Shimla, Aug 22 (IANS): The South Asia's biggest mountain biking rally in Himachal Pradesh is getting more tougher and winding this edition, with the cyclists having to ascend to 12,500 metres via 90 percent off-road tracks, organisers said Friday.

The organisers of the 10th edition of Hero MTB Himalaya Sep 27-Oct 3 said the route, through the lesser explored interiors of the Himalayas, will twice climb the Jalori Pass (at 9,669 feet) in Kullu district, the toughest point in the rally.

"The seven-day high-altitude endurance mountain biking will cover 500 km with an elevation gain of 12,500 metres," Mohit Sood, president of the Himalayan Adventure Sports and Tourism Promotion Association (HASTPA), the local club organising the event, told IANS.

The route for the 10th year is special. "It's been a long and an absolutely new route. We will be climbing the mighty Jalori Pass twice and will be conducting the race on 90 percent off-road sections. Jungle tracks, jeep tracks, single tracks, rocky and gravel sections will form the majority of the route. That's what these top riders are looking for," he said.

Organisers are expecting participation of over 70 intrepid bikers from India and abroad. Teams from the adventure wings of the Indian Air Force and the Indian Army will also take part.

On an average, a cyclist will pedal 80-90 km every day, with one day of rest, and have to ascend 2,000-2,500 meters each day. The highest point of the rally will be 3,223 meter Jalori Pass.

"What started with only 20 riders in 2005 has now reached a stage where top international riders are willing to participate. Last year we had Luis Lea Pinto -- the world no 9 compete here -- and this year too we have an array of internationally acclaimed riders," Sood said.

He said the rally will pass through Shimla, Narkanda, Ani, Jibbi, Ghadagushaini, Chatri, Luhri, then again back to Narkanda and finally culminate in the state capital.