About Fitment Recommendations
Over The years we have recommended fitment for a great variety of cars and if your project isn't too radical we can most likely recommend some proven wheel dimensions.
However, if you are lucky enough to be building something unique or pushing the limits as to how much tire and wheel can be stuffed under a super low ride, there will be some measuring required.
What we encounter most often are projects that have tires and wheels whose dimensions are less than ideal. Having these "rollers" to use as a starting point is very helpful. Of course the closer they are to fitting properly, the easier it is to optimize your fit.
It is fairly common to go larger diameter and wider wheels for looks, performance and brake clearance. So for your reference we created a tire size chart that lists the overall dimensions, in inches, of most of the metric tire sizes that our customers are likely to consider for their cars and trucks. We hope that you'll find this to be a helpful tool in determining your ideal tire size and eliminate the extra time calculating dimensions or surfing the web for information.
See the Chart HERE.
Wheel Measurements and Backspacing
Backspacing is just one way to specify the wheel offset. Over the years, “width and backspace” have become the most common way among Hot Rodders to describe a wheels dimensions. In hindsight, “frontspace” might have been a better, more direct measurement to use, since the distance from the mounting surface out to the outer wheel lip and its proximity to the fenders for looks and clearance is of primary concern.
First of all, wheel rim width is measured inside from bead to bead. It’s the width the tire sees. Just as wheel diameter is the diameter of the bead where the tire mounts (the diameter of the hole in the tire). Most wheels have about a 1/2″ lip on each side. So a 8″ wheel (bead to bead) usually measures about 9″ wide overall.
Backspace is a overall measurement, from the mounting surface of the wheel in to the innermost part of the wheel lip.
Frontspace is the distance from the mounting surface to the outermost part of the wheel lip. Frontspace and backspace added together will be about an inch wider than the wheels (bead to bead) width. Got it?
Once again, what we encounter most often are projects that have tires and wheels whose dimensions are less than ideal. Having these “rollers” to use as a starting point is very helpful. Of course the closer they are to fitting properly, the easier it is to optimize your fit.
Put a straightedge across your wheel lips (right next to your tire sidewalls) and measure your backspace and frontspace. Knowing both and adding them together then subtracting an inch can prevent confusion caused by assuming you have a certain width wheel.
People often know they have a little fender rub when they turn all the way left or right and want to move the tire and wheel in farther. They need more backspace (and less front space). Turn as far to one side as possible, shut off the engine and look under the car to make sure there is enough clearance to move the tire and wheel in without hitting the sway bar, control arm etc. Turn the wheels the other direction and check for clearance again.
Or they have the room and want to go wider and need to figure out how much.