Matters of moment, December 1977

A front-wheel-drive breakthrough

Before the war cars with front-wheel-drive, the Alvis and Tracta for example, were regarded as oddities until Citroen, DKW, BSA and a few more suggested that it was not so odd after all and soon the great Traction-avants from Paris and Slough effectively showed up rear-drive disadvantages. Pulling the smaller cars along by their front castors is now becoming universal and the layout of FWD in conjunction with a transversely-mounted engine, so effectively introduced by Sir Alex Issigonis for the revolutionary Mini-Minor, is justifiably popular. However, those who have heard the irritating rattle set up by the transfer gears, necessary between crankshaft, and gearbox with this layout, from the Mini, through the BMC 1100s, even present in the more luxurious 1800, and not altogether eliminated from many of the current designs of various makes, know this to be the “Achilles heel” of an otherwise desirable engine and transmission layout.

Now Renold, the chain people, have come up with a breakthrough. They told us about it at their impressive Research and Development Centre, close to Manchester Airport at Wythenshawe, where they test their many products in conditions of clinical cleanliness in an 84,000 sq. ft. building containing ten double test-cells and full laboratory and testing facilities. To many people Renold are thought of primarily as chain manufacturers. While it is true that they make every kind of chain and have absorbed other such makers, like Coventry, Brampton, etc., and that last year Barry Sheene won the 500 c.c. World Motorcycle Championship on Renold Five Star chain, they also make every other kind of gearing, worm gears included, milling machines, hydraulic motors and drives, variable-speed gear, conveyor-link-chain, coating machines, two-pedal fork-lift trucks, and much more besides, all of which we inspected (except the trucks) in the Leyland and Guy articulated mobile showcases-cum-cinemas which Renold use for publicity-tours.

The purpose of our visit was to see this very impressive Renold test centre, for which Mr. D. N. C. Davies, CEng., FIMech.E, MSAE, is responsible, and to try the chain-primary-drive which they have developed, starting in 1962, and which Saab has now adopted. In this case it is used with longitudinally-mounted power units, where the gearbox is not in line with the crankshaft. The claimed advantages are quietness, lower cost as simple and fewer bearings are admissible, and sprockets are cheaper than a gear-train, smoother take-up, higher efficiency, and an easy alteration of ratio if required. This Renold-Saab drive embodies triple staggered chains made to even closer tolerances than usual, and a clever self-lubricating tensioner. It has evolved from exhaustive tests of 16 converted vehicles from Mini to 7-litre Oldsmobile Toronado, a Maid having covered some 200,000 miles. There was a demonstration car at the 1967 Motor Show. Saab came to Renold as the World’s acknowledged chain experts; they will make the staggered-tooth sprockets themselves and Renold will supply the other parts of this Renold chain-drive.

We tried the drive on a Saab 99 Turbo and it was not only silent but was snatch-free from 20 m.p.h. in top gear. The Saab Turbo itself is an unexpectedly quiet car, which accelerates most effectively, for example from 75 to 90 m.p.h.

The journey to Manchester, which was made in that outstanding new Ford model, the Granada 2.8iS, on those excellent Michelin TRX tyres, was an eye-opener. Not only is it nice to know that Sweden came to Britain to solve Saab transmission problems but our respect for Renold was greatly enhanced after seeing this magnificent Research and Development Centre, where test rigs work to taped instructions, running without need for supervision day and night. Renold products, from minute worm gears to enormous chains for driving marine-engine o.h.-camshafts, were impressive. Renold obviously hope to apply their chain-primary-drive to cars other than Saabs; we noticed a Renault 14 in the experimental shops, a car which might well benefit from a quieter drive between its transverse engine and gearbox, vide C.R.’S road-impressions published in Motor Sport last month.

Mr. Davies recalled a motorcycle TT in which a Renold chain broke as the winner crossed the finishing-line. He was able to tell the naturally disgruntled champion that this showed efficiency, because it is a well-known adage that a racing machine should he designed to such close tolerances that it will give maximum performance for the distance of a race and then fall apart. When a Renold chain broke after three laps in another TT race, it was a different matter! From such disasters, however, stemmed any decisions by Renold to carry out extensive research; but for racing, Mr. Davies doubted whether the present fine Research Centre would have been built. Incidentally, today’s’chains last throughout a TT race and the same ones have been used for another; lubrication from Renold aerosols has materially extended chain endurance in racing and on ordinary machines. The moral of this Editorial is that if Britain is not hampered by politics she can match the World when it comes to engineering and that here is yet another example of the proven value of motor, or in this case motorcycle, racing. . .