Holden Astra TwinTop 2007 Review

Try to show off, and things are sure to go wrong. For instance, you can be left sitting in a new convertible like a dill as its roof at first refuses to budge, then partly raises itself only to halt, whirring and buzzing furiously, halfway aloft like a sail.

Memo to self: in future, read the handbook before trying to demonstrate fancy technology.

Holden's Astra TwinTop is yet another of the new breed of convertibles with a multi-piece folding hardtop. It turns out to be simple to operate when you know how.

Once everything was correctly in place and everyone was well away from what the driver's handbook calls the “action zone of the roof”, the TwinTop did its thing with robotic precision.

It proves to be a nifty machine, albeit one that costs almost $50,000.

In my defence, the handbook devotes five pages to explaining how the roof should be operated, using the phrase “risk of injury” twice in the first five lines. Looks like the lawyers gave the engineers a hand there.

For those who want the open-air experience of a convertible along with the security of a solid-roofed coupe, the fast-growing flock of versatile cars like this answer their prayers.

And, unlike many rivals, the Astra's roof can be made to go up or down while the car is on the move — up to 30km/h. In another handy feature, it can be operated while you're standing outside, using the remote-locking gizmo.

How cool would that be: parking your open convertible in some hip street, then casually pressing the remote button to shut the roof as you walk away. Of course, with my luck, it wouldn't work.

But, honestly, the roof is simplicity itself. Just press a button on the top of the windscreen and the boot lifts, the roof splits into three sections, various flaps extend, motors and hydraulics do their thing, the side windows go up and down — it's like a robotic ballet.

Luggage space is 440 litres when the roof is in place, and 205 litres when it's folded down. So you need to pack

light for the wind-in-the-hair option.

The open-air TwinTop joins quite a family of European-made Astra models: hatchback, wagon and coupe, with engines in 1.8, 1.9, 2.0 and 2.2-litre sizes, fuelled by petrol or diesel.

It's the dearest of the bunch, more than twice the price of the entry-level Astra CD hatchback. That's understandable, as the engineering and packaging involved must have been quite a challenge.

It's a big step ahead of Holden's previous Astra convertible, which appeared in 2001. That was the traditional sort, using a fabric roof.

Like the TwinTop, it had a 2.2-litre engine, but the new car has a more advanced fuel-injection system (shared with the sporty SRi hatchback and coupe), improving power and torque.

This powerplant — developing 110kW, compared with just 90kW in base-model Astras — has the TwinTop scooting along happily, easily overcoming the extra weight of the roof system and the reinforcing added to make the open car feel reassuringly solid.

The car I drove had the optional four-speed transmission, which didn't seem to impede its progress, though life would be sweeter if Holden offered the six-speed it reserves for the diesel Astra.

No matter, because the TwinTop is zippy enough, and with the roof up it looks and feels like a coupe: solid and secure.

Retractable hardtops like this are becoming so widespread — VW's Eos has just arrived, and a Ford Focus is on the way — they're practically the conventional type these days.

Maybe pretty soon we'll even be able to operate them without having to read the handbook.