Utter confusion is usually written all over peoples faces when I explain to them why I constantly swap rims on my car. Eventually I end up giving myself a facepalm because they still don’t understand why. Even if I compare it with shoes, how it ranges from runners (performance lightweight) and designer-level (high-end).
Looking back now, I realise I’ve been through so many sets of wheels. All the trial and error that I went through taught me the importance of having the correct specs when purchasing the perfect set. This isn’t an easy task, especially for people who have never bought a set of rims before. So to save people the hassle, I’ve compiled a list of things to look out for when purchasing a set of sweet wheels for your ride.
1. Factory Fitted Wheel Specification
It is important that you know the original specs of your car. It sets a baseline for what you can fit and what you can’t. The important things you need to know from the factory specification:
- Rim Size
Measured in inches in the format of ‘diameter x width’ (e.g. 18″ x 9.5″ is read as 18″ diameter wheels that are 9.5″ wide).
- Rim Offset
Measured in millimetres. This figure determines the distance the rims sit from the hub. A positive number will result with the hub sitting further out from the centre of the wheel across its width. While a negative number will mean the hub sitting further in from the centre of the wheel.
- Tyre Profile
Measured in a combination of millimetres, percentage and inches in the format of Width/Height Ratio/Rim Size (e.g. 235/45R18 is read as 235mm width/45% of 235mm and made to fit 18″ wheels).
- Hub Flange Size or Hub-Centric
This is the size of the lip on your hub that will align the rim to the centre. Normally aftermarket wheels will be larger than the hub to accommodate a wide range of cars hence may lead to the need for hub-centric rings.
- Stud Pattern or Pitch Circle Diameter (P.C.D.)
Measured in millimetres and shows the number of lugs (e.g. 5×114.3 can be read as 5-lug equally spaced in an 114.3mm diameter circle).
2. Research Other People’s Specs
If you own a fairly popular car such as a Mitsubishi Evolution, you can usually find its specifications on forums or Facebook groups as some people may have posted their own build thread online. By putting together the specs of other peoples cars you can work out the rough approximations on what will fit and what won’t. Don’t be afraid to pop the question on forums or Facebook groups either, there will always be people who are willing to help. And obviously you’ll get the odd troll wasting everyone’s time as the internet is vastly filled with those so called “car enthusiasts” who don’t help the community as a whole with informative comments.
3. Experimenting the Fitment
Obviously some of us like to be different and have purchased a car where not many people have ventured into the world of modification. In this case it may be a lot harder to find proven set-ups online to assist you in getting the right fitment. Don’t worry though as there are a few websites which can help you work out the right size for your needs. Before you check out the following links you will need to have a rough idea on the dimensions of the wheels you are looking to fit (i.e. Rim Size, Rim Offset and Tyre Profile).
There is also a very informative thread someone else has written up to help work out the wheel’s offset if you have a measuring tape, calculator and the wheels in front of you. Trust me, with this walkthrough you’ll have a deeper understanding on wheel offset.
4. Laying the Stress Off the Studs or Wheel Bolts
Some people may not be aware how important the hub flange is when it comes to changing wheels. This hub flange is as important as eating vegetables on a daily basis, and the basic reasoning behind this is to keep the outer wheel concentric to the wheel bearing creating a well balanced spinning force. It also removes the stress off the studs or wheel bolts and I’ve seen them snap on a friend’s car before, trust me that’s the last thing you want happening. From my experience in swapping so many different types of rims, not all of them are the same size as your hub, and this is where hub-centric rings come into play. Simply find a set of vernier callipers, measure the inner ring of your wheel and the outer diameter of your hub flange. After the two measurements, you can usually find the right sizes online stores such as eBay.
5. The Rubber Fitment
One thing that people sometimes don’t take into consideration is tyres, I am guilty of this at times as well. For my very first set of rims I ran the incorrect sized tyres, resulting with my guard taking off chunks of the tyre wall. This indeed is dangerous as you are weakening the tyre wall’s integrity so running the right sized tyre is very important. Usually if you ask your local tyre fitter, they can make the right call on what size you can run. Bare in mind if you want to stretch your tyres, some shops refuse to do it so its best to do the research and find out which ones do.
On the topic of stretched tyres, this one is tricky especially if you have not done it before. As each manufacturer has different thicknesses in tyre walls, its close to impossible to know exactly what kind of stretch you will get. In the past I’ve wrecked a few sets of tyres before, I’ve done some research and found some sites that will help minimise these issues.
Willtheyfit.com will also give you a rough estimate on the amount of stretch you will get provided you have the desired tyre size you are looking for.
Another great website to look into is Tyrestretch.com, they contain an extensive list of branded tyres which have been stretched and uploaded to the site.
6. Looking After Your Fenders
Keeping an eye out on your guards are important especially if you want to run a wider setup. Pumping or rolling the fenders is an easy way to minimise any contact from the tyre when running that kind of set-up. If you don’t look after the guards, they usually will end up buckling and breaking or rubbing chunks off your tyres. Best thing to do is to contact your trusted panel beaters or automotive body works who will be able to provide the suitable solutions to help you fit the desired wheels you are after. Alternatively if you want to try it yourself properly (meaning not using poles to roll your guards), you can find fender rollers roughly online for $150.
7. Protecting Your Precious
Lock nuts or lock bolts can reduce the likelihood of your new wheels getting stolen. Things to consider when purchasing these things is to make sure you have the right size and type. Seriously, you wouldn’t believe the amount of people purchasing the wrong sizes or types of nuts and bolts.
- Make sure you find out what type of lug nut or bolt you need to suit your rim. Whether it is a tapered or acorn-seated lug nut / bolt.
- Thread size of the lug nut or bolt, because the last thing you want is to cross thread them.
Funnily enough, eBay has written up a very detailed buying guide for people purchasing new lug nuts or bolts which also includes size and pitch chart of most car manufactures. Have a look on The Definitive Guide to Buying Wheel Nuts for Your Car on eBay.