Mud and Snow, (or M+S, or M&S), is a description applied quite subjectively by manufacturers for all-season and winter tyres designed to provide improved performance under low temperature conditions, in comparison to summer tyres. The tread compound is normally softer than the ones used in tyres for summer conditions, hence allowing for better grip on ice and snow, but it does wear out more quickly at higher temperatures. Tyres may have well above average numbers of sipes in the tread pattern to grip the ice. There are no traction performance needs which such a tyre has to meet; M&S relates to the percentage of tread void area.

Dedicated winter tyres will bear the “Mountain/Snowflake Pictograph” if designated as a winter/snow tyre by the American Society for Testing & Materials. Winter tyres will typically also carry the designation MS, M&S, or the words MUD AND SNOW (but see All-season tyres, below).

Some winter tyres are designed to accept the connection of metal studs for additional traction on icy roads. The studs also roughen the ice, thus allowing for better friction between the ice and the soft rubber in winter tyres. Use of studs is regulated in most countries, and even prohibited in some locales because of the increased road wear caused by studs. Typically, studs are never used on heavier vehicles. Studded tyres are used in the upper tier classes of ice racing and rallying.

Other winter tyres rely on factors other than studding for traction on ice, e.g. highly porous or hydrophilic rubber that adheres to the wet film on the ice surface.

Some jurisdictions may require snow tyres or tyre chains on vehicles driven in certain areas during extreme weather conditions.

Mud tyres are specific tyres with large, chunky tread patterns designed to withhold the muddy surfaces. The large, open design also lets mud to clear quickly from between the lugs. Mud terrain tyres also are wider than other tyres, to spread the weight of the vehicle over a bigger area to stop the automobile from sinking too deeply into the mud. In saying that, in reasonable amounts of mud and snow, tyres should be thinner.  If the tyre is thinner, it will have more pressure on the road surface, therefore allowing the tyres to enter the snow layer and grip harder snow or road surface that is underneath. This penetration doesn’t work when the snow is too deep where the vehicle will sink into the snow and ‘snowplow’ the snow in front. In this case, wider tyres should be used, as they have a larger contact patch and are better able to ‘float’ on top of the snow or mud.

If you need new tyres or any tyre advice, contact Foxman Auto services now on 02 9314 6699.

A tyre is composed of several parts.

Tread

The tread is the part of the tyre that comes in contact with the road surface. The part which is in contact with the road at a given instant in time is the called the ‘contact patch’. The tread is a thick rubber, or rubber/composite compound created to provide an appropriate level of traction that does not wear away too quickly. The tread pattern is characterized by the geometrical shape of the grooves, voids , lugs and sipes. Grooves run circumferentially around the tyre, and are required to channel away water. Lugs are the part of the tread design that contacts the road surface. Voids are spaces between lugs that allow the lugs to flex and evacuate water. Tread patterns feature non-symmetrical (or non-uniform) lug sizes circumferentially so as to minimise noise levels at discrete frequencies. Sipes are valleys cut across the tyre, usually perpendicular to the grooves, which allows for the water from the grooves to escape to the sides in an effort to prevent hydroplaning.

Tread lug

Tread lugs provide the contact surface necessary to provide traction. As the tread lug enters the road contact area, or footprint, it is compressed. As it rotates through the footprint it is deformed circumferentially. As it exits the footprint, it recovers to its original shape. During the deformation and recovery cycle the tyre uses flexible forces into the vehicle. These forces are described as Force Variation.

Tread void

Tread voids provide space for the lug to flex and deform as it enters and exits the footprint. Voids also provide channels for rainwater, mud, and snow to be channeled away from the footprint. The void ratio is the void area of the tyre divided by the entire tread area. Low void areas have high contact area and therefore higher traction on clean, dry pavement.

Rain groove

The rain groove is a design element of the tread pattern specifically arranged to channel water away from the footprint. Rain grooves are circumferential in most truck tyres. Many high performance passenger tyres feature rain grooves that are angled from the center toward the sides of the tyre.Some tyre manufacturers claim that their tread pattern is designed to actively pump water out from under the tyre by the action of the tread flexing. This results in a smoother ride in different types of weather.

Sipe

Tread lugs often feature small narrow voids, or sipes, that improve the flexibility of the lug to deform as it traverses the footprint area. Off-road Tyre enthusiasts have been siping tyres for years for greater traction, as many manufacturers now offer already siped off-road-tyres.

Wear bar

Wear bars (or wear indicators) are raised features located at the bottom of the tread grooves that indicate the tyre has reached its wear limit. When the tread lugs are worn to the point that the wear bars connect across the lugs, the tyres are fully worn and should be taken out of service.

Bead

The bead is that part of the tyre that contacts the rim on the wheel. The bead is typically reinforced with steel wire and compounded of high strength, low flexibility rubber. The bead seats tightly against the two rims on the wheel to ensure that a tubeless tyre holds air without leakage. The bead fit is tight to ensure the tyre does not shift circumferentially as the wheel turns. The width of the rim in relationship to the tyre is a reason in the handling characteristics of an automobile, because the rim supports the tyre’s profile.

Sidewall

The sidewall is that part of the tyre that bridges between the tread and bead. The sidewall is largely rubber but reinforced with fabric or steel cords that provide for strength and flexibility.

Shoulder

The shoulder is that part of the tyre at the edge of the tread as it makes transition to the sidewall.

Ply

Plies are layers of relatively inextensible cords embedded in the rubberto hold its shape by stopping the rubber from stretching in response to the internal pressure. The orientation of the plies plays a large role in the performance of the tyre and is one of the main ways that tyres are classified.

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In some jurisdictions, proof of inspection is required before a vehicle licence or license plate can be issued or renewed. In others, once a vehicle passes inspection, a decal is attached to the windshield, and police can enforce the inspection law by seeing whether the vehicle displays an up-to-date decal. In the case of a vehicle lacking a windshield (e.g., a trailer or motorcycle), the decal is usually attached to the vehicle body or license plate.

With regard to a safety inspection, there is some controversy on whether it is a cost-effective way to improve road-traffic safety.

Vehicle inspection in Australia is done on a state basis. Each state or territory has the authority to set its own laws pertaining to vehicle inspections, all (with the exception of the self-governing territory of Norfolk Island) have some form of inspection, either periodically or before a transfer of ownership.

Constant car inspections are important to ensure safety of the vehicle.

For trustworthy and quality car services and repairs, contact Foxman Auto on (02) 9314 6199 or visit their website here: http://www.foxmanautoservices.com.au/