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).
Specification sheet detailing tyre equipment and available makes for various car models.
| Identifier | ExFiles\Box 45\1\ Scan380 | |
| Date | 5th November 1926 guessed | |
| TYRE EQUIPMENT FOR ROLLS-ROYCE CARS. (a) Dunlop Equipment for Rolls-Royce Cars. TYRE EQUIPMENT. Size. | Type. | RIMS ON WHICH MOUNTED. | INFLATED. TYRE DIMENSIONS. | | | Overall. Diameter. (Approx) | Overall. Width. (Approx) | Effective. Radius. (Approx) | | | ins. | ins. | ins. 40/50 H.P. CARS. {35 x 5 | Dunlop Cord Straight Side. | Flat base detachable flange rims. | 35" | 5.65 | 16.625 {33 x 6.75 | Dunlop Cord Reinforced Balloon, Wired Type. | 5"x21" Well-base | 35" | 6.64 | 16.375 6" for 21" | Dunlop Cord Medium Pressure, Wired type. | 5"x21" Well-base | 33.625 | 6.12 | 15.75 20 H.P. CARS. {32 x 4½ | Dunlop Cord Straight Side. | Flat base detachable flange rims. | 33.5 | 5.0 | 16.0 {33 x 6.00 | Dunlop Cord Reinforced Balloon, Wired Type. | 4½"x21" Well-base | 33.625 | 5.88 | 15.75 {5¼" for 21" | Dunlop Cord Medium Pressure, Wired Type. | 4½"x21" Well-Base | 32.5 | 5.35 | 15.187 (b) Other makes of tyres available. [Handwritten Note in left margin: High Pressure] {32 x 4½ | Avon, Collier, Davies, Dominion, Englebert, Firestone, Fisk, Goodyear, Goodrich, Henley, Macintosh, Michelin, Miller, Moseley, North British, Pirelli, Rapson, Stepney, St.Helens. {33 x 5 | Avon, Davies, Dominion, Englebert, Firestone, Fisk, Goodrich, Goodyear, Henley, Macintosh, Michelin, Miller, Moseley, North British, Pirelli, Stepney, Rapson. [Handwritten Note in left margin: 20H.P] 33 x 6.00 21" | Englebert, Dominion, Firestone, Fisk, Goodrich, Goodyear, Macintosh, Miller. [Handwritten Note in left margin: Phantom] {33 x 6.75 21" | Dominion, Englebert, Firestone, Fisk, Goodrich, Goodyear, Michelin, Miller, Pirelli. 33 x 6.20 for 21 Rim. | Dominion, Firestone, Fisk, Goodyear, Michelin, Miller. [Handwritten Note at bottom] We dont-want customers to fit 6" balloon tyres on the front axle of the phantom | ||