91�ȱ�

Geraint Thomas says he will probably have to sacrifice next year's Tour de France in his bid to defend the .

The Welshman this year as the highest-placed British rider in the Tour's general classification.

But the 25-year-old says he will probably now focus on .

"I could still ride it but I could miss it as well, I don't want to jeopardise my preparation for the track as it means so much," Thomas told 91�ȱ� Wales.

"I think I'd regret it if I rode the Tour de France and wasn't as good as I could be on the track and we ended up coming second.

"I'd probably kick myself forever, because London is a once in a lifetime opportunity and I've been lucky enough to be in my prime to go for that gold medal.

"With the Tour, by the end of it, it'll be over 90 hours [of racing] and on the track it's four minutes of effort, it's quite a big difference.

"Obviously the road gives you the strength and the endurance. The way the team pursuit is now you need all that but I think it's a bit too close.

"I don't know if there's actual evidence but it's one of those feelings you get that you don't have that top end and that real punch - and for sure you need that on the track."

Bradley Wiggins, Paul Manning, Ed Clancy and Thomas triumphed in the 2008 Beijing Olympics, setting two world records on the way to winning team pursuit gold.

The pull of repeating that success on home soil seems set to relegate the Tour for one season, as Thomas edges back to competition inside the velodrome.

Chris Boardman, an Olympic champion at the 1992 Games in Barcelona before turning to the road, has to put the Tour de France before other considerations, especially after a ended the 31-year-old's race early this year when he was tipped for a podium spot.

But Thomas is at a different stage of his career and has plenty of time to hone his Tour performances, whereas he will only get one chance to ride in a home Olympics.

With the emphasis seemingly firmly back on the track, Thomas has definitely ruled out competing in the road race event at London 2012, , despite his growing reputation.

"I think the road race is out of the question really because it's before the team pursuit," Thomas added.

"To really commit to the team pursuit properly, it's so fast and so technical that I think I'd need more time on the track.

"I wouldn't be able to ride the road race, I think it would jeopardise my chances for the team in the team pursuit.

"With the Tour de France, it's still one of those things that's up in the air at the minute, I'm not too sure when I'll make the decision."

Thomas will next be in competitive action in the , which starts on 8 August and covers routes in the Netherlands and Belgium over seven days of racing.