A potted History of the Flat Tanker

To begin at (or near) the beginning… it all started a little over 120 years ago…

The Dark Ages (or the Veteran era)

Motorcycling as we know it today began at the very tail end of the 1890s, evolving from the almost universal starting-point of strapping a new-fangled petrol engine to a safety bicycle. (… And what’s not to like about that when all’s said and done? Um… global warming perhaps… but they didn’t know about that then, so let’s move quickly on…)

The evolution of the species rapidly took off with a wide array of ideas about how best to make it all work… many of them completely barking mad. Inevitably over the next decade and a half natural selection ensured that some sort of common point was reached, heading towards an optimisation of sorts of this simple objective. What we tend to overlook today is that although we remember the petrol engine was in its infancy, the bicycle itself had only reached the universal pattern of the ‘safety bicycle’ with two wheels of the same size, a diamond frame, a seat close (enough) to the ground and geared drive sometime just before the end of the 1870s, and only became a common sight during the following decade, the near-universal pattern that is still in use today. A fortuitous sequence of events - if the petrol engine had reached a point where it could be fitted to a bicycle prior to the 1880s then the ensuing carnage of motorised ‘ordinaries’ (penny farthings) would have probably wiped out a generation of petrol-headed pioneers before the motor cycle could emerge kicking and screaming (and banging and thumping) into the 20th Century… (Although the irony of that statement isn’t lost on me, standing as we do today on the teetering edge of the precipice that is climate change… more thoughts about that to follow…)

By 1911 there was a real point of debate about whether the motorcycle had reached the epitome of its design. Serious questions were asked by those who saw motorcycling as a young man’s sport about whether variable speed gearing and a clutch had any place on a motorcycle (despite the fact that cars had clearly had both from the very start) and if not, then perhaps the pinnacle of design had already been achieved. If nothing else, busy town and city riding on a bike that would stall when stationary and could only be re-started with a push (if you were lucky) or by putting it on the rear stand and pedalling like the clappers must surely have caused even the most ardent supporters of the old-world view to question their logic. Then again, nobody’s ever implied that motorcyclists were any more sane than the rest of the population in the course of history. Stories abound of how to negotiate a busy tee-junction at the top of a steep hill, or generally how not to.

In any case, the matter had already been settled by the time the First World War began. At that point LPA (light pedal assistance) was a thing of the past meaning that seat heights had come down, and if any lingering doubts remained, the reality of war service meant that practical developments would continue to arrive in short order.

1915 (the coming of the Vintage era and the emergence of the Flat-Tanker)

By 1915 a pattern for motorcycle design for the next decade had emerged. With hindsight this became the demarcation line for the veteran era to pass into the vintage, defined by the release of the Triumph Model H, the Trusty Triumph of the Western Front. This particular model still continued with a belt final drive but within a short space of time the move to chain and the steady coalessence around something like 21” wheels ensured that by the start of the 1920s the universal pattern of the flat-tanker had arrived.

The 1920s and the Flat-Tanker

In design and evolutionary terms, the flat-tanker represents a point of singularity. Prior to that, a diverse range of solutions existed side by side and without the benefit of hindsight it was clearly difficult for the protagonists of the day to see which would prevail, or even whether they were ultimately heading for a single place.

The term ‘flat-tanker’ simply derives from the frame/fuel tank arrangement with the top frame tube taken high and above the tank, leaving the fuel tank as something akin to a biscuit tin sitting between the two remnant cross bars of the heavy-duty bicycles that were inevitably first pressed into motorcycling service. This in turn is a throwback to the high-saddle motorcycle arrangements up to the early nineteen-tens when the need for ‘light pedal assistance’ (when often as not, the use of the word ‘light’ in this context was somewhat misleading) meant a high bicycle-type seat was an important feature. You wouldn’t expect to get up a steep hill or indeed at one time to win the TT without it! Larger size steel-framed touring bicycles still persist with the double tube arrangement to this day, as does the classic butcher’s bike. A few notable manufacturers side-stepped the flat-tank solution and never conformed to the norm but the vast majority found themselves ploughing the same furrough throughout the decade until they broke free again from around 1928. By then only a handful of marques still persisted with the flat-tank leaving them at severe risk of being left behind and having to move on as urgently as possible. Ironically, but logically, it is these marques today which we see as representing the pinnacle of the flat-tanker, Norton, AJS and Sunbeam among them.

In reality though, the term Flat-Tanker is a catch-all that defines a deeper uniformity of engineering and design architecture that went far beyond the fuel tank and frame. With very few exceptions, the Flat-Tanker of the 1920s also conformed to all or most of the following:

• A ‘two-and-a-half dimensional’ design, arranged along the bike centreline

• Diamond frame

• Girder Forks

• Rigid rear end

• 21” wheels (or similar)

• ‘In-line’ engine arranged along the centreline of the bike, either single cylinder, v-twin, horizontal twin or, very rarely, an in-line four

• Total-loss engine oiling

• 3-speed gearbox with hand change

• Chain primary and final drive

• (upto around 1926 when wired-bead tyres came in) A front brake designed to prevent stripping the tyre off the rim under braking rather than for retarding forward motion

Engineering design and the architecture of motorcycles began to diversify again from around 1930 and motorcycles became increasingly 3-dimensional in their frames and engine layouts. Once the link to the humble bicycle was finally broken, an open-season started for a splintering-off of a myriad solutions, all representing step-changes in the performance of the individual parts and ultimately the motorcycle as a whole. (The arms-race between engine performance and chassis performance*, with chassis very much subservient to the needs of the engine had already set the tone for the first 20 years of the motorcycle and then continued largely in the same way until the 1990s - and arguably beyond - but that’s another story.)

To add to the diversification, all this was rapidly overlayed at the same time by the inevitable specialisation of motorcycles for different purposes.

From that single seed-point comes all that followed… sportsbikes, roadsters, nakeds and super-nakeds, tourers, sports-tourers, adventure bikes, dirt bikes, cruisers, cafe-racers, bobbers, choppers, scramblers and trackers, motards and super-motos, all manner of competition bikes from road-racers to flat-trackers, to motocrossers and trials. Right the way through to the evolutions of today, the brat-bikes and the retros and - most exciting of all in the last 100 years - the soon-to-be earth-moving (and Earth-saving) shift to electric motorcycles. Most exciting of all since what’s going to happen in the next few years will be the most intense and rapid re-definition of motorcycling since that point, over 90 years ago, when the Flat-Tank era ended and the ground beneath our wheels made a seismic shift. A shift that left the Flat-Tanker forever preserved in that long-ago and far-away place, in “the lovely sunlit gone-for-ever Land which lies beyond Time’s ridge” (in the words of Roy K Battson in The Land Beyond The Ridge, 1973, the finest book on motorcycling ever written, bar none.)

A personal view

(…as if what’s written above isn’t!)

One major point for me about the flat-tanker is that it represents the final point at which form truly followed function, in the same way that a Fordson tractor or a clipped-wing Spitfire is a thing of true beauty, because, and specifically because, a ‘stylist’, in that deplorable term we’ve had imposed on us from the car industry, never went near it. Once a saddle tank becomes part of a brand’s design identity then by definition someone has to ‘style’ it (that word again…) Brough Superior and Coventry Eagle (by way of McEvoy) had been there first but largely took the same direction as each other and then by the start of the thirties (and the end of the Vintage Era) the form of the fuel tank became a signature for each manufacturer, followed very quickly by a large number of the components that made up the rest of the bike. By the mid-thirties Edward Turner and Jack Wickes were showing everyone how it should be done, and moving Triumph into a near-unique position in the history of the British manufacturers as a result.

(Given my job, the above statement might come as a surprise but as a motorcycle engineer and designer I have spent my career balancing the various constraints and attributes that make a new model a success and ‘styling’ is clearly but one of those elements, albeit for the last few decades of an importance that is almost impossible to overstate.)

The new (old) rock and roll

So with that off my chest, "what’s all this got to do with rock and roll?” I imagine I hear you ask… Well now, I’m glad that you did.

In my very simplified world-view, the Flat-Tanker is a bit like rock and roll… actually a lot like rock and roll. Popular culture and deeply rooted heritage came together with rock and roll to a point of singularity and then, in far less than a decade, exploded again into what became the post-rock and roll era. Everything that came after was touched by it and the echoes of it run through what we have today despite the massive fragmentation into different genres and identities that reach way beyond music. This would be a great modern-day illustration of what the Flat-Tanker means in the evolution of motorcycling if only rock and roll wasn’t itself nearly 70 years old!! Oh well, the World moves on…

My only-slightly more ancient parallel is the 40 years of the Danelaw in the England of the 9th Century. That’s going back a bit I grant you, but the frontier established by Alfred the Great and Guthrum the Viking at that time ultimately lasted for no longer than the Berlin wall but in that time set the path for the changes that led to the evolution of the modern English language… but then there’s 1066 and all that, and the rest of the last millenium, so maybe this isn’t really helping…

*Note, in UK industry-speak, ‘chassis’ is the catch-all term for everything that’s not the power-train. It includes frame, front and rear suspension, wheels and tyres, brakes, seats, bodywork, fuel system, lighting, electrics etc, etc. In fact, everything that’s not the power-train(!)