The teams had their first taste of the new type of Pirelli tyre today, with two sets of an experimental medium tyre using a new Aramide rear construction allocated to each driver for Friday's two free practice sessions. As usual, they also had this weekend's two nominated compounds at their disposal: P Zero White medium and P Zero Red supersoft, in original 2013 specification.

Rain in the first free practice session during the morning meant that teams only got around 20 minutes of dry running at the very end of the hour and a half. Up to then, the Cinturato Green intermediates and to a lesser extent the Cinturato Blue wets had been used, with Toro Rosso's Jean-Eric Vergne the first to sample the new slicks. Force India's Paul di Resta put in a quick lap on the medium tyres to set the fastest time before a yellow flag effectively ended the session.

The afternoon remained cool but was much drier, with the cars lapping five seconds faster than they had been in the morning. Ferrari driver Fernando Alonso set the fastest time of the weekend so far on the supersoft tyre: 1m14.818s – half a second faster than the equivalent time last year. Friday's most consistent driver was Lotus's Romain Grosjean, who was third-quickest in both sessions.

Paul Hembery: The rain in the morning meant that the drivers didn't really get to assess the new construction of the rear as thoroughly as they would have liked to, but initial feedback has been positive. We'll be analyzing a lot more data about this new construction over the next few days before drawing a final conclusion, but we don't expect this to be a massive change. It's only a minor alteration to ensure that none of the previous delaminations - which do not impact on safety - recur, and it doesn't affect the fundamental characteristics, performance or durability of the tyre. Canada is always one of the most challenging circuits for the tyres, because of the layout of the track and also the heavy braking, which puts plenty of heat into them. Conditions today could well be representative of what we have in the race, with around 17 degrees ambient and track temperature, and we've seen good durability and performance from both compounds so far - with little graining despite the cool temperatures. It's hard to make a prediction about the number of pit stops at this point because the track is still very green and there are so many variables here, but we've seen some long runs from the supersoft in practice with no significant drop-off in performance, so this certainly looks set to be the tyre to qualify on tomorrow.

Pirelli fact of the day: Montreal has the lowest pit stop time loss of the year, with the cars losing just 16 seconds from the beginning to the end of the pit lane. This encourages many of the drivers to opt for a ‘sprint' strategy with a high number of pit stops, particularly if the car is fast anyway. The high probability of a safety car means that a flexible strategy can often win the race, making the task of formulating the strategy even more complex for the engineers.

Check out our Friday gallery, here.