BMW's long-awaited second generation Mini convertible has a unique new option feature - the 'Openometer'.

This, the automaker said, records the time spent by the owner driving with the top down, "meaning passengers can measure their visual coolness inside, even if it's cold outside."

In other respects, the completely redesigned drop-top is the same sort of evolutionary product as the well-received hatchback versions launched here at the end of 2006 and carries over the same design of fully retracting canvas roof that can be part-opened in 'sunroof' mode.

The new version, again built at BMW's dedicated Mini plant just outside Oxford in England, goes on sale in the UK on 28 March with global market launches to follow.

The revised convertible will be sold in Cooper and Cooper S versions with the same new 1.6-litre petrol and (eventually) diesel engines from the PSA/BMW joint venture in place of the old Chrysler Brazil-made 1.6-litre petrol four and 1.4-litre Toyota diesel used in the outgoing line, sales of which ended earlier this year.

UK Cooper prices will start at GBP15,995 'on the road' (about US$24,000) and the Cooper S from GBP18,995 ($28,500).

The first-generation Mini convertible was a best seller in the UK in the small convertible segment between 2004 and 2008 and about 164,000 first generation cars were delivered worldwide.

The new drop-top will be offered with two exclusive new colours - 'interchange yellow' and 'horizon blue'. Roof colour options are black, 'denim blue' and 'hot chocolate'.

One big change for the UK is standard air conditioning with a cooled, lockable glovebox.

The automatic canvas roof can be fully retracted or closed using a roof-frame mounted toggle switch in just 15 seconds and works at speeds of up to 20 mph - handy if it starts to rain just as the lights turn green.

As with the previous model, the full-width electric roof can be retracted about 40cm (about 16 inches) to create the effect of a sunroof and this function works at up to 75mph (120/km/h).

Unlike its predecessor's fixed anti-roll bars the new model features a single-piece roll bar situated behind the rear seats, ensuring passenger safety in the event of a crash. The roll bar will extend in milliseconds at the point of impact to protect the car's occupants should the car overturn. Rear passenger headrests are now height-adjustable, too.

The body structure, floorpan, A-pillars and side sills have all been strengthened to offer greater crash protection. BMW claims this also significantly reduces 'scuttle shake', whilst body stiffness is further improved over the first generation convertible. Yet weight is down 10kg.

Luggage capacity has been increased to 125 litres from 120 with the roof open and from 165 to 170 litres with the roof up. With the rear seat folded down and roof closed, luggage space totals 660 litres, 55 litres more than the old model.

Bike rack preparation will also be standard.  The mounting points are obscured from view and positioned behind the rear bumper so owners are able can easily attach multi-function carriers.

Like the equivalent hatchback and Clubman models, the Cooper convertible has as standard a 120hp 1.6-litre I4 petrol engine with fully variable valve management, using technology based on the BMW Group's Valvetronic technology.

The Cooper S gets the 175hp unit with twin-scroll turbocharger and direct fuel injection. Six-speed manual transmission is standard with both while a six-speed automatic is optional.

Technologies based on BMW's EfficientDynamics systems are now standard and include auto start stop, brake energy regeneration and shift point display.

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