From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Chart detailing standard tire and rim sizes and their equivalent replacements.
| Identifier | ExFiles\Box 158\1\ scan0064 | |
| Date | 18th May 1928 | |
| A-12177. TIRE AND RIM STANDARD Tire Cross Section Rim Diam. | 4.50 | 4.75 | 5.00 | 5.25 | 5.50 | 6.00 | 6.50 | 7.00 Row 18: 5.25-18 Replaces 28 x 5.25 6.00-18 Replaces 30 x 6.00 6.50-18 Replaces 30 x 6.20 7.00-18 Replaces 30 x 6.75 Row 19: 4.75-19 Replaces 28 x 4.75 5.00-19 Replaces 29 x 5.00 5.25-19 Replaces 29 x 5.25 5.50-19 Replaces 29 x 5.50 6.00-19 Replaces 31 x 6.00 6.50-19 Replaces 31 x 6.20 Row 20: 4.75-20 Replaces 29 x 4.75 5.00-20 Replaces 30 x 5.00 5.50-20 Replaces 30 x 5.50 6.00-20 Replaces 32 x 6.00 6.50-20 Replaces 32 x 6.20 7.00-20 Replaces 32 x 6.75 Row 21: 4.50-21 Replaces 30 x 4.50 Row: Rim* Section Width 2.75 Flat Base or Drop Center 4" 4" 4" 4-1/2" 4-1/2" 5" Row: Max. Tire Width on Rims 4.75 4.85 5.15 5.35 5.60 5.95 6.40 6.90 *Rim widths given are nominal except the 2.75-in size, which dimension is the actual width between flanges. METHOD OF MARKING Tires shall be marked with the tire cross-section followed by the rim diameter on which the tire shall be used, under which designation shall be placed in smaller type the work "Replaces" followed by the former name size of the tire. STAMPED: MAY 18 1928 A-12177 | ||