2017 BMW 4 Series Convertible

2017 is a change year for the US 4 Series: the new B46 turbo four in the volume 430i replaces the 428i's 240 hp N20, lifting output to 248 hp — competent for a compact luxury convertible but modest against a coupe/convertible band calibrated to 520 hp.

258 lb-ft arriving from 1450 rpm is the B46's real strength — it makes the 430i feel considerably quicker than its horsepower suggests in ordinary driving, which is what an open-top cruiser is asked to do.

Six seconds flat is mid-pack for the segment — quick enough to be satisfying but held back by roughly 3,900 lb of curb weight from the folding hardtop and the chassis reinforcement a convertible needs.

The B46 pulls cleanly from low revs with little turbo lag and reviewers found it "always in the torque band," but a four-cylinder is an acoustic step down in a $51,000 luxury convertible — the one body style where engine noise is unavoidably part of the experience.

The ZF-sourced 8-speed Steptronic was the segment benchmark in this era — quick, decisive, well-matched to the turbo four's torque curve, and unobtrusive left alone; EPA lists it as the only transmission for the 2017 430i Convertible.

xDrive is a $2,000 option on both the 430i and 440i Convertible rather than a top-trim exclusive, so all-wheel drive is genuinely available across the range — but it is a road-biased system with no low range, terrain modes or off-road provision, and rear drive is standard.

Two distinct gas engines — the 248 hp turbo four and the 320 hp turbo six, each with RWD or xDrive, plus the 425 hp M4 Convertible above them — is real choice within a small range, but every one is gasoline: no hybrid, PHEV or EV option existed in the F33 generation.

27 MPG combined is a respectable result for a nearly two-ton rear-drive luxury convertible with a folding hardtop, helped by standard auto stop-start and the 8-speed's tall gearing, but it sits below mid-band against a convertible range calibrated to 42 MPG.

23 MPG in town is the weakest of the three EPA figures — the curb weight the retractable hardtop imposes tells most in stop-and-go, where the small turbo four's efficiency advantage largely evaporates.

34 MPG on the highway is the car's best efficiency figure and the one that matters most for its intended use — the roof-up hardtop gives it a coupe's aerodynamics on a long cruise, something a soft-top rival gives away.

A 15.8-gallon tank paired with 27 MPG gives roughly 427 miles between fills — enough for a genuine day's touring, and well clear of the smaller 2 Series, though only mid-band in a 300–650 mile convertible range.

At 27 MPG combined the 430i burns roughly 555 gallons a year, but the running cost is set as much by the premium-fuel assumption as by consumption — the EPA still puts it $3,000 above an average vehicle over five years, which lands it low in a band anchored at $1,000/yr.

BMW specifies 91 AKI premium as recommended rather than required for the B46 turbo four, with 89 AKI usable at reduced output — but every EPA rating and cost figure for the car is computed at premium pricing, so in practice owners pay it.

NHTSA has never crash-tested any F32/F33-generation BMW 4 Series, coupe or convertible — normal for a low-volume luxury two-door. Estimate held mid-band: the F33 shares its platform and much of its structure with the F30 3 Series, which tested well, but a retractable-hardtop body with no roof structure has no tested result to lean on.

IIHS has no ratings page for the 4 Series in any body style for 2017 — neither Top Safety Pick nor individual crashworthiness results exist. The closely related F30 3 Series sedan earned Top Safety Pick+ for 2017 (small overlap improved to Good on cars built after November 2016 via suspension and adjoining-structure changes), which is supportive but does not transfer to the convertible's own body. Untested with no known concerns lands at the bottom of the middle band.

The 2017 430i Convertible has essentially no standard driver assistance — not AEB, not blind-spot, not lane departure, and not even a rearview camera. The $950 Driver Assistance Package buys the camera and front/rear park sensors; the $1,700 Driver Assistance Plus package is what adds forward collision warning with city collision mitigation and pedestrian detection, blind-spot monitoring, lane departure warning, surround-view cameras and speed limit info. Adaptive cruise is a separate standalone option.

AEB is optional rather than standard, and the 2017 system is BMW's pre-LCI Active Driving Assistant: forward collision warning with low-speed City Collision Mitigation and pedestrian warning, not the full-speed autobrake of later generations. IIHS ran no front crash prevention test on any 4 Series, so there is no Superior/Advanced rating and no night-pedestrian evidence at all.

Active Blind Spot Detection is alert-only (mirror icon plus steering-wheel vibration) and reaches the car only inside the $1,700 Driver Assistance Plus bundle. Rear cross-traffic alert was not offered on the pre-LCI 4 Series in the US; the closest substitute is the surround-view camera in the same package. Optional, alert-only, and missing cross-traffic entirely puts this in the low band.

The only lane function offered is lane departure warning — a vibration through the steering wheel — inside the optional Driver Assistance Plus package. There is no lane keep assist with steering intervention and no lane centering of any kind on the 2017 US 4 Series; BMW's Active Lane Keeping Assistant arrived on this platform later.

Active Cruise Control with Stop & Go is available as a standalone option and is the strongest piece of the car's driver-assist kit: full-speed-range radar cruise that will brake to a halt and resume in traffic, and reviewers of the period rated BMW's implementation smooth. It scores mid-band rather than high because it costs extra on a $51k car and works alone — there is no lane centering to combine with it, so no highway assist behavior exists.

No hands-free highway driving is offered in any configuration. BMW had no such system in the US in 2017 — Highway Assistant did not appear until years later and never on the F33 4 Series — and the car does not even offer hands-on lane centering.

The 2017 model year is the last pre-LCI year in the US: adaptive xenon headlights with LED accent rings and LED fog lamps are standard, with adaptive full-LED units optional. Steerable xenons were decent-to-good output for the era, but IIHS never rated the 4 Series' headlights, and the standard-LED upgrade the rest of the range got arrived only with the MY2018 refresh that went on sale in March 2017.

Top down the sightlines are as good as any car on the road. With the retractable hardtop raised the picture inverts: thick rear pillars, a shallow backlight and a high beltline create real over-the-shoulder blind zones, and the compensating hardware — rearview camera, park sensors, surround view — is all optional, so a base car has none of it. Averaging the two states with the camera not standard lands just below mid-band.

The convertible carries two rear seats with LATCH/ISOFIX anchors, so a seat can be fitted — but everything about the access is hostile. It is a two-door: the front seats must be tipped and slid forward to reach the back, the lift-over into the rear buckets is high, rear legroom is minimal, and a rear-facing seat leaves the front passenger crowded. Two seats is the ceiling and three-across is impossible.

The F33 Convertible is a strict four-seater with a fixed 2+2 rear bench, unchanged for 2017 — a change year for engines, not for the body. Four is the floor of the convertible normalization band, though it is two more seats than the roadsters this car is grouped with.

Measured with the three-piece retractable hardtop raised, front headroom is 40.4 in — at the top of the segment band, helped by the steel hardtop's more upright roof profile versus a stowed fabric top.

42.2 in of front legroom sits mid-band — enough for tall drivers on the standard power sport seats, and identical to the F32 Coupe since the two share the same front structure and 110.6 in wheelbase.

37.1 in of rear headroom with the hardtop raised is unusually good for a convertible 2+2 and near the top of the segment band — the folding steel roof preserves a taller rear roofline than a stowed soft top allows. Top down the measurement is moot.

33.1 in of rear legroom is well clear of what a Mustang Convertible offers and roughly a segment norm for a 2+2 — genuinely usable for children or a short adult trip, but tight behind a tall driver, and the rear seat is consistently flagged as the car's practical limit.

13.0 cu ft with the roof up (370 L) is among the largest trunks in the convertible class and near the top of the band; the trade-off is that stowing the three-piece hardtop cuts it to 7.8 cu ft (220 L), so open-air motoring and luggage compete directly for the same space.

Storage is adequate but conventional: a modest covered center console bin, small door pockets, a glovebox and rear-seat side nets, plus a through-load hatch behind the rear seats on cars ordered with the through-loading system. There is no underfloor storage and no onboard power, and the tonneau cover that must be deployed before the roof will operate eats trunk space rather than saving it.

Standard equipment is better than the segment norm — power-adjustable front sport seats with power side bolsters and driver memory, with 4-way power lumbar in the Premium Package — and reviewers rate the car comfortable over long stints. The two rear buckets are the limiter: firm and short-trip only, which keeps the item out of the top band.

The standard suspension is well damped and absorbs broken pavement without crashing, and the reinforced hardtop structure means essentially no scuttle shake. It falls short of plush because the run-flat tires transmit sharp impacts and the M Sport Package's sport-tuned suspension trades away comfort.

The insulated three-piece steel hardtop makes this one of the quietest convertibles of its era — testers report very little road noise even at autobahn speeds with the roof up — and the wind deflector keeps top-down buffeting manageable. Run-flat tire roar is the main intrusion, so it is quiet for a drop-top rather than quiet outright.

Dual-zone automatic climate control is standard, and the convertible-specific Cold Weather Package is genuinely well judged — three-stage heated front seats, a heated steering wheel and neck-warming vents that make top-down driving workable below freezing. It stays mid-band because all of that is optional on a $51,000 car and there are no ventilated seats.

BMW's own MY2017 pricing release puts the entry 430i Convertible at $50,995 delivered — comfortably past the $55,000 ceiling of the convertible normalization band before a single option is added, which is what a compact luxury drop-top costs.

The 248-hp 430i is the volume convertible, but BMW's à-la-carte structure means almost none leave a lot at the $50,995 base: the Premium Package (~$2,200), Cold Weather Package ($950) and metallic paint push a representative car to roughly $55,500, and xDrive adds $2,000 on top of that. Navigation and even a reversing camera are extras in 2017, so the typically-equipped figure sits well above sticker.

Class estimates for the 4 Series put five-year scheduled maintenance in the $3,500–$4,700 range and repairs near $2,000–$3,100, and RepairPal's ~$968/yr BMW brand average corroborates the order of magnitude; the figure is nudged up for the F33's power retractable hardtop, a multi-motor mechanism the coupe-derived class data does not price in. BMW Ultimate Care covers scheduled service for the first 3 years/36,000 miles, so most of the spend lands in years 4–5.

iSeeCars puts the 4 Series convertible at 45.7% depreciation over five years (54.3% retained), and that curve tracks the car's real trajectory well — its 10-year point implies roughly a third of MSRP, matching KBB's current $17,010 fair purchase price on the 2017 430i Convertible. The figure is shaded slightly below the model-line average because the four-cylinder 430i retains less than the 440i and M4 that lift it, and because it is a nameplate average rather than a 2017-specific residual; a 2017 car's five-year mark landing in the inflated 2022 used market cuts the other way.

BMW's New Vehicle Limited Warranty covered all 2017 models bumper-to-bumper for 4 years or 50,000 miles, transferable to subsequent owners — a year longer than the mainstream 3/36 standard and the norm across the German luxury field.

BMW published no powertrain coverage beyond its bumper-to-bumper term for 2017 — the engine and drivetrain are protected for the same 4 years/50,000 miles, short of the 5-year floor the segment band begins at and far short of the 10-year terms some rivals offer. That matters more than usual here, because 2017 introduced an all-new B46 four and B58 six with no field history.

Still generous by segment standards — 3 years/36,000 miles of complimentary scheduled service under BMW Ultimate Care plus 4 years of unlimited-mileage roadside assistance, where several luxury rivals include only a first visit. But 2017 is the model year BMW cut the program: cars through MY2016 carried 4 years/50,000 miles of free maintenance, and wear items such as brake pads now require the paid Ultimate Care+ upgrade. Apple CarPlay was also a $300 charge rather than a perk.

$55,500 volume-trim price minus its estimated resale value after 5 years (52% retained, or about $28,860) leaves about $26,640 in depreciation. Add the projected $6,100 in 5-year maintenance and repairs, and owning this vehicle for 5 years costs about $32,740 in total.

The two predictors point in different directions on this specific model year, so it lands mid-band. J.D. Power's own MY2017 study named the 4 Series best in its segment at 90 days, and the brand held up at three years in the 2020 VDS — but Consumer Reports' owner survey for the 2017 car is only "about average," a full step below the verdict CR gives the run-out 2020 F33, and its trouble spots include the convertible-specific electrical faults (top sensors, window issues) alongside emission-control, suspension and A/C evaporator problems. Two structural reasons hold it here rather than higher: 2017 is the first US model year of the B46 four in this car (the 428i's N20/N26 is gone), so the volume buyer got an unproven-in-this-application powertrain, and NHTSA's owner record for the year is dominated by a single clustered failure mode rather than scattered noise.

Measured on this model year rather than today, BMW is near its high-water mark. Consumer Reports' October 2017 survey placed BMW 5th among all brands — up four spots and its first top-five finish — and J.D. Power's 2020 VDS, which surveyed these exact three-year-old MY2017 cars, ranked BMW 8th of the industry against a 134 PP100 average. That is materially better than the brand's standing on MY2018 and MY2019 cars. Held just below the top band because only one of the two studies puts BMW top five, and J.D. Power published no BMW PP100 figure for 2020 to size the gap to Genesis and Lexus.

Two NHTSA recalls on the 2017 430i, and both are the same defect — seat-mounted side airbag inflator initiators that may fail to ignite in a crash, issued twice (December 2016 and February 2017) to catch different production batches, with the remedy in each case a full airbag-module replacement. A repeat campaign on a restraint system is the kind of recall the framework marks down. The year does escape two campaigns that bracket it: the water-pump-connector fire recall stops at the 2016 428i because the B46 replaced the N20/N26 for 2017, and the driveshaft-separation recall covers only the M4. What pulls the score below the "typical activity" midpoint is the non-recall record — NHTSA's 23 complaints for the year cluster hard on cooling (cracked plastic oil filter housing emptying the coolant, electric water pump and connector failures, thermostat leaks, several ending in a tow or overheating), with a documented BMW TSB for the leaking coolant part, plus a convertible-specific "retractable top not locked" fault and repeated seat-occupancy-sensor failures.

The volume 430i Convertible pairs the B46 2.0L TwinPower Turbo four — the SULEV sibling of the B48, and a genuine upgrade on the N20/N26 it replaced for this model year — with the ZF 8HP automatic, one of the most proven transmissions in service across four brands. Nine years of field data have broadly vindicated the B46/B48 family. It scores a notch below the equivalent 2 Series and the 2020 F33 for two reasons specific to this car and year: 2017 is the engine's debut application in the 4 Series rather than a settled one, and the family's known weak point is not theoretical here — the plastic oil filter housing and coolant-system leaks show up repeatedly in NHTSA's own complaint file for the 2017 4 Series, several times as an immobilizing failure, on a car now long past every warranty.

This is the last pre-facelift F33 cabin — BMW announced the 4 Series LCI on 24 January 2017 with its upgraded interior trim, but that entered production in March 2017 as MY2018, so a 2017 buyer gets the original 2014 design. Reviewers land it squarely mid-band: good materials and a premium-feeling build, a chrome character line framing soft-touch surfaces and wood, but too much hard plastic on the centre console, standard SensaTec vinyl that does not imitate leather well, and a dash-top screen described as looking like an afterthought. Against a Mercedes C-Class Cabriolet, reviewers gave the interior to the Mercedes outright — respectable for a mid-$50k luxury convertible, plainly not class-leading.

The best-evidenced item on this car: J.D. Power's Initial Quality Study for this exact model year named the BMW 4 Series highest-ranked in the Compact Premium Car segment for problems reported in the first 90 days, in the study's best-ever year for new-vehicle quality. The three-piece retractable hardtop supports the reading — sealing and refinement to coupe standard when raised is a harder assembly target than a soft top, and it is a body BMW had been building at Munich for four model years by 2017. Not higher because the owner record is not spotless: an Edmunds owner reports interior trim flaking and peeling within eighteen months, panoramic-roof rattle at highway speed is a documented complaint on the fixed-roof cars, and NHTSA holds two reports of spontaneously shattering glass roofs against the 2017 4 Series family.

Coverage is a real strength — 344 BMW passenger-car and SAV centers in the US at the end of 2017, dense across every metro market and broader at regional level than Audi or Jaguar — and the car shipped with a 4-year/50,000-mile warranty plus four years of unlimited-mileage roadside assistance. What holds it mid-band is that MY2017 is precisely the year BMW cut its included maintenance: 2016-and-earlier cars carried BMW Scheduled Maintenance for 4 years/50,000 miles, 2017-and-later get BMW Ultimate Care at 3 years/36,000 miles. That coverage is also non-transferable, so a used buyer of a 2017 — which by now is every buyer — inherits none of it, and BMW sat outside the luxury top five in the Customer Service Index study contemporary with this model year.

Availability is the easy half — the F33 shares its B46/B58 engines, ZF 8HP transmission and most chassis hardware with the high-volume F30 3 Series, so after nine model years the specialist aftermarket and used-parts pool are as deep and cheap as European parts get. Cost is what pins the score down. BMW's brand-average annual repair bill runs roughly half again the industry norm, standard run-flat tires are an expensive consumable, and a 2017 is years past both the 3-year/36,000-mile Ultimate Care plan and the 4-year/50,000-mile warranty, so the cooling-system failures this year is known for land entirely on the owner. The convertible adds its own bill on top: the F33's rear-quarter body drains clog with debris, water reaches the rear window regulator and top motors, and the resulting failure — which disables roof operation entirely — is a four-hour-plus dealer-priced job needing diagnostic tools to cycle the top for access.

The volume 430i leaves the factory with iDrive's 6.5-inch display; the 8.8-inch higher-resolution screen only arrives with the optional Technology Package that also brings navigation. Both sit below the segment band floor, and the touch-capable iDrive display did not reach the US 4 Series until the LCI facelift arrived for MY2018.

iDrive remains one of the best-executed interfaces of its generation — a fast tile-based menu driven by the console rotary controller with programmable shortcut buttons, backed by real physical climate and audio controls that keep eyes on the road. The volume car's 6.5-inch non-touch screen and plain rotary controller are a step below the 8.8-inch, touchpad-equipped setup the Technology Package buys.

2017 is the first model year Apple CarPlay could be ordered on the 4 Series at all, and BMW's implementation is wireless — but it is a roughly $300 paid extra that first requires the optional navigation system, so the volume car as configured has no phone projection. Android Auto is simply absent: BMW did not add it until the iDrive 7 cars years later, which the F33 never received.

BMW Navigation with real-time traffic is good native mapping, but on the 2017 car it is optional rather than standard — it and the enhanced voice control both arrive only with the Technology Package. The voice system itself is the pre-iDrive-7 command-word type: reliable for addresses and contacts, not conversational.

The standard nine-speaker system with HD radio and a CD player is a competent base setup, and the 16-speaker Harman Kardon surround system available in the Premium Package is a well-regarded upgrade. Convertible acoustics work against any system with the roof down, though BMW compensates volume for roof position.

The 2017 car is analog-only: conventional dials with a small monochrome-and-color info strip between them, with no digital cluster offered at any price. BMW added the configurable digital instrument cluster to the 4 Series as part of the LCI facelift, which reached the US as a 2018 model.

At best the car can pull map updates over the air through BMW ConnectedDrive when the optional navigation system is fitted — and the volume 430i is not fitted with it. Whole-vehicle over-the-air software updates arrived with BMW's Remote Software Upgrade on the iDrive 7 platforms and were never extended to this generation; everything else is a dealer visit.

BMW Connected — then barely a year old — plus ConnectedDrive Remote Services covers the core set: remote lock/unlock, vehicle finder, vehicle status and send-to-car destinations, with services included for the first years of ownership. There is no remote engine start on this generation, no digital key, and functions become subscription-gated once the included term lapses.

Device power is the car's weakest technology area: a single USB-A port plus an auxiliary jack, nothing at all for rear passengers, no USB-C anywhere and no household outlet. Wireless phone charging exists only as a standalone extra-cost option.

The volume 430i Convertible does not leave the lot fully keyless — Comfort Access proximity entry and keyless ignition are Premium Package content, and on the convertible that package is also what buys remote top operation from the fob. No remote engine start and no phone-as-key exist on this platform. Ordinary convenience for a car of this price.

Nothing is standard: even the rearview camera and front/rear parking sensors are bundled into the $950 Driver Assistance Package, and the surround-view and side-view cameras and the self-parking system sit further up the option sheet. A 2017 luxury convertible that ships without a backup camera is behind the class, and the thick rear quarters with the hardtop raised make the omission worse.

BMW's full-color head-up display is available on the volume 430i Convertible inside the Technology Package and is one of the better implementations of its era — large, crisp and legible with speed, navigation and speed-limit data. It is optional and bundled with navigation rather than standalone, which holds it to the middle band.

A two-door 2+2 with no rear doors makes every child-seat installation a matter of tilting and sliding a front seat and reaching over a high sill, and with the hardtop raised the low roof opening makes leaning in awkward. Two rear positions is the hard ceiling, and the stroller that fits the 13 cu ft trunk stops fitting once the roof is stowed.

The 2017 car has essentially no standard driver assistance — no automatic emergency braking, no blind-spot monitoring, no lane departure warning, not even a rearview camera; forward collision warning arrives only in the optional Driver Assistance Plus bundle. Compounding it, neither NHTSA nor IIHS ever tested this body, so a family buyer has no independent crash credentials to weigh either.

Better than most convertibles for a family — 33.1 in of rear legroom and 37.1 in of rear headroom with the top up genuinely seat two children, and the insulated hardtop keeps long stints quiet. But there are no rear amenities at all (no rear vents, no rear USB), and four people's luggage does not fit alongside a stowed roof.

The 248-hp B46 with 258 lb-ft from 1,450 rpm and the ZF 8-speed make low-speed traffic effortless, the ride is well damped, and the hardtop cycles in about 20 seconds at low road speed so the open-air option costs nothing at a stoplight. The recurring irritants are the auto stop/start restart and top-up rearward visibility on a car with no standard camera.

27 MPG combined is respectable for a near-two-ton convertible, but every mile is on premium fuel and the EPA puts annual cost at about $2,800 — and the run-flat tires this car rides on are an expensive, frequently replaced consumable. Average-at-best commuting economics.

A compact 182.6 in footprint and roughly 37 ft turning circle make city work manageable in principle, but the volume 2017 car has no camera and no parking sensors — both live in the $950 Driver Assistance Package — while the hardtop's thick rear quarters and shallow backlight are exactly the sightlines a camera would fix. Manageable with care rather than easy.

There is no work case here at all: no US tow rating, no bed, no meaningful payload headroom, and a trunk that shrinks to 7.8 cu ft the moment the roof is stowed. A luxury two-door convertible is the opposite of a work tool.

The B46/ZF8 driveline is durable enough in ordinary use and the F3x platform is well proven, but nothing else about the car suits abuse — leather and soft-touch surfaces throughout, run-flat tires, low ground clearance, and a complex three-piece powered hardtop with seals and hydraulics that is an expensive failure point rather than a fleet asset.

No onboard power, no bed or tie-down system, no factory hitch, no roof rack possibility on a retractable hardtop, and no washable surfaces or upfit ecosystem of any kind. There is nothing in the F33's provisions aimed at work.

This is the car's strongest mission after commuting: a well-isolated hardtop cabin with very little road noise at speed, power sport seats good for hours, a composed highway ride and roughly 427 miles from the 15.8-gallon tank at 27 MPG. It stops short of the top band because the Active Cruise Control that would cut highway fatigue is a standalone option the volume car usually lacks, and rear passengers will want out well before the fuel does.

xDrive all-wheel drive is a $2,000 option on the 430i Convertible and makes the car usable in bad weather, which is the whole of its outdoor credential. Ground clearance is minimal, the tires are low-profile run-flats, there is no tow or roof-rack capability, and nothing about the packaging supports camping or gear.

13.0 cu ft is a genuinely useful convertible trunk and the fold-down rear seatbacks with the optional through-loading hatch let long items pass into the cabin, but the trunk opening is shallow and awkward, the roof-stowing tonneau cuts capacity to 7.8 cu ft, and there is no roof rail or hitch to fall back on for bulky gear.

Quick steering, a near-50:50 rear-drive layout and a stiff reinforced structure give the F33 secure, composed cornering with no scuttle shake, and the M Sport Package's sport suspension tightens it further. It cannot reach the top band because roughly 3,900 lb of curb weight and the convertible's higher center of mass blunt the agility the F32 Coupe finds on the same platform.

The electric rack is accurate and quick off center with sharp turn-in, and weighting is natural in Comfort mode. Reviewers split on it: road tests of this model year call the steering precise, while the persistent criticism of the F3x generation is that it is numb by BMW's own historical standard — precise enough, short on genuine feedback.

Ventilated discs at all four corners with BMW's well-tuned pedal give firm, progressive response and repeatable stops from highway speed, and the run-flat tires' stiff sidewalls contribute short, stable stopping distances. 2017 is also one of the years the optional M Sport Brakes were still offered on the convertible, which BMW later withdrew. No instrumented figure for the 2017 Convertible specifically was located.

The new-for-2017 B46 2.0-liter turbo puts 258 lb-ft on a plateau from 1,450 rpm, which makes it feel effectively lag-free, and the ZF 8-speed is the benchmark conventional automatic of the era — quick, decisive and sensibly calibrated. The one persistent complaint is the auto stop/start restart, unsmoothed by any 48V system.

The four-cylinder is smooth and well isolated, and with the top down the engine note is audible rather than intrusive. It is acoustically ordinary next to the B58 six in the 440i — competent and inoffensive rather than a reason to drop the roof, which matters more here than in a coupe.

BMW's European figure for the F33 430i Cabrio is 11.3 m curb-to-curb, which converts to 37.1 ft and matches the 37 ft Cars.com publishes for the 2017 car; mid-band for the segment and unchanged across the generation.

A low, adjustable seating position with power sport seats including adjustable side bolsters and driver memory, plus iDrive's rotary controller alongside retained physical climate and audio keys, makes the cabin easy to work in without looking away from the road. It falls short of the top band on sightlines: with the hardtop raised the thick rear quarters create real over-the-shoulder blind zones on a car with no standard camera.

Roof down on a good road the 430i Convertible is genuinely enjoyable — rear drive, a willing turbo four and an open sky, with Dynamic Driving Control offering Comfort, Sport and Sport+. But the tuning is deliberately grand-touring: BMW left the convertible's chassis calibrated for its extra weight and a touring audience rather than sharpened with the LCI, and the four-cylinder soundtrack does not compensate.

The core of the car is standard — power retractable hardtop with wind blocker, 18-inch wheels, adaptive xenon headlights, power sport seats with driver memory, dual-zone automatic climate and a nine-speaker system — but the 2017 list is thin where it counts for the money. Upholstery at base is SensaTec imitation leather, navigation is a paid option or part of the $1,950 Technology Package, heated seats need the $950 Cold Weather Package, Apple CarPlay costs $300, and a reversing camera is inside the $700 Driver Assistance Package on a $50,995 car — the last of those a year before backup cameras became federally mandatory.

Fair rather than generous. $50,995 buys 248 hp and a folding hardtop, while a Mustang GT Convertible delivers roughly 435 hp for around $10,000 less — the drop-top premium is real. Within the luxury set it is competitive: 2017 brought the new 248-hp B46 four and 320-hp B58 six in place of the 240/300-hp units at broadly flat pricing, which is a genuine content gain, and the hardtop is a structural advantage over the soft-top Audi A5 and Mercedes C-Class cabriolets at similar money. The extras list is where it slips — a car this expensive shouldn't charge separately for a camera and CarPlay.

Five factory configurations of the convertible body alone — 430i and 430i xDrive with the 248-hp four, 440i and 440i xDrive with the 320-hp six, and the 425-hp M4 Convertible above them — spanning $50,995 to $75,695, with rear- or all-wheel drive at both mainstream power levels, Sport/Luxury/M Sport design lines, and a deep à-la-carte package catalogue.

2017 was the second-best year in the nameplate's history and the only one in the F32/F33 run that grew: 39,634 US deliveries, up 10.8% on 2016's 35,763, against a BMW brand year that was essentially flat. Only the 2015 peak of 46,079 beat it, and every year afterward fell — 31,379 in 2018, then 18,621 and 9,495 — so 2017 caught the generation at its commercial high-water mark rather than on the way down.

BMW is a top-tier aspirational badge with a loyal following, and the roundel does real work on a car sold substantially on image. Two small qualifiers keep it off the top of the band for 2017: Mercedes-Benz rather than BMW held the US luxury sales crown in this period, and the enthusiast conversation of the era was that the F3x cars had traded some of the brand's steering-feel reputation for refinement. In hindsight the F33 has aged well — the last 4 Series with a conventional kidney grille and the last with a folding hardtop.

Real buyer benefit without desperation pricing. Documented 2017 4 Series transactions show stacked factory rebates and credits on top of dealer discount — one lease deal carried a $2,500 rebate plus a $1,000 credit against a $55,895 sticker, and buyers were routinely advised to target invoice-or-below plus roughly $3,000 in available incentives. BMW Financial Services' subvented leases plus standing loyalty, military and college-grad bonuses did the rest. Short of the clearance-level flexibility a runout year brings, because 2017 was a mid-cycle year with rising sales.

Squarely mid-cycle, and better-placed than the raw generation age suggests. 2017 is the fourth model year of the F32/F33 launched for 2014, but it is a change year rather than a carry-over: BMW fitted the all-new B46 four and B58 six (248 and 320 hp, replacing 240 and 300), updated navigation to iDrive 5.0, and added wireless charging and a Wi-Fi hotspot. The offset is that the LCI facelift was known to be arriving for 2018, so a 2017 buyer was one year ahead of a visible restyle.

One of the better-reviewed years of the generation. U.S. News scored the 2017 4 Series 8.3/10 and ranked it among its top-rated luxury small cars, citing driving dynamics, cabin technology, materials and predicted reliability; Edmunds called it one of the top luxury sport convertibles with an engaging character few rivals match. It stops short of the top band because the 4 Series collected no 10Best or NACTOY honors — Car and Driver's 2017 10Best went to the BMW M2 and M240i instead — so it was consistently praised without being the trophy car of its class.