Triumph 1924 Model SD 550cc 1 cyl sv



Triumph 1924 SD  550 cc side valve combination  frame # 336253 engine #94110

The SD (Spring Drive)  was in fact a somewhat modernised version of the famous model H, which had grown out of the “Trusty” veteran Triumph. By the mid-twenties belt drive was losing its appeal to many motorcyclists, so Triumph designed a model with chain secondary drive. 
The primary chain is protected by a well-engineered  aluminium case and runs in an oil bath to minimize maintenance of chain and clutch. The powerful 550 cc engine (bore x stroke =85×97)  has lots of torque. 
The machine is equipped with three speed  Sturmey Archer gearbox,   26×3 beaded edge tyres and full electric Lucas  lighting, an expensive accessory in those years. 
The stylish  sidecar is a “ Whitley” . 
This SD combination is a fine example of  high quality twenties British motorcycle technology and  is a  well restored  strong runner.