Steering options: Chris Nolan said the vehicles have front and rear steering capabilities, both controlled from the driver’s seat.
Greg Wane
CHRIS Nolan calls them extreme vehicles, but they look more like beach buggies on steroids.
He claims the machines are the most radical 4x4s on the planet.
The purpose-built vehicle can tackle the most severe terrain, climb vertically over rocks and hold their position at a 180 degree angle.
Chris runs Ragged Edge 4×4 extreme driving range based at Avalon Raceway where adrenalin junkies looking for a near death experience can drive one of these monsters around a course of rocks and impossibly steep grades.
“It’s all about unlearning what people have learned about four-wheel-driving. Some drivers will find it very foreign to the type of driving they are used to,” Chris said.
“About the fastest these things will go is about 10km/h. It’s all about angles and gearing.”
A 350 Chev crate engine powers the big 44-inch tyres.
“You can drive them up a wall put it in front wheel drive and you can drag the nose of the vehicle across the face of the wall then drive it side ways along the wall. A lot of this stuff you can’t do with a normal vehicle,” Chris explained.
“With these, you can disconnect the front or rear-wheel-drive and can actually drive them like a bobcat with a skid steer.”
“They are pretty basic just gear driven but they just split the drive train.
“With a rear wheel driven car they go straight through the rear wheel drive shaft.
“In our cars there is an idler gear in the transfer case and another gear that sends the same power to the front – very, very simple.”
Or, as Chris explained, there are front and rear steering options. The front wheels are controlled with the conventional steering wheel and the rear wheels can be turned using a rudder-type control located beside the driver’s seat.
“When both front and rear wheels are used to steer, the vehicle can be pivoted on its own length.”
After Chris completed a fine arts degree about 10 years ago he got interested in four-wheel-driving and built up a competition car thinking the sport might be poised to get really big.
“The sport really didn’t go anywhere, but I decided to stay with the extreme vehicles,” he said.
“I originally modified a Land Cruiser but that led to other problems where we couldn’t legally take it on the road. So we were restricted to using it on private property. That’s when I developed a business model for the Ragged Edge experience at Avalon Raceway.”
Chris said the main design consideration with the vehicle is to keep the centre of gravity as low as possible.
“The engine has been mounted right down low in the chassis. With a normal four-wheel-drive the engine usually sits above the diff.
“In this vehicle the engine sits behind the diff which is why we can do off-camber work and the vehicle stays quite stable.
“The transfer case is a custom unit that was developed in America and is favoured by the competition teams.
“It has got a ratio of 6:1 depth. Most four-wheel drives would be in a 1:1 in high range and 2:1 in low range, where as these vehicles are 6:1 in low range.”
Chris said the vehicle has been built from scratch using parts from a Rockwell 10-wheel drive military vehicle.
“The Rockwells are big beefy things and we have grafted the knuckle and outer hubs.”
The chassis is built from box tube and the cage is attached to the chassis rail and body panels are bolted to the chassis.
Although the vehicles are built tough and driven at slow speeds, maintenance is high.
“We spend the weekend breaking them and the following week Rally Motors fixes them for us.”
The weak area is the diff, while the sheer size of the tyres and the gearing are mostly responsible for the damage to the front wheel pinions and differentials, he said.
“So far we have blown up 10 diffs.
“The angles we drive the car at also affect the oil pressures so we have to be careful not to over fill them.
“Gearbox drive shafts also tend to take a battering but this is par for the course in this type of business.”
