• Inspired by the BMW 2002, the 1-series redefines the entry-level luxury vehicle with typical BMW refinement and balanced performance.
• The rear-wheel drive 128i is available as either a coupe or convertible. The 128i is powered by a 230-hp 3.0-liter dual overhead cam, inline six-cylinder engine mated to either a six-speed manual transmission or a six-speed automatic with steering wheel paddle shifting. Standard safety features include six airbags on the coupe, four on the convertible, anti-lock brakes, adaptive brake lights, stability and traction control and run-flat tires with pressure monitoring. The 128i features the usual BMW creature comforts such as a 10-speaker audio system, auxiliary input jack, automatic climate control, leather wrapped steering wheel and multi-way adjustable front seats.
• For 2011, a new harman/kardon surround sound system is optional.

The 2011 BMW 1 Series comes in Coupe and Convertible models in two versions: the BMW 128i and the BMW 135i.

The 2011 BMW 135i benefits from an all-new inline-6 engine, here using a single turbocharger to produce 300 horsepower, and paired with the sporty 7-speed Dual Clutch Transmission from the Z4 Roadster. (Code-named N55, the 2011 engine replaces last year's 300-hp twin-turbo inline-6.) The 2011 BMW 135i is also available with a 6-speed manual gearbox, which we found silky smooth and a pleasure to operate. Fuel economy from the 135i even edges that of the 128i, with an EPA-estimated 20/28 mpg City/Highway for a 2011 135i Coupe.

The 2011 BMW 128i Coupe and Convertible continue to be powered by the normally aspirated 3.0-liter inline-6 that generates 230 hp and 200 lb-ft of torque. They're available with 6-speed manual or 6-speed Steptronic automatic.

An M Sport Package adds a sports suspension that favors handling over ride quality.

The BMW 1 Series is nearly seven inches shorter overall than the 3 Series. The 1 Series wheelbase is four inches shorter than that of the 3 Series, and it's a significant 2.7 inches narrower in width. The 1 Series brings BMW's highly developed rear-wheel-drive platform to compete with cars in the entry luxury coupe class that mostly use front-wheel drive.

In many ways, the 1 Series is nothing more or less than a scaled-down version of the 3 Series, with similar looks, similar equipment and similar performance and handling. Indeed, it uses many of the same components and systems. The 135i is a smaller, lighter package with the same engine as the 3 Series for a lot less money. The BMW 1 Series was launched in the U.S. as a 2008 model, initially only as a coupe.

We like these cars. They're comfortable, sitting in one is like sitting in a 3 Series. Underway, they are sporty and agile, driver's cars, with the feel of rear-wheel drive. We found a 128i Convertible is a delight and it has enough power. Most fun to drive is a 135i Coupe, though we recommend against the M suspension due to the hard ride. The new single-turbocharged engine turns the 135i into a little hot rod, and it seems to have a bit more torque lower down, where we use most of it in everyday driving.

We're fond of the M Aerodynamics Package standard on the 135i, including the huge air intakes below the bumper, necessary for cooling the turbocharger intake air. The 128i has a cleaner, albeit more conventional, full-width opening below the bumper, divided into three parts by two angled struts. The outboard sections are then sub-divided horizontally, with a fog light at the top and a small grille underneath. The bottom edge of the opening turns up at the ends, smile-like.

At the rear, the 128i dispenses with the 135i's prominent spoiler, in favor of a more gentle lip integrated into the trunk lid. And the 128i's rear bumper is entirely body-color, lacking the black-out panel seen on the 135i. Drag coefficient actually improves, from 0.33 to 0.31 Cd.

Put the top down on the convertible models, and the flared shoulder line that's shared with the coupes seems to form a single surface that surrounds the interior, like the deck of a small boat. For both convertible models, drag coefficient increases slightly to 0.34.

We found the steering, cornering, and braking performance of the BMW 135i to be exemplary, perfectly matched to the huge acceleration power of the engine. Driving a 300-hp, 3400-pound rear-drive coupe built on a short-wheelbase chassis adds up to a great deal of driving enjoyment, especially when the engine's torque curve is absolutely flat from 1200 to 5000 rpm and the engine redlines at 7000 rpm.

The 2011 135i benefits from a new inline-6 that uses a single twin-scroll turbocharger instead of twin turbos. It makes the same power as the 2010 version but gets better fuel economy. With more than 100 hp per liter, this 24-valve engine is engineering magic. BMW fans worried that the single turbo will sap power can rest easy. The turbocharged engine makes this car a hot rod. It's hard to tell, but power is perhaps more responsive at low speeds, though not quite as willing as speeds and revs increase. The engine is sprightly from a stop without a modicum of turbo lag. It keeps building power up the rev band, pushing a 135i with the manual transmission from rest to 60 mph in a mere 5.1 seconds. The DCT cuts off another tenth. Both numbers are impressive for a vehicle of this price point. Top speed is electronically limited to 130 mph (or 149 mph with the Sport Package).

Fuel economy for the 2011 BMW 135i is an EPA-estimated are 20/28 mpg city/highway with the manual transmission, 18/25 mpg with the DCT.

The manual transmission is a pleasure to operate. It's silky smooth and clutch take-up feels natural. The DCT is also an excellent transmission. It uses two clutches, one to hold the current gear and one to ready the next, so shifts are almost seamless. It can be used as a normal automatic or shifted manually via steering wheel buttons or the gearshift (push down for downshifts, pull up for upshifts). There are several modes of sportiness, ranging from relaxed to lightning quick. The sportier settings can make the shifts a bit abrupt, and we would prefer the easier-to-use steering wheel paddles in the M3, which downshift on the left and upshift on the right.

Because the BMW 135i Coupe is essentially a scaled-down 335i, its ride, steering, and handling carry the same exemplary qualities as the larger car, though with a greater element of tossability due to the lighter weight and shorter wheelbase. Its smaller front tires are matched to the job of pointing the car while the fatter rear tires lay the power down in wonderfully linear fashion. The car's weight is distributed 52/48 on the front and rear tires.

Ride quality in the 135i Coupe, or other models with the sports suspension, can be an issue. The ride is hard, with sharp bumps pounding through, and the car jiggles over broken pavement. It's a matter of taste, so try the firmer setup before you buy. We're inclined toward the standard suspension. Those moments of driving joy may be offset by too many everyday moments of annoyance as the car tries to beat the road into submission. The standard suspension is easier to live with every day.

The 135i's brakes use massive six-piston calipers at the front and twin-piston calipers at the rear, with 13.3-inch front discs and 12.75-inch rear discs and a built-in brake drying and anti-fade feature.

The 128i isn't quite as quick as the 135i, but it still delivers a fun and sporty driving experience. Its 3.0-liter inline-6 breathes at atmospheric pressure without the benefit of turbocharging. It does feature the same Valvetronic valvetrain management and aluminum/magnesium construction as the 135i unit, but it lacks direct injection, a system that aids both power and fuel economy. It develops 230 horsepower and 200 pound-feet of torque, which, in the slightly lighter, 3250-pound 128i, should still get your attention when you put the pedal to the floor. BMW lists a 0-60 mph time of 6.1 seconds with the manual transmission and 6.7 seconds with the automatic.

Fuel economy is worse, surprisingly, for the 128i than for the 135i. EPA ratings are 18/28 mpg city/highway with either transmission.

The standard suspension in the 128i is softer than in the 135i, but weight distribution is a marginally better 51/49. Brakes are 11.8-inch vented discs all around, but again, that is more than adequate for the 128i's more modest, no, make that less extravagant, performance.

We found the 1 Series Convertible impressively solid in both the 128i and 135i. We detected little cowl shack over even bumpy roads. While BMW added extra bracing to firm up the body structure, the convertible still isn't as solid or quick to react to steering inputs as the coupe. Nonetheless, it's still plenty sporty and it has the added advantage of open air fun.

Electronic driving aids abound in the 1 Series, including antilock brakes with electronic brake-force distribution and cornering brake control, dynamic traction control, dynamic stability control, and a switch that can disable the DSC system for track days or generally more involving driving through the woods.

We found the front bucket seats to be very comfortable and supportive, with big side bolsters. The steering wheel tilts and telescopes, helping drivers of different shapes and sizes to find the ideal driving position.

Order the optional navigation system and you get BMW's iDrive, which integrates navigation, entertainment, telephone, and other controls via a pop-up screen on the top of the dash and a mouse-like knob on the console.

The 1 Series continues with an older version of iDrive that doesn't have the ease of use of the newer system found in other BMWs. It includes a central control knob with a separate Menu button, while other version add CD, Tel, Radio, Nav, Back and Option buttons around the controller. Those extra buttons provide easier access various functions, eliminating a few steps. Both versions require some time to learn, but the system in the 1 Series is a little more daunting. Having tried iDrive numerous times, we're used to it and not entirely annoyed, but many drivers will find it overly complicated.

All 1 Series coupes come with a 60/40 split folding rear seat than can almost triple the trunk's 10 cubic feet of space. A storage package for the trunk area includes some tie-downs and straps and a 12-volt power point for external accessories. Without that folding seat, the trunk would be rather small.

The convertibles feature a soft top that can be raised or lowered in 22 seconds, even while driving at speeds up to 25 mph, so you don't need to worry whether that stoplight will be long enough to finish the roof operation. The soft top takes up less trunk space than a convertible hard top would, which is partly why the design uses a soft top. Still, it eats up two cubic feet of cargo space, leaving 8 cubic feet, which is small but not too bad for a convertible.

The convertible's interior room suffers a bit, though hardly enough for a real convertible enthusiast to notice. Front leg room is reduced by a quarter inch, and head room by three-quarters of an inch. The losses in rear-seat room are more consequential, where shoulder room contracts by nearly a foot. Leg room is reduced by three-quarters of an inch, and head room by just 0.1 inch. Coupe or convertible, the two-passenger rear seat is rather inhospitable. You really can't sit back there if anyone up front is taller than Tom Cruise, and the convertible will have two adults knocking shoulders. The back seat is best left to small children and packages.

The optional leather upholstery for the convertible incorporates what BMW calls Sun Reflective Technology, a special pigment which reflects both heat and ultraviolet rays. BMW claims this technology can keep the surface of the seats 20 degrees cooler than conventional leather under the same sun, while also helping the hides last longer. Additionally, the convertible's automatic climate control system adds a top-down mode that reacts less to interior temperature and more to the exterior climate and sunlight. We like the idea but didn't get enough time in the sun to see if it really works.

NewCarTestDrive.com correspondent Jim McCraw reported on the 135i Coupe from Munich, Germany, with Kirk Bell in Chicago, and John Katz in Pennsylvania.