Entries for the annual festival - which offers 20km, 40km and kiddies' races on the Saturday to complement the 60km feature event on the Sunday - close at midnight on Friday.
Organisers, who are catering for up to 1 400 riders across the three main events, said limited slots were still available in what they billed "the Bushveld's biggest mountain bike bash".
"The most exciting part is to see how whole families take part in the riding," said ASG Events' operational director Darren Herbst.
He said participants and their families would have access to the 4 700ha nature reserve as day visitors, which is not generally permitted outside of scheduled events.
Herbst said the event, which is based a mere 45-minute drive from Pretoria, continued to grow in popularity each year.
"To get the serious cyclists out here is awesome, but our focus is to get families to come and enjoy the weekend."
He said the races on the Saturday were specifically designed to offer families riding options that suited their ability.
As each race that formed part of the Bestmed Sondela Mountain Bike Classic occupied its own timeslot, Herbst said adults could also opt to build their own mini stage race.
He said special combination price packages were available for those who wanted to combine either the 20km or 40km on the opening day with the marathon on the second day.
After the adult events on the Saturday morning, three to five-year-olds will do battle on a specially built 500m track in the afternoon, while youngsters up to eight can tackle a 5km single-track course.
"In my experience, there is no other mountain biking weekend that is as geared towards every member of the family," said Herbst. "It's a proper festival of riding combined with quality family time in a relaxed environment where the kids are as happy as the parents."
He said the feature race on the Sunday was scheduled to start at 9am to give participants ample time to drive to the venue on the morning of the race.
The 20km and 40km events start at 11am and 8am respectively, with the kiddies taking to the dirt from 1pm.
Proceeds go to the Sondela Wildlife Rehabilitation Centre.
Visit www.asgevents.co.za to enter or for more information.
Caption: Participants in the Bestmed Sondela Mountain Bike Classic can look forward to riding through prestige bushveld during next weekend's event. Photo: Snappa.Photo