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).
Measurement of tyre wear on E.R. Hall's Bentley after the 1935 Ulster T.T. race.
| Identifier | ExFiles\Box 30\5\ Scan110 | |
| Date | 17th September 1935 | |
| 17th September, 1935. MEASUREMENT OF TYRES ON E.R.HALL'S BENTLEY RUN FOR 19 LAPS IN ULSTER T.T. RACE ON SEPTEMBER 7TH 1935. Rear Tyres. 6.50 - 19 Original. After 19 Laps. Loss. Circumference. 103.3 101.55 1.75" Tread Depth. .4375" .197" 0.240" Average Wear per Lap = 0.0126" Total Laps until smooth = 34 Laps. Tread under the pattern is equal to at least 5 laps before the breaker would show. ------------------------------ Front Tyres. 5.50 - 19 Original. After 19 Laps. Loss. Circumference. 98.7 Nearside 97.1" 1.6 Offside 97.7" 1.0 * Very difficult to obtain accurate measurement owing to tyres wearing down badly on one side. Tread Depth Nearside .4175" .187" .2305" Offside .4175" .261" .1565" Average wear per Lap Nearside .0121" Offside. .0082" Total Laps until Smooth. 34.5 50 The tread under the pattern is good for at least 10 laps before the white cushion will show. In the case of the rear tyres there seems to be nothing abnormal in the wear. There was practically no difference between the nearside and the offside wear. The front tyres show quite a difference in wear between the nearside and the offside, the former wearing down very much faster. It is impossible to compare the wear on the tyres used during the race with those used in the practice laps as in the latter case the tyres were tried out on two different cars, namely, a racing and a touring Bentley, the latter car being much heavier than the racer. | ||