Triumph 1924 “SD” 550 cc side valve single frame # 393200 engine # 99852 IGH
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.
Some new features for 1924 were the internal expanding front brake and the forward mounted gearlever. In the spring of 1924 a new tapered tank became available so we think the machine on offer was manufactured early in 1924.
Accessories include André steering damper, acetylene lighting set and pillion seat.
This “SD” has been amazingly well preserved in its original livery, it’s the most authentic specimen we have ever come across.
For detailed information on this model consult Peter Cornelius’ “The Facts” booklet, surf to http://users.actrix.co.nz/cornelius/Triumph/