2018 Mercedes-Benz C300 Cabriolet

More than a century before the invention of the automobile, France introduced the world to the cabriolet: a two-wheeled, horse-drawn carriage intended for short jaunts about town. The compact carriage notably featured a folding roof that could be tucked away in good weather or raised to protect passengers from nature’s elements.

Although the cabriolet carriage was long ago succeeded by the automobile, the principles of the 18th-century rig’s trick folding top live on in modern-day convertibles such as the 2018 Mercedes-Benz C300 cabriolet. First introduced for the 2017 model year, the C300 cabrio is the newest member of the German brand’s compact C-class family.

Raindrop, Softtop

Like Mercedes-Benz’s larger E- and S-class convertibles, the C300 cabriolet forgoes a fancy retractable hardtop for a simpler softtop. The power-operated cloth roof is well insulated and stows beneath the car’s integrated rear tonneau cover in less than 20 seconds and while traveling at speeds up to 31 mph—a full 20 mph greater than the limit for the BMW 4-series convertible. (The C300’s roof also can be raised in less than 20 seconds, again at speeds up to 31 mph.)

While BMW claims the 4-series’s retractable hardtop adds a whopping 463 pounds to the two-door’s curb weight, on our scales this C300 cabriolet weighed a less egregious 236 pounds more than a similarly equipped 2017 C300 coupe. The extra heft didn’t seem to bother the car’s 241-hp turbocharged 2.0-liter inline-four, which pushed the rear-wheel-drive convertible to 60 mph in 6.1 seconds and through the quarter-mile in 14.7 seconds at 94 mph, figures that are nearly identical to those of the C300 coupe.

A likely reason the cabriolet keeps pace with the lighter coupe is its smooth-shifting nine-speed automatic transmission, which subs in for the seven-speed unit found in the 2017 C300 coupe and sedan. (For the 2018 model year, all C300 body styles feature the nine-speed automatic; only the cabrio had it in 2017.) The upgraded gearbox also benefited the C300’s passing performance, with this cabriolet scooting from 30 to 50 mph in 3.7 seconds and from 50 to 70 mph in 4.6. Both times are 0.1 second ahead of the seven-speed C300 coupe.

Although fuel economy is rated by the EPA at 22 mpg in the city, 29 mpg on the highway, and 25 mpg combined, we observed just 22 mpg over the course of the cabriolet’s stay with us. Nevertheless, we did manage to coax 32 mpg from the C300 on our 75-mph highway fuel-economy loop.

Sticky and Stiff

Wearing $500 worth of 19-inch wheels wrapped in Pirelli P Zero Run Flat performance tires, the droptop C300 never wanted for grip. The sticky rubber and stiff chassis helped the compact convertible skirt around our 300-foot skidpad at 0.94 g. Stopping from 70 mph, however, ate up 158 feet of tarmac—not bad, but 13 feet longer than a 140-pound heavier Audi A5 convertible on similar rubber.

Our test car also featured the $1325 AMG Line package, which brings an aggressive exterior body kit, a flat-bottom steering wheel, aluminum pedal covers, and package-specific tuning for the suspension, steering, and brakes. The firmer suspension together with the 19-inch run-flat tires’ thin and unforgiving sidewalls exacerbated the car’s stiff ride. We’d recommend forgoing the big wheels or the AMG Line package. Or better yet, skip both.

As in the sedan and coupe, the cabriolet’s interior features a contemporary dashboard design and high-quality materials. This C300’s Crystal Grey vinyl seats (MB-Tex in Mercedes-Benz parlance), natural grain black ash wood, and brushed-aluminum trim pieces bestowed a slight Scandinavian vibe to the German droptop’s interior.

At a base price of $52,195, the C300 cabriolet comes standard with dual-zone automatic climate control, a proximity key with push-button start, LED headlamps and taillights, blind-spot monitoring, and power heated front seats with Mercedes-Benz’s Airscarf neck heaters. Additionally, our $58,640 test car also came equipped with the $2100 Multimedia package (navigation and an 8.4-inch center screen) as well as the $1650 Premium package that adds power-folding side mirrors, a premium sound system, a partition within the convertible’s nine-cubic-foot trunk, and the brand’s Aircap system, which relies on an electrically deployable spoiler mounted on top of the windshield and a wind blocker aft of the two diminutive rear seats to suppress top-down turbulence. The car’s sticker was further inflated by a $750 coat of Selenite Grey paint and a set of wheel locks for $150. Notably missing from the options sheet were the $350 Smartphone Integration package that adds Apple CarPlay and Android Auto compatibility and the $1700 Driver Assistance package that includes active safety items such as adaptive cruise control, lane-keeping assist, and automated emergency braking. As in the sedan and the coupe, all-wheel drive is a $2000 option.

While the 2018 Mercedes-Benz C300 cabriolet’s handsome exterior, attractive interior, and high-quality soft top provide the compact convertible with an undeniable charm, its brittle ride quality makes this particular example a hard sell against more forgiving but equally competent convertibles such as the Audi A5. We’d recommend you skip the sporty stuff and live easier—it is a cabriolet, after all.

Specifications >

VEHICLE TYPE: front-engine, rear-wheel-drive, 4-passenger, 2-door convertible

PRICE AS TESTED: $58,640 (base price: $52,195)

ENGINE TYPE: turbocharged and intercooled DOHC 16-valve inline-4, aluminum block and head, direct fuel injection

Displacement: 122 cu in, 1991 cc
Power: 241 hp @ 5500 rpm
Torque: 273 lb-ft @ 1300 rpm

TRANSMISSION: 9-speed automatic with manual shifting mode

DIMENSIONS:
Wheelbase: 111.8 in
Length: 184.5 in
Width: 71.3 in Height: 55.3 in
Passenger volume: 86 cu ft
Trunk volume: 9 cu ft
Curb weight: 3868 lb

C/D TEST RESULTS:
Zero to 60 mph: 6.1 sec
Zero to 100 mph: 16.6 sec
Zero to 120 mph: 26.1 sec
Rolling start, 5–60 mph: 7.0 sec
Top gear, 30–50 mph: 3.7 sec
Top gear, 50–70 mph: 4.6 sec
Standing ¼-mile: 14.7 sec @ 94 mph
Top speed (governor limited): 129 mph
Braking, 70–0 mph: 158 ft
Roadholding, 300-ft-dia skidpad: 0.94 g

C/D FUEL ECONOMY:
Observed: 22 mpg
75-mph highway driving: 32 mpg
Highway range: 550 miles

EPA FUEL ECONOMY:
Combined/city/highway: 25/22/29 mpg