After legendary Triumph boss Edward Turner retired from his motorcycle factory in 1963, he holed up in a BSA subsidiary, CarBodies Ltd of Coventry, but simply couldn’t keep his hand off his original passion, two wheels. Having entered the hallowed pantheon of Motorcycle Greats with his popular, stylish, and sometimes avant-garde machines from the 1920s onwards, he is best remembered as the man who made a parallel-twin engine look like a twin-exhaust-port single cylinder machine (the 500cc Speed Twin of 1938), which fit snugly into the existing ‘Tiger 90’ single-cylinder chassis. This new combination had magic in name, looks, and performance, and set the tone for the British motorcycle industry for the nearly 50 years.The prototype Triumph DOHC twin as built in 1968; note the reverse-cone muffler (very similar to the first Tiger 100 ‘cocktail shakers’ of 1938), disc brake, and square tank styling, akin to the Ducati Monza [from Jeff Clew’s book, Edward Turner: the Man Behind the Motorcycles]Edward Turner visited Japan in 1960, and was devastated to see firsthand the technical superiority of both the motorcycles and production methods of the Japanese industry, regardless the bikes built at that time were of small capacity (250cc and under), or clones of larger foreign machines (eg, the Kawasaki ‘W1’ copy of the BSA A10, and the Rikuo H-D clone). Turner came home to sound the alarm, but was unable to rouse his Board of Directors to make the necessary investment (during their years of greatest profitability, when they conceivably could have invested) to produce a modern motorcycle design in England. Frustrated, Turner chose to retire, unhappy with the direction of the British industry as a whole. Still, he had always done interesting work as a freelancer, having come up with an advanced overhead-camshaft single-cylinder bike in 1925, and penned the foundation for what became the overhead-camshaft Ariel ‘Square Four’ in 1928 – which got him a job at Ariel under Valentine Page, and his radical design developed into metal by 1930.A youthful Edward Turner, while still at Ariel Motors in the early 1930s. A man of Olympian design talent, with a monumental ego to match! [Quarto]From the sidelines in 1967, Turner sketched out a direct challenge to the Honda CB450 ‘Black Bomber’, whose performance nearly equaled his beloved but aging line of 650cc Triumph twins… the Honda rubbing salt in the wound with an electric starter and leak-free, reliable running. Turner poached a few Triumph employees to build up a running prototype of his double-overhead-camshaft, twin-cylinder 350cc bike with a short-stroke, 180degree crankshaft – exactly the spec of the Honda, but with 100cc less capacity. Turner was confident his decades of experience squeezing power from his twins would yield excellent performance from this smaller engine, and so it proved to be. The little bike hit 112mph in tests, about 7mph faster than the Honda. The styling was clearly inspired by the contemporary Ducati Monza, which wasn’t the first or last time the English took a leaf from the book of Italian bodywork.Wesley Wall of the NMM staff tests the prototype [Chris Pearson]While an advanced machine on paper, with a mechanical disc brake, those cams up top, and excellent performance, the reality was, Turner had designed a hand grenade. The Triumph brass, including new Triumph Chairman Eric Turner (no relation) instructed chief engineer Bert Hopwood to ready the experimental machine for production. Hopwood, performing an autopsy on the little machine after it broke its crankshaft on test, considered the design “fundamentally unsafe”, and set about, with Doug Hele, designing a wholly new motorcycle, with enough of the ‘ghost’ of Turner’s idea clearly visible to satisfy the Board.The restored prototype of the Triumph Bandit, brought back to life by the National Motorcycle Museum [Chris Pearson]Hopwood’s version of the DOHC twin, called the ‘Bandit’, had a stronger crankshaft, a chain primary drive instead of expensive gears, a 5-speed gearbox, electric starter, and a frame based on Percy Tait’s 500cc grand prix racer, designed by Ken Sprayson of Reynolds Tube. The Bandit was a real winner, with the same performance as Turner’s machine, but promised reliability, excellent handling, and truly modern specification. BSA shifted its mighty girth and tooled up for production in 1971, but less than 30 machines were built before the plug was pulled on the whole enterprise, as BSA declared bankruptcy, and the British motorcycle industry began a period of free fall.The chain-driven camshaft drive can be clearly seen on the end of the crankshaft, as well as the shifter gate. [John Woodward]Turner’s prototype has been restored to running condition by John Woodward, on staff at the National Motorcycle Museum in Birmingham. Many thanks to Mick Duckworth for forwarding these photos and information about the prototype!Pull the pin, lad, and it’ll shortly explode…the original ‘hand grenade’ crankshaft of the Bandit. [John Woodward]Paul d’Orléans is the founder of TheVintagent.com. He is an author, photographer, filmmaker, museum curator, event organizer, and public speaker. Check out his Author Page, Instagram, and Facebook.
Never knew that Edward Turner had a part to play in creating the Squariel, the British motorcycle industry was such a small world, way back when it was a big player. That’s why I love this site, it never fails to show me something I didn’t know before.
Anonymous said…
I am a new reader, learning of your site from David Blasco of royalenfields. Great site!
I noticed on the fotos of the 1938 speed twin and the ‘Tiger 90’ both equipped with girder front ends. My question to you is “Whatever happened to the girder?”
Harley currently produces a springer, and in the mid 90s I had a mountainbike (ProFlex)with a girder style front fork, haven’t noticed any in production today and I suppose, some decades.
Why the demise of the design? When did they cease? What was the last production bike with it. Did anyone ever make chopper (extended) style girder forks?
Thanks for a great clean historical site on motorcycles.
Matt
Hi Matt,
‘girder’ forks still exist, they just look different now. BMW’s Paralever suspension uses the same basic principle, and the Britten race bike too. Telescopic forks have their problems, like diving while braking, which girders don’t have. The travel of girders is shorter though…
Hi Matt. Girders were used in production bikes through the 1930s and in a few bikes after WWII. The last production bike to use conventional old-styled girders was probably the BSA M20 / M21.
Like Paul said, they typically don’t offer as much travel as telescoping forks. They also cost quite a bit to manufacturer, with a lot of parts that need to be brazed together, plus a lot of machining operations to make all the various links and bushings. Teles were pretty simple and cheap to build. Teles also have simple methods to have damping, which girders never did well.
There were a lot of home made extended girders on choppers in the 1970s, some were 20″ longer or even more. The strength/weight ratio of a girder is better than a tube for a long span.
Some flat track dirt racers still prefer to run girders, as they give good strength during side loading as the bike is pitched into a corner.
regards,
Pete
Vincent had perhaps the best girder forks of all time . The previous iteration of what once was called Confederate Motorcycles along with Britten has brought the girder into the late 20th – 21st century … with the best of the new girders being created by madman , genius extraordinaire JT Nesbit … with many after market companies also offing updated versions of the ubiquitous girder … that in my opinion .. despite the slight lack of travel ( in comparison to a telescopic fork ) offer the best combination of ride , handling and comfort available .
Also in addition since bicycles have been making their way onto this site … back in the early nineties several Mt Bike companies were experimenting with and offering girder forks on their bikes
Unfortunately .. motorcyclists ( and bicyclists )… being the major league xenophobes that they are .. have been unwilling to experience the joys and benefits of the the girder … despite the fact that it is now a century old technology being updated . Thus the market placing once again placing limitations on the research , innovation and evolution of what again … in my never humble opinion … is the most elegant solution available when it comes to two wheels . The girder fork .
PS; The only reason girders cost more to manufacture than telescopic is supply and demand …. period .. because in reality they are simpler and easier to manufacture . Don’t believe me ? Assuming you’ve got some skills in the workshop .. trying building a fully functioning telescopic fork from scratch versus a girder . Guaranteed the girder will garner more positive results … in less time … and function better in the end .
😎
PS; How in the ___ did this one escape me in light of the fact that one is in my garage and ridden regularly .. which I’ve nicknamed the Acoustic Motorbike ? Damn ! One cup ( coffee ) too few I guess ..
Moulton bicycles . THE most advanced bicycle in the world bar none . Relying solely on girder forks for its full suspension ( for decades ) road and ATB bicycles since the inception of the company .
Why ? Because as Sir (Dr) Alex Moulton .. one of the most celebrated engineers who’s innovations ( both by himself as well as his family ) still exist on every car and motorcycle made , the Millennial Bridge in London …etc – et al … used to say …
Its the only two wheel front suspension solution worth using
Indian had a very good one in the late ’40s. Good travel and no ‘stiction’,and also good damping due to an auto type shock.They need careful setup but handle well. S.
The telescopic fork had its force in its oil damping of which most girders couldn’t compeed.
Anyhow would girder damping and suspension be situated at the steering head, making most of the (weight of the) construction un suspended, and as every goal of suspension have ever since been to reduce the unsprung weight have the girder become obsolete except of nostalgic use at ex choppers.
I rode an Ariel 600cc square 4 some 50yrs ago,girder forks/rigid frame,super torque but the rear cylinders tended to get overhot.
Turner’s twins motors all used the vertically split”clamshell” crankcase design,too bad the Brit’s didn’t see the wisdom of Horex’ horizontally split 1950s design as Yamaha did.Hardly rocket science,all the automobiles of the 1930s had used it.
The XS650 and all the Japanese inline 4’s are more basically robust due to that old innovation.
i think girders may make a comeback-but in the custom world,rather than production bikes;i for one would be glad to see it! try not to cringe my dad had a Triumph TT (chopped) with a chrome girder-it looked bada$$
Turner was a designer of nice shapes , but make a lot of big mistakes on the mechanical components. The squariel became usable only after Val Page modified it completely and work much more better now, with some Morgo real oil pump. I remember the ad for the Bandit and Fury in Motor Cycle News when i was touring in England with my parents. The Fury and Bandit was more some prototypes than ready to sale machines (at what non competitive price??).
Remember that Turner said after dismantling some Honda bikes in the Triumph factory :
“That those machine are of bad quality and outdated” and also that “youngsters started with some Japanese bikes, but will buy some English ones when they wanted some bigger ones!”
And yet no mention of his tour de force in 1957-58 ,the two aluminium V8 hemi -head engines for Daimler . The 2.5 litre fitted to the Daimler SP250,’Dart’ and its mighty 4.6 litre big sister which produced 240bhp and went into the Majestic Major .
I’m fascinated by the fact that Turner owned a Riley 9 when he designed the first parallel twin and the layout of the twin is identical to the Riley, twin high camshafts, short pushrods, two rocker shafts and hemi heads.
In designing the two Daimler V8 engines, supposedly he owned a Cadillac at the time and he and Jack Wickes looked up the parts manual to see how to design a V8.
The Daimler V8s share a similar design layout to the Triumph parallel twins and in fact Triumph Bonneville pistons will fit the 250 V8. You could say that the Daimler V8 is a V8 version of the Riley 9 which was 1100cc.
I guess it makes him look like a copyist rather than an original thought creator?
Edward Turner was among the greatest stylists in motorcycle history, but he was not a qualified engineer. He had very interesting ideas, like the Square Four, which had to be re-designed by more experienced engineers to work properly. Yes Turner copied the valve gear from his Riley for the Triumph twin motor, and re-used what he knew and copied other designs to create the Daimler 250 V8. This prototype DOHC twin was a perfect case in point – it was extremely poorly designed, but when revamped by more talented engineers, it was a real winner.
Jack Wickes, chief Draughtsman for Triumph Motorcycles and referred to by Turner as “My pencil” is generally credited with the colour schemes and the appearance of Triumph motorcycles which made them look as though they were going fast even when static?
I’m never sure how much credit to give Wickes for the original revamps of the Triumph singles (Turner’s first job there) into the ‘Tiger’ range, and there’s other evidence that Turner deserves credit for the general outline of Triumph twins too. For instance, Turner was told the head angle for the Speed Twin was wrong, but he refused to change it as it would ‘ruin the lines’, even though it would have improved the handling! I’m convinced that Wickes was an amazing right-hand man to Turner, but that he was indeed the inspiration for the ‘look’ of Triumphs. Wickes definitely deserves credit; he designed (well, copied from Jawa) the famous Triumph headlamp nacelle of the 1950s, and no doubt worked in all the details from a vague sketch of Turner’s.
Vincent HRD “Girdraulics” unloved by many, were unlike those that preceded being duraluminium, lightweight and machined to close tolerances rather than a mild steel spring hanger prone to distortion under load.HRD allowed consistent wheelbase length under compression, extreme rigidity, and better “feel”. As bikes of the time had to assist practical family transport, girdraulic trail could be quickly altered with minimal tools,like so many practical features of these machines,to allow fitting of a sidecar.