What are sidan speed trials?

Some articles on speed, sidan speed trials:

Brough Superior Motorcycles - Racing History (partial)
... Riders of Brough Superiors have won many races—TT, sprints (drag racing), hillclimbs, and top speed ... Unlimited Capacity Solo Machines, Cefn Sidan Speed Trials. 10 Miles for Unlimited Solo machines, Cefn Sidan Speed Trials ...

Famous quotes containing the words trials and/or speed:

    Without trials and tribulations, no one can become a Buddha.
    Chinese proverb.

    Wait, Kate! You skate at such a rate
    You leave behind your skating mate.
    Your splendid speed won’t you abate?
    He’s lagging far behind you, Kate.
    David Daiches (b. 1912)