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).
Test report comparing two sets of large size tires against a standard set.
| Identifier | ExFiles\Box 158\1\ scan0111 | |
| Date | 15th June 1937 guessed | |
| GRYLLS - Where are we with standardisation. Noise? Rm.{William Robotham - Chief Engineer} TEST OF 2 SETS OF LARGE SIZE TIRES. The first set lent which I shall call A SET was tested over about 4000 kms. The second set, B SET, tested over about 3000 kms. ---- Both sets give 50% better springing over cobble stones ( route pavée ) and quite 20% better springing all round. A set seemed to give softer riding than B but the rear tires were nearly worn out after 4000 kms whereas B are still in good condition after 3000 kms. Both sets were cut ( adérisés ). A seemed more silent than B at speed and B are definitely noisier when cornering at speed ( both inflated to 2 kgs ). There seems to be more reaction on pavés with A than B but both are unpleasant when the road is really bad. Here is a table of the standard set and sets A & B. | | Standard | A set | B set | |---|---|---|---| | Steering | Excellent | Jerking over bad roads & heavy | same as A but slighty better | | Cornering | Good | Excellent better than standard | Excellent but noisier than A | | Breaking | Good | Excellent better than standard especially on wet or not adherised surfaces ( pavé de bois ) | Same as A but a little noisier | | Road Holding on heet surfaces | Fair | Good, better | Good Better | | Springing | Fair | Better than standard | Not as soft as A, better than standard | | Noise to speed ratio | Fair | Fair | Noisier than either A or standard | 1339 X Sandrin tyres | ||