The offset, measured in millimeters, can be negative or positive, and is the distance from the hub-mounting surface to the rim’s true centerline. A positive offset means the hub-mounting surface is closer to the outside edge of the wheel, i.e. the wheel wraps around the hub and brake hardware more deeply; a negative offset means the hub-mounting surface is closer to the inside edge of the wheel and wheel sticks outwards more than inwards.
When selecting aftermarket wheels, a wheel with too little positive offset will be closer to edge of the fender, and one with too much positive offset will tuck inside the fender and be closer to the suspension components. Wheel width, offset and tire size all determine the way a particular wheel/tire combination will work on a given car. Offset also affects the scrub radius of the steering and it is advisable to stay within the limits allowed by the vehicle manufacturer. Because wheel offset changes the lever-arm length between the center of the tire and the centerline of the steering knuckle, the way bumps, road imperfections and acceleration and braking forces are translated to steering torques (bump-steer, torque-steer, etc) will change depending on wheel offset. Likewise, the wheel bearings will see increased thrust loads if the wheel centerli
ne is moved away from the bearing centerline.(courtesy Wikipedia)
H¬†=¬†High¬†Positive or FWD (Front Wheel Drive) typically +45, 40, 35 offsets
M¬†=¬†Medium¬†Offset or RWD (Rear Wheel Drive) Typically +20 offset
L¬†=¬†Low¬†Offset or RWD (Rear Wheel Drive) Typically 0 offset
At wheelsupport.com , you will fine lots of info about your wheels , rims .
You will fine bolt pattern. you will find stud pattern. you will find information about the wheels and rims on your car.
you can also find the information about your lug nuts, CB ( Center Bore ) or Center hole and offset of your rim. Most rims are interchangeable from one car to another car.
To find out you need to compare your bolt pattern with the bolt pattern of the wheel you have on hand. Sometimes its difficult to find out about the specific information about the rims if you only have the wheels but no stud or bold pattern information . i used to take my rim to a junk yard and try one on a different wheel hub with off course with calipers on the rims. Then i recorded the make, model and year of the car and was looking for the wheel information about that rims. That way i was finding my car's bold pattern. Now I am quite used to recognizing the stud pattern. Its my eyes that do the magic. i can easily tell if a rim will fit a car or not.
Its a couple factor that really decide if a rim will fit into a car.
Bold pattern | Stud pattern :
Used to describe the amount of lugs your car, or wheels, have, and also the measurement in between them.
For example, 5x4.5 This would be 5 lugs, spaced 4.5" across.
Also measure in mm, for example 5x114.3. 5 lugs, spaced 114.3 mm apart. 5x4.5 = 5x114.3
CB (Center Bore or Center Hole ) :
The centerbore of a wheel is the size of the hole in the back of the wheel that centers it over the mounting hub of the car.
Some factory wheels have a centerbore that matches exactly with the hub to reduce vibration by keeping the wheel centered. Wheels with the correct centerbore to the car they will be mounted on are known as hubcentric. Hubcentric wheels take the stress off the lug nuts, reducing the job of the lug nuts to center the wheel to the car.
Wheels that are not hubcentric are known as lugcentric, as the job of centering is done by the lug nuts assuming they are properly torqued down. Centerbore on aftermarket wheels must be equal to or greater than that of the hub, otherwise the wheel cannot be mounted on the car.
Many aftermarket wheels come with "hubcentric rings" that lock or slide into the back of the wheel to adapt a wheel with a larger centerbore to a smaller hub. These adapters are usually made of plastic but also in aluminum. (Courtesy of Wikipedia)
Offset is the measurement of where the mounting surface of the wheel is (where the bolt holes are), compared to the centerline of the wheel. Usually referred to as negative, positive, or zero offset or Low, Medium or High. other property of the wheels are also effective in deciding to purchase a rim for your car but basically i found the above properties most important.