Climbing the height of Mt Everest is no mean feat.
Especially in 24 hours.
Many of the individual riders and teams competing in the Gloworm 24 Hours of Nduro this weekend will climb the height of Mt Everest (8848m).
The event in the Whakarewarewa Forest will see mountain bikers, in teams or as individuals, complete as many laps of the 14.3km course as possible.
Event organiser Tim Farmer said each lap had 339m of climb and riders in the 24-hour event would climb, on average, the height of Mt Everest and would cover about 340km to 350km.
The annual event features a 24-hour, 12-hour, six-hour and three-hour race.
Farmer said they had 187 riders entered this year which was up on last year, and 30 riders in the solo 24-hour race.
Among the elite riders attending this year will be current 24-hour solo world champion Jason English (Australia).
"I can't see anyone beating him, if they don't get lapped three times by him then they are doing well," Farmer said. "I would say he will beat most of the teams as well."
He said it was great to have him in Rotorua for the event.
Farmer said they would be hosting the 2016 World Solo 24 Hour Mountain Bike Championships in January next year, which was a huge event for Rotorua.
He said this was the first year they had held the Gloworm 24 Hours of Nduro in January.
"We are trying to align it best we can with the world champs."
A small section of the Whakarewarewa Forest trail network will be closed for racing, but most trails will be open to the public.
-Based at Waipa car park, the event starts at noon tomorrow for all riders.