The M135i ushers in the second generation of BMW’s three-door 1-series, which will initially be sold with the choice of four petrol and three diesel engines.
Set for UK sale beside the existing five-door 1-series from September, Munich’s rear-wheel drive hatchback will be 85mm longer and 17mm wider than its predecessor, introduced in 2005, but the same height.
In line with the new five-door 1-series, it is also based on a larger platform; the wheelbase is 30mm longer and tracks are extended by 51mm at the front and a more considerable 72mm at the rear, giving it a more substantial footprint.
The dimension stretch and packaging advantages give the new car 21mm more rear legroom and 30 litres more luggage space than before, at 360 litres.
New to the line-up is the entry-level 114i model, powered by a 101bhp version of BMW’s turbocharged 1.6-litre petrol engine. First reported by Autocar in March, this engine delivers the same combined fuel economy and CO2 emissions as the more powerful 116i — which uses a 134bhp version of the same engine — at 51.4mpg and 129g/km.
Also new is the Volkswagen Golf GTI-rivalling 125i, which runs a 216bhp version of BMW’s turbocharged 2.0-litre petrol engine.
Endowed with 228lb ft of torque at just 1350rpm, the 125i claims a 0-62mph time of 6.4sec in standard six-speed manual guise, or 6.2sec with the optional eight-speed automatic gearbox, and a top speed of 152mph. Combined economy is put at 42.8mpg (auto 44.1mpg).
Among the diesels are 114bhp, 141bhp and 215bhp versions of BMW’s widely used 2.0-litre four-pot in the 116d, 118d and 125d respectively — the first of which forms the basis of a frugal 116d EfficientDynamics model with optimised aerodynamics and altered gearing, netting it claimed economy of 74.3mpg and a 99g/km CO2 rating.
From November, BMW plans to sell the M135i and five-door 120d with the option of four-wheel drive. The former has been ruled out for the UK because it will only be produced in left-hand drive. However, the latter is expected to go on sale in Britain in mid-2013.
Like the five-door 1-series, the new three-door will be available in two trim levels: Sport Line and Urban Line. Buyers will also be able to specify an M Sport styling package.