So you want to buy some new wheels for your DSM? Well, there's a few things you should consider first...
To see what has worked for your fellow DSM'ers, check the fitment guide.
A wheel has 5 specifications in 3 categories that define the size and fit of a wheel:
Width & Diameter:
This is the number you normally size wheels with, as in a 16x6 inch wheel. Stock DSM wheels come in 14x5.5, 16x6, or 17x6.5. The 3000GT and Stealth came with 16x8, or 17x8.5 wheels (some also came with 15"). The wheel should be no less than 70% of the tire's sectional width, and ideally would be almost as wide as the tire. If you want wider tires, consider getting wider rims as well.
Centerbore & Bolt pattern:
This is the diameter of the hub and the diameter of the circle that the bolts form. All DSM's (Talon/Eclipse/Laser/Avenger/Sebring) and 3000GT/Stealth models have a 67.1mm (2.64") centerbore and a 5x114.4mm (4.5") bolt pattern. Yes, this means you CAN put the wheels from a 3000GT on your DSM!
Offset:
This is the distance from the centerline of the wheel to the mounting surface. This is the main focus of this FAQ.
Wheel Offset
Offset is measured from the centerline of the wheel to the surface that the hub will mount to. Offset away from the car is positive, towards the car is negative.
Standard (or zero offset) and negative offset wheels (or 'deep-dish' wheels) are found on some rear wheel drive cars, and those Hondas trying for the 'open-wheel' look (the ones that look like roller skates...)
The picture on the left is a positive offset wheel, like those found on DSM's. The mounting surface for the hub is displaced away from the centerline of the wheel, so that the center of the rim is closer to the center of the car than the hub's mounting surface. Increasing the offset will move the rim closer to the centerline of the car, decreasing offset will move the wheel outward, away from the centerline of the car.
Offset is also related to another term, Rear Spacing. Rear spacing is measured from the inner edge of the wheel to the hub mounting surface. It is a convenient measurement in that, as long as the rear spacing remains the same, the clearance to the suspension also remains the same. So if you increase wheel and tire width both by 2", your rear spacing does not change, although your offset will decrease 1". Usually this term is used with racing wheels, where fenders are not in the way and tire width is measured in inches.
When you are trying to determine the offset you want, you will be limited by the make and model of wheel you are looking at. Manufactures don't make them in an infinite variety.
The stock offset for DSM and 3000GT/Stealth wheels is +46mm. That is, the hub mounting surface is 46mm from the centerline of the wheel, and away from the centerline of the car. Changing to a different offset will change several things:
- Clearance
Clearance is the primary reason to change offset. For example, on 2G cars, a 225mm wide tire will just fit with the stock offset, leaving about 4mm of clearance to the suspension. This is about the minimum clearance to fit without rubbing, as the tire will flex under cornering. In order to fit a 235mm wide tire on the car, the offset must be adjusted so the tire moves outward, away from the suspension. Since a 235mm tire is 10mm wider than a 225mm tire, it must have an additional 5mm of clearance on the inside. So you need at most a +41mm offset to fit 235's.
On 2G cars, there is a flange that sticks into the wheelwell from the fender. If your car is heavily laden, or has been lowered, a 235mm tire on +35mm offset rims will rub on this flange. You can roll this flange up and out of the way, however. It may be possible to fit 245mm tires on a 2G with a +40mm offset wheel...more on this to come!
- Scrub Radius
Scrub radius is the distance from the point where the steering axis meets the ground, to the center of the contact patch of the tire. Zero scrub radius is desirable. Increasing the scrub radius will result in more kickback through the steering wheel when you hit bumps and increased steering effort.
- Track
Track is the distance from centerline of the right wheel to centerline of the left wheel. Note the front track and rear track may be different. Increasing track will provide more stability during cornering.
- Bearing Load
The bearings in the suspension were designed to take loads within certain angles. Increasing the offset beyond a certain point can severely increase the wear on bearings and suspension components in general. +35mm or maybe +30mm is about the limit for DSM's. If you want to make some money, buy stock in aftermarket companies who make wheel bearings for Hondas, those guys with the wheels sticking way out will be needing some soon...