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Nuts & Bolts
How is an alloy wheel made up and what are all the different parts called?
Alloy wheels on the face of it (pun intended) are relatively simple, they consist of a big round bit of metal shaped nicely to look good and then some holes drilled into it to let you fit the wheel to your car. However, like most things in life, there is more than meets the eye when it comes to alloy wheels. So what are the parts? Well, you have the rim, the face (see now the joke makes sense), the barrel, the mounting face and the rear lip. What are each of these I hear you ask, well let's look further into it...- The Rim - Generally this it the outside most part of the front facing part of the wheel, also known as the front lip. This part is usually the part that will take the most amount of the abuse when you curb a wheel or if you are running on really low profile tyres and as such, it is generally rolled to increase its strength. When we talk about a polished lip wheel, this is the part that is polished and creates almost like a halo around the wheel.- The Face - The money maker, the make or break of an alloy wheel, the face of the wheel is the piece that holds the design. Be it 5 Spoke, Mesh Design or any other version of a wheel you can think off, this is the wheel's main selling point and what makes it look like it does. There are different things you need to look at when we are talking about the face and the design and we cover the different designs in an upcoming help page [HERE].- The Barrel - This is what makes the width up of the wheel it's the middle part going from the front lip/rim and the face to the rear lip. When you are looking at staggered wheels for your BMW or Mercedes-Benz this would be the only part that really changes and the wheel would look the same and generally have the same face however when you put the 18x8 and the 18x9 together there is an obvious difference in the length of the barrel. Unless of course you are looking at wheels that have concave or deep dishes as part of their design, but more on that [HERE].- The Mounting Face - This is where the magic happens, i.e. where the wheel actually marries up the car hub. So this part of the alloy wheel that the bolt holes are drilled into and where we are going to be putting our spigot rings into. Essentially it is the part of an alloy wheel that changes the most from car to car due to changes in PCD or Offset.
How do I clean my rims? How do you clean brake dust off rims? What is wheel sealant?
In basic terms, wash them. Cleaning your wheels regularly is really the best way to keep them in the best condition and looking like new, however we do have some recommendations on how to keep them at their best.
Regular washing is good, but using the correct wheel cleaner is the best. For instance, using some car shampoo to wash your wheels is better than just using water, however a dedicated wheel shampoo (like Orchard Autocare Wheel Cleanse or Sonax Extreme Wheel Cleaner) is obviously the way forward. These are designed to be strong enough to cut through brake dust and general traffic dirt but are safe enough to not damage the finish. Besides consider they are a fraction of the price of a full wheel respray it makes sense to be using the right cleaner.
We often get asked, what is a wheel sealant or how do I use a wheel sealant? Really they are exactly the same as what you will use on your car’s paint, however specifically designed to the tough enough to stop brake dust from eating through them and most are designed to withstand the high temperatures from braking. Using a good sealant in coordination with a good shampoo will make the cleaning of your wheels even easier as the sealant acts like a small force field holding the dirt off the paint so it cannot bond with it and become stubborn, then the cleaner effortlessly removes said dirt from the sealant. Here at Performance Alloys we have always used Orchard Autocare Speed Seal with great results.
For REALLY dirty wheels we recommend a good fallout removed (we use Orchard Autocare Iron Cleanse). This will instantly react with the brake dust and start to break it down, this also has the cool effect of turning the solution purple as it does it.
Pay attention to your nuts!! Or bolts of course. Like everything in life the small details can make or break it and with alloy wheels it is the nuts and bolts that will do it. When you are cleaning your wheels make sure to clean around them too as dirt gets caught in their holes rather easily and is usually overlooked. If your nuts are rusty why not have a look at ours? We carry a whole host of wheel nuts and bolts in loads of different fitments, sizes and finishes. If you want the best finish that is the hardest wearing we have ever seen then check out the McGard range - personally I recommend the the full McGard fitting kit as not only does it have the chip resistant / corrosion resistant and generally awesome nuts/bolts but it also includes a set of 4 McGard locks.
OCD wheel cleaning
Ok so the following tips are for people who either have really dirty wheels and need them cleaned or people who want really clean wheels or well anyone who is interested.
Now let’s say you have power hosed the wheels down, used a fallout remover, wash the wheels and are still not happy enough yet to put your new sealant on them, what else can you do? Well alloy wheel paint can generally be treated the same as car paint but using specific products. So what do you do?
Get the wheels off the car. Rather simple, jack the car up, take the wheel off and give yourself better access to it, this way cleaning the inner barrel is going to be much much easier.
If you haven’t already done so, use the same steps as above on the inner barrel (or if you are reading this before hand then start with removing the wheel). This way the whole wheel will be in the same condition and no chance of contamination from hidden dirt.
Now you’ve got the majority of the dirt off it’s time to go after the rest of it. So to start you will probably find small black spots all over the barrel and possibly the face, these are most likely tar. Simple to remove so long as you have a good tar remover (Orchard Autocare Tar Cleanse is out house choice!).
Now to get super clean wheels you need to get your hands on a clay bar. Follow the instructions on whichever one you get and you will be able to actually feel the difference in the alloy, the clay actually pulls out all the tiny parts of dirt trapped in the paint to give the paint a super smooth finish and usually the difference can be seen as the paint is much clearer and deeper.
The final step is to lightly polish your wheel to make sure that any gloss in the wheel is fully revitalised and to make the paint pop.
Once you have followed all these steps then you are ready to apply your alloy wheel sealant safe in the knowledge that your wheels are as clean as possible and the sealant will keep them in this condition!
Now some of you may be asking what about my tyres? Why go through all this to just leave the tyres? Well we cover all aspects of making and keeping your tyres looking 100% over HERE.
Questions asked on Google:
What is wheel offset? What is the offset of a wheel? What is alloy wheel backspacing? What is the ET number on alloy wheels? What is negative offset? How do you know the offset of a rim?
Put simply the offset of an alloy wheel is one of the measurements that makes up it’s fitment and then in turn dictates whether it will fit onto the car or not. So mixed with the PCD, Diameter and Width of the alloy wheel we will be able to tell you if the wheel fits your car.
*View our page on Wheel Sizing how to measure an alloy wheel [HERE]*
Want to know more? Well technically speaking the offset is the distance in mm from the centreline of the wheel to the mounting face of the alloy wheel. Simple enough so far. Since it is a physical measurement and the mounting face can be in front of or behind the centreline then the offset can be POSITIVE or NEGATIVE. See the image below for a visual representation of this.
So what is the difference in positive and negative offsets?
Ok so let’s look at this in 3 ways.
Positive Offset and,
Nice and simply a ZERO offset is when the wheel’s mounting face is inline with the it’s centreline. This means they both line up and there is no difference, therefore nothing measure, therefore an offset of ET0. Don’t worry we will get onto the whole ET thing in a moment.
[Click here to see wheels with an ET0 offset] - this will be wheels with ET0
A POSITIVE offset is when the mounting face is IN FRONT of the centreline of the wheel. So putting it in it’s basic terms, if you were to cut the wheel in half you would see the mounting face would be on left of the centreline, as in the image above. If you are looking at the wheel straight on from the front they tend to be a flat style or with a small dish or possibly a slight concave.
[Click here to see wheels with POSITIVE offsets] - this will be all wheels with ET1 and above.
Now a NEGATIVE offset is one that has the mounting face BEHIND the centreline of the wheel. This means that the mounting face of the wheel sits much further into the wheel and if you cut the wheel in half you would see the mounting face on the right hand side of the centreline. See the image above. These wheels tend to be an aggressive fit, with lots of concave or extreme dishes, sometimes both!
[Click here to see wheels with NEGATIVE offsets] - this will be all wheels with ET-1 and below.
How do I find out what my offset is? What is the ET number on a wheel? What is backspacing?
Einpresstiefe, or for those whose German may not be so up to date, Insertion Depth, more commonly known in the wheel and tyre industry and as a wheel’s ET. This a number usually stamped on the rear spoke or mounting face of an alloy wheel, e.g. ET45. this would mean the wheel has a POSITIVE offset of 45mm, which we now know means the mounting face is 45mm in front of the centreline. If however you take your wheel off and look in the back and see it is for instance ET-12 this will then mean you have an offset of NEGATIVE 12, or the mounting face is 12mm behind the centreline.
Backspacing is rather simple, its the distance from the back edge of the rim to the mounting face, i.e. the space in the back of the alloy wheel. Simple.
So the alloy wheel is not stamped with an ET number, so now we need to measure the offset of your wheel. This involves a little bit of maths, although relatively simple.
First we are going to take the overall width of the wheel, remember just because the wheel is marked 18x7.5 does not mean the wheel is actually 7.5 inches wide (more on this and other wheel dimensions HERE) [link to the wheel measurements page]. General rule of thumb, is to add an inch, so a 7.5” wheel will in reality be 8.5” wide. Now we convert this into millimetres, which is 216mm, half this will then give us the distance to the centreline, i.e. 108mm. Now we measure the distance from the edge of the back rim to the mounting face, the wheel’s backspacing, let’s say it is 155mm, the offset will then be the difference in these 2 numbers. So the offset of this example is ET47 as the distance between the mounting face and the centreline is 47mm (155 - 108 = 47).
1 - Get the overall width of the wheel in mm.
2 - Find the centreline, half the overall width.
3 - Measure the distance from the back edge of the rim to the mounting face.
4 - Minus the centreline from the distance of the bach edge to the mounting face.
5 - Kick back and revel in the fact you just measured an alloy wheel offset.
PCD stands for Pitch Circle Diameter, this is the bolt pattern and is specific to the car make and model and sometimes even the exact year of car will affect which PCD it has. Most cars, trucks and SUVs will come in either 4 stud, 5 stud or 6 stud PCDs with a few even being 3 stud or 8 stud. The pitch is the diameter of the circle that actually intersects the centre of the bolt hole/stud.
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