Because of the sub-standard crash test results achieved by the new BMW 3-Series convertible, it is feasible that BMW will be rushing the new 1-Series into crash testing programmes around the world, so as to not repeat the disaster that the world witnessed when the highly respected American Insurance Institute for Highway Safety (IIHS) revealed, earlier this year, the unsatisfactory test results for the new BMW 3-Series convertible.

The Convertible is the fourth derivative of 1 Series to be launched and will carry over much of the styling and technology from the recently-announced Coupé model. The obvious addition is an electro-hydraulic fabric roof that opens or closes in 22 seconds. The convertible roof is available in black, beige or, as a world first, an innovative anthracite silver fleck which is a fabric material interwoven with fine shiny metallic fibres.

Exterior design
Viewed from any angle, the BMW 1 Series genes are clear in the new Convertible. From the front, BMW’s trademark double headlamp unit and large kidney grilles dominate. In profile, the relationship to the Coupé is clear. Both cars share a virtually identical silhouette and a long bonnet, short overhangs and set-back greenhouse proportions.  The distinctive, horizontal shoulder line runs from the front of the bonnet, through the long, frameless doors and onto the end of the boot lid. This line visually connects the front and rear. It is complemented by the 1 Series’ typical lower swage line and contoured sill, both designed to visually elongate the appearance of the car.

From the rear, the boot lid finishes in a discrete lip spoiler that houses the integrated third brake light and typical L-shaped rear light clusters use LED-powered light conductors.

Also in common with Coupé models, purchasers of 135i Convertibles receive the M Sport aerodynamic package as standard. The 135i Convertible features a redesigned front valance with large air intakes assisting engine breathing and brake cooling. Re-profiled sill panels and a rear diffuser integrated into the rear bumper add to the car’s sportiness. The 135i Convertible also features 17-inch light alloy wheels and six-pot brake callipers on the brakes (two-pot on the rear).

Interior design
The interior of the new BMW 1 Series Convertible features stretched horizontal lines that visually dominate the cockpit. With space for four occupants and 305 litres of boot space with the roof up (260 litres with the roof down), there is room to convey occupants and some luggage.

In line with the recently launched 3 Series and 6 Series Convertible, owners of 1 Series Convertible models benefit from SunReflective Leather Technology whenever leather seat coverings are specified. BMW is the only manufacturer to offer this technology that uses ‘cool pigments’ during production to reflect infrared rays of sunlight.  This reduces the surface temperature of the seat surfaces by up to 20 degrees Celsius when compared to conventional leather upholstery.

Also carried over from the new BMW 3 Series Convertible are specific settings for the air conditioning system.  Alongside the standard ‘gentle’, ‘medium’ and ‘intensive’ settings, the system recognises when the roof has been opened and defaults to a ‘convertible’ mode. In this situation, the ventilation control reacts less to the interior temperature and more to the outside temperature and sunlight factors to establish the intensity of the ventilation supplied.

Safety is a consideration for BMW and the 1 Series Convertible comes with an additional tier of protection in the event of a roll-over. A sensor registers an imminent danger and, alongside the relevant airbag deployment, two roll-over bars extend from behind the rear seats in a fraction of a second to help protect the safety cell.

But safety in a rear-end collision is a matter which will interest many, given the poor rating achieved by the new 3 Series convertible in American conducted crash testing.

Engines
At its European launch, the new BMW 1 Series Convertible will be offered with four petrol and one diesel engine. The five launch models are:

EfficientDynamics
The new BMW 1 Series Convertible is the latest in the line of BMW models announced in 2007 to benefit from a raft of performance and economy measures under the banner of BMW EfficientDynamics.

Brake Energy Regeneration features on all models and uses Alternator Control and an Absorbent Glass Matt battery to harness engine power that would normally have been lost during engine over-run or braking. An optimum gear shift indicator also features on all manual gearbox cars to inform the driver of the appropriate gear for the most economical driving.

All models feature a new, clutched air conditioning pump. When not in use, the pump decouples and uses only 200 watts, or ten per cent, of the normal power needed to drive a conventional pump. In addition, other than the range-topping 135i Convertible, all models feature electronic power steering. In contrast to conventional hydraulic power steering, the 1 Series’ electronic system operates on an ‘on demand’ basis, reducing engine output normally needed to power the steering hydraulics.

All four-cylinder manual gearbox cars feature BMW’s Auto Start-Stop system as standard. In urban traffic, when the gear is deselected and the clutch pedal raised, the engine automatically cuts out, thus eliminating emissions and any fuel consumption while static. When the traffic starts moving, the clutch is depressed in order to select the gear to pull away and, immediately, the engine fires back into life.

Drivetrain and chassis
All BMW 1 Series models feature a six-speed manual gearbox as standard with buyers able to choose an extra cost option of a six-speed automatic gearbox on all models. Steering wheel-mounted paddles enabling manual shifts of the auto ’box are standard on 135i cars and optional on 125i models.

Finally, in common with 135i Coupé customers, purchasers of 135i Convertible models also benefit from BMW’s electronic differential lock. Promoting a sporting style of driving, the electronic differential lock works when the car is accelerating hard out of corners or tight bends. In this situation, it electronically slows the spinning inside rear wheel to enhance vehicle traction and ensure that all available power is transferred to the road.

Predictably, the new 1-Series convertible will come to Australia in due course. Local availability and specifications will be announced at a later date.