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).
Report comparing the effects of tyres, shock dampers, and steering settings on vehicle wobble.
| Identifier | ExFiles\Box 17\3\ Scan026 | |
| Date | 14th August 1926 guessed | |
| - 2 - A . - COMPARISON of TYRES. (I). - Dunlop 33x6" triple stud well worn; tendency to wabble 65 - 58 MPH. (II). - Ditto absolutely new treads. Reduction in (I) wabbles 20%. (III).- Michelin 33x6.8 (same size as Dunlop 6.75) new tyres. Considerable improvement .Period 67-62 M.P.H. Reduction over (I) wabbles 50%. (IV). - Dunlop S.S. CORD at 45 Lbs/SqI. Absolutely no wabbles. B . - EFFECT of SHOCK DAMPERS. (I). - Dunlop 33x6" well based ,well worn Triple stud tyres fitted ( i.e.A(I) ). Shock dampers uncoupled. Genuine high speed wabbles builds up 65-55 M.P.H. Intensity of Wabble 200% worse than A(I). (II). - Dampers coupled up and high pressure loading increased to 150 Lbs. Improvement on A(I) not more than 15%. C . G EFFECT of TOE IN. (I). - Dampers fitted at 75 and 35 Lbs/SqI. Spring loaded cross steering tube inadvertently erected giving 1;00" Toe In. Wabbles 100% worse than A(I). D . - EFFECT of FRICTION IN STEERING. (I). - Spring loaded cross steering tube erected with maximum load on ball(special springs throughout) but no spring controlled movement of ball. Otherwise conditions as in A(I). Improvement in wabbles over A(I) 75%. Very large reduction at once noticable in steering shocks. E . - EFFECT of SPRING CONTROL BALL MOVEMENT ON CROSS STEERING TUBE. Condition as in D(I) only ball pads withdrawn to give .100 spring controlled movement of ball each end. Shocks 75% worse than D(I) or as bad as A(I) i,e.{Mr Elliott - Chief Engineer} flexibility in cross steering tube counteracts friction effects .Confirms DERBY Tests. | ||