While most of the cycling world is gearing up for the Vuelta a Espana, the North Americans offer a preview of the exciting stage racing to come by hosting one of the two biggest stage races on the continent. In just its 3rd year of existence, the USA Pro Challenge has been able to attract a formidable line-up spearheaded by the reigning Tour de France champion and with its high altitude, it offers a unique challenge for the cycling elite. A mountainous course and an uphill time trial makes it a race for climbers and a more international field could potentially reduce the North American dominance that has been prevalent during its first two years.

Europe may still be the main continent for professional cycling but during the last decade, a number of high-quality North American events have been created. Nowadays, the second part of the calendar is loaded with races on the big Western continent to such an extent that a rider can make up a very busy race schedule without even crossing the Atlantic to get to Europe. The Tour of Utah kicked off the action last week, and next week the racing continues with the biggest of the autumn stages on North American soil, the USA Pro Challenge. With the brand-new Tour of Alberta, racing then heads to Canada where it all comes to a conclusion with the two WorldTour one-day races in Quebec and Montreal in early September.

With its inaugural edition taking place in 2011, the USA Pro Challenge is a new event but it has already established itself as one of two marquee events in the USA. While the Tour of California attracts the cycling elite during the spring season, the Colorado race is the highlight of the American autumn season. A smooth organization and intriguing courses have been enough to convince a number of European cycling stars to cross the Atlantic to contest the two events that form the backbone of the American racing scene.

The creation of the USA Pro Challenge was announced in the autumn of 2010 by Colorado governor Bill Ritter and a certain Lance Armstrong who hoped to reignite racing in Colorado. The state had been put on the cycling map during the 80s when the Coors Classic was listed as the fourth largest race in the world, only surpassed by the three grand tours. With plenty of sponsorship dollars already found, the race made an immediate move into the top class of American stage racing, being one of just three big UCI stage races on the continent alongside the Tour of California and the Tour of Utah.

Being hosted by well-known organizers Medalist Sports, the event was able to attract a star-studded line-up already in its inaugural edition. To present the entire Tour de France podium on the start line in its first year of existence was seen as a major coup and while last year's line-up may not have had the same standard, it was still a first-quality field.

Despite the presence of international stars, the race has, however, had the same problem of North American domination that has continually haunted the Tour of California and all other major stage races on the continent. Levi Leipheimer beat compatriots Christian Vande Velde and Tejay Van Garderen in the inaugural edition while those three riders also made up the podium one year later with Vande Velde taking the win ahead of Van Garderen and Leipheimer.

That local domination may be partly due to the feature that makes the USA Pro Challenge a unique event on the calendar of major UCI races. With the entire race being held at more than 1300m of altitude, most of it taking place at more than 2000m and the race reaching its highest point on Independence Pass more than 3500m above sea level, no other high-level UCI race is held at a similar altitude. That turns the race into a unique challenge and makes it less of a surprise that the race has been dominated by local riders who are familiar with the unusual conditions.

On paper, the race has much better conditions to develop into a race for the best international riders than the Tour of California. With its spring dates, the Californian race is mostly a Tour de France preparation for the European riders who are up against local riders for which the race is a clear target in itself. Held in the autumn, the USA Pro Challenge is seen more as an objective also for the European riders than a mere preparation event. For the riders that don't race the Vuelta, there aren't many mountainous stage races in the second part of the season and the American race stands out as one of the few events to red-circle. For some riders, the race is mainly preparation for the world championships but most of them are here to chase results.

This year the race has assembled what is probably its best ever field. Spearheaded by reigning Tour de France winner Chris Froome, the line-up contains world stars like Richie Porte, Andy Schleck, Andreas Klöden, Tony Gallopin, Greg Van Avermaet, Michael Rogers and Peter Sagan who mix it up with the cream of the American stage racers. Vande Velde, Tom Danielson, Andrew Talansky and Van Garderen have all made the race their key autumn objective and will be joined by a host of in-form pro continental and continental riders to form the basis for a very high-calibre event.

Last year, Vande Velde and Van Garderen were involved in a very tight battle for the leader's jersey during the opening stages but defending champion Leipheimer left both of them behind on the queen stage and appeared to have the race win locked up with just the final, flat time trial to come. However, Vande Velde produced the ride of his life in Denver city to finish second behind Taylor Phinney and so take what is arguably the biggest stage race win of his career. Vande Velde and Van Garderen will both be back this year but we should see at least one new face on the final podium with Leipheimer now having joined the list of ex-professionals.

The course

With its high altitude and mountainous terrain, the race is - at least on paper - one for the climbers. The Colorado climbs are, however, very different from the ones found in some parts of Europe where steep ramps and irregular sections offer the perfect launch pads for attacks. As opposed to this, most of the ascents found in the American state are long, gradual climbs that are not very steep. Hence, it has been very difficult for attackers to make a difference during the first two editions which have mostly come down to a gradual elimination race in the mountains - with the high altitude playing a significant role - and a crucial time trial.

With the first edition mostly being decided by the uphill time trial to Vail, organizers tried to make the race more difficult for the second edition by including an uphill finish on Flagstaff Mountain.  With only small time differences being created, most of the race once again came down to the time trial which was held on a flat course in Denver. This year, the organizers have tried to make the course even more selective with two stages for the climbers but the uphill time trial in Vail which is back after a one-year absence, should once again play the most crucial role for the final GC.

Despite the many climbs, the race has always had its opportunities for the sprinters. This year will be no different as the race kicks off with a short 97,6km circuit race around Aspen. The race consists of three laps on a 33km circuit (the site of the official start is located a few kilometres into the first lap) which contains two categorized climbs with KOM points on offer on the final two laps. The circuit is mostly up or down and the top of the final climb is located just 9,7km from the finish line. From there, the terrain is only slightly rolling and it should be possible for the sprint teams to keep it together for a final bunch kick. Peter Sagan will relish the opportunity to open up his second-half season account after a modest showing in the RideLondon classic.

On Tuesday, the GC comes into play for the first time with a long 202,9km stage from Aspen to Breckenridge. The race has an extremely tough start as the riders head up the mighty Independence Pass almost immediately after the official start. In the two previous editions, the riders have gone the other way up the climb before speeding down the descent to finish in Aspen but this year the course has been reversed. The climb is not overly steep but has a length of almost 30km and as it takes the riders up to more than 3500m, the high altitude will come into play. From the top, it's a long descent to the intermediate sprint in Buena Vista and then a long, gradual, uncategorized climb. It leads directly to the bottom of the short Hoosier Pass whose top is also at more 3500m and which resembles the Independence Pass. From the top 24,1km remain and they will mostly consist of a descent towards the finish in Breckenridge. The downhill section will, however, be disrupted by the short 2km Boreas Pass which has some rather steep sections and whose top is located just 4km from the line. From then, it's fast downhill all the way to the finish line. The stage is most likely to develop into an elimination race on the long climbs in the early part of the race while the GC riders will probably attack each other on the final ramp in an attempt to open up the first slight time gaps.

The sprinters could very well get back into the spotlight on stage 3 which takes the riders from Breckenridge to Steamboat Springs via a 170,4km course. The first 85km mostly consist of a long, gradual descent which is only disrupted by the short Swan Mountain at the 11,3km mark which should be the perfect launch pad for an early attack. From the intermediate sprint in Kremmling after 88,4km, the roads point slightly upwards as they lead to the bottom of the Rabbit Ears Pass. It's another typical Colorado climb which is not very steep but offers a high altitude to deal with. From the top, 33,7km remain and they consist of a short rolling section on the top of the climb and a fast descent which leads to the flat run-in to the finish in Steamboat Springs. The final climb will probably be too tough for some of the sprinters but if Peter Sagan is at his best, he should have no trouble surviving the ascent and the stage appears to be perfectly suited to his characteristics.

Thursday is the day of the queen stage and the day for the climbers to shine. The 165,6km course takes the riders from Steamboat Springs to an uphill finish in Beaver Creek. The first part of the stage contains a number of smaller climbs that could spur the creation of an early escape with the only categorized ascent coming at the 35,8km mark. The riders then face an easier section with only slightly ascending roads which get steeper towards the end and ends up with another KOM sprint. A fast descent and a short flat stretch leads to the bottom of the first of three final climbs. From the top of the first one, 51,9km still remain and as the ascent is followed by a gradual descent and a long, flatter section, it will be too early for the race favourites to kick into action. Instead, it will come down to the climb up the Bachelor Gulch which has never been included in the race before and is seen as the toughest mountain ever used at this altitude. Unlike most Colorado climbs, this is a steep, irregular climb that is set to offer some spectacular, aggressive racing. The top is located at the 11,7km to go mark and from there the riders will face a very technical descent. The stage finishes with a short ramp up towards a ski resort and the combination of those two final climbs offers the perfect chance for the climbers to gain some time on the eve of the time trial.

While the queen stage will have opened up some time gaps, the most decisive stage is likely to be the 16,1km Vail time trial which is back after a one-year absence. It is another one of those strange combinations of flat and uphill time trials that were also used in the Tour of California and the Tour de Suisse earlier this season. No part of the course is completely flat but the first 8km only offer some almost unnoticeable gradients and will suit the time trial specialists. The climbers hope to limit their losses on this section before using their strengths during the final 8km which take the riders from around 2600m of altitude to around 3000m at the finish. The climb is not very steep and another of those gradual Colorado ascents that characterize the race. The stage was last used in 2011 when Leipheimer beat Vande Velde with less than a second to unseat race leader Van Garderen. A look at the results of that stage indicates that it's a stage for the all-rounders but that the time trial specialists may be slightly favoured over the climbers. Nonetheless, Colombian Rafael Infantino proved that the uphill specialists may shine on this course by finishing 3rd, losing just 4 seconds to Leipheimer and Vande Velde. Only 7 riders finished within a minute of Leipheimer's time and so big time gaps can be expected despite the short distance.

The GC will mostly be decided when the riders get to the weekend which offers two easier stages. The first of those is a 185,4km stage from Loveland to Fort Collins. From the start in Loveland, the riders head along flat roads in a western direction towards the Rocky Mountains National Park. On the outskirts of the park, they will make a small loop that sends them up the big Devil's Gulch climb. At more than 30km, it's a very long ascent but only the final few kilometres are steep, and it should not produce too big time differences. A couple of rolling kilometres and a smaller climb follow at the top before the riders head down the long descent towards Loveland. Before getting to the starting city, they will turn to the left to travel towards Fort Collins. The final 50km are mostly flat but contains a number of nasty climbs that could be used to derail the sprinters' plans. A bunch sprint is the most likely outcome but as fatigue has started to set in, it could also be the day for a breakaway to stay away to the finish.

As usual, the race finishes in Denver on Sunday. After last year's time trial, the race will go back to the format of its inaugural edition by putting the sprinters in the spotlight on the final day of racing. The short 116,5km stage consists of 8 laps on a completely flat 14,6km circuit in downtown Denver. The circuit has plenty of long, straight sections but the riders will have to deal with a number of turns when they get closer to the finish line. Two sharp left-hand turns follow in quick succession with 1,9km to go while the peloton will turn right when they pass the flamme rouge. The final left-hand corner is located just 300m from the line and positioning will be important when the sprinters battle it out for stage honours in a fitting conclusion to a week of spectacular high-altitude racing.

The weather

The weather conditions for the first two editions of the race have generally been pleasant and the riders should enjoy another beautiful week of racing. The usual pattern of afternoon showers in Colorado will, however, make sure that the riders are unlikely to race the entire race in sunny conditions.

The race should get off to a beautiful start in Aspen with 20-degree temperatures, almost no wind and beautiful sunshine. The day will end on a more cloudy note but it should remain dry for the first day of racing. The conditions should be similar for the second day but the riders are likely to face afternoon showers and slightly lower temperatures.

Wednesday will offer similar conditions with afternoon showers expected but the lower altitude means that the temperatures should touch the 25-degree mark at the finish. The weather for the queen stage will be another identical copy of the conditions for the previous stages but the riders will now cross their fingers that it stays dry for the technical decent off Bacehelor Gulch.

At the moments it seems that the riders will get the worst conditions for the time trial where more rain and 17-degree temperatures are expected. The weather will improve for the weekend as the riders leave the highest altitudes. Sunshine and 30-degree temperatures are expected for both Saturday's and Sunday's stages.

The favourites

Despite the presence of numerous world stars, the race once again shapes up as a battle between the riders that usually dominate the major North American stage races. Chris Froome and Richie Porte made it clear on the pre-race press conference that they have done very little training since the Tour and that they were massively affected by the altitude. They will use the race to get back into racing while also providing solid support for their teammates.

Despite the many climbs, the battle for the overall win is likely to boil down to the queen stage on stage 4 and the all-decisive uphill time trial on stage 5 with stage 2 offering a possibility to gain a few additional seconds. The major weapon for any overall contender will be a solid ability to fly up the climb in Vail on Friday while also keeping up with the best one day earlier. Furthermore, the altitude cannot be underestimated: the winner is likely to be a rider who has experienced high-altitude racing in the past.

The team to beat is Garmin-Sharp which lines up a very strong roster in one of its biggest home races. Defending champion Christian Vande Velde crashed out of the Tour and his recent performance in Utah and his own pre-race comments suggest that he is not where he needs to be to contend for the win. That doesn't mean the American team won't have their say in the race. On the contrary, they have multiple cards to play.

One rider is more suited to the course than any other. Young Andrew Talansky has made uphill time trials his specialty, finishing 2nd behind Bradley Wiggins in the Crans Montana time trial in last year's Tour de Romandie, 2nd behind Richie Porte in the Col d'Eze time trial in this year's Paris-Nice and 2nd behind Chris Froome in this year's Tour de Romandie uphill prologue. Being a strong time triallist also on the flatter sections, this year's mixed time trial in Vail suits him perfectly.

The American has steadily progressed since his professional debut in 2007, making his breakthrough performance when he finished 2nd behind Wiggins in last year's Romandie. He finished 7th in last year's Vuelta before upping his level a further notch during this season with a 2nd place performance in the Paris-Nice. He went on to match Chris Froome on the final mountain stage of the Dauphiné - the only rider to do so in the high-level field - and finished 10th in his debut Tour de France. The kind of climbing legs that brought in those results should allow him to stay with the best on Thursday's queen stage.

While the course suits Talansky perfectly and while he is backed by a strong team, he may still end far down the GC. He hasn't raced since the Tour and very few know how he's going right now. During the Tour de France, he told Cyclingnews that he looked forward to racing the second half of the season without any pressure, having already reached his major season targets. He specifically pointed to this week's race as a "fun" event and that kind of relaxed attitude could go both ways. Either he will just use the race as mere training or his mental approach could be what allows him to step onto the top step of the podium. Being part of an American team, he is unlikely to turn up without any kind of competitive form.

If Talansky fails to make an impression, Garmin has another card to play. Tom Danielson was clearly the strongest in the recent Tour of Utah, leaving behind race leader Chris Horner on the Empire Pass to take the lead on the final day of racing. At that point he had already used a lot of energy to work as a domestique of young Lachlan Morton and he would probably have been even more dominant if he had been the clear-cut captain right from the beginning. While Talansky's condition is uncertain, no one can deny that Danielson is strong at the moment and unlike Talansky, Danielson has plenty of results on his palmares that shows his ability to race at high altitude.

Danielson has made the USA Pro Challenge some kind of specialty. In 2011 he proved his abilities in the uphill time trial to Vail by finishing 4th on that stage before going on to finish in a similar position on GC. Last year he took a fantastic solo win on the big stage which included passages of the Cottonwood and Independence Passes but struggled a bit on the uphill finishes, ultimately finishing 7th on GC. This year he is going much stronger and with the uphill time trial suiting him perfectly, he could very well continue his recent domination of the North American stage races. The only major concern is if a heavy race schedule that has included both the Giro and the Tour will start to catch up with the 35-year old.

Saxo-Tinkoff lines up a versatile roster spearheaded by Michael Rogers. The veteran Australian had an injury-plagued first part of the season but showed his first signs of improvements at the Tour of California where he overcame his lack of racing to finish 2nd. He took 6th at the Dauphiné before going on to what has been his stand-out ride of the season in the Tour where he would have ended in the top 10, had the team not sacrificed his GC result for the team time trial win.

Rogers has made one-week races with a crucial time trial his specialty and this week's race suits him well. He has performed well in tough time trials in the past and should do so again this time around. If he is on form, he should be one of the best in Vail but like Talansky, his current fitness level is a big question mark. He hasn't raced since abandoning in San Sebastian, stating at the pre-race press conference that he would take a day-by-day approach. How he will handle the altitude is also a concern but he has all the capabilities to win this race.

Tejay van Garderen is one of the riders who has made it very clear that he is in Colorado to win the race and so improve on his 2nd and 3rd places from the past two years. History shows that he races well at altitude and the course suits him well. Among the GC contenders, he is probably the best time triallist. He often struggles to keep up with the best on the climbs but with no tough uphill finish, the route plays into his hand.

What speaks against a win for van Garderen who has spent time at altitude to specifically prepare for the time trial in particular, is his performances in uphill time trials. In 2011 he lost the leader's jersey after a disappointing ride in Vail and earlier this year he cracked in the difficult time trial up Flumserberg in the Tour de Suisse. Being more of a time triallist than a real climber, he would have preferred last year's flat Denver course which would have played to his strengths. To add another stage race win to his California victory, he has to overcome his difficulties in uphill races against the clock.

One rider who would have had no chance on last year's course is Janier Acevedo. The Jamis captain would have lost too much time in the flat time trial. As opposed to this, the course for this year's edition suits him well and being a Colombian, he will only relish the opportunity to race at high altitude.

The Colombian has been one of the stand-out performers on the North American racing scene this season, winning a tough uphill finish and finishing 3rd overall in the Tour of California. Most recently, he also stepped onto the lower step on the podium in the Tour of Utah. In California, he was the fastest rider up the steep climb that came at the end of the time trial which shows that he knows how to pace himself up the climb. Colombians don't have a reputation as time triallists but they usually shine in uphill races against the clock with Infantino's 3rd place in Vail two years ago being a prime example. If Acevedo can make a similar performance, he has a good shot at overall victory.

Another Colombian who may shine in this race, is Darwin Atapuma. The Colombia captain is clearly on form at the moment, having recently won one of the hardest stages in the WorldTour race Tour de Pologne. A crash took him out of contention in the mountainous Tour de l'Ain and now he has set his sights on the Colorado race as the event to make up for that disappointment. His characteristics are similar to Acevedo's and he will be another rider who will benefit from the high altitude. What speaks against a stand-out performance from the Colombian is his apparent lack of time trialling ability, even when it's uphill. In the mountain time trial of the Giro, he finished a modest 52nd and he has to improve on that performance to contend for the win this week.

Cannondale is mostly focused on stage wins with Peter Sagan but the team also has a genuine GC contender. Damiano Caruso returns to the race for the second year in a row and his debut performance in Colorado suggests that he handles the altitude well, having finished 12th overall. He has had a turbulent season so far. Originally scheduled to race the Tour, he was thrown into the Giro a few days prior to the start when Ivan Basso had to forfeit his participation due to a cyst. Having started the race under-prepared, he got better as the race went on and only a fruitless attack on a transitional stage saw him fall out of GC contention.

Besides his past credentials in the race, what makes him a winner candidate in this race is his ability as an uphill time triallist. He finished 3rd in the mountain time trial at the Giro and if he can reproduce that kind of performance in Colorado, he should be in the mix. His explosive nature makes him well-suited to the two crucial climbing stages and their short, explosive ramps. He hasn't raced much recently but he did a fine ride in San Sebastian to finish 28th which suggests that his form is not too bad.

Finally, we will point to young Joe Dombrowski. With Froome and Porte ruling themselves out of the GC battle, the Sky captaincy duties fall onto the shoulders of Dombrowski and fellow American Ian Boswell with Kanstantsin Siuotsou being their dark horse. Dombrowski has had a difficult first year on the WorldTour and hasn't been able to take his chance in the Tour de Suisse and Tour of Austria when he was relieved from his domestique duties.

Last year he did, however, prove that he has what it takes to compete with the best in mountainous stage races, winning the Baby Giro and finishing 12th, 4th and 10th in California, Utah and Colorado respectively. Only his lack of time trialling ability prevented him from finishing higher in California and Colorado. With an uphill time trial this time, he should not be too disadvantaged and he can certainly not complain about the high-level team support he can expect.

***** Andrew Talansky

**** Tom Danielson, Michael Rogers

*** Tejay van Garderen, Janier Acevedo, Darwin Atapuma, Damiano Caruso, Joe Dombrowski

**George Bennett, Mathias Frank, Lucas Euser, Philip Deignan, Andreas Klöden, Ian Boswell, Kanstantsin Siutsou, Tobias Ludvigsson

* Rory Sutherland, Lachlan Morton, Tiago Machado, Michael Schär, Rohan Dennis, Christian Vande Velde, Andy Schleck, Chris Froome