| Models | Backbore | Cup Volume | Cup Volume | Cup Diameter r2 | r4 | Rim | ||||
| 63 | Number | Description | Cubic Inches | Inch | mm | Fraction | @.032" | Contour | Bite | Alpha Angle |
| 63Z* | 1 | Small | .0604 | 0.63 | 16 | 40/64 | 0.639 | Flat Med. - Wide | Medium | High |
| 63Z** | 1 | Small | .061 | 0.63 | 16 | 40/64 | 0.643 | Flat Med. - Wide | Soft | High |
| 63SZ | 1 | Small | .0620 | 0.63 | 16 | 40/64 | 0.641 | Medium | Medium | Medium High |
| 63S | 1 | Small | .064 | 0.63 | 16 | 40/64 | 0.641 | Medium | Medium | Medium High |
| 63MS | 2 | Medium Small | .068 | 0.63 | 16 | 40/64 | 0.641 | Medium | Medium | Medium High |
| 63M | 2 | Medium | .071 | 0.63 | 16 | 40/64 | 0.641 | Medium | Medium | Medium High |
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Quick Comparison - The GR 63 Series cup diameter is generally between a conventional 10 1/2 and 7 diameter. Classic Blank is standard. Studio, Symphonic, and FatBoy are available as a special order on some models. Backbores, other than listed, are special orders. |