So what's that about? You retract the 'undercarriage' as for normal PTW use, and it's got another set in case you lean over too much? Doesn't that complicate things rather - if you haven't got free roll it's a multi-track, so wouldn't you get an awkaward transition every time you touched down? It's been demonstrated that even damped roll makes a PTW, or even a free tilter undrivable, and putting 'training wheels' on a childs bicycle just makes it more difficult to learn to ride as a TW.

So what's it like? Is an Ecomobile so dificult to ride wheels up? What do the 'training wheels' train you to do?

The training wheels don't train you to do anything. They are a 'damage limitation tool' which prevents damage to the Eco (or Monotracer) if the newbie pilot fails to keep the machine balanced on two wheels when he or she first 'raise the undercarriage'. You may think this would not be difficult, and for some people it isn't, but for many it is. I have personally watched several very experienced motorcyclists put the wheels up and fall over....put the wheels up and fall over.....all day long, for several days in a row. Other people 'get it' straight away, including a rare few with very little experience of motorcycles.
It's the near-instant transition which catches people out – the transition from half-ton, triple-track 'ugly duckling' weird 'double sidecar outfit', where you heave on the bars left to go left, and it leans right as you do so – to a beautiful half-ton 2-wheeled monotrack 'swan', where you countersteer right to lean gracefully left......It's also possible to get fired off to the left or right into the nearest ditch, rather than straight ahead, if you don't have the machine symmetrically balanced when you put the wheels up.
Back in 1988, there were no training wheels, and I had to learn the hard way, which was like learning to swim by jumping in the deep end, off a diving board. I'm pleased to say that I never dropped it once during my training period, neither in the initial empty car park nor out on the road, which was just as well since the Top Gear cameras were rolling the very first time that I flew the Eco 'solo'! PNB

Ok, Yes I understand the problem in transiting between multi-track and single track control reversal, it's just that it seemed that fitting another set of multitrack wheels would add another transition to the mix. But I guess if it's that difficult the second set would have some use in reducing damage.

It's always seemed to me that the 'open loop' (no feedback) outrigger system Peraves use urgently needs improvement. In conjunction with various other people I've looked at outrigger systems and a 'closed loop' fully interactive system, probably foot operated, is certainly possible, probably with commercially available componentry. This would include the ability to park the vehicle vertical, regardless of surface slope - within reasonable limits of course - and allow it to be rolled to vertical on the outriggers before retraction. The main issue is the power supply, but the E-tracer powertrain makes electric power the obvious choice. However, my converations with Peraves, such as they are, indicate that they regard the difficult outrigger operation as part of it's exclusivity. Pity thry havn't got any competition...