Good morning and welcome to ESPNF1's live coverage of the first free practice session for the German Grand Prix. It's the first of two back-to-back races ahead of the summer break, and it could be a make or break two weeks for the championship contenders

The two championship leaders - Fernando Alonso and Mark Webber - are the only drivers to win two races so far this season, while third-placed Sebastian Vettel has never won the German Grand Prix (or a race in July). Behind those three, Lewis Hamilton really needs McLaren to improve, and Kimi Raikkonen has yet to win this season. Are we about to see the front two or three break away?

It's a crucial weekend for McLaren, which has a number of upgrades that are currently the main story in the paddock. Jenson Button says it's the biggest update that he's seen since joining the team, but the noises so far have come from the team talking up their own chances rather than its rivals being wary

We'll get our first look at the new upgrades during FP1, and the most noticeable - according to Martin Whitmarsh - will be the sidepods. Lotus also says it has "interesting" new parts, so we've got plenty to look forward to seeing this morning

The teams will be keeping an eye on the weather, however, as it is currently overcast with a threat of rain at Hockenheim. Sam Michael said that McLaren needs dry running to analyse the new parts, but it may not get that luxury all day

As always we want to hear from you during our live coverage, so get in touch in one of the following ways. Either email us using the link above or Tweet us @ESPNF1

And our first email in is from Neville, who asks: "Before it gets busy, whilst the points may not reflect this Schumacher has been far better in 2012. Is this the opinion of the Paddock as well?"

I assume you mean better than last season, Neville, and that is indeed the consensus among most observers. Schumacher has had really bad luck with mechanical failures this year so far, and without those I think the points total would reflect his improvement too.

Rahul emails in to ask: "What your take on this race from the point of view that this is the time we are in Hockenheim with the Pirelli? Also please brief us on the updates of major players like Ferrari, mclaren, red bull."

Well I think Hockenheim is not hugely different to other tracks on the calendar - it's a bit similar to Bahrain in terms of corner speed and the odd long straight - so I don't think the tyres will be any more prominent than usual. In terms of updates, McLaren were mentioned below, we're yet to see or hear what Red Bull has (but they'll have some small bits) and Ferrari has some aerodynamic parts including an intricately sculpted diffuser

Siddhesh asks: "Is it going to be the wet-dry weekend of Silverstone all over again? Can't say that was all that fun. . ."

It looks like being a bit unsettled today - but not the rain levels of Silverstone - with a threat of showers on Saturday too but a dry Sunday expected. I think we'll see more dry running than we did in Britain

Luthando emails in to say: "McLaren started the season showing very strong qualifying pace with race pace that was largely good enough but nothing special, except for races at Montreal and Barcelona, could it be that McLaren have a fundamental issue that affects their tyre usage which is limiting their development scope. I think this car is only marginally faster than the Melbourne spec MP4, whereas RedBull and Ferrari (even Lotus) have found oodles of time."

Personally, I think it's that McLaren has gone in the wrong direction slightly when developing the car, and has also failed to maximise the car's potential as often as the likes of Red Bull and Ferrari. It was also beaten to the first major upgrade by Red Bull in Valencia, so the updates this weekend are crucial for McLaren

Just to let you know of the driver changes for FP1 before we get under way: Jules Bianchi is in for Paul di Resta at Force India, Valtteri Bottas takes over Bruno Senna's Williams and Dani Clos is in for Narain Karthikeyan at HRT

We've got a dry start to the session at least, but the radar says a shower will pass close to the circuit at 10:05 local time

FP1 has started, and it's the Toro Rossos who are first out followed by Kovalainen and Glock

We've just seen Jenson Button's updated McLaren, and he's actually covered by a sheet as he sits in the car for now as aero paint is sprayed on the sidepods

The rear end of the McLaren is tighter and there appears to be an update to the diffuser too. There are also laser sensors under the car which were shining out of the back

We've got an experimental hard tyre being run by Pirelli today, so each team has an extra two sets of those tyres to be handed back

Ferrari has flo-viz paint on Alonso's front wing, while we see Raikkonen and Kobayashi struggling to slow their cars on the experimental hard tyre - the race compounds are the soft and medium this weekend

Kobayashi is running a sensor that is monitoring the air flow out the rear of the car between the rear wheels and the diffuser

Toro Rosso bleeding Vergne's brakes and with his car in a number of bits right now, so we may not see him back out for a little while. His team-mate Ricciardo, however, is back on track

Everyone has completed an installation lap, Ricciardo is back in the pits too

McLaren now taking a number of images to help analyse the new parts and wiping off the flo-viz paint

Button heads back out and joins Ricciardo on track

Kovalainen is out on track too; Caterham hoping to get more out of its upgrades that it brought to Silverstone, with technical director Mark Smith thinking there's another 60% to come from them this weekend

Kobayashi has completed a timed lap (though not at racing speed) - a 1:55.569

Button looks to be on a flying lap so this should be our first proper time of the day

And Button does a 1:18.759

Button improves to a 1:17.410 second time round. Perez has done a 1:23.198 and Kovalainen a 1:24.236 on the hard tyre

Perez improves to a 1:20.665

Paul di Resta chatting away to Adrian Sutil in the Force India motorhome

Button is on the mediums and does a 1:17.240

Grosjean does a 1:19.251

Appears to be a new exhaust layout for Williams - the outlets seem to be angled higher at the rear wing rather than the diffuser

Petrov runs wide at turn two on the hard tyre, while Kobayashi runs over a piece of debris as he exits the pits

Button improves in all three sectors to do a 1:16.595

The fastest lap time in Friday practice when we were last here two years ago was a 1:16.265 by Alonso in FP2

@RenaultSportF1 on Twitter: "It's raining out on track..."

Robert emails in from Darwin to say: "Wow! Button is doing some impressive times after the new upgrades, hopefully it will be like this on race day!"

I hate to ruin your fun, Robert, but we haven't seen representative times from Vettel, Alonso, Webber or Hamilton yet so can't really judge how good these times are

The sprinkling of rain is making the circuit slippy and drivers are carefully coming back to the pits

Race control has officially declared the track wet

A number of drivers ran wide as the rain started. Kovalainen was the most dramatic - running wide on to the gravel

Petrov was keeping an eye on Vettel behind and going slowly but still had to catch the car under braking for the turn six hairpin

Vergne is on medium tyres and managing to keep the car on the island so he's still running out there on his own

Lotus is blocking the camera's view of Kimi Raikkonen's car, including team press officer Andy Stobart who has just tweeted (as @Lotus_F1Team) "Lots of interest in Kimi's car today"

It appears to have stopped raining so Ricciardo has joined Vergne out on track

Hamilton and Massa also head out

Di Resta now monitoring the FP1 session from the Force India pit wall with Jules Bianchi out there in his car

Massa is on the experimental hard tyre and he radios in to say the track is "OK"

Massa does a 1:21.540

The experimental hard tyre is designed to have a large operating window compared to the current hard, but Pirelli says it is with a view to 2013 rather than for this year

Alonso heads out on medium tyres

It's started raining again. A lot of Lotus mechanics around the rear of Raikkonen's car and there are reports Lotus has a Mercedes-style double DRS system

This shower is heavier than the one we had earlier and Kobayashi has just bounced across the gravel at turn 12

Massa stays out on the hard compound tyre, while everyone else has pitted

So you know how slippery it's getting, Massa's first sector is around ten seconds off the pace

Massa is doing constant speed tests, as Ferrari confirms on Twitter: "Felipe is still running but not pushing: he is working on some aero test."

Massa back in as Kovalainen heads out. Sector three is the wettest part of the track

Tom in Foster City gets in an early prediction for the weekend: "In the home country of Aufrecht Melcher Grobaspach (AMG), the karma has to be with all Mercedes engined cars, and I pick Hamilton."

Pic's joined Kovalainen on track, but Kovalainen is struggling to turn in at the hairpin with the slippery track

Pic stays out and Bottas joins him

Ricciardo also heads out on track but the radar says light rain will continue to fall on and off for about half an hour

Bottas touches the outside kerb at turn ten and spray comes off his tyres

How interesting is the rear of Raikkonen's Lotus? Well, take a look for yourselves:

© Sutton Images

Those slots either side of the air intake on the roll hoop are new, and with cool temperatures expected (and a car that works well in hot conditions) you'd have to say they're not for cooling purposes...

The Lotus exhausts are also pointing towards the rear wing, while there's an outlet above the floor that appears to come from those intakes beside the roll hoop

Vergne with lightning reflexes to catch his Toro Rosso as it tries to swap ends on him more than once at turn one

Kovalainen heads out - the new Caterham exhaust layout looks a lot like the Red Bull one

Still spots of rain as Webber goes through turn one on the experimental hard tyre

A busy track, only Massa, Kobayashi and Raikkonen not on track

Schumacher radios in to tell his team "There's another shower coming in a couple of minutes" - local knowledge at work

Alonso goes second quickest on a 1:17.795 on the medium tyre

Grosjean locks up on hard tyres - his car doesn't have the same outlet at the rear as Raikkonen's does (nor the roll hoop intakes)

Hamilton doesn't threaten the apex at the hairpin on the head tyre

Hamilton goes fourth with a 1:18.845

Raikkonen is the only man not to do a timed lap - although Kobayashi still hasn't improved on his 1:55.295 from earlier so is 38.7s off the pace

Rosberg going quickly on medium tyres so track conditions improving

Rosberg does a 1:17.915 for third quickest

Hulkenberg goes second with a 1:17.599 - still over a second slower than Button though who set his time before any rain

Kobayashi is out on the intermediate tyre. It's not wet enough for that, but Schumacher was predicting another shower...

And now it is raining again so drivers head for the pits

Hamilton and Massa both ran wide due to the rain, no damage done though

Kobayashi still running an aero sensor on his Sauber so he's probably carrying out constant speed tests

Raikkonen returns to the pits - still plenty of interest surrounding that car

Kobayashi has improved to a 1:44.896, so he's only 28.3s off the pace now. Progress.

A shot of the updated McLaren for you too as we wait for this shower to pass:

© Sutton Images

With just over 22 minutes left we have an empty track

Luthando emails in to say: "I understand why they do it, but it just looks silly when teams are trying their best to stop others from seeing their solutions (THIS times its LOTUS), The sport's commercial backbone is based on maximizing coverage which means that if you do well there's more TV time for the very clever tricks ur trying so very hard to keep under wraps."

It's a fair point, but of course by covering your car it increases interest and therefore all the cameras try to get a shot. In fact, the Lotus has been getting more interest than the McLaren during this session now

Rahul asks: "How is Jenson so quick? We have not seen such times from Lewis"

Button did his time when the track was dry at the start - before any rain fell - while Hamilton hadn't been out to do a proper flying lap at that point

Perez and Kobayashi head out on track - Kobayashi on intermediates but without his sensor now

Perez is also on inters and is told not to destroy them as they might be needed later

Kobayashi is finally doing a proper timed lap at the 13th time of asking

Kobayashi does a 1:24.349 - it's probably not quite wet enough for intermediates out there

Chris in sunny Perth (for the next few minutes as it's sunset) says: "Quite a change in the sidepods on the McLaren - they are more like the Ferrari of a couple of years ago, but what's with the turning vanes on the top surface? that's quite radical for this year. Too early to tell if they work yet though ...."

The turning vanes are common on a number of cars this season; they're clear on the Toro Rosso so harder to spot but Red Bull also have them

The rain has stopped so we have cars back on track on slicks

The track is dry enough for times to start improving too as we see fastest first sectors from Schumacher and Massa

Webber goes wide at turn 12 and has to back off to avoid reaching the gravel - there's about a car and half's width of astroturf before the gravel

Schumacher has gone third and Perez fourth

Schumacher now goes second, 0.787 slower than Button

Alonso now second on a 1:17.370 on medium tyres

A busy track - only Glock and Raikkonen in the pits - means it's tough for drivers to get a clear lap to improve

Raikkonen heads out - no turning vanes on the sidepods of that Lotus that I can see and I was wrong earlier, Ferrari don't have them either

Glock rolls down the pit lane and needs his Marussia mechanics to come and push him back to the garage

Radeshen emails in to ask: "Why does Ferrari not have the turning vanes on the side-pod top surface but almost everybody else has. Could it be because they use their rear view mirror supports to generate a similar vortex?"

It's unlikely the mirror supports would be as effective, but it all depends on the sidepod shape and airflow over it - just adding some turning vanes could be to the detriment to the overall aerodynamic package otherwise every team would have them

Hamilton now second - 0.498s slower than Button

Schumacher locks up and runs wide at turn two, while Alonso also runs wide on to the astroturf at turn 12

Bottas is in the tyres, he's gone in to the barrier backwards at turn 13. That's probably the first mistake we've seen from him in his Friday practice appearances

Bottas locked the rears under braking for turn 13 and spun before bouncing across the gravel and hitting the tyres - breaking the rear wing. He went in fairly quickly but is fine. That will stop anyone from improving at the end of the session though

Raikkonen is on a good lap but has to back off for the yellow flags. He was about a 0.5s off through sector two

Hamilton sets the fastest middle sector but then has to back off and pit

Everyone continued pushing until reaching that final sector - Vettel ran wide at turn two

So the session ends with a McLaren one-two ahead of Alonso. It looks good for the team, but with Vettel 12th and Webber 20th Red Bull was clearly not chasing headline times so we don't know what the relative performance is

It was a very disjointed session, but McLaren would rather be one and two than languishing further down the field. Will that pace continue in FP2? And will see just how quick Raikkonen's updated Lotus is? Join us in two hours for the build up to the second session to find out. Bye for now.