Light Alloy Wheels Tips

Word Explanation 
Wheel Equipment on which a tire is attached and held – they generally consist of a rim and disc part and are attached on to the axel hub to support the load.
Rim Part on which a tire is attached and held
Disc Part to be attached on to the axel hub to hold the rim
Flange Outer rim part to hold the tire in the horizontal direction when seen from the front – its various shapes are represented by symbols, B, J, JJ, K, L, etc. (refer to JIS 4218, Outline of Rims for Passenger Vehicles)
Bead seat Part of the rim to contact the tire’s bead part to hold the load in the direction of its radius
Well A trough with a certain width and depth provided on the bottom part of the rim to make it easier to put on or remove a tire from the rim
Inset The distance (mm) from the wheel’s center line to the disc attachment surface
P.C.D. Stands for Pitch Circle Diameter
Rim type Normal Rim and Reverse Rim
(1) Normal Rim:
Standard shape – tires are put on or removed from the outer rim side
(2) Reverse Rim:
Reversed version of the normal rim - tires are put on or removed from the inner rim side
Bolt hole Holes for the thru bolts to fix the wheel to the hub
Bolt & Nut Bolts (Hub bolts) to fix the wheel to the hub specified by their respective corresponding vehicle models – nuts are available in different sizes and pitches in 3 categories as per shape of their bottom surface, i.e., tapered bottom, spherical bottom, and flat bottom. Note that nuts with different bottom shapes are needed per different vehicle models.
Hub Diameter Diameter of the hole in the center of the wheel