Chris Froome not underestimating 'critical' stage 15 at the Tour de France

Team Sky's Chris Froome says that stage 15 over the Grand Colombier has been a bit underestimated, but should be an extremely tough day for those wanting to win the Tour de France.

Froome leads the overall by 1-47 on Dutchman Bauke Mollema (Trek-Segafredo) and 2-45 on Adam Yates (Orica-BikeExchange). The 15th stage to Culoz, a stage perhaps overlooked because it is neither in the Pyrenees nor the Alps, includes 4080 metres of climbing over its 160 kilometres from Bourg-en-Bresse.

Froome stepped off the stage after accepting the yellow jersey following stage 14, won by Mark Cavendish (Dimension Data), and immediately answered questions about stage 15.

"It is a tricky stage, I know the roads there. It's been a bit underestimated, because it's not a summit finish, but it's an extremely tough day with over 4000 metres of climbing," Froome explained.

"If someone is not ready for it then they could get caught out."

The stage climbs the Grand Colombier at 1501 metres before turning down to Culoz, a small town known for its walnut and onion tart.

The race finishes in Culoz, but before doing so, races another 23.5 kilometres and climbs halfway up the Grand Colombier from the other direction via the famous S bends.

Watch: Highlights of stage 14 at the 2016 Tour de France

"We are looking at it as quite a key stage in this middle part of the race," Froome said. "The final descent [of 14 kilometres], given where it is, is going to be the most critical one tomorrow."

The only other time the Grand Colombier featured in the Tour was when Sir Bradley Wiggins was defending his yellow jersey in 2012. Then the climb, offering views of Mont Blanc, was too far from the line to make a difference.

Several of the hopefuls still wanting to upset Froome to win the Tour could try to take advantage of the Jura stage before the race enters the Alps on Wednesday.

"I'll see if I have the opportunity to attack or not," said Nairo Quintana (Movistar), who placed second overall behind Froome in 2013 and 2015.

"I have good legs and maybe it's a good chance to gain time, but the third week will really be tough and dangerous, and with many opportunities."

“People are fearful of what’s coming up,” Orica-BikeExchange Sports Director Matt White said. “Tomorrow is one of the hardest stages of the Tour.”