Saturday, 1 July 2017

The Shepherd Special



This is a short blog on an innovative and influential motorcycle race frame.

Eric Shepherd was a motor mechanic by trade and had a garage in Perth. He was also a keen motorcycle road-race competitor, who raced at both the Scottish mainland circuits and IOM TT. In the early 1960’s Eric built a couple of highly unusual frames for the period, in which were fitted Triumph twin engines. The senior class bike used a 500cc unit construction engine and the junior class a 350cc unit T21. This pair of bikes was raced by Eric throughout the 60’s and into the early 1970’s and every year he was to be found at the Beveridge Park race meeting in the summer. He also raced both machines at Gask and Crimmond in 1967.

Shepherd 350cc Special - Crimmond 1967
 


Eric also raced in both the Senior and Junior TT races for the first time that year and his frame caused considerable interest in the paddock. Unfortunately he finished in neither event, but his radical frame design had not gone un-noticed and would be seen again.

In 1980 the complete rolling chassis from the 500cc bike was purchased minus the Triumph engine. Hugh Ward fitted a 350cc BSA Goldstar engine, canting the tall engine forward in order that it would fit below the main frame tubes. He also used the BSA gearbox and clutch. This bike was subsequently raced by Dick Irwin from Haddington in the Manx Classic Grand Prix.

Shepherd 500cc Special with Goldstar engine fitted


So, what was innovative and influential about Eric Shepherd’s frames?
Well firstly they were very low and sleek and had a continuous tube running from the bottom of the steering head to the swinging-arm pivot on both sides of the frame. There were also no front down-tubes to the frame, the engine and gearbox being suspended in their engine plates from a cross-member between the main frame tubes. A steady tied the cylinder head to a second cross-member between the main tubes, which was positioned just back from the steering head and provided additional support to the engine unit.

You have to remember this was 1964 and nothing like this had been seen before. If you accept that the most radical improvement in frame design since the 1950’s came in the form of the McIntyre Matchless, which had been fabricated at Bellshill by Bob & Alex Crummie in 1962, then one has to acknowledge that the Shepherd Special was also very innovative.
To confirm this point, let us look at the then current ‘state of the art’ racing frame produced by a well-respected and most able fame manufacturer.
Seeley Catalogue 1968



Undoubtedly a light and good handling machine, when judged against the hot-bed of ideas that are found in a racing paddock, it is fair to say the basic frame concept was somewhat conservative in approach. To put it in perspective, the above was the design offered in the 1968 edition of the company catalogue, a full 4 years after Eric had produced his pair of radical machines.

So was the Shepherd frame influential?
You will have to be the judge of that, but let us look at the MK4 Seeley frame. As in the Shepherd frame, the main tubes run continuously from the bottom of the steering head to the swinging-arm pivots on both sides of the frame. The cross and additional frame-bracing tubes are very similar in disposition and the overall concept remarkably akin.

Seeley Mk4 Commando


Shepherd Special


Casting our minds back, let us remember that the MK2 frame that followed on from the one shown in the 1968 catalogue was also a full duplex affair. In the MK3 frame the main frame tubes ran from the swinging-arm pivot to the top of the steering head, crossing inside the seat-rail tubes below the petrol tank. This was also the first Seeley frame that dispensed with the front down-tubes, but suffered from premature failure due to a lack of section at the point where the tubes crossed.



So it was not until the 1970’s that a very similar frame to the Shepherd Special was produced in any numbers by a major specialist frame manufacturer. Judged on that fact alone, Eric Shepherd’s frame was indeed influential.




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