(I know most parts of these topics have already been covered on this site but just thought it'd be good to have it all in once clean post)
This info was collated from: http://www.amgaustralia.com
Tyres - General Info & Maintenance
They're round, black and made of rubber. Tyres. Not the most exciting part of a car, are they? Tyres are a vital component of your vehicle however, and have a big influence on its performance.
Your tyres have to transmit all of the cars driving, steering and braking force to the road surface through four contact areas, each approximately that of a size 10 men's shoe; on all types of surfaces and in varying weather conditions.
That little bit of rubber has to do an awful lot.
You’re travelling along the highway at 100klm/hr and your engine seizes, your windscreen wipers stop or your battery dies? What happens? Generally speaking, not much. You slow down, pull over and sort the problem. And when your tyre blows out?
It can mean Game Over for you and your passengers, and anyone else who gets in the way.
So what’s riding on your tyres? More importantly, who? Please take a moment to view some of the information we have provided in this section and make sure you are making the best decisions when it comes to round, black rubber.
Tyres are high technology items that have been continually refined and improved by over 100 years of research and development. The wheel and indeed the tyre have been improved upon and these days we are riding on a great deal more than rubber, as the diagram below shows...
Maintenance
Continuing to use worn, damaged or simply the wrong tyres can literally mean the difference between life and death.
A set of new tyres on your car can cost upwards of $400 so it's well worthwhile looking after them. Regular checking is vital - if you don't catch a leaking tyre early it could be ruined in no time at all. Some things to consider:
Tyre pressure – check this every 2 weeks and use a reliable pressure gauge (check them when they are cold). Make sure you maintain the recommended pressure at all times. Around 80% of passenger car tyres run with some degree of under-inflation and this affects tyre longevity, passenger safety and fuel consumption
Tread – the minimum legal tread depth in Australia is 1.6mm. This is the minimum depth and it is worth noting that your stopping distance in wet weather may increase up to 70%, compared with a new tyre. To ensure long life and even tread wear, rotate your tyres at every service, or at least every 6 months. Front tyres on a front wheel drive car wear 2 ½ times faster than the rear tyres so it is even more important to do this. Once uneven tread wear has set in, it is impossible to stop.
Load - Utes, panel vans and 4WDs - check the tyre pressure is right for your load. Check the tyre placard and /or the owner’s manual for the correct pressure for the load.
Ouch - Avoid scuffing and hitting kerbs when parking your vehicle.
Valve cap - Make sure all your tyres have a valve cap, as it is the main seal.
Tyres - Sidewall Markings
In Australia, the only markings required on a tyre sidewall are as follows:
• Manufacturers Logo or brand name
• Tyre Size, Series, Rim Size, Load and Speed Rating/Symbol
• Serial No. - date code (when tyre was built; week & year. eg 2704 is the 27th week of 2004)
• Details of construction showing tyre size, radial, tubeless or tubed
• Country of Origin
• Mould Number
• Factory code number
On the sidewall of a tyre you will notice a number codes and markings which relate to its various features. As an example, a tyre could have the code P205/65 R16 95 V printed on the side wall, and this is broken down as follows:
P - type of vehicle the tyre was made for (P=Passenger, C=Commercial, LT=Light Truck)
205 - section width of the tyre in millimeters
65 - height of the sidewall described as a percentage of the section width. Larger numbers mean a more comfortable ride. Smaller numbers mean better performance but a harder ride.
R - radial ply construction (steel belts running across the tyre from lip to lip). 98% of tyres today are of radial ply construction as they deliver greater stability, less wear and better fuel economy
16 - diameter of the wheel rim in inches
95 - load index. The maximum load capacity of the tyre. 95 equates to 690kg (please refer to "Load Index & Speed Rating" below)
V - speed rating. Indicates the maximum speed at which the tyre can carry its rated load. V equates to 240klm/h (please refer to “Load Index & Speed Rating" below)
Load Index & Speed Rating
Reference tables and further information can be found in the “Tyres – Load Index & Speed Rating” section (select from Top).
Tyre Age
Tyres carry a three digit code on the sidewall indicating the month & year of manufacture. For example; 129 means the tyre was manufactured in December 1999.
Other Markings
M&S - mud and snow tyres
DOT codes - (denotes US Dept. Of Transport codes; place of manufacture etc)
E-marks - (European Community codes)
UTQGS - Uniform Tyre Quality Grading System; a system that covers grade markings for tread wear, traction performance & temperature resistance on all tyres manufactured & sold in the US. This system may be shown on tyres sold in Australia and may be "helpful" when buying tyres in Australia, however it cannot be taken as a safety rating or guarantee as to how well a tyre will perform on Australian roads as they are based on tests carried out in the US under very specific conditions for that specific market.
For further information, please speak directly with your professional tyre retailer.
Tyres - Load Index & Speed Rating
The Load Index is an assigned number ranging from 0 to 279 that corresponds with the maximum load carrying capacity of a tyre. Most passenger car tyre load indexes range from 62 to 126.
The Speed Index is an assigned letter ranging from J to Z that corresponds to the reference maximum speed at the associated load index.
These two elements put together are called the Service Description and are mutually dependent (one takes into account the other).
Please visit this link for further information on the load index and the speed symbol with their corresponding values
Load Index and Speed Ratings Here
So then, in relation to the above load and speed rating information, the sidewall code "P215/65 R 16 95 H" means the tyre is rated to 690kg of load (each tyre) up to a maximum speed of 210klm/h.
Drivers should be aware that these ratings exist to protect the public from the possible outcome of overloading a tyre. You should also bear in mind that these load ratings apply to a properly inflated tyre (see "Tyres - Inflation").
Overloading a tyre - either by carrying more weight than it is designed to carry, or by running at a lower than specified pressure, can cause heat build up than can destroy the tyre. Even at low speeds a blow-out can be fatal.
Tyres - Selection
If you are replacing tyres on your car, it is essential that they meet the minimum standards that are detailed on your Tyre Placard (see example below), which can normally be found in the glove box cover, doorjamb or under the bonnet. Every new car sold in Australia since 1973 has been required to have this placard.
When you do replace your tyres, you must ensure that the load carrying capacity is at least equal to, if not better than, the sizes shown on the placard. You must also comply with local road and vehicle legislation. Legislation requirements can vary from state to state.
Check with the transport authority in your state to confirm the legislation that applies to you:
The NSW Roads and Traffic Authority
VicRoads
Queensland Mainroads
Mainroads Western Australia
Northern Territory Dept of Transport and Works
Dept of Transport Tasmania
Transport SA
ACT Dept of Urban Services
You need the right tyre to ensure maximum life and lower cost (overall). There are many factors to consider when purchasing tyres for your car and these should be discussed in detail with your professional tyre retailer. Put the pressure on and see f you can get the dealer to provide a free balance and/or rotation after 5,000klm. It’s the squeaky wheel that gets the grease...
Driving style – Are you a lead foot or driving Miss Daisy? You’ll need to match the right tyre for your driving style or adjust how you drive (perhaps the correct tyre would be best).
Vehicle type – There is a vast difference between the forces at play on the tyres of a car, 4WD, commercial van, light truck etc. There are vastly different tyres for each type of vehicle.
Road surface – Have a think about what type surface you expect to be driving on most of the time. ie sealed, gravel, good/poor condition, dry/wet etc.
Load/weight – You might regularly have a tonne of bricks on the back or perhaps just the weekly shopping. Be absolutely certain your tyres can handle the load expected.
Budget – The best things in life (like love for example) are free. Not so with tyres sorry. You’re going to have to decide how much you can afford and bite the bullet. Your tyres are crucial to keeping your vehicle safely on the road, so don’t cut corners here. It may literally be a matter of life and death. The great news is that the rise in the cost of tyres over the past 15 years has been 20% less than the cost of living. What’s riding on your tyres?
Tyre Compound – This refers the rubber in the tyre being soft or hard. Softer tyres will stick to the road a great deal better but are more expensive and wear out faster (eg 20,000klm). Harder compound tyres will not grip quite as well but are often cheaper initially and will last longer (eg 60,000klm).
Profile – This refers to the side wall of the tyre and is also known as aspect ratio or series. A higher profile will mean a softer ride but not quite the performance, especially on sharp turns, as the tyre will roll less. A lower profile will be a harder ride but will be more responsive to sudden turns.
Caution – Second hand tyres. These can be risky unless you know their history and can be sure they haven’t been damaged or abused.
Wheels - A Wheel Good Story
Wheels. They compliment tyres quite nicely. In fact it has been said that tyres feel all hollow and empty inside without them. In turn wheels are much more rounded and stable with a tyre on board and are capable of telling a much more gripping tale. From the very beginning it was a match made in heaven.
So who exactly invented them? It is not precisely known but according to archaeologists it was probably invented around 8,000 BC in Asia. The oldest known wheel however, was discovered in Mesopotamia and dates back to 3,500 BC. One clever little Sumerian (who must be kicking themself for not lodging the design with the International Patent Office) came up with the design which is believed to have evolved as shown below...
The rest as they say is history, and a fine history at that. What a pleasure it would be to take a 19x9.5, AMG Style IV, 2 Piece Titanium Grey Painted wheel with a Machined Outer Lip and Protective Coating back to that clever Sumerian inventor and say “Look what you started...”
We may well reinvent the wheel before we can travel back in time so let us give thanks and roll on into the future...
Have a look around you and I bet there is some type of wheel within sight. On a shopping trolley, computer mouse, door, engine, sticky tape dispenser… the list is endless. Its impact on our lives is prolific by any standard.
With that said, you’re hardly visiting our site to listen to us wax lyrical about wheels on a shopping trolley now are you? Rumour has it you are here to give your chariot that more refined look, make it a little more sporty, go one up on the Jones’, or perhaps just make it look “fully sick”.
Whilst the Egyptians, Romans and Greeks certainly made some worthwhile improvements, we at AMG believe we have the best looking wheels on the planet. We’d love to show you are wares…
Wheels - Maintenance & Care
Now that you have made a significant investment in the wheels for your car you’ll want to take the very best care of them. Some simple steps will help maintain the look of your wheels for years to come…
Washing
Modern wheels enhance your car’s appearance and performance but there’s a catch. You must take extra care if you want them to stay looking good. The biggest challenge comes when heated dust particles from your brake pads settle on your wheels and get baked on (notice that your front wheels especially have that coat of black dust on them?). Leave it there for too long and a process known as “galvanic corrosion” will set in and destroy the wheels finish. Sounds horrendous, doesn’t it?! Five minutes work on the weekend will keep it at bay (or a coffee and read of the newspaper at Car wash Café will suffice).
Painted Finish
First of all, make sure you wash your wheels when they are cool. It can be much harder to clean wheels effectively when they are hot and you also run the risk of warping your disk brake rotors if they are cooled rapidly with water.
As the finish on your wheels is similar to your vehicle’s paint job (in most cases), we recommend that you use water and a mild detergent that is designed for washing vehicles. Refrain from using chemical cleaners as many of them contain caustic substances that can damage the clear-coated finish by clouding or even removing it. If you wash your vehicle regularly there should be no need to use them.
It’s a great idea to wax your wheels 3-4 times per year to maintain the new look and also keep road grime and the elements from damaging the finish.
Chrome
The same rules apply as above though greater care is required as chrome plating is generally more delicate. Be sure not to use any abrasive chrome polishes as this could scratch the chrome plating. If you live in a climate where road salts are used in winter, we recommend removing the wheels during this time. Chrome wheels will rapidly pit and become cloudy due to long term exposure to the chemicals in road salts.
Note:
If you do wish to use a specific wheel cleaner, bear in mind there are two types:
Acid-based: many car detailers and car washers use these to get the job done quickly with the least amount of effort.
Non-acidic or acid-free: These are much gentler on the wheel though will require a touch of elbow grease (effort) combined with a soft sponge.
As with anything in life, take good care of them and they will last a long time.
Maintenance
Tighten your nuts
Sound painful? It won’t take that long. Perhaps when you get your car serviced ask the team to check this for you. It’s rare that they will work their way loose but when they do, you may get to see your beautiful wheel trundling off down the road whilst you fight for control of your vehicle.
Careful Driving
Wheels and gutters are notoriously bad at getting along. Indeed, some drivers are themselves notoriously persistent in introducing the two. The most obvious solution? Don’t hit them. Still, with that said, perhaps we can offer some more pertinent advice:
• Allow an extra inch or two when puling into the kerb.
• Use your left side mirror to watch your back wheel as you reverse in (adjust it down slightly).
• Keep well clear if going in forwards and then use your side mirrors as above
• If in doubt, don’t guess. Start again (the world can wait and still survive)
Repairs
Depending on the scale and severity of the damage, many alloy wheels can be repaired. Contact the distributor from whom you originally bought your wheels to discuss
Wheels - Variations
There are varying types of wheels to be found on a car these days, mostly under the banner of steel or alloy wheels. Within this you can then have one-piece or composite (2 & 3 piece) wheels.
Steel
Steel disc wheels, still found on the majority of cars sold, are inexpensive, durable, heavy and flexible. If you’ve ever wondered why hubcaps fly off cars in old movies, and will still do it today on any high speed cornering, it’s because the wheels flex and pop the covers off. We recommend you don’t try this at the last corner on the way home. Steel wheels have their place but today they should be considered unacceptable for any performance use. Besides that, they just don’t look as good now do they?
Alloy
Alloy wheels are lighter than steel which improves the steering and speed of the car. Lighter wheels are easier for the suspension to control, improving ride and handling, and are easier to accelerate and decelerate. Alloy wheels are also better heat conductors thereby improving heat dissipation from the brakes, which reduces the chances of brake failure (which generally occurs under more demanding driving conditions).
Alloy wheels are generally considered better looking than hubcaps though they are more expensive.
or 
We’ll let you decide.
There are generally two types of alloy wheels; magnesium (or “Mag”) and aluminium, though sometimes a mixture of both has been used. The more common aluminium wheel of today is often mistakenly called a mag wheel. Not so.
Be aware that alloy wheels are prone to galvanic corrosion if appropriate preventative measures are not taken (see “Wheels – Maintenance & Care” at Top)
Magnesium or “MAG”
This type of wheel first came about in the 1950’s and was modelled on aircraft technology (with the stipulation that the car should remain on the road). They are most often used on racing tracks these days as they are lighter, giving better performance. However, they have been banned in some UK motorsport as they have been known to catch fire. Exciting stuff. Don’t panic if you have mag wheels though as this tends to occur when a tyre blows and you keep driving on the rim. If you blow a tyre, stop immediately.
Some variants of mag wheels have a low corrosion resistance though they are rather expensive.
For the die-hard magnesium fans amongst us, never fear. Magnesium is set to revolutionise the engine industry in the years ahead, replacing aluminium engine blocks. Aluminium is around 66% lighter than steel, whereas magnesium is about 75% lighter. Check out the CSIRO website for more information http://www.csiro.au/science/ps18z.html
Aluminum or “AL”
They are NOT called Al. Just seeing if you are still paying attention. Most modern day alloy wheels are made from an aluminium alloy and are done so from one of several processes; casting, forging and billet.
Casting is done by pouring molten metal into a mould shaped more or less like the finished wheel, and letting it cool. Some polishing and finishing is then done to complete the wheel. There is a slight variant to this called pressure casting where the metal is pumped into the mould creating a less porous structure. The vast majority of alloy wheels are cast and provide many years of good service (ie they will go round and round).
Forging is an interesting process. Basically a chunk of aluminium is heated slightly so that it is soft and pliable, and is then slammed with hundreds of tons of force to press it into the rough shape of a wheel. In doing this the structure of the metal is changed whereby the crystals, or grains, change from a non-directional structure to a multi-directional high-integrity structure.
We could bore you to tears with the exact science of this so instead we’ll let 2 pictures speak 2,000 words. Fig A is the structure of the alloy in a cast. Notice how there are different sized crystals in different areas, depending on how it is poured. In Fig B the alloy has been smashed so hard that the crystals have been “coerced” into a uniform structure. Imagine a bed sheet of average quality with varying thread counts across its width and breadth. It’s strong but in time will break down. Now think of the finest Egyptian sheet with high density, uniform threads.
Figure A 
Figure B 
The forged “blank” is then placed in a spin-forging machine to spin out and forge the rim section.
Ultimately this process creates a wheel that has little to no porosity (preventing corrosion and cracking) and is about the strongest aluminium possible. The diagram below illustrates the forging process.
Billet is the process of forcing metal into a hallow cylinder which is then pressed out through an opening of a particular shape. Think back to when you pressed Play-Doh and it came out in little tubes, cylinders, stars, squares etc. The metal tube is then cut into discs and these are then machined using CNC (Computer Numerically Controlled) millers to carve out the finished product.
The advantage of billet over casting is that it uses a solid piece of metal rather than liquid metal poured into shape, which can be affected by many variables including such things as humidity and the presence of foreign objects (depending on manufacturing standards).
The billet process can be rather expensive as each item requires much more time to be handled and cut.
One-Piece & Composite (2 & 3 PIECE) Wheels
Wheels can be created as a single piece structure or made up of two and three pieces.
One-piece wheels are usually much cheaper to produce as they require no additional assembly. The initial setting up of tools/machines is more expensive but the manufacturing process is much quicker. It is often lighter as well as there are no extra bolts for the connection of the pieces.
Composite wheel’s main advantage come from providing exact fitment and are of course easy to repair. For those of you who have not read our “Wheels – maintenance & Care” section and have hit a gutter, with a composite wheel you can remove the outer rim and have it repaired or replaced. Composite wheels tend to be a bit heavier due to the extra bolts etc required for connecting the pieces, and they take more money and time to build as expensive humans are required to assemble the pieces.
Wheels - Offset, Wheeltrack & PCD
Offset
If you are thinking of purchasing a set of aftermarket alloy wheels, selecting wheels with the correct offset is very important. So what is offset, and why is it so important?
Offset is a measurement of how far the mounting face of the wheel (on the brake side) is away from the centre line of the wheel. If the mounting face lines up exactly with the centre line it is called “Zero Offset”, if the mounting face is further out towards the show side of the wheel, this is called “Positive Offset”, and if it is further inside the wheel (towards the brakes) then this is called “Negative Offset” (this is much rarer). There are two common ways to measure this though they both provide a different number:
Backspace: Measure from the brake side edge of the rim to mounting surface of the wheel (as shown in the “Straight Edge” section of the diagram below. This will generally be a reasonably high number (at least 80mm or more).
Centreline: Measure the total width of the wheel (X) and then halve this (X/2). Measure the backspace (A) and then subtract “A” from “X/2”. You now have the centreline offset. In Australia this is written as 35P (35mm positive) or 10N (10mm negative). In Europe it is usually written as ET35 etc.
Making sure you have the correct offset is important as it will affect where your wheel sits in relation to your vehicle. A high positive offset means the wheel will sit further inside the wheel and might rub up against the brakes or suspension. Worst case scenario, you will not be able to steer. A high negative offset means the wheel sits further out from the wheel arch and this can cause the tyres/wheel s to rub against the wheel arch. It is illegal for your tyres/wheels to stick out past your wheel arch in Australia.
In addition to this you must also be aware of limitations to changes made to your vehicles Wheeltrack
Wheeltrack
Wheel track is the distance between vehicles wheels (side to side). It is measured from the centreline of each wheel to the other. The fitment of wider wheels will often increase the Wheel Track and this can be associated with Offset as well. Increasing the Wheel Track can increase the load on bearings, axles, suspension joints and steering tie rods.
On a passenger vehicle the wheel track must not be increased by more than 25mm beyond the maximum specified by the vehicle manufacturer for that particular model. This means that the offset may not be changed by more than 12.5mm per wheel.
Wheel Track reduction is NOT permitted without the approval of the relevant registration authority.
Off-road and commercial vehicles fitted with front and rear beam axles may increase the Wheel Track up to 50mm in total.
All wheels fitted to the front or rear axles must have the same diameter, offset, width and mounting configuration (except the spare).
Where a two-axle vehicle is fitted with different width single tyres, the narrower tyres must not be less than 70%of the width of the wider tyres. As an example: if you were running 10 inch (254mm) wide tyres on the rear, your front tyres can only go as narrow as 7 inches (17.78mm).
PCD
PCD stands for Pitch Circle Diameter which basically means the diameter of an imaginary circle running through the centre of each bolt hole. The most common PCD values are 100mm and 114.3mm, the difference arising due to manufacturers using metric or imperial measurements (4.5 inches = 114.3mm).
You will need to ensure that your new wheels have the same stud pattern (4 and 5 stud shown above) and same PCD as the wheel hub on your vehicle. In addition to this you need to ensure you have the same centre location method and that the centre spigot is the same diameter as the original wheel. If this is not the same a metal adaptor ring should be used.
This info and more can be found at: http://www.amgaustralia.com
Rep awarded.
