Chain Chatter

by "CARROZZINO"

In the two recent circuit races at Floreffe and Mettet we had interesting examples of a mechanical problem that confronts those who race sidecars. If you can bring yourself to consider the sidecar outfit as a unit in itself and not a normal racing motorcycle with "chair" attached, there are numerous modifications that can be made to improve performance, most of which bears relation to racing-car practice, for the sidecar outfit can, in many ways, be considered as a car with a wheel missing. Among these modifications is the question of weight distribution and one of the easily movable factors is the four gallons of petrol, normally carried very high up above the engine. This weight of some 50 lb. can usefully be disposed elsewhere and numerous experiments have been tried, the latest being that of ex-World Champion Eric Oliver. As described last month the fuel tank sits between the rear wheel and the sidecar platform and this requires an S.U. electric pump with battery in the sidecar to deliver the fuel direct to the carburetter. Here we come to the point of this discussion, for at Floreffe Oliver lost a certain first place due to one of the battery leads coming adrift, and the following week at Mettet he was again robbed of first place due to the fuel tank breaking away from its mountings. Had he retained a normal fuel system, as on the standard "Featherbed" Norton, he would have had two more wins to his credit, for there would have been no battery wire to become detached, and on the second occasion had the tank mounting broken, the tank itself would have rested in its place due to gravity, as has often happened on solo machines.

Apart from the question of weight distribution, this altering of the fuel system also allows the rider to sit lower and reduces frontal area, so the question is whether to gain speed and handling at the risk of introducing other possible causes of retirement. It is all a matter of compromise, as is the sidecar outfit itself, and for years sidecar men refused to think of anything new. Now, however, experiments are appearing more and more frequently, each having advantages and disadvantages, but whether it is better to have a complicated but more scientific outfit, or to retain the simple sidecar layout with its inherent reliability, comparatively, of course, is still a debatable point. On both occasions mentioned above it was Cyril Smith who took the place of the leader when he was delayed; thereby making the score Smith 2, Oliver 0, by the same method as Smith became World Champion last year.

In the solo classes, Floreffe was interesting as it was the first Continental outing of the factory Norton, A.J.S., N.S.U. and Guzzi machines: The Nortons were fast, bearing in mind they were rehashes of last year's models, while the A.J.S. machines, both 350 and 500, have a long way to go. Although Lomas, on the N.S.U. 250-c.c twin, won his race, Anderson showed that the Guzzi was faster, if not reliable. N.S.U. are making a very serious bid for 250-c.c. World Championship honours this year and at Hockenhiem they finished 1-2-3, but it was noticeable that Anderson rode his 250 Guzzi only in the 350-c.c. event ! B.M.W. still seem to be probing about in the dark and their latest 500-c.c. solo is fitted with a copy of the "Earles" leading-link front fork, using the same horizontal twin engine, but much progress is being made with petrol-injection. In the sidecar race at Hockenhiem, the two works riders, Kraus and Knoll, harried Oliver in no mean manner, while Smith could not keep up. It is good to see Knoll on a works machine, for this young German rider has excellent riding ability and a first-class mechanical knowledge. During the past year or two in German International races his home-prepared Rennsport B.M.W. outfit has been a constant worry to the Norton private owners. It was he who first adapted a Lockheed brake system to his outfit, operating on all three wheels, which gained him many valuable yards in competition with faster machines. Mention of his Lockheed brakes brings us the full circle to the opening paragraph this month - the question of car practice and the balance between complication and reliability. On a hydraulic system, one leak and there are no brakes, but on the normal outfit many riders have finished races with a rear brake rod stripped or front nipple pulled out, the independent operation of the brakes always assuring some sort of retardation. Sidecar brakes, rear suspension, sidecar suspension, streamlining, banking, all come in this province and all continue to be in a state of flux. The only certainty is telescopic forks, which are now a sine-qua-non, but only after much experimentation.

At the time of going to press the T.T. practice has yet to start, so rumours such as Duke on a Gilera, Anderson with a Guzzi Four, and so on, cannot be substantiated, but by the time these words are read more will be known. The T.T. itself is a week ahead from the date or issue, so that the outcome must wait until July, but there is every indication of fierce compotition in all classes.