what this mean>??

[carlosc]

few hours ago i saw some wheels in the web (summit racing). and some of the wheels have this measure:

Backspacing (in) and Offset (mm)

what this measure exactly mean>???

[bluemustang]

--------------------------------------------------------------------------------

Q: What is wheel backspacing?

A:The distance from the inner edge of the wheel to the hub mount pad. Note: Sometimes the distance from the outer edge of the wheel to the hub mount pad is referred erroneously to as offset. BE CAREFUL!

Q:What is wheel offset?

A: It is the distance from the centerline to the hub mount pad (where the wheel attaches to the hub). POSITIVE OFFSET - The hub-mounting surface is toward the front or wheel side of the wheel. NEGATIVE OFFSET - The hub mounting surface is toward the back or brake side of the wheels centerline.

[carlosc]

hub mount pad?? i dont understand this words, you explain it very well but a dont speak english so well, and dont understand the previous words, i 'll use a dictionary

[79Ghia50Stang]

he hub is what pokes thru the small hole that is in the center of the wheel... therefore the wheel mount pad is where the wheel and hub actually make contact