Britain's Geraint Thomas wins stage one
Welshman clocks 16 minutes four seconds for 14km time trial
Team Sky team-mate Vasil Kiryienka is second
Defending champion Chris Froome sixth
GC contender Alejandro Valverde out after big crash
Team Sky's Michal Kwiatkowski fades slightly in the second half, coming home in 16 minutes 19 seconds to move into third place.
His team-mate Vasil Kiryienka still leads, having gone eight seconds quicker.
Quick-Step's Matteo Trentin is the man sandwiched between the two Team Sky riders.
Just as we look at Chris Froome's main challengers, his Team Sky team-mates offer a reminder of how much of a trump card they are when considering the overall winner.
Michal Kwiatkowski has matched current leader Vasil Kiryienka's checkpoint time of nine minutes 20 seconds.
Froome is actually in the Team Sky car following Kwiatkowski, sussing out the course before he goes at 17:32 BST.
As we wait for most of the general classification riders to start, let's take a look at some of Chris Froome's main challengers for the Tour title.
Froome's former Team Sky team-mate Richie Porte is the man in form this year, winning a couple of early season stage races and finishing second in the Criterium du Dauphine.
However, whether the 32-year-old Australian has the legs for the three-week test ahead is debatable. He took over as Team Sky's leader when Froome pulled out after a crash in 2014, but struggled in the high mountains and finished 23rd.
His best result was last year's fifth but the BMC Racing rider tends to have one bad day that destroys his chances.
Image source, Getty ImagesTaylor Phinney is a talented time triallist and could challenge for the stage but even he is nervous in this rain.
He goes at 17:14 BST.
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Rob Hayles
Former GB cyclist on Radio 5 live sports extra
That really was a good ride there by Kiryienka. His mouth was wide open all the way along the finishing straight, it is longer than the riders think.
He may not keep top spot for long though as looking at the time Matteo Trentin set, that suggests his team-mate Marcel Kittel has it in him to go quickest.
I feared I'd put the mockers on Vasil Kiryienka when his back wheel slid out halfway round but the Belarusian was simply pushing his bike to the limit.
It's paid off as the 2015 world time trial champion comes home in 16 minutes 11 seconds to take the top spot from Matteo Trentin.
I imagine Kiryienka will now be off to debrief Team Sky team-mate Chris Froome. The defending champion starts his run at 17:32 BST.
Image source, Getty ImagesRob Hayles
Former GB cyclist on Radio 5 live sports extra
Two-time stage winner Matteo Trentin has just set the fastest time and he is a pretty good sprinter. His team-mate Marcel Kittel will be looking to join him up there shortly.
Where do we go from here? This year's route is a bit of a curious one, with fewer time trial kilometres than ever before and several intriguing stages.
Organisers appear intent on breaking Team Sky's recent dominance, which has been characterised by their ability to control the pace of the race. The mountain climbs are generally shorter and steeper, while two short individual time trials should not allow Chris Froome to gain too much on his challengers.
As well as the Grand Depart, Dusseldorf also hosts the start of stage two, which finishes in Liege, Belgium.
From Belgium, the race heads through Luxembourg and on into north-eastern France and then south towards the Alps to end week one.
A rest-day transfer to the Dordogne region in the west is followed by a second week dominated by the Pyrenees mountains before the Alps take centre stage for the final week.
For the first time since 1992, the race visits all five of France's main mountain ranges, but there are just three summit finishes.
...and sure enough, Trentin flies in to edge out Nikias Arndt and take the top spot with a time of 16 minutes 14 seconds.
Peter Sagan puts in an impressive effort to come home in 16 minutes 29 seconds and slot into third place.
Looks like he won't be third for long though - Matteo Trentin is absolutely flying...
Image source, Getty ImagesQuick-Step Floors' Matteo Trentin has posted the fastest time at the first checkpoint, with nine minutes 24 seconds.
Rob Hayles
Former GB cyclist on Radio 5 live sports extra
Had it been dry, the riders would have had a lot more traction but if it was dry they would have all thrown caution to the wind and maybe there would have been more crashes as more riders would have been riding flat out.
Britain's Scott Thwaites, a team-mate of Mark Cavendish at Dimension Data, also lost time after falling out on course.
The first of the potential favourites for stage one victory and the first yellow jersey of the Tour is about to get under way
Chris Froome's Team Sky team-mate Vasil Kiryienka is capable of an imposing time trial performance on his day and his time could give us an indication of what is needed to win this stage.
Here are the rest of the stage contenders' start times. All times in BST...
Vasil Kiryienka (Team Sky) 15:42
Jonathan Castroviejo (Movistar Team) 16:24
Jos van Emden (Team LottoNL-Jumbo) 16:54
Taylor Phinney (Cannondale-Drapac) 17:14
Primoz Roglic (Team LottoNL-Jumbo) 17:16
Tony Martin (Katusha-Alpecin) 17:20
Steve Cummings (Dimension Data) 17:23
Stefan Kung (BMC Racing Team) 17:28
Chris Froome (Team Sky) 17:32
Two-time world road race champion Peter Sagan is under way.
One of the sport's great characters, the Slovak is the firm favourite to retain the green points jersey that he has won five straight times.
Should he repeat the feat this year, he will equal Erik Zabel's record.
While Zabel was a versatile rider, he mainly won his points in the sprints, whereas Sagan has a rare ability to mix with the sprinters and tackle minor climbs.
Consistent high finishes on various terrain means he has dominated the points competition since Mark Cavendish took the title in 2011.
However, race organisers also appear keen to stop Sagan's fun and give the pure sprinters more of a sniff. But can anyone stop him?
Image source, Getty Images
BBC Radio 5 live sports extra
Live commentary of stage one, courtesy of the BBC Radio 5 live team of Simon Brotherton and Rob Hayles, has just started. Listen by using the media player tab at the top of this page.
Thibaut Pinot comes home in a time of 16 minutes 53 seconds. His fellow general classification riders will fancy going under that.
Here are the top three as things stand. Plenty of big names to come but Arndt's time is looking like a very strong early benchmark as the rain continues to fall and makes the ground slicker.
FDJ's Thibaut Pinot is out on the course. The 27-year-old Frenchman has flattered to deceive in terms of challenging for the overall prize in recent years but has improved his time trialling so should hold his own here.
Pinot opted to race the Giro d'Italia - the first three-week Grand Tour of the season - this year.
Conventional wisdom decrees you can't race the Giro and then challenge at the Tour these days. But will miles in the legs actually help Pinot go deeper into the Tour this time?
Image source, Getty ImagesA German leads the standings - and Arndt's countryman Tony Martin is favourite for the stage.
It would be a fitting victory, given this is the first Grand Depart to take place in Germany since 1987, when the country was divided and the Berlin Wall still stood.
In cycling terms, it's also a notable return to a country that had not long ago turned its back on the sport after a series of doping scandals enveloped its biggest stars, none bigger than Jan Ullrich.
Ullrich remains the only German to win the Tour thanks to his 1997 victory but was implicated in the Operacion Puerto doping scandal in 2006 and retired in February 2007.
A formely huge figure in German sport fell from grace and cycling went the same way.
But broadcaster ARD started showing the Tour again in 2015 and a new generation of German riders - including Martin and sprinters Marcel Kittel, Andre Greipel and John Degenkolb - seem to have reinvigorated interest in cycling in the country.
A few ropey timings on the race graphics - a classic quirk of the Tour - Grivko actually posted 16 minutes 21 seconds earlier.
Looks like Nikias Arndt of Team Sunweb may have just about beaten that time... yes, the German goes top of the standings with a time of 16:20.
Britain's Luke Rowe has just come in too, the Team Sky rider not troubling the top with a time of 17:54.
Image source, EPA