Join Date: Jul 2004
Location: melbourne, australia
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some info on changes to the snow chain requirements in NSW...............
The RTA is reviewing the NSW laws for snow chains to include other than 2WD vehicles .
" other than 2WD vehicles" includes AWDs and 4WDs as there is no difference in these two names in the definitions of the RTA and the Commonwealth Department of Transport.
If the new law is passed and the implementation requirements are finalized the new regulations will likely apply from 2008
This change has come about because of the increasing number of "incidents" involving AWD vehicles in the areas where snow chains are required to be carried in NSW.
RTA has wants to improve the road safety for ALL road users and to reduce the congestion and delays on the roads when an incident occurs.
RTA statistics show more than 50% of these incidents involve other than 2WD vehicles.
Snow chains are fitted to either the front or rear of AWDs based on the information supplied in the vehicle owners manual.
Many vehicles have insufficient clearance between the tyre and the suspension to allow any chains to be fitted.
The owners manual will show tyre sizes that snow chains can be fitted to correctly.
In this age of litigation there is a liability component if a vehicle is used with chains fitted to a tyre size where the owners manual states “ The use of snow chains is not permitted.”
The RTA also advise that safety of any AWD vehicle in snow and icy conditions is determined by the tyres.
High speed rated summer tyres, all-season tyres, off-road tyres and all-terrain tyres, by definition are not winter/snow tyres.
AWD summer tyres become like hard plastic when the temperature falls below 7° thereby losing the flexibility needed to build up sufficient grip for braking, for starting traction and for cornering.
Off-road and all-terrain AWD tyres are not specifically designed for winter/snow driving either.
These types of AWD tyres are designed for off-road driving on gravel, sand and rocks and have a very high noise level.
First and foremost, the single most important aspect of a winter tire is the tread compound that remains soft at lower temperatures.
Under cool conditions—not just cold or frigid conditions—the rubber in the tyre gets even harder.
This stiffer tread compound does not conform to irregular road texture as well, and as a result has less actual contact with the road surface.
A winter tire compound remains soft and pliable at lower temperatures.
Because off-road tyres have very limited siping on their tread they provide little traction in icy conditions.
Many AWD tyres are rated M/S, M+S or M&S, i.e., mud and snow.
The term “mud and snow” is very misleading.
Established by the USA Rubber Manufacturers Association, the M+S designation refers only to the tread pattern.
The M+S standard calls for a tyre with grooves at the outside of the tread that extend into the centre.
It also means that 25% of the tyre tread contact surface be open, i.e., a more open tread pattern.
However, there are no performance standards to meet or traction tests to pass.
Any tyre with grooves at angles and with 25% of the tread void can be labeled as M+S.
And on icy snow and on ice, the open tread grooves have zero effect on performance.
Control of the vehicle comes strictly from equal parts of the compound adhesion and the effects from the tread sipes.
In 1999, the RMA defined a real “snow” or winter tyre with its severe snow-rating.
The RTA is using AWD tyres that pass this performance test and are embossed with the "snowflake on a mountain peak" icon.
Severe snow-rated tyres must provide traction at least 10% better than a standard reference test tyre.
The off-road, all-terrain and all-season M+S tyres cannot pass this test.
The M+S rating doesn’t mean much.
The severe snow rating does.
Always remember that no matter how many safety features an AWD vehicle has it is the tyres that determines how it drives and handles on snow and ice.
Rud chains in stock at Roof Carrier Systems. give richard a call on 03 9822 9539