Drysdale's unique 2-wheel drive, 2-wheel steering motorcycle up for grabs
A fascinating and utterly unique piece of motorcycle history is about to go under the hammer on eBay, with less than two days remaining on its auction. Australian inventor Ian Drysdale, best known for his radical V8 sportsbikes, built the bizarre Dryvtech 2x2x2 motorcycle back in his post-university days in 1990. Not only does it feature hydraulic two wheel drive, it also uses hydraulic two wheel steering. With the auction set to start at AU$10,000, the 2x2x2 would be a bizarre and irreplaceable addition to any collection – or a really interesting ride for those brave enough to take it for a spin.
Two wheel drive motorcycles are nothing new. Over the years we've covered a number of different 2WD systems that have met with varying degrees of success. But the theory is the same – the non-driven front wheel of a motorcycle is one of its greatest liabilities. It gives the rider no help in getting over obstacles and up steep hills, and it can lock and tuck in low-traction situations, resulting in crashes.
What we've seen much less of is the motorcycle that not only drives, but steers with both wheels. The process of countersteering a motorcycle bends the brain enough before trying to work out how the heck the physics works when the rear wheel steers as well.
The Dryvtech 2x2x2 (two wheels, two-wheel drive, two wheel steering) is the brainchild of Australian motorcycle designer Ian Drysdale, who built it as a test bed for his two wheel drive ideas back in 1990 just after he finished university.
It uses a 250cc, Maico-based two stroke engine to drive a "horrendously expensive" hydraulic pump, as Drysdale puts it. The 9-piston hydraulic pump has an operating pressure of 4,500psi and yet uses no seals at all, running metal on metal. This gives you an idea of the insanely fine tolerances it has to run, and thus the expense. Drysdale priced a reconditioning kit for this pump, which is normally used to operate the landing gear on a Sabre jet fighter, at AU$18,500 (US$15,313), so it's a bit of an understatement to say he was lucky to find the full, working pump in excellent order at an aircraft wrecker's for $40 (US$33) when he was building the 2x2x2 on a uni student's budget.
That central pump drives a pair of motors in the front and rear wheels. The highly pressurized oil is run down steel tubes that follow the bike's front and rear swingarms, using a complex concentric pivot to follow the angle of the swingarm without releasing the pressure. Where most 2WD dirtbike designs channel some 5-10 percent of the total power to the front wheel, the Dryvtech bike is totally tuneable using a pressure reducing valve.
The 2x2x2 was always going to use hub-center steering and as it turns out, that's what made Drysdale incorporate two wheel steer. "I had to have two wheel steering," Drysdale tells us, "not so much for performance reasons, but because I wanted to keep the bike fairly slim and I had my heart set on hub steer. The front swingarm restricts the large diameter wheels, which affects the steering lock. I was looking at two wheel steer purely as a way to address maneuvrability in tight spaces."
There's no direct mechanical connection between the handlebar and either set of wheels. Instead, the 2x2x2 uses another hydraulic system to manage steering. Turning the handlebar steers both wheels, but not at the same time necessarily, and not at the same rate. "The front steers for the first 5 or 8 degrees of the handlebars," says Drysdale, "and then the rear wheel starts to come around." That lets the front wheel initiate counter-steering, and reduces the rear wheel's effects at higher speed. At low speed, once you turn the bar further, the back wheel turns in the opposite direction to the front and pulls the bike around quite sharply as the rear wheels follow the same track as the front.
As for whether the two-wheel steer might offer any performance advantages, Drysdale is unsure: "The wheel motors needed to be a bit bigger, so you couldn't really ride the thing hard enough to prove it, but getting out of a slide was interesting. You could flick the handlebars and suddenly the rear wheel was steering out of the slide as well. I didn't really play with it enough to work out if that was an advantage." Either way, with the two wheels driving and the rear wheel assisting with steering, grip and drive were extraordinary in low-traction situations. It was "almost impossible to get any wheel spin" even at full lock and full throttle in slippery mud – the bike would tend to highside rather than kick out.
Ian Drysdale hasn't laid eyes on the bike for some 15 years. Despite the loud objections of his friends, he sold it to Tom Wheatcroft who showed it as part of his Donington automotive collection for a number of years. "When Tom died, his sons weren't into bikes, so they auctioned off all his bikes to get rid of them. It was bought by the guy that runs the Australian Motorcycle Museum up in Queensland, I reckon that's who's selling it at the moment. I rode past the museum a couple of years back and was going to pop in, but it was 8 am and it wasn't open yet, so I rode on."
Drysdale isn't much of a sentimentalist: "I'm a designer, my favorite project is always my next project. It was gathering dust in my shed. So I've got no real desire to buy it back. But I do hope somebody buys it that's willing to put it on display, or at least appreciate it for what it is."
So what is it? We reckon it's an extraordinary experimental vehicle with a fascinating thought process behind it and some very clever engineering solutions. It's absolutely one of a kind, and a great example of how motorcycles go undervalued in the rare vehicle market – given that the eBay auction starts at just AU$10,000 (US$8277.50).
For a bunch more information, and a lot more technical depth on the Dryvtech 2x2x2, check out the old Drysdale Motorcycle Company website or the new website that shows a few of Drysdale's more recent projects, but has less detail.
The eBay auction goes off in less than two days.
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Man, it's a piece of strange and unique engineering that might one day influence another unique piece of engineering. And now it's a museum piece. For people to muse over.
It's not a noisy, fast-moving toy for the bush bogans. For that, you can buy any number of stinking 2-stroke bikes from just about anywhere.
I would be very cautious about actually trying to ride this beast, though. A 4,500 psi hydraulic system that has been in storage for years is a wonderful opportunity for disaster.