Chris Froome admits thinking about Tour de France rival Alberto Contador spurs him on in training, insisting the Spaniard can "smell weakness" and knows "when you're having a bad day".

The duo's battle for cycling supremacy began in 2013 when Froome stunned Contador with a superb display to seal his opening Tour de France victory.

Contador, however, has two yellow jerseys to his name and the 32-year-old gained a psychological edge by outpacing Froome to win at September's Vuelta a Espana.

Combat will resume at the Tour de France on July 4, with both riders desperate to reassert their dominance after crashing out last year.

"When I'm out training, I'm thinking, 'I wonder what he's up to today, I wonder how hard he's training'," said Froome at Team Sky's pre-season camp in Majorca.

"Alberto can smell weakness. He can smell it when you're having a bad day."

Contador was stripped of a third Tour triumph in 2010 after he tested positive for clenbuterol but Froome "doesn't look back anymore" and insists his rivalry with Contador is one of sportsmanship and respect.

"If someone's better than me, they're better, I'm not even going to go down that road of thinking that they're on something or that they're cheating," Froome said.

"Alberto and I have both got mutual respect for each other as rivals, we don't glower at each other or try to put each other off the road or anything.

"And even from a sportsmanship point of view, if one of us punctures, or has a mechanical problem at the wrong moment you're not going to be racing off the road to benefit from that.

"I respect that side of Alberto. He is an extremely tough rival for me. If anyone knows how to win the Tour de France, it's him."

The duel takes on added flavour given the pair's contrasting styles.

While Contador is a rhythmic racer, Froome is less orthodox, with Lance Armstrong describing him as "the Jim Furyk of cycling", in reference to the golfer's unconventional swing.

"'I'll take it. I know my style is different to other guys but like Lance says, it works," Froome said.

"I am always someone who can put his head down, push on the pedals as hard as I can and try to get the most of what my body will allow me.

"Alberto compares himself to the other guys more than I do, he's more responsive to other riders. I probably like to ride my own pace.

"When guys start attacking, I don't necessarily have to follow them immediately."

Contador's challenge in Paris may be stunted by his decision to take on the Giro D'Italia less than five weeks before, while Froome is disadvantaged by the Tour route, which includes less time-trialling than in previous years.

The Team Sky rider wants to weigh 66kgs – he is currently 70kgs – by the time the race comes around and, for all the strategic factors, Froome admits winning can come down to hunger, in both senses of the word.

"It's very much the battle of who's the hungriest, not just in terms of eating, but also how badly do you want that victory? How badly do you want to win the Tour de France? You can call it the Hunger Game," Froome said.

"There's loads of days when I always tell myself, 'wait until September when the season's over and you can have as many of those as you want'.

"White chocolate, I have a weakness for white chocolate, nutella and pancakes – they're all dangerous."

Froome may be losing weight but he is building strength too, particularly in his lower back, putting in extra gym sessions five times a week to avoid the persistent problems he suffered in 2014.

As well as the Tour this year, he plans to race at Vuelta Andalucia, Tirreno-Adriatico, the Tour de Romandie, Criterium Dauphine and the Fleche Wallonne.

Long-term, however, Froome hopes to compete for another 11 years and take his place among the greats with multiple Grand Tour victories.

"I'd love to still be racing come 40, that would be my goal," Froome said.

"I think it's as much a mental thing as physical. I just hope that I can keep this same hunger and determination."