So you want to upgrade the look of your vehicle by adding some beautiful custom wheels. You've saved up some money and narrowed your search down to a couple of wheels. Now what? This guide will give you the knowledge to buy custom wheels with confidence. Below you will find a list filled with custom wheel terminology, as well as, directions on how to measure you own bolt pattern and offset. So lets get rollin (no pun intended).

1) First we will introduce common wheel terminology that will help you understand the rest of this guide:

• Bolt Pattern- This is also commonly referred to as the lug pattern which is the arrangement of the bolt holes on a wheel. For example a 5 bolt wheel with 127 mm between opposite bolt holes will be referred to as a wheel with a bolt pattern of 5x127.
• Center Bore- This is also commonly referred to as the Hub Diameter which is the size of the hole in the center of the wheel.
• Offset- The offset of a wheel is the distance from the mounting surface of the wheel to the true centerline of the rim. A positive offset means the mounting surface of the wheel is positioned in front of the true centerline of the wheel. This in effect brings the tire in to the fender well more. Conversely, a negative offset means the mounting surface of the wheel is behind the true centerline of the rim / tire assembly. This will cause the tire to stick out away from the vehicle. 

2) Now that you are armed with the basic terminology lets find out how to determine what will fit your vehicle. For a wheel to fit your vehicle you will need a couple pieces of information the bolt pattern and offset. So how can you find out this information:

• The best thing to do is to call your custom wheel company, hopefully Colossal Rims (which has a self titled website), and ask. They should be armed with information on fitment for most any vehicle. Make sure you inform the custom wheel company of your vehicles year, make and model. This includes any special brake modifications, as a bigger than factory brake can change the offset of the wheels that will fit your vehicle. Once they have this information they will be able to determine your vehicles bolt pattern and offset. Now make sure you are aware that not all wheel manufactures produce all bolt patterns and offsets. So some wheels will not be available for your ride.
• So you want to measure the bolt pattern and offset yourself...well here is how you do it:
• To measure vehicles with a 4, 6, or 8 lug pattern measure from the middle of two holes directly across from one another. So if you measure the bolt pattern and get 4.5 inches that will equal a 4x114.3mm bolt pattern.  
• To measure vehicles with a 5 lug pattern measure from the back of one hole to the center of the second bolt hole (should not be a bolt hole directly next to the first hole).
• To calculate offset you'll need the following measurements:
  ::: Wheel backspace: The easiest way to measure backspace is to lay the wheel face down onto the ground so the backside of the wheel is facing up. Take a straight edge and lay it diagonally across the inboard flange of the wheel. Take a tape measure and measure the distance from where the straight edge contacts the inboard flange to the hub mounting pad of the wheel.
  ::: Wheel Width
  ::: Wheel Center line (wheel width / 2)
• Subtract the wheel's center line from the wheel's backspace to get offset. If backspace is less than the wheel's centerline the offset is negative. If backspace is greater than the wheel's centerline the offset is positive.

So what size can you go to on your vehicle? Well these days you can just about put on any size wheel on a vehicle with the proper modifications. If you dont want to make modifications to your vehicle then the rule of thumb is to stay within 3% of your current wheel size. Your current wheel size can be determined by looking at your tires. For example the tires will have a set of numbers such as 265/35/20 the last number is your wheel size of 20". This is important because larger variances can cause problems with transmission shift points which can decrease fuel mileage. It can also confuse braking system computers which can even lead to brake failure.

Well now you have been through a quick guide on how to buy custom wheels. If you ever have questions you can always contact Colossal Rims for quality information and customer service.