Flat 213.5 km - Reims to Nancy
Bunch sprint finish expected in Nancy
France's Julian Alaphilippe in race leader's yellow jersey
A day to stay safe for Britain's defending champion Geraint Thomas
Use the play icon to listen to BBC Radio 5 Live Sports Extra commentary online from 14:00 BST
James: Rode 20,675 miles from Deadhorse, Alaska down to Ushuaia, Argentina in 22 months. Gave me saddle sores plus a sense of just how incredible these Tour de France cyclists really are!
Max: Did Jogle (John O’Groats to Lands End) a couple of years ago solo in a week. Whilst congratulating myself I heard the record was 5 days ... there and back. Awesomely me, but madness.
Allow Twitter content?
This article contains content provided by Twitter. We ask for your permission before anything is loaded, as they may be using cookies and other technologies. You may want to read Twitter’s cookie policy, external and privacy policy, external before accepting. To view this content choose ‘accept and continue’.
Bring on the mountains......
#bbccycling
Keep them coming folks. Tell us all about your longest rides.
Image source, @DrJimmyOne climb to go. The Cote de Maron with 15km to go.
And the peloton has brought the breakaway group back to about 40 seconds.
Can't see them reaching and escaping over that intact.
Image source, Getty Images#bbccycling
Mark: I did 1440km in London-Edinburgh-London in 2013. It was 110 hours with a max stop of three hours sleep. Didn't look good!
Howard: Longest ride 3445 miles ,coast to coast across the USA in 7 weeks.
Image source, TourdeFranceAdam Yates was bang on the money on Monday tipping Julian Alaphilippe to win stage three into Epernay.
The Mitchelton-Scott rider wasn't far off with Ineos in the team time trial on Sunday either, but is he going to be spot on today?
Just have a read of his guide here which covers the first 10 of the 21 stages that make up the 2019 Tour de France, with pointers to where the race will be won and lost.
1. Frederik Backaert, 20 points2. Michael Schar, 173. Yoann Offredo, 154. Elia Viviani, 135. Sonny Colbrelli, 116. Peter Sagan, 107. Matteo Trentin, 98. Michael Matthews, 89. Michael Morkov, 710. Andrea Pasqualon, 611. Greg Van Avermaet, 512. Ivan Garcia Cortina, 413. Andre Greipel, 314. Cees Bol, 215. William Bonnet, 1
Michael Schar (CCC), Yoann Offredo and Frederik Backaert ( both Wanty-Groupe Gobert) are being reined in by the peloton now.
Their advantage is down to one minute and 30 seconds.
Image source, Getty ImagesWe're now well over halfway through the fourth of 21 stages at this year's Tour de France.
The 3,480km (2,162 miles) route has a mix of flat sprinter-friendly days, like today, time trials and climbs up some of the highest mountain passes in Europe.
But if you've not seen this inhumanely difficult test of endurance, tactics and speed with your own eyes before or just fancy a quick refresh before this race gets into full swing....
Well, BBC Sport has got everything you need to know about the race here.
#bbccycling
Image source, @TheSpenneyMeanwhile back in the peloton....
Unlucky for some, Italy's Elia Viviani takes 13 points.
Allow Twitter content?
This article contains content provided by Twitter. We ask for your permission before anything is loaded, as they may be using cookies and other technologies. You may want to read Twitter’s cookie policy, external and privacy policy, external before accepting. To view this content choose ‘accept and continue’.
The intermediate sprint is done and dusted and Frederik Backaert takes 20 points.
The Wanty–Groupe Gobert rider whose speciality is the one-day classics, timed his effort to perfection to accelerate clear of his erstwhile buddies Michael Schar and Yoann Offredo.
#bbccycling
Image source, @mummyjillyWe're about five minutes from the intermediate sprint and the peloton are closing in on the breakaway group.
The gap is down to two minutes.
Image source, Getty ImagesThe peloton is just steadily creeping through Menil-aux-Bois in north-eastern France, which is literally surrounded by acres of barley fields.
One of the astounding things about the Tour de France is the sheer number of people that line the roads over the course of the three-week race.
Between 10-12 million fans are expected to line the route, spending on average seven hours out following the race (Almost like writing a live text on a stage!).
And that's more live spectators than an Olympic Games or Fifa World Cup.
#bbccycling
Image source, Getty ImagesThe 213.5km drag from Reims to Nancy is the fourth longest stage at La Grand Boucle in 2019. And the spectacular scenery is pretty much compensating for the lack of action on the road.
But what's the longest in hours or distance that you've been welded to your saddle for?
Feel free to let me know using the hashtag and pictures from a leg sapping ride always go down well.
For what it's worth Michael Schar is now tied in fourth place in the King of the Mountains classification, level on one point with Julian Alaphilippe and Nairo Quintana.
Lotto-Soudal's Tim Wellens leads the competition with seven points.
Swiss rider Michael Schar has got more in his legs as the breakaway group ascend the Cote des Rosieres.
The 32-year-old isn't bad in the mountains so this one-kilometre stretch is a piece of cake as he eases clear of Frederik Backaert and Yoann Offredo to scoop up the solitary King of the Mountains point on offer.