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).
Procedures followed to improve the riding on model 12-MC.
| Identifier | ExFiles\Box 43\2\ Scan087 | |
| Date | 18th December 1925 | |
| Oy4-E-121825 -4- December 18, 1925. weigh 120 lbs. on the front and 480 lbs. on the rear axle. Thus front spring required = Sprung load rear spring required = 1 1/2 sprung load.) Procedure followed to improve riding on 12-MC. 1. We first removed all gaiters. The gaiters were well oiled but the springs had rusted. Leaves were spread and lubricated with mixture of kerosene and engine oil. Heavy oil soaked out of gaiters and replaced with kerosene and engine oil. Gaiters replaced. Some improvement in rear. Front springs too lively. Increased tendency to pitch. 2. Hartfords removed. Replaced by Lovejoys at rear. Some of harshness removed. Tendency to pitch remains. 3. Car bumped in front. Front rubber bumpers cut down to give front clearance of 2.150". V notch cut in back of rubber for increasing its flexibility. Bumping in front cured. 4. 6-3/4" 6 ply cord tires on 21" wheels fitted. 40 lbs. in front, 45 lbs. at rear. No observable increase in tendency to wobble. Riding softer. 5. Front shock absorbers fitted with stronger springs and new un-oiled leathers to give 50 lbs. on each front ball. Improvement in tendency to pitch. Front riding harsh. 6. Rear springs replaced by 1900 and 2000 lbs. Springfield springs, giving 6.200 clearance at rear without passengers. Riding improved. Front riding still harsh. Note: Clearance with original springs was 6.900" car empty, corresponding to 5.100 deflection of rear of spring, i.e. original springs approximately flat with car empty. A copy of our spring loading table is attached for reference. The rear springing was now practically the same as all Springfield closed cars, and the riding was still considered unsatisfactory. We confined our attention from now on to the front suspension. 7. The front springs were removed and measured with the following results:- (Note the springs were not clipped and were compressed by a hollow block around the centre bolt.) | ||