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).
The performance and disadvantages of balloon tires, including mileage and handling characteristics.
| Identifier | ExFiles\Box 53\2\ Scan094 | |
| Date | 11th February 1924 | |
| -3- (3) Snow and Ice (cont'd.{John DeLooze - Company Secretary}) The balloon tires practically ignore such obstacles, we find, and it is on this fact that their greater safety in winter depends. (4) Mileage. The 32x6 would have run another 2 or 3 thousand miles. The limiting mileage is therefore apparently about 14,000 miles for the 6" balloon against 8000 or 9000 for the standard 35x5. On the Hup nothing whatever has happened for 8000 miles, in fact one tire was only pumped up for the first time after 6000 miles. (5) Disadvantages. (a) We find increased difficulty in steering as the chief disadvantage. (b) We do not find that the 32x6 or 34x7 decrease the steering lock. (c) We do not find increased body clearance necessary although due to the tilting of the axle the 34x7 tire by its increased width is rather close to the inner corner at maximum bump and would scratch its chains in this position. Most cars do this however at maximum bump and so long as no bolt heads or nuts project inside the mudguard to catch the chains and cut them, it does not appear to do any harm. We would add for American tires:- (d) Pronounced increase of tread noise in covered bodies at certain speeds synchronising with the natural note of the body. This occurs on any surface but is of course more pronounced the harder the surface. (e) Slinging of mud to the sides of the roads due to the wide tread. Also dust raising on country roads in summer. (f) Rebound or throwing effect at the rear on waves in the road unless shock absorbers are set up tight. We have not yet had an opportunity to try balloon tires with the American Dunlop herringbone tread which we find most satisfactory on standard tires. We are inclined to favor the 33x5 which is similar to the 32x6 but on a 21" instead of a 20" rim. This gives adequate road clearance and appears a moderate step in the right direction. Oy. M.{Mr Moon / Mr Moore} Olley MO/E | ||