Free practice 3

Welcome to ESPNF1's commentary for the final practice session ahead of qualifying for the Canadian Grand Prix. It looks like we'll have another dry session this morning but there is a chance of rain this afternoon for the all-important qualifying hour.

We should get a good idea of who looks good for qualifying in this session with the first proper runs on super-softs. We did see most of the drivers out on the red-striped tyres yesterday but red flags for accidents and traffic meant that most the frontrunners did not get a competitive lap in.

Just to remind you of Kobayashi's big shunt yesterday here's a photo...

© Sutton Images

For those of you with an interest in Le Mans, we've just seen a huge accident involving ex-F1 driver Allan McNish. Fortunately he walked away from it, but his race didn't last any longer than an hour.

Back in Canada the session is about to get underway...

The session is underway and immediately a whole bunch of cars hit the track.

The big news so far this weekend is that Pedro de la Rosa has stepped in for Sergio Perez at Sauber after the Mexican felt a littl queezy following FP1. It's going to be an uphill struggle for de la Rosa to get back in the groove this weekend and this session will be crucial.

As we discussed yesterday, Sauber's reserve driver Esteban Gutierrez is in Mexico and missed out on his big chance to step in. He didn't sound too pleased about it on Twitter but it seems as though it was just bad luck that he wasn't attending this race.

All the cars bar Webber, Hamilton, Schumacher and Rosberg have been out for an installation lap. We're also hearing that Kobayashi is in a brand new chassis today following his accident yesterday. D'Ambrosio also had to take a new chassis overnight.

We also saw Vettel in the barriers yesterday morning at the 'Wall of Champions'. He described it as a "mild impact" and the Red Bull team were able to put the car back together again in time for the afternoon session.

Here's Lotus' plans for the morning session: "More tyre comparison and set-up work. Also try new items in braking system, which should help us - especially if we get wet weather"

Rosberg is out on track and immediately pushing quite hard on a set of soft tyres. The Mercedes did not complete any meaningful low-fuel running yesterday so they will have a busy time this morning. They were trying to solve their tyre wear issues yesterday on heavy fuel and according to Ross Brawn the team was happy with their progress.

Rosberg sets a 1:15.934 which is pretty quick for his first lap out of the box. He's now going faster on his second lap.

Webber has a problem and, you guessed it, it's to do with KERS. The team has the car in pieces and he's left the garage so it looks as though it will take some time to fix it.

Schumacher has taken over from Rosberg on track but has only completed slow laps so far. He's pushing a bit harder on his current lap but is someway off Rosberg.

De la Rosa has his own set of very smart Sauber overalls today. Yesteday he had to make do with his McLaren ones as he was only called in to replace Perez at the last minute.

Red Bull confirms: "Mark's car has a KERS battery issue. We're working on it"

Kobayashi is currently second fastest but is 3.640 seconds off Rosberg.

The circuit still looks like its lacking grip. Both Lotuses have just been off at different parts of the circuit, skipping chicanes. No damage done.

Button sets his fastest lap of the day with a 1:15.208. That's 0.174 off Rosberg.

One of the problems for the drivers this weekend has been the getting temperature into the tyres. The surface doesn't offer up much grip and the tyres tend to grain rather than increase in temperature. Getting that temperature in the tyres will be crucial if we have a dry qualifying hour.

Button goes quickest with a 1:14.942. That's the fastest time we've seen this weekend.

Rosberg is improving again and we now have Alonso, Vettel and Hamilton out on track.

Vettel goes quickest with a 1:14.162, 0.018 faster than Rosberg's most recent effort.

Alonso sets the fourth fastest time with a 1:14.918. That's his fastest time of the weekend so far, but 0.756 off Vettel.

Webber is still in the garage with nearly 30 minutes gone in this hour long session.

Rosberg is on the super-softs and goes fastest with a 1:13.919. Vettel is currently on the softs and just 0.138 shy of the Mercedes.

Hamilton just bounced across the grass at turn four. So he's clearly pushing quite hard on the soft tyres.

The times are pretty impressive so far and faster than last year. But in 2004 Ralf Schumacher's pole position time was a 1:12.275. So we have some way to go yet before they trouble that. Of course, that was in the V10 era and at the peak of the Bridgestone v Michelin tyre war. The BMW in the back of Schumacher's Williams was also a pretty powerful bit of kit and that counts for a lot on the long straights here.

Hamilton has now improved to fourth with a 1:14.795. He's 0.876 off Rosberg and has now returned to the pits.

Renault is impressed by the pace so far this morning: "Times are looking rapid this morning with another German, Rosberg, leading the field."

Rsoberg returns to the track in the Mercedes. The rest of the top six are still in the garage.

Di Resta is looking quick again in this session with the eighth fastest time. He was sixth fastest yesterday and could be one to watch this weekend.

Ferrari says: "Now it is time for super-soft tyres"

Expect the times to drop. Although the difference between soft and super-soft doesn't seem to be as big here as the difference between the two compounds at other circuits.

Vettel is out on track now.

Rosberg is clearly focusing on longer runs now as his team asks him to focus on minimising tyre degradation at the rear. It's all about limiting wheelspin out of the slow corners.

Barrichello skips the chicane at turn nine.

The BBC's Ted Kravitz is reporting that Red Bull's KERS only produces two-thirds of the power of the likes of the Mercedes unit. They've decided to do that on purpose in order keep the rear of the RB7 snug and tight to improve aero performance.

Alonso is third fastest on his new set of super-soft tyres but is on a quicker lap now. But as I type he runs too deep into the turn 10 hairpin and ruins his lap.

De la Rosa has become the latest driver to skip the chicane at turn four as we see a replay of Buemi coming perilously close to the outside wall.

Massa goes third fastest on the super-softs with a 1:14.078.

Alonso clocks an identical time to Rosberg with a 1:13.919. Remakable. It should be a very close battle between Mercedes and Ferrari in qualifying this afternoon.

Ian asks: "I've never quite understood the car + driver weight. I believe the combination of car and driver must be a minimum weight but (in the same team) do both cars weigh the same even though one driver may be heavier than the team mate?"

You're right about the car + driver weight which has to equal 640kg. The drivers that are lighter use ballast to make up their weight which is an advantage as it can be placed lower in the car.

Massa is 0.037 off the top two now. It's so close at the top at the moment.

Buemi is not happy with his tyre pressures after running wide at turn eight. He's back in the garage sounding desperate as the team try to remedy the problem.

Ten minutes left in this session and still no sign of Webber.

Alonso has just set the fastest lap so far with 1:13.701 and he's several laps into his super-soft tyre run.

Alonso is now back in the pits.

News on McNish after his nasty crash at Le Mans just before the start of this session, Audi says: "News from the Medical Center: Allan McNish is OK but the Audi team doctor will take him to a hospital for precautionary checks "

Ferrari's low-fuel running seems to be over. The team says: "Now they should try a run with the aim to do practice starts"

Darker clouds are starting to gather overhead, hinting at rain later today.

Vettel has just started his latest run on the super-soft tyres, will he improve?

Team-mate Webber is still in the pits and it's looking less and less like he will get a run ahead of qualifying.

Vettel backs off to give himself some free track behind Sutil's Force India. Maybe his next lap will be a quick one and a true indicator of the Red Bull's pace this weekend.

All teh cars bar Glock and Webber are on track so its getting pretty busy out there.

Vettel is faster through the first two sectors and gets a slipstream from Rosberg down the straight.

Vettel goes quickest with a 1:13.381, 0.320 up on Alonso.

Button's latest lap was 0.954 off Vettel. It's not looking that good for McLaren.

But as I type, Hamilton puts in a decent first sector... although he's 0.4 seconds off through sector two ... and finishes the lap over a second off the pace.

De La Rosa has had a big shunt at the end of the session. Having seen a replay it's not as bad as we first thought. He lost the rear end in turn four, slapped it against the barrier on the outside and then spun across the track and into the opposite barrier.

The right rear of the car looks in a bad state, but hopefully the car can be repaired in time for qualifying. Not good for de la Rosa's confidence though.

And the session has come to an end with that accident. Vettel was fastest by 0.320 to Alonso.

Webber didn't set a time all session because of that KERS problem. It's still unclear quite who is quickest, but Red Bull and Vettel will certainly be near the top.

Thank you for joining us this morning. Make sure you come back for qualifying, it should be a brilliant session.