“And these tyres are called slicks, because they’re very slick!”Murray Walker – legend
What constitutes a ‘slick’ racing tyre? Most have some allowance for tread expansion or initial deformation – the odd cross cut in the past, or tiny incisions at the edge today.
So what about four shallow circumference grooves? Not at all like the awful grooved F1 tyres of the new millennium – rather, very shallow channels to allow for tyre expansion, that are quickly worn away. Slicks? Maybe?
Let’s jump in the time machine and set course for May 1938… the Tripoli Grand Prix.
This first race for the new 3-litre Grand Prix cars was dominated by Mercedes-Benz – Auto Union having withdrawn, their new cars not yet ready. So, it was Mercedes-Benz W154 1st, 2nd and 3rd… with their slick rear tyres.
These appear to be the Continental tyres normally supplied for the record week runs. Most likely the new AVUS version – a direct development of the 1936 Caracciola 3-litre record tyre – and set down in drawings on 3rd August 1937.
Herr Hubenor – Continental’s pre-war head of research – explained to Cameron Earl in 1946 how this design was further developed for the Mercedes-Benz T80 land speed record car. Earl’s own drawings demonstrate how at speed the bulging sidewalls rise. The expanding tread causes the grooves – of little more than 1mm depth – to ‘disappear’. No doubt to be quickly obliterated by torque & asphalt.
And so we return to the 1938 Tripoli grid. I believe we are looking at the Mercedes-Benz team preparing to start the Grand Prix on carefully scrubbed, slick rear tyres.
Firestone may have introduced slick tyres to Formula One in 1971, but were they 33 years behind Continental in Grands Prix? Was this the first Grand Prix on a road course to be started & won on slick tyres?