Know How to Measure Wheels Correctly Before Deciding to Buy a New Set
Being aware of proper wheel measurements required for your vehicle is critical for the performance and safety of your ride.
Once you know how to measure wheel size it will prevent you from making the mistake of purchasing wheels solely based on looks.
A lot of wheels on the market today can be factory manufactured or custom built. Factory wheels are basically installed every stock vehicle but they may not be desired wheel for the owner. Custom aftermarket wheels are very popular in these circumstances as they satisfy the owner’s vision of beautiful styling that compliments their car. Purchasing the correct wheel for your automobile means purchasing one that fits and looks great. Every type of wheel has specific measurements that make it right or wrong for the vehicle whether it is a car, van, SUV or truck. As a rule of thumb, you will always need to measure new wheels to know which ones you are buying.
First of all, take your stock wheel and place it flat on the ground with the inboard flange facing upwards. The inbound flange is the rim of the wheel that will be facing inwards towards the body of the vehicle when it was put on. For this instance you will need to figure out the backspacing which is measured from the inbound flange down to the hub center that is centered onto the axle. You can use a flat and straight wooden board to lay across the width of the wheel on the inbound flange and then take a regular ruler to measure downwards to the center hub which is considered to be the wheel's backspacing.
Next, you will be required to measure the lug pattern of the axle that the wheel will be mounted to. These lug nuts will be centered on the axle and stick out from the axle and the wheel that it is secured with. Depending on your car, lug nuts come in various patterns of 4, 5, 6, or even sometimes 8 lug nuts. For the even numbered patterns you can measure from the center of one lug hole to the center of the lug hole that is directly opposite from the one being measured. With odd numbered patterns, you can measure from the top of the top lug hole to the center of the lug hole two away from the starting hole. This particular measurement allows you to purchase the correct lug pattern for a replacement wheel.
Afterwards, you will need to measure the centerline of the wheel to determine if the replacement wheel has, or potentially needs, a positive or negative offset. The offset is determined by the placement of the center hub in relation to the centerline. To locate the centerline you will need to measure from the inboard flange all the way out to the outboard flange and then divide by 2. You can do this with a basic straight ruler or retractable tape measure. The actual “offset” of the wheel is the backspace of the wheel in comparison to the centerline. An illustration of this would be that if the backspace was 6 inches and the wheel centerline was 7 inches this would mean that the wheel has a negative offset. If the wheel's backspace was 6 inches and the centerline was also 6 inches then the offset would be considered to be positive. Making sure you have the correct offset allows the tires to spin freely within the space provided by the wheel well where the axle, body panels and frame are located. An incorrect offset will cause the wheel to rub on the inside or outside of the wheel well, or in really bad circumstances the brake calliper or rotor which could cause damage and impair driving.
In the procedure of figuring out how to measure wheels for your car you firstly need to determine which tire you would like to buy since this will immensely help in figuring exactly what wheel to fit it with. The wrong wheel measurements will result in it being non-compatible with your tires which will waste both time and money for you. Remember that the wrong offset will result in uneven weight distribution and damage to surrounding components so pay attention to these tips on how to measure wheel size.