Welcome to our live coverage of the 2012 Olympic women’s time trial from London. 24 women will tackle the 29km route at 90-second intervals, which starts and finishes at the famous Hampton Court Palace.
Today’s weather is currently overcast with some light rain in London. Temperatures are currently hovering at around 17 degrees Celsius and there is a chance of heavier showers early on this afternoon. The riders will be hoping to have completed the course before then.
Clemilda Fernandes Silva of Brazil will be the first to head onto the course at 12:30 local time. Here are some of the key start times for later on in proceedings:
Elizabeth Armitstead (Great Britain) 12:52:30
Emma Johansson (Sweden) 12:54:00
Amber Neben (United States of America) 12:55:30
Emma Pooley (Great Britain) 12:57:00
Clara Hughes (Canada) 12:58:30
Linda Villumsen (New Zealand) 13:00:00
Marianne Vos (Netherlands) 13:01:30
Judith Arndt (Germany) 13:03:00
Kristin Armstrong (United States of America) 13:04:30
Silva is one of two sisters at the Games. Her sister Janildes was the early attacker in the road race.
And we're underway. Next up is Pia Sundstedt of Finland, who is also an endurance mountain biker and cross country skiier.
Defending Olympic champion Kristin Armstrong (USA) is the favourite to win today and is the last rider out on the course. At the 2008 Olympics in Beijing she beat Great Britain’s Emma Pooley into second place by a comfortable margin of 25 seconds. Pooley re-opposes today in front of her home fans and will be desperate to go one better.
At 29km, the course is roughly 25% shorter than the one last time in Beijing. There are time splits at 9km and 20km.
Lieabet de Vocht is next off. She was national TT champ in 2009 and 2011, and road champ in 2010. She's the sister of Wim de Vocht, who rides for Accent.Jobs-Willems Verandas.
Ashleigh Moolman (RSA) had a fine placing in the road race in 10th. Third at the Tour de Free State, she was runner up to Cherise Taylor in the RSA TT champs, but that was way back in March. Taylor protested about her selection.
It's now the turn of Audrey Cordon. She got into the breakaway briefly in the road race with Ellen van Dijk. Aged 22, she was 2nd in the French time trial championships.
Russia's Tatiana Antoshina is a bit more experienced than youngster Cordon. She celebrated her 30th birthday at the Games. She won the Trophee d'Or in 2011.
Aggressive start by the Russian. She gone off hard and fast.
Next off is Elena Tchalykh, who is Azerbaijan's only time trial competitor today. She's also an accomplished track rider - third in the world championships for three years. She's 38 years old.
The next woman off, Tatiana Guderzo, is one of the bigger names among the early starters - she's been on the podium of the Giro Donne, four time Italian TT champion, and was world champion in Mendrisio (road race).
Guderzo also took bronze in the road race in Bejing in 2008.
Canadian Denise Ramsden is another young rider who is on the Optum Pro Cycling team in the USA. Only 21, she's not exactly new on the international scene but is getting the nod from her federation for development here. She is the national road race champion, having beaten Clara Hughes in a two-up sprint.
The initial starters are closing in on the first time check.
Olga Zabelinskaya is the bronze medalist in the road race here in London. She had her medal hopes on the time trial, but already accomplished that goal. We'll see how intense the parties have been since then...
Emilia Fahlin is next up. The Swede is a fan favourite and a top time trialist. Shes' twice been Swedish TT champion before but not this year.
Fahlin rides with Specialized-Lululemon
And Silva has gone through the first time check in 15:38.
Trixi Worrack is Germany's number two time trialist. She was second to Arndt in the German championships, and is a past German RR champion.
Noemi Cantele (Italy) won silver in the TT in the 2009 worlds, and was national TT champion in 2009 and 2011.
Over half of the 24 riders are now on the road.
Shara Gillow (Australia) has the Olympics in her genes. Her father represented Zimbabwe in 1980.
She has won the Australian national TT championships for the last two years.
Fans will remember that Eleonora Van Dijk was the woman doing most of the work for Vos in the road race on Sunday. How much she will have left for this TT? She's also a past trackie, as most of the Dutch are. She was scratch race world champion in 2008.
Lizzie Armitstead (GBr), silver medalist in the road race, also got her start on the track. She was part of the world champion team pursuit squad in 2009. She gets a rapturous reception from the home fans.
Emma Johansson (Swe) has been at the top of the women's peloton consistently for years. She's dual Swedish champion, and has been on the podium of numerous World Cup races, but has only won one. She took silver in the road race in Beijing.
Armitstead caused a stir in cycling circles earlier in the week when she spoke out against sexism and inequality in the women's ranks. Read all about what she had to say right here.
Here comes Emma Pooley of Great Britain to the start. As mentioned earlier, she finished second in Beijing. She is well-fancied here but might prefer a more undulating course. Time will tell.
Like Armitstead, Pooley gets a tremendous reception from the crowd.
Pooley loves nothing more than riding flat out on her own. She's won a number of races that way like at numerous World Cups and the 2010 Worlds.
Clara Hughes (Canada) is the oldest competitor and the most experienced at the Olympics. Turning 40 in September, she made her comeback specifically for this event. She already owns two Olympic cycling medals - both time trial and road race from 1996, and also a gold medal in speedskating.
Linda Villumsen started her career with a Danish license, but changed her nationality to New Zealand in 2010.
She's been Danish road race champion three times, won silver in the time trial at the worlds in 2011, and bronze in the previous two worlds.
Marianne Vos (Netherlands) is on top of the world. What can you say? She's won so many races it's hard to count them. One stats site has over 150 wins to her name between track cycling, cyclo-cross, mountain bike and road. Only Leontien Van Moorsel Zijlaard has won medals in both the time trial and road race. But back in 2000, she also won a gold on the track as well...
And Vos has gone off very quickly. Time trialling isn't her strength but she can never be ruled out.
Judith Arndt (Germany) is the reigning world champion, she separated from her former teammates to join the new GreenEdge team. She won silver in the road race in Athens, famously flipping the bird because the German federation didn't choose Petra Rossner, who she felt could have won gold.
She's been world champion twice - once in the TT and also the 2004 road race (she did not flip the bird when she won the worlds road race)...
Defending champion Kristin Armstrong (USA) is racing to win gold for her son, which she had between Beijing and now. She had a hard time coming back last year and lost her bid to race worlds after a protest by Amber Neben. She flew to Copenhagen only to find out she'd lost the arbitration when she stepped off the plane.
And that's it - all the riders are out on the course
Armstrong has come back with a vengance this year and has been killing the time trials. Even after crashing and breaking her collarbone in the Exergy Tour she was faster than most of the field. Twice world champion, three time US champion, she took 2nd in the Tour of Flanders this year, showing that her form this year is absolutely world class.
Olga Zabelinskaya is the leader through the first checkpoint in a time of 14:13.
Johansson over a minute down on Zabelinskaya
Pooley will be next through the first split...
Amber Neben (USA) goes into second through the first check
Pooley goes through the first split in 14:06 and is the virtual leader through that point. Crowd loving that...
Pia Sundstedt (Fin) has posted the quickest finishing time in 40:01.
Villumsen (13:57) and Hughes (14:05) quicker than Pooley through the first check...
Vos is approaching the first time check...
Vos is 71 seconds down in 13th place...
Arndt through the first check in 4th (14:06)
Armstrong goes through the first split in first position
In 13:56:38 - very tight between her and Villumsen
Arndt was surprisingly slow and she and Pooley could be battling for bronze if Villumsen and Armstrong keep this up.
Arndt has caught Vos...
Zabelinskaya takes the lead with a finishing time of 37:37 - the first sub-40 minute time
Neben has overtaken Johansson
Still only one rider under 40 minutes as the big guns approach the second split.
Pooley through the second split in second place - but 20 seconds slower than Zabelinskaya
Worrack into second at the finish in 39:20
Clara Hughes faster than Pooley through the second split and is second quickest.
Villumsen approaching the second split...
Villumsen into first place at the second split - seven seconds quicker than anyone else
Van Dijk into second at the finish
Judith Arndt is just three seconds down on Villumsen's time. She's picked up considerably over the second sector. Just waiting on Armstrong now...
Armstrong 4.8 seconds quickest through the second split. Is she on course for a repeat victory?
Rain now coming down a little stronger here
SECOND CHECK: Armstrong, Villumsen, Arndt, Zabelinskaya, Hughes, Pooley
Pooley finished in 38:37. She's currently second but a medal looks out of the question at this stage with faster riders out on the course...
Hughes through in 38:29 - in the silver medal position so far.
Villumsen up into second position. Zabelinskaya still leading.
Armstrong sweeps past Vos with a few km left. Three minute swing there. Amazing.
Arndt quickest. Sets Armstrong a target of 37:50 for the gold...
GOLD MEDAL FOR ARMSTRONG
She somes home in a time of 37:34 for a comfortable win
TOP THREE FINISHERS
1 K Armstrong (USA)
2 J Arndt (Ger)
3 O Zabelinskaya (Rus)
Armstrong's winning margin was just under 16 seconds
Tremendous performance there by Armstrong. At the grand old age of 38 she has proved that she is still the world's best time triallist.
Solid performance by Arndt in second but the real surprise was Zabelinskaya, who beat big names like Villumsen and Pooley to the bronze medal.
There will be full results and a full report right here as we get them.
Stay tuned to Cyclingnews for full live coverage of the men's time trial, which starts at 14:15 BST.
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