and braking, or high-speed use with hard cornering and braking
Given the cost of 4WD tyres – $200 to over $500 – it’s well worth thinking about.
Tyre companies offer a compromise: 4WD tyres designed for the road. They don’t have the macho tractor-tread look and won’t be so useful in the mud, but they’ll last longer and give better braking on wet tarseal.
However, if you drive a 4WD that never leaves the road, you still need tyres that are designed for the vehicle. That’s usually because of the extra weight involved.
When buying, it’s useful to know 4WD tyres frequently have their sizes measured in old fashioned inches. The alternative is metric – the same way as car tyres. Yes, it just adds to the confusion!
A 4WD tyre with the markings 31 x 10.50 R15 LT M/S 109Q means ...
|Symbol||What it means|
|31||The overall diameter (31 inches). Not always shown.|
|10.50||The tyre width (across the tyre). 4WD tyres often show this in inches (10.5) when fitted to the correct rim and inflated. A larger number means a wider tyre. It could also be metric, and include the profile (eg 265/70).|
|15||Rim diameter (inches).|
|LT||Light truck, includes 4WD. Not always shown.|
|M/S||Mud and snow. Can be M+S.|
|109||The load index. 109 means this tyre can support a maximum load of 950kg.|
|Q||The speed rating, in this case 160km/h.|
|10PR||The ply rating. Shown as an alternative to load index and speed rating on older designs.|
The NZTA has imposed a speed limit of 80km/h, which is marked on the label.
You’re supposed to drive on it only for a short distance - to get yourself home or to deliver the car to the nearest tyre fitter.
Keep it pumped up tight to the pressure marked on the label or tyre. This is usually around 60psi or 420kPa. They are safe only when used at the right pressure, which is usually at least twice that of a normal tyre.
Used within the guidelines, they are safe. Running them too soft or too fast can be dangerous.
If you would rather have a proper spare, and you want to keep your costs down, check the wreckers’ yards. You may be able to pick up a cheap rim (we’ve seen them for $30 to $50) and then get a good second-hand tyre put on it. Make sure it will fit your hubs and the spare wheel well.
Watch those emergency repairs as well. “String repairs”, where a length of stringy material is forced through the hole from the outside, or sealant repairs (injected through the tyre valve) are not permanent. Both are done without removing the tyre from the rim and are not safe for long-term use.
If you get one of these done, you should have the tyre taken off the car and fixed properly as soon as possible.