This is a pretty old motorbike. The photo dates back to 1957 – 58 and even then the bike was seven or eight. The giveaway is the apparent lack of rear suspension. But in fact the rear end was sprung.For this is a 500 cc Triumph Speed Twin notorious for its spring hub. How did it work? I don’t know. I was more interested in blaring up to the Lake District on it. My guess is the capacious hub accommodated substantial springs arranged radially and that the spindle “floated” at the springs’ notional junction. A horrifying concept which delivered its horror during cornering.
So long as the bike was upright the horror was disguised. But bikes heel over on corners and the springs could not respond logically to this radical change in applied force. My friend Richard, who sold me the bike, put it this way:
“The rear end of the bike flexed during cornering. These oscillations were absorbed in the hub and then re-transmitted – out of phase with the bike’s forward progress – back to the frame. The bike behaved like an animal having a nervous breakdown.”
Should my old Speed Twin be included in a blog called Works Well? Definitely. On one of those Lake District trips the pillion was occupied by a girl-friend who had expressed an interest in rock climbing. Having survived my instruction in Langdale she incautiously referred to my sedate progress on the way back. I’d been holding back on her behalf. A mile or two of open throttle with the Triumph pythonising its way between the dry stone walls returned our conversation to a more even-handed state.
