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The C-Class Cabriolet’s pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The 124 Spider doesn’t offer pre-crash pretensioners.
The C-Class Cabriolet has a standard Active Brake Assist, which uses forward mounted sensors to warn the driver of a possible collision ahead. If the driver doesn’t react and the system determines a collision is imminent, it automatically applies the brakes at full-force in order to reduce the force of the crash or avoid it altogether. The 124 Spider doesn't offer collision warning or crash mitigation brakes.
The C-Class Cabriolet offers all-wheel drive to maximize traction under poor conditions, especially in ice and snow. The 124 Spider doesn’t offer all-wheel drive.
The C-Class Cabriolet’s optional lane departure warning system alerts a temporarily inattentive driver when the vehicle begins to leave its lane and gently nudges the vehicle back towards its lane. The 124 Spider doesn’t offer a lane departure warning system.
The C-Class Cabriolet offers an optional Surround View System to allow the driver to see objects all around the vehicle on a screen. The 124 Spider only offers a rear monitor and rear parking sensors that beep or flash a light. That doesn’t help with obstacles to the front or sides.
The C-Class Cabriolet’s driver alert monitor detects an inattentive driver then sounds a warning and suggests a break. According to the NHTSA, drivers who fall asleep cause about 100,000 crashes and 1500 deaths a year. The 124 Spider doesn’t offer a driver alert monitor.
The C-Class Cabriolet has standard Mercedes-Benz Emergency Call, which uses a global positioning satellite (GPS) receiver and a cellular system to get turn-by-turn driving directions, remotely unlock your doors if you lock your keys in, help track down your vehicle if it’s stolen or send emergency personnel to the scene if any airbags deploy. The 124 Spider doesn’t offer a GPS response system, only a navigation computer with no live response for emergencies, so if you’re involved in an accident and you’re incapacitated help may not come as quickly.
Both the C-Class Cabriolet and the 124 Spider have standard driver and passenger frontal airbags, front side-impact airbags, side-impact head airbags, front seatbelt pretensioners, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, daytime running lights, rearview cameras and available rear cross-path warning.
The Mercedes C-Class Cabriolet weighs 1353 to 1576 pounds more than the Fiat 124 Spider. The NHTSA advises that heavier cars are much safer in collisions than their significantly lighter counterparts. Crosswinds also affect lighter cars more.
A hardened steel chain, with no maintenance needs, drives the camshafts in the C-Class Cabriolet’s engine. A rubber cam drive belt that needs periodic replacement drives the 124 Spider’s camshaft. If the 124 Spider’s belt breaks, the engine could be severely damaged when the pistons hit the opened valves.
A reliable vehicle saves its owner time, money and trouble. Nobody wants to be stranded or have to be without a vehicle while it’s being repaired. Consumer Reports rates the C-Class Cabriolet’s reliability 15 points higher than the 124 Spider.
J.D. Power and Associates’ 2019 survey of the owners of three-year-old vehicles provides the long-term dependability statistics that show that Mercedes vehicles are more reliable than Fiat vehicles. J.D. Power ranks Mercedes 13th in reliability, above the industry average. With 115 more problems per 100 vehicles, Fiat is ranked 31st.
The C-Class Cabriolet’s 2.0 turbo 4-cylinder produces 95 more horsepower (255 vs. 160) and 89 lbs.-ft. more torque (273 vs. 184) than the 124 Spider’s standard 1.4 turbo 4-cylinder. The C-Class Cabriolet’s 2.0 turbo 4-cylinder produces 91 more horsepower (255 vs. 164) and 89 lbs.-ft. more torque (273 vs. 184) than the 124 Spider Abarth’s standard 1.4 turbo 4-cylinder.
In heavy traffic or at stoplights the C-Class Cabriolet’s engine automatically turns off when the vehicle is stopped, saving fuel and reducing pollution. The engine is automatically restarted when the driver gets ready to move again. (Start/Stop isn’t accounted in present EPA fuel mileage tests.) The 124 Spider doesn’t offer an automatic engine start/stop system.
The C-Class Cabriolet has 5.5 gallons more fuel capacity than the 124 Spider (17.4 vs. 11.9 gallons), for longer range between fill-ups.
In its Green Vehicle Guide, the U.S. Environmental Protection Agency (EPA) rates the Mercedes C-Class Cabriolet higher (6 out of 10) than the Fiat 124 Spider (3). This means the C-Class Cabriolet produces up to 23.4 pounds less smog-producing pollutants than the 124 Spider every 15,000 miles.
The Mercedes C-Class Cabriolet comes standard with an automatic transmission, for driver comfort, especially in the city. Automatic costs extra on the 124 Spider.
A nine-speed automatic is standard on the Mercedes C-Class Cabriolet, for better acceleration and lower engine speed on the highway. Only a six-speed automatic is available for the 124 Spider.
All wheel drive, available in the C-Class Cabriolet, provides the best traction for acceleration in wet, dry, and icy conditions. In corners, all wheel drive allows both outside wheels to provide power, balancing the car. This allows for better handling. The Fiat 124 Spider is not available with all wheel drive.
For better stopping power the C-Class Cabriolet’s brake rotors are larger than those on the 124 Spider:
The C-Class Cabriolet’s standard front and rear disc brakes are vented to help dissipate heat for shorter stops with less fading. The rear discs on the 124 Spider are solid, not vented.
The C-Class Cabriolet stops much shorter than the 124 Spider:
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Car and Driver
For better traction, the C-Class Cabriolet has larger tires than the 124 Spider (F:225/45R18 & R:245/40R18 vs. 195/50R16). The C-Class Cabriolet’s tires are larger than the largest tires available on the 124 Spider (F:225/45R18 & R:245/40R18 vs. 205/45R17).
The C-Class Cabriolet’s standard 225/45R18 front and 245/40R18 rear tires provide better handling because they have a lower 45 series front and 40 series rear profile (height to width ratio) that provides a stiffer sidewall than the 124 Spider Classica’s standard 50 series tires. The AMG C 43 Cabriolet’s optional 225/40R19 front and 245/35R19 rear tires have a lower 40 series front and 35 series rear profile than the 124 Spider Lusso/Abarth’s 45 series tires.
For better ride, handling and brake cooling the C-Class Cabriolet has standard 18-inch wheels. Smaller 16-inch wheels are standard on the 124 Spider Classica. The AMG C 43 Cabriolet’s optional 19-inch wheels are larger than the 17-inch wheels on the 124 Spider Lusso/Abarth.
The Mercedes C-Class Cabriolet’s wheels have 5 lugs for longer wheel bearing life, less chance of rotor warping and greater strength. The Fiat 124 Spider only has 4 wheel lugs per wheel.
Changing a flat tire near traffic can be dangerous and inconvenient. The run-flat tires standard on the C-Class Cabriolet can be driven up to 50 miles without any air pressure, allowing you to drive to a service station for a repair. The 124 Spider doesn’t offer run-flat tires.
The C-Class Cabriolet offers an optional space-saver spare tire so you can replace a flat tire and drive to have the flat repaired or replaced. A spare tire isn’t available on the 124 Spider, it requires you to depend on roadside assistance and your vehicle will have to be towed.
The C-Class Cabriolet has vehicle speed sensitive variable-assist power steering, for low-effort parking, better control at highway speeds and during hard cornering, and a better feel of the road. The 124 Spider doesn’t offer variable-assist power steering.
The C-Class Cabriolet’s drift compensation steering can automatically compensate for road conditions which would cause the vehicle to drift from side to side, helping the driver to keep the vehicle straight more easily. The 124 Spider doesn’t offer drift compensation steering.
For a smoother ride and more stable handling, the C-Class Cabriolet’s wheelbase is 20.9 inches longer than on the 124 Spider (111.8 inches vs. 90.9 inches).
For better handling and stability, the average track (width between the wheels) on the C-Class Cabriolet is 2.7 inches wider in the front and 1.9 inches wider in the rear than the track on the 124 Spider.
The C-Class Cabriolet’s front to rear weight distribution is more even (51.1% to 48.9%) than the 124 Spider’s (53.5% to 46.5%). This gives the C-Class Cabriolet more stable handling and braking.
The C 300 Cabriolet handles at .94 G’s, while the 124 Spider Abarth pulls only .87 G’s of cornering force in a Car and Driver skidpad test.
For excellent aerodynamics, the C-Class Cabriolet has standard flush composite headlights. The 124 Spider has recessed headlights that spoil its aerodynamic shape and create extra drag.
The front grille of the C-Class Cabriolet uses electronically controlled shutters to close off airflow and reduce drag when less engine cooling is needed. This helps improve highway fuel economy. The 124 Spider doesn’t offer active grille shutters.
The C-Class Cabriolet has standard seating for 4 passengers; the 124 Spider can only carry 2.
The C-Class Cabriolet has 1.4 inches more front headroom and 2.7 inches more front shoulder room than the 124 Spider.
The C-Class Cabriolet has a much larger trunk with its top down than the 124 Spider (7 vs. 4.9 cubic feet). The C-Class Cabriolet has a much larger trunk with its top up than the 124 Spider (8.8 vs. 4.9 cubic feet).
With its convertible body style, locking rear seatbacks and remote trunk release lockout, the C-Class offers cargo security. The 124 Spider’s non-lockable remote release defeats cargo security.
The C-Class Cabriolet uses gas struts to support the hood for easier service access. The 124 Spider uses a prop rod to support its heavy hood. It takes two hands to open the hood and set the prop rod, the prop rod gets in the way during maintenance and service, and the prop rod could be knocked out, causing the heavy hood to fall on the person maintaining or servicing the car.
J.D. Power and Associates surveys of service recipients show that Mercedes service is better than Fiat. J.D. Power ranks Mercedes fifth in service department satisfaction. With a 127% lower rating, Fiat is ranked 31st.
The C-Class Cabriolet has a standard remote vehicle starting system, so the vehicle can be started from inside the driver's house. This allows the driver to comfortably warm up the engine before going out to the vehicle. The climate system will also automatically heat or cool the interior. The 124 Spider doesn’t offer a remote starting system.
To help each driver find a more comfortable driving position, the C-Class Cabriolet has a power telescoping steering wheel. Much better than just a tilt steering wheel or adjustable seat, this allows a short driver to sit further from the steering wheel while maintaining contact with the pedals. The 124 Spider doesn’t offer a telescoping steering wheel.
When three different drivers share the C-Class Cabriolet, the memory system makes it convenient for all three. Each setting activates different, customized memories for the driver’s seat (memory seat optional for the front passenger), steering wheel position and outside mirror angle. The 124 Spider doesn’t offer a memory system.
The C-Class Cabriolet’s standard easy entry system raises the steering wheel, making it easier for the driver to get in and out. The 124 Spider doesn’t offer an easy entry system.
The C-Class Cabriolet offers an optional heads-up display that projects speed and navigation instruction readouts in front of the driver’s line of sight, allowing drivers to view information without diverting their eyes from the road. The 124 Spider doesn’t offer a heads-up display.
The C-Class Cabriolet’s power parking brake sets with one touch and releases with one touch or automatically. The 124 Spider has a lever-type parking brake that has to be strenuously raised to engage properly. It has to be lifted up more and a button depressed to release it.
The power windows standard on both the C-Class Cabriolet and the 124 Spider have locks to prevent small children from operating them. When the lock on the C-Class Cabriolet is engaged the driver can still operate all of the windows, for instance to close one opened by a child. The 124 Spider prevents the driver from operating the other windows just as it does the other passengers.
The C-Class Cabriolet’s front and rear power windows all open or close fully with one touch of the switches, making it more convenient at drive-up windows and toll booths, or when talking with someone outside the car. The 124 Spider’s power window switches have to be held the entire time to close them fully. Only its front windows open automatically.
If the windows are left open on the C-Class Cabriolet the driver can close them all at the outside door handle or from a distance using the remote. On a hot day the driver can lower the windows from a distance using the keyless remote. The driver of the 124 Spider can only operate the windows from inside the vehicle, with the ignition on.
In case of a sudden change of weather, the C-Class Cabriolet has a standard remote convertible top that can be raised from a distance to protect the interior of the vehicle from damage. The 124 Spider doesn’t offer a remote top, so the driver will have to run to the car, get in and manually raise the top to prevent the interior from being damaged.
The C-Class Cabriolet’s rain-sensitive wipers adjust their speed and turn on and off automatically based on the amount of rainfall on the windshield. This allows the driver to concentrate on driving without constantly adjusting the wipers. The 124 Spider Classica’s standard manually variable intermittent wipers have to be constantly adjusted.
The C-Class Cabriolet has a standard automatic headlight on/off feature. When the ignition is on, the headlights automatically turn on at dusk and off after dawn. The 124 Spider has an automatic headlight on/off feature standard only on the Lusso/Abarth.
While driving with high beams on, sensitive light sensors available for the C-Class Cabriolet detect other vehicles which could be blinded and automatically switch to low beams. The 124 Spider doesn’t offer automatic dimming high beams.
To shield the driver and front passenger’s vision over a larger portion of the windshield and side windows, the C-Class Cabriolet has standard extendable sun visors. The 124 Spider doesn’t offer extendable visors.
The C-Class Cabriolet’s sun-visors swivel front-to-side to block glare from the side windows. The 124 Spider’s visors are fixed into the windshield header.
The C-Class Cabriolet’s standard outside mirrors include heating elements to clear off the mirrors for better visibility. Fiat offers heated mirrors for extra charge, but only on the 124 Spider Lusso/Abarth.
When the C-Class Cabriolet is put in reverse, the passenger rearview mirror tilts from its original position. This gives the driver a better view of the curb during parallel parking maneuvers. Shifting out of reverse puts the mirror into its original position. The 124 Spider’s mirror doesn’t automatically adjust for backing.
Optional air-conditioned seats in the C-Class Cabriolet keep the driver and front passenger comfortable and take the sting out of hot seats in summer. The 124 Spider doesn’t offer air-conditioned seats.
On extremely cold winter days, the C-Class Cabriolet’s optional heated steering wheel provides comfort, allowing the driver to steer safely and comfortably before the car heater warms up. The 124 Spider doesn’t offer a heated steering wheel.
The C-Class Cabriolet’s standard dual zone air conditioning allows the driver and front passenger to choose two completely different temperatures so people with different temperature preferences won’t have to compromise. This makes both the driver and front passenger as comfortable as possible. The 124 Spider doesn’t offer dual zone air conditioning.
A built-in pollen filter removes pollen, exhaust fumes and other pollutants from the C-Class Cabriolet’s passenger compartment. This helps prevent lung and/or sinus irritation, which can trigger allergies or asthma. The 124 Spider doesn’t offer a filtration system.
To keep a safe, consistent following distance, the C-Class Cabriolet offers an optional Active Distance Assist Distronic, which alters the speed of the vehicle without driver intervention. This allows the driver to use cruise control more safely without constantly having to disengage it when approaching slower traffic. The 124 Spider doesn’t offer an adaptive cruise control.
To quickly and conveniently keep personal devices charged without cables tangling and wearing out, the Mercedes C-Class offers an optional wireless phone charging system (Qi) in the center console. The 124 Spider doesn’t offer wireless personal charging.
The C-Class Cabriolet’s optional Active Parking Assist can parallel park or back into a parking spot by itself, stopping and changing direction automatically. The 124 Spider doesn’t offer an automated parking system.
The Mercedes C-Class comes in coupe, convertible and sedan bodystyles; the Fiat 124 Spider isn’t available as a coupe or sedan.
Consumer Reports® recommends the Mercedes C-Class Cabriolet, based on reliability, safety and performance. The Fiat 124 Spider isn't recommended.
J.D. Power and Associates rated the C-Class Cabriolet first among compact premium cars in owner reported satisfaction. This includes how well the vehicle performs and satisfies its owner’s expectations. The 124 Spider isn’t in the top three in its category.
The Mercedes C-Class outsold the Fiat 124 Spider by over 20 to one during the 2019 model year.
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