ayjay,
good question regarding what size wheels fit. I will be buying some alloys at some point. It's good to know the car for which the wheels were intended/taken from, as most people (private sellers) sell their wheels by describing the car they fit, rather than the dimensions of the wheel.
Maybe you could invite members with finished cars to post their wheel sizes. That is; diameter, offset and width, and, if secondhand, the car they were fitted to. The stud PCD should all be the same for all of us, since we all (bar one or two?) have sierra hubs.
With respect to your question on
what is wheel offset; this is a snippet from Wikipedia:
"
The offset of a vehicle's wheel is the distance between the centerline of the wheel and the plane of the hub-mounting surface of the wheel. It can thus be either positive or negative, and is typically measured in millimeters. Offset has a significant effect on many elements of a vehicle's suspension, including suspension geometry, clearance between the tire and suspension elements, the scrub radius of the steering system, and visually, the width of the wheel faces relative to the car's bodywork. Zero Offset - The plane of the hub mounting surface is even with the centerline of the wheel.
Positive Offset - The plane of the hub mounting surface is shifted from the centerline toward the front or outside of the wheel. Positive offset wheels are generally found on front wheel drive cars and newer rear drive cars.
Negative Offset - The plane of the hub mounting surface is toward the back or brake side of the wheel's centerline.
"Deep dish" wheels typically have negative offset or a very low positive offset.
To maintain handling characteristics and avoid undue loads on bushings and ball joints, the car manufacturer's original offset should be maintained when choosing new wheels unless there are overriding clearance issues."
Plenty of links to info. and pictures here:
Links to wheel offset information and pictures
The
actual wheel offset used by builders would of course be useful to know.
Hope that helps
