Sunday 6 March 2022

Loose Lines [Issue 14, Nov-Dec 1988]

Whatever happened to motorcycle design? Oh yes, I know you can buy some high tech Jap multi that has been honed to perfection on the computer aided design screen and bungs out enough hp per litre to make manufacturers of racing cars plain envious, but how much do you want to bet that the design of the resulting motorcycle has been determined by a bevy of production engineers, stylists and marketing men with the real engineers who actually do the work placed in a troubled secondary position where any real innovation will only be incorporated if it’s in line with other factors that have little relevance or interest to real motorcyclists? I, for one, find it inconceivable that some Jap engineer is going to stick to his guns in the face of corporate orthodoxy in a society governed by such strange mores that disgruntled employees have to spend the early hours battering and screaming at dummies of their bosses, just to get the angst out of their system.

Given an unfortunately intimate knowledge of the British engineering scene in which disgruntled, underpaid engineers actually sabotage designs at the drawing board stage, I can only guess from some of the unreliable and ill conceived designs emanating from Japan that the psychological effectiveness of bashing images of the papasan early in the morning is somewhat lacking in effectiveness; and if I know the Asian mind at all well, behind the singing of company songs, et al, there is as much muttering and bitterness as at a British Leyland (or whatever they call themselves these days) trade union meeting; in Asia the surface calm has little connection with the inner turmoil.

There is a whole side to motorcycle design that is ignored and little understood, but one that can only work in the context of the whole motorcycle. Yes, I know, things like tyre and chain wear are not very sexy or exciting, but given a bit of thought and clever engineering they could be improved to such an extent that the first manufacturer to make a radical advance would maybe just sweep the board in a world where many bikes seem interchangeable save for the names. There are some small bikes that go through chains and tyres in less than 5000 miles - they are not heavy, nor are they particularly rapid. It follows that the design of the rolling chassis is so terrible that nasty things happen to the consumables it may just be that their manufacture is so cheap and nasty that nothing lines up once the whole is assembled, but this is 1988 and we are talking Japan Inc., so surely things haven’t become quite that desperate. And anyway, the converse is also true, there are some heavy, powerful bikes that have much better chain and tyre life than could be expected.

Take chain wear (forget O-ring chains, I know people so knocked out by the thought of stripping down a complicated suspension system just to fit a new chain that they sell the bike instead) - at least a 21 tooth gearbox sprocket is needed for low wear rates and the swinging arm has to be mounted as near as possible to the engine sprocket. The latter suggests swinging arm bearings in the engine casings, whilst the former means somewhat large redesign of most gearboxes (just try hammering on a 21 tooth sprocket in the cramped space provided for the usual 15/16 tooth job if you dispute this). The gearbox also has to be strengthened to take the increased load exerted by the larger sprocket.

But that’s the easy bit. Just try to work out the optimum relationship between swinging arm length, rear suspension movement and weight distribution with regard to both tyre and chain wear. Within this, the chain itself has to have an optimum strength excessive build leaving the chain so heavy that it tears itself apart under its own momentum, too weak and it falls apart. The curious use of a rubber cush drive in the back wheel to smooth out the drive line may keep the rider happy but does nothing for the life of the chain. Tyre wear is even more complex but one that is actually getting better now that the Japanese have at last conceded that lower mass, strong frames, good geometry and proper suspension are a more wholesome way of producing decent handling than relying on the grip and strength of the tyre for everything.

But there’s still a very long way to go before wear rate become anywhere near as good as in the auto world. What if, for instance, the forces produced by rising rate suspension do nasty things to rear tyre wear, would you swap the comfort for better wear? Reasonable tyre wear from a £35 tyre should be at least 20000 miles, if the Japs applied their minds to the problem - with lighter mass and stiffer frames they’re halfway there.

One of the most hideous sights in the world of motorcycle engineering is when some whizzo stylist bungs a drum brake into a cast wheel originally designed for a disc. Advances in pad materials have surely made the drum brake a viable proposition once again. Designing a cast wheel with a drum brake in mind should produce a wheel that costs no more than normal (and that’s before the cost of discs, calipers, etc are taken into account) - by using different linings and shoe materials as well as SLS or TLS designs different braking forces can be obtained in the same wheel to suit a capacity range from 100 to 500cc. The old problem of drum brakes overheating and distorting are overcome by the basic strength of the cast wheel, of which the drum is part, whilst this large chunk of alloy gets rid of the heat rapidly. I see no reason why pad life should be less than 30000 miles, the whole act maintenance free save for occasional cable adjustments.

Mention fuel economy of a mid-weight bike to some car owner and they will become even more incredulous that anyone would actually forsake the comfort and convenience of some four wheel jalopy - considering that 100mph plus bikes were able to do 70mpg back in the sixties, a 100mpg average should not be too difficult in the high tech eighties (and if that sounds impossible it’s only because the Japs haven’t given a damn about economy for the past twenty years). The very things that make, say, a Honda CBR600 so damn powerful (low friction losses, highly efficient valve gear, air cheating GRP, etc) could equally make it very economical with a change of emphasis and use of a single carb (which also dumps all that time consuming carb balancing, costs less and saves money).

All the things that help a modern motorcycle to become more user friendly (just think how easy life would be if maintenance was reduced to just the odd oil change) also reduce the cost of production. Motorcycling is not really about cheap commuting, it’s really about getting Porsche type kicks on the cheap (and, yes, I agree you can have that kind of fun on a £20 MZ but that’s not the point I’m trying to make). Knowing the general stupidity of British bosses, I doubt very much if the Japanese importers can conceive that once having achieved correctness in the basics of motorcycles design (which the British had well sorted twenty years ago) they should combine it with stunning looks.

The thing that Tory politicians hate most about motorcyclists is that they can get Ferrari style performance for less than the price of a silly hatchback; equally the importers, if not the manufacturers, in search of easy money have decided that to have fun on motorcycles you now have to pay running costs nearly on a par with a Porsche. The only reason for this is stupidity, ignorance and greed. This is not all that surprising because the motorcycle business en masse is still run by many of the figures who were involved in the collapse of the British motorcycle industry. I had naively assumed that these arseholes (how else can you describe them?) had retreated to some obscure corner of the kingdom where they could hang their heads in shame for the rest of their lives, but I keep seeing these all too familiar names cropping up in the trade press, apparently still in charge of large segments of the UK import business.

Surely, in Thatcher’s brave new world, where creative capitalism is supposed to rule the roost they would have been relegated to more suitable occupations, such as collecting garbage or sweeping streets. But that would be to assume a fair world which is about as likely as a UK government dumping the stupid helmet law or de-taxing motorcycles to help clear the congestion in the streets of Shit City.

Bill Fowler