BMW M4 Convertible review
“The soft-top BMW M4 Convertible isn’t as focused as the coupe, but open-air thrills and massive performance still appeal”
- Ferociously quick
- Four usable seats
- Impressive tech
- Not quite as composed as coupe
- Smaller boot
- Not exactly good value
The BMW M4 Convertible aims to balance sports car performance with the ability to make the most of good weather. Depending on your point of view, that might make the M4 Convertible seem conflicted or the best of both worlds.
Of course, that applies to any performance coupe, although at the time of its launch the fabric-roofed M4 is curiously short of rivals. There’s no fast version of the Audi A5 Cabriolet any more, and the Mercedes-AMG C 63 Cabriolet is off sale too. A Porsche 911 Cabriolet might be the best alternative, but at that price you’d probably be looking at the BMW 8 Series Convertible instead.
Convertibles tend to be heavier than the coupes they’re based on, because the chassis needs to be strengthened to compensate for the missing roof. The extra weight of the M4 Convertible is slightly noticeable compared to the coupe, both in terms of its straight-line acceleration and through the corners, but BMW has ensured the M4 Convertible still drives sweetly.
Given that the M4 Convertible tips the scales close to two tonnes, its incredible acceleration is all the more noteworthy. Four-wheel drive is standard (there’s no rear-wheel-drive version of the convertible) and helps marshal the power output to enable a 3.7-second 0-62mph time. Like the M4 Coupe and the BMW M3, the M4 Convertible uses a 3.0-litre turbocharged petrol engine with 503bhp.
You can share the performance with three mates, because the M4 Convertible is a usable four-seater. Headroom is tight in the back with the roof in place, as it is in the coupe, but peel the roof back (which can be done at up to 31mph) and there’s unlimited headroom to enjoy. The boot is smaller than the coupe but, even with the roof down, there’s as much space as some family hatchbacks.
The occupants in the front seats get the same level of equipment as in the M3 and M4, including a top-drawer infotainment system and heated front seats.
MPG, running costs & CO2
In a time where every Porsche 911 Cabriolet has a six-figure price tag, it’s not all that surprising that the BMW M4 Convertible starts north of £85,000. Just don’t think about the fact that, even adjusted for inflation, that’s around £20,000 more than the starting price of the last-generation M4 Convertible.
BMW’s official figures suggest that you can extract 27.7mpg from the current car, which might be possible if most of your journeys are at a steady cruise. Use the car as it’s intended and you’ll probably struggle to reach 20mpg. Road tax (VED) costs over £500 for the first five times you renew it, and group 46 insurance means premiums will be high too.
You’ll also pay the ‘M tax’ when it comes to servicing and maintenance. A three-year service plan costs £45 per month for the M4, compared to £25 per month for a regular BMW 4 Series. Parts and consumables (such as tyres and brakes) will also cost more than they would on a less powerful car.
Engines, drive & performance
The BMW M4 Convertible follows the same formula as the M3, M4 Coupe and BMW X3 M. A 3.0-litre turbocharged six-cylinder petrol engine provides 503bhp in M4 Competition spec (the only one offered to UK buyers), and that power is managed by an eight-speed automatic gearbox. While the M4 Coupe gets a choice of rear-wheel drive or BMW’s xDrive all-wheel-drive system, there’s no two-wheel-drive option on the convertible.
The four-wheel-drive system isn’t short of grip, but the extra weight that the convertible carries improves it further. In any of the lower gears, the M4 shoots forward with impressive urgency. You’re unlikely to care that the convertible is two tenths of a second slower than the coupe; the 3.7-second 0-62mph time is certainly fast enough.
With the ability to send varying amounts of power to the front and rear wheels, the xDrive system imbues the M4 Convertible with agility that you wouldn’t expect given its heft. There are numerous settings to play with to tune its handling and engine response just how you like it.
You’re better off with the M4 Coupe if you’ve got a lot of racetrack driving planned, because the extra weight (and some flex in the chassis) is noticeable on the Convertible. To some extent, that flex can be felt on the road too, and the ride is firmer to cope with the necessary strengthening. Drop it back into Comfort mode and it’s a little more forgiving.
Somewhat disappointingly, the engine noise isn’t much better or louder with the roof down. With a lot of the sound piped through the speakers, there’s no aural reason to buy the convertible over the coupe.
Interior & comfort
The interior of the BMW M4 Convertible might not look all that different from the old model, and it might not have the theatricality of a Porsche 911, but that’s no bad thing. It is intuitive, with physical, easy-to-use buttons still featuring. This analogue approach to touchpoints is contrasted with a set of crisp digital dials and a great infotainment touchscreen.
Standard equipment includes a head-up display, a Harman Kardon sound system, wireless phone charging and electrically adjustable heated front seats. The M4 also gets carbon-fibre trim and red ‘M’ shortcut buttons for a sportier feel than a standard 4 Series. Despite its price, there are still a number of options to choose from; packs with added technology or comfort features are appealing, while there are M packs that add performance features or BMW’s snug carbon-fibre seats.
Practicality & boot space
Buyers of the M4 Convertible may well have practicality somewhere on their priority list, because it’s more usable than a BMW Z4 or Porsche 911. There are four seats and you can get adults in the rear ones, although legroom is on the tight side, so back-seat occupants might not want to go on huge journeys. Headroom is also limited when you have the roof up, but then the coupe isn’t the last word in spaciousness either. At least with the convertible you can drop the roof.
Boasting 385 litres with the roof up, the M4 Convertible’s boot is a decent size. While it’s down on the coupe, it’s about the same size as what you get in the Volkswagen Golf R hatchback, albeit with a much smaller boot opening. Retract the roof and it takes up 85 litres, or about half the space that the old M4’s folding metal roof took up.
Reliability & safety
BMW was ranked 21st out of 29 brands in our 2021 Driver Power survey, with just under a fifth of owners reporting faults in the first year. Value for money was something that was criticised – that doesn’t really apply to the M4 – but it scored well for acceleration, handling and interior quality. In our 2022 survey, the BMW 3 Series, which shares a lot of parts with the M4, came in a respectable 33rd position in our list of the best 75 cars to own.
Being based on the 3 Series, the M4 can claim an excellent safety score; the 3 Series scored 97% for adult protection in Euro NCAP crash tests. A lot of standard safety features including lane assist and autonomous emergency braking are fitted, and you can add more on the options list.