The 6.4:1 Fun Ratio: The BMW M235i xDrive Convertible

2 Series | November 7th, 2016 by 1
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A friend of mine once tried to calculate the psychic benefit of a day spent driving a convertible with the top down versus a day …

A friend of mine once tried to calculate the psychic benefit of a day spent driving a convertible with the top down versus a day spent driving a conventional tin-top. He based his conclusion on a conflation of intersecting and rather nebulous factors and ultimately, after much contemplation and cyphering and more than a few bourbon cocktails, came up with a ratio of 6.4:1; to wit: The joy derived from a day spent driving with the top down is equal to 6.4 days driving around with a top welded on. Seems legit.

The challenge of writing about convertible cars is fundamental; it’s difficult to write anything overly critical about a convertible car, any convertible car, by dint of the fact that’s it’s a convertible and thus, by definition, it’s a machine conceived by its designers to encourage joy and liveliness in its owner; and really, what kind of a sour puss really, truly, criticizes that goal?

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Well, me for one. Because the goal of providing open air driving pleasure in no way obviates a designer or manufacturer from actually, you know, designing a good car. And for every example of a brilliant success (hello, Jaguar F-Type Convertible! Hello Mazda MX-5 Miata!), there’s an equally egregious example of it all going wrong (I’m talking to you, Nissan Murano Crosscabriolet and Toyota Camry Solara).

It’s no easy feat to chop the top off a car and have it still work in all the myriad of ways, both mechanical and visual, that a car needs to work.  For one, a top mechanism adds weight and complexity.  For another, it also takes away rigidity from a vehicle’s structure, which can play havoc with all kinds of virtuous goals, from handling to stability to noise management (what engineers call NVH, for “Noise, Vibration, and Harshness”).  And then there’s the subject of design, as removing the rigid top while also needing to store the folding top mechanism introduces all sorts of challenges that simply bending metal into an elegant form doesn’t have.

In short, it’s easy for a manufacturer to screw it all up…

Which BMW most assuredly has not done with the M235i xDrive Convertible.

(Thanks to the fine folks at Baron BMW in Merriam, KS, for the extended test drive.)

The coupe version of the M235i is easily one of the most elemental and enjoyable cars in the entire BMW lineup, and replacing the fixed top with a folding fabric roof has done nothing to diminish the fun.  Nor have the aesthetics of the 2-series taken a hit by cutting off the roof.  The angular, fluid rectangles that make up the profile of the M235i Coupe survive well with the roof removed, and the multi-layered fabric roof imparts a delicate and successful visual line that’s rarely present in folding hard-top convertibles.  It’s a great looking car.

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My particular test model came finished in Black Sapphire Metallic paint and a Black Dakota Leather interior and was equipped with BMW’s Cold Weather Package, Driver Assistance Package, and Technology Package.  It also was outfitted with some lovely cosmetic appointments from the M-Performance catalog, along with the dynamite M-Performance Exhaust.  All of which inflated the car’s base price of $50,750 to an as-tested price of $61,980.

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The power plant deserves much of the credit for maintaining the M235i’s general goodness.  The 3.0-liter, turbocharged inline-6 cranks out 320-hp at 6000 rpm, with 330-lb/ft of torque available at a lulling 1300rpm, which propels the car to 60mph in a touch less than 5 seconds.  The engine note, especially with the optional M-Sport exhaust, has personality to spare, with a lovely overrun burble, and joyously flatulent bursts and cackles to amuse occupants and bystanders alike.  The motor is smooth and tractable at all points of the range, with little perceptible turbo lag down in the very lowest revolutions giving way to steady power as revs build.  While the Convertible carries an extra NFL lineman’s worth of girth over the Coupe, the engine is more than up to the task of hiding that extra weight, and the performance of the car suffers only modestly.  With all that, the car manages to return EPA mileage of 20mpg in city driving and 30mpg on the highway.  It’s an efficient little powerplant.

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While the M235i is available with a 6-speed transmission, the xDrive version I drove here is only available equipped with the 8-speed automatic with paddles.  It’s a shame BMW didn’t fit one of its trick double-clutch units to this car (Mission Numero Uno:  Don’t cannibalize the M2), though this ZF model does an admirable job of fooling the user to that fact.  The transmission is smooth, quick shifting, and responsive, and in manual mode it rips off shifts almost as quickly as a double-clutch unit.  This is a great automatic transmission.  In Sport and Sport+ modes, the car holds gears to higher RPMs, downshifts with abandoned, and is almost telepathic.  In fact, I generally found myself letting the car shift itself rather than using the paddles, as it seemed to sense what I was about to do before I did it.  And the transmission responds almost immediately to paddle commands when in manual shifting mode, with little attendant lag.  Contrast this shift programming with that of the Cadillac ATS-V, an otherwise brilliant car hamstrung only by a transmission that was lazy and impertinent to manual input commands.

On the road and unrushed, the M235i motors along in a pleasant, almost genteel experience.  The two-layered folding top is remarkably quiet, with very little wind noise noticeable below 80MPH.  There’s a touch of wind harmonics around the rear-view mirror above 70mph, but I remember this from the Coupe I drove as well and is likely more about the shape of the mirror than anything else.

The gold-standard litmus test of any coupe-to-convertible conversion is how well the rigidity of the structure is maintained, and on this I tip my hat to the engineers at BMW.  Only the smallest amount of cowl shake is perceptible, most noticeable when the cornering angle sharpens over suddenly uneven pavement (or railroad tracks), but it’s really only noticeable if you’re trying to notice it.  And what’s absolutely maintained is the intrinsic goodness of how the M235i handles.  The car corners nearly flat and is hugely balanced; neutral in the extreme, with a pivot point somewhere directly under the driver’s derriere.

But the greatest trait of the car is its relative lack of grip compared to other contemporary full-on M-cars.  Wait, what?  Lack of grip compared to a full-blown M-car?  How can that be in any way good?  Part of the joy of driving is getting a car to dance on its tip-toes, sliding ever so perceptibly at the limit and transmitting its intentions through the chassis and up through the steering wheel and seat-of-the-driver’s-pants.  And the fact is, modern BMW M-cars have so bloody much grip as to make this interplay virtually impossible at anything other than extra-legal speeds preferably on a racetrack.  My current daily driver is an M4 Coupe that has grip limits so high they can’t reasonably be exploited on normal roads, and when I do give it a go, I’m always aware I’m frankly being pretty damn irresponsible.  (That doesn’t always stop me; hey, I’m a little boy, so sue me.)  Enter the M235i, with massive but not overblown grip that can be explored on virtually any back road on any given day (especially when it’s damp!  Woo-hoo!); it’s a hoot.

Now, about that xDrive moniker in the M235i xDrive Convertible’s name.  “xDrive” is BMW’s permanent all-wheel drive system, which under normal driving conditions distributes power between the front and rear axles in a 40:60 split.  But when the system detects slip, up to 100% of power can be sent to either axle in a tenth of a second via an electronically controlled multi-plate clutch, a much speedier system than those using slower-to-react hydraulic fluid systems.  It’s a drama-free system and works seamlessly in all conditions, and it’s easy to see why BMWs so equipped have begun outselling their more traditional rear-wheel drive companions.  In this application, it serves to plant to car even more tenaciously.  And while the M235i is available in rear-wheel-drive as well, I’d happily live with the xDrive system, especially if the car were a daily or year-round driver in a climate where wet or slick roads were seasonal possibilities.

The interior appointments are pure contemporary BMW, rather austere and purposeful but with high-quality materials and surfaces and build-quality that’s absolutely top-notch.  One typical issue unique to convertibles is wind encroachment at speed, and BMW handles this here with a nifty removable baffle that fits behind the front seats and folds flat when not manually deployed. While it’s a bit ungainly in appearance, it works incredibly well and quiets the airflow in the cabin (especially above 60mph) like flipping a switch.  Unless you’re using the rear seats for actual passengers, I recommend leaving the baffle installed and deployed whenever the top is stowed in its cubby.

The M2 may be the apex predator in the 2-series line (and some argue it’s the best driving car BMW makes at the moment), but the M235i Convertible (in xDrive guise or not) is as enjoyable a performance car as I’ve driven in years.  I can’t imagine the M2 Convertible (if there ever is such a thing) being any better of a car on actual roads. I certainly don’t remember the last time I had so much fun just going for a drive.  The M235i xDrive Convertible might not be the ultimate “Ultimate Driving Machine” in the BMW lineup but it surely gets my vote for Most Joyous Driving Experience.


Postscript:  Shortly after I spent a day with the M235i xDrive Convertible, BMW released the spec’s for the 2017 model and, alas, the car has morphed into the M240i in various trims.  The primary difference is the motor, which BMW lifts from the all-new 340i sedan.  The new 3-liter inline-6 motor now makes 340-hp and 369-lb/ft of torque and will undoubtedly motivate the little convertible in an even more delightful manner than before.

Review by Konan On Cars

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