The wheel dates back to around 4000 B.C when artisans used them for spinning pottery. Later, the Mesopotamians took two discs, stuck one on each end of a hunk of wood and made the world's first axle. Not quite a set of Volks, but we've got to give them props for coming up with the first wheel. The chariot followed, then the underpinnings of an industry yet to be conceived for about another 6,000 years or so. Stuff this old is never simple.
Most know what it takes to bump up horsepower. You wouldn't swap out that set of high-lift, aftermarket cams for some stockers. You wouldn't yank out your Lude's H22A for a beat-down 1.5-liter D-series. Buying a set of wheels shouldn't be any different, that is, if you care about going fast.
Making Them Fit
There's more to making a set of wheels fit besides their willingness to be stuffed inside your Civic's fenderwell. Besides the wheel's overall diameter, you need to consider more complicated measurements; some as simple as whether or not they'll bolt to the hub, to trickier matters like how offset changes affect handling.
Bolt Patterns
Bolt pattern is the first thing to check when shopping for wheels. Discerning your bolt pattern is simple: Start by picturing an imaginary circle that passes through the center of each lug. This is the bolt pattern or bolt circle. Most Hondas use a 4x100 bolt pattern: four lugs and 100 millimeters between the center points of any two non-adjacent lugs. For five-lug rims, measure the distance from the center of any hole to the farthest edge of the hole, two spots over.
Centerbores
Hondas, like most OEMs we can think of, use hubcentric wheels. Wheels like these rely on a machined hole on the inside of the wheel that fits snugly over an extruded portion of the hub. This both positions the wheel and takes vertical stresses off the wheel studs unlike older, non-hubcentric wheels which rely on the studs for both positioning and carrying stress loads. If you're fitting aftermarket hubcentric wheels to your Honda, this machined hole is often times larger than what you need due to manufacturing versatility. Make sure to get the right size ring adapter. If you're off even just a bit, your wheels will vibrate worse than a cheap coin-operated bed at Motel 6.
Offset
It sounds simple, but offset may be a wheel's most mysterious characteristic. By definition, it is simply the distance from the hub mounting surface to the wheel's centerline. A wheel's offset falls into one of three categories: zero, positive or negative. If you can use a tape measure, you're halfway there. But interpreting the results and understanding why you should care about it requires an explanation.
Offset matters. For one, it determines whether brake calipers, struts, and suspension members will fit behind the wheel. Off by just a few millimeters and those new Brembo calipers might not fit. Off by anymore and the wheel might hit a strut, a shock or not sit on the hub.
Besides fitment issues, offset also affects handling, steering response and ride quality. Offset isn't something you change haphazardly to make a wheel fit. Honda did its homework here, so mess with it at your own peril. Make changes with caution or you may alter the car's scrub radius and worsen torque steer, among other things.
If you're adding a wider wheel, you need less positive offset, meaning the wheel needs to be placed farther out to make clearance. If offset remained the same, then half the extra width of the wheel would be shoved under the fender and most likely hit something. Plan for this ahead of time with some basic calculations on your current rims prior to ordering up some new platters.
Before you can measure your current wheel's offset though, you'll need to figure out its backspace measurement. Lay the wheel flat on the ground, rest a straight edge across its surface and measure the distance between the wheel's hub mounting surface to the straight edge. This is its backspace. Then subtract this number from the wheel's width and divide by two.
A zero offset means the hub mounting surface lines up with the wheel's centerline. A positive offset, like you'll find on front-drive Hondas, means the hub mounting surface lies toward the outside half of the wheel. These push the wheel/tire in closer to the car. Conversely, a negative offset means the hub mounting surface is closer to the brake side of the wheel, and you'll typically find that these suit rear-drive cars, no matter how badly you want some fat-lip deep dishes on your hatch.
There's another easy way to measure offset: flip the wheel over and read the offset number etched in the metal.