BMW I3 vs BMW 420i

What's the difference?

Yes, it’s pricey for a small hatch, but this little BMW is a city car like no other. The i3s is tailor made for the urban environment, and six years on retains the quirkiness and charisma that stood it apart at launch, and it can still hold its head high among the current EV crop. 

The BMW 420i is a terrific car if you're after a bit of style and sophistication. Not everyone will warm to your car's nose, but if you get it de-chromed, like this white one, it really does look pretty good. It's a car that uses very little fuel, moves along smartly and is brimming with a decent amount of tech, even if it could do with a bit more safety gear at this price. 

I reckon this car is settling well into the automotive landscape and ignoring it because of a few loudmouths think the grille is too big would be a terrible waste.

Built around a carbon-fibre reinforced plastic (CFRP) tub, the i3s is ultra-light (for a battery-electric vehicle), super strong, and unlike anything else on the road.

At just over 4.0m long, close to 1.8m wide, and a fraction under 1.6m tall, the i3s is compact, upright, and boxy. A classically polarising design, with some crossing the street to avoid it, and others (like me) loving its unique proportions and stand-out styling.

The nose is tall, short and upright, with the distance from the base of the front windscreen to the front axle (car designers call it the ‘dash-to-axle ratio’) unusually short.

That’s because the electric motor sits in the back of the car driving the rear wheels, with only a small front boot compartment required to house charging cables and other bits and pieces.

Despite the lack of anything of substance behind it, BMW’s signature ‘kidney grille’ is present and accounted for, with swoopy LED headlights (and DRLs) either side. Our test car’s ‘Fluid Black’ finish with ‘i Blue’ highlights dialed up the little car’s charismatic personality.  

One of the i3’s most impressive party tricks is its counter-opening ‘clamshell’ doors, and the engineering trickery used to create a B-pillar free side opening (including the strength of the carbon body structure) means the high window line follows a jagged path from front to back, the rearmost hatch windows shrinking the rear glass area appreciably.

The i3s’s standard 20-inch (dual) five-spoke alloy rims, although slightly wider in this performance model, are alarmingly skinny. But taking the car’s relatively light weight (1245kg) and urban-centric purpose into consideration, the narrow, low-rolling resistance rubber makes sense.

With the roofline and sides of the car tapering distinctly towards the back, the rear view is suitably idiosyncratic, highlighted by flush-fit, vaguely U-shaped LED tail-lights. 

The hatch window is small, and the bumper sits high to marry with the load space floor sitting on top of the motor and transmission.

And when it comes to moving inside, BMW offers a choice of three ‘interior worlds - ‘Loft’, ‘Lodge’, and ‘Suite’ - featuring renewable natural fibres, recycled plastics, naturally tanned leather, and open-pore wood (sourced from 100 per cent Forest Stewardship Council-certified forestry).

But irrespective of where everything comes from, the end result is inviting, comfortable and sub-zero cool. Our car’s ‘Suite’ interior was combined with ‘Oak dark matt’ wood, and ‘Vernasca’ brown leather to stunning effect.

A tunnel-free floor, gently curved dash and digital screens for instruments and media let you know you’re in something different and special. It might be six years old, but the i3 still feels contemporary and distinctive. 

The internet exploded when it became clear the big kidney grille was for real. To be fair, BMW did itself absolutely no favours by ensuring the photos of the 4 Series made the twin grille look Easter Island statue sized. 

And it persisted in doing them naked, without number plates to break up the look. In the flesh, it all works, the nose is striking but not completely overblown. 

BMW coupe elegance reigns supreme in profile, however, with excellent proportions, and even in base form the wheels are the right size. The slim tail-lights and sculpted tail complete the look. It's a car I think most people love looking at. Hardly anyone mentioned the grille.

The cabin is excellent, as are all of the newer BMW interiors. It's not really a base model, given the price, but the mix of Alcantara and synthetic leather is very pleasing. 

The big screens for the media and instruments headline the cabin with high-tech style and while it's not avant-garde, it's sharp and feels premium, which is just as well.

Wide-opening clamshell doors make getting in and out of the i3s a breeze. But bear in mind you have to open the front door to get to the latch for the back one, which can be a pain.

The driver and front passenger enjoy heaps of room, in an open environment, but there’s only a single cupholder in the centre console, so let the coffee cup wars begin.

Aside from that there are seriously big bins in the front doors, a modest glove box, and a handy elasticised pocket near the floor at the base of the bulkhead.  

Outlets for 12-volt and USB are provided, and there’s a small oddments tray at the rear of the centre console.

Slip around to the rear and you’re in anything but limousine territory. Sitting behind the driver’s seat set for my 183cm height, head and legroom are modest but do-able. And remember it’s two seats only back there.

In terms of storage, there are two cupholders between the seats but no storage pockets or bottle holders in the doors. You won’t find adjustable ventilation outlets either, but that’s not a huge factor in car of this stature.

The boot’s volume is quoted at 260 litres with the 50/50 split-fold rear seatback upright, which is enough to easily swallow the largest 124-litre suitcase in the CarsGuide three-piece set. The smaller 95- and 36-litre cases will sit side-by-side without a problem.

Fold the rear seat down and you have 1100 litres of space at your disposal, with tie-down anchors, an elasticised pocket and 12-volt power provided.

Don’t bother looking for a spare of any description, a repair/inflator kit is your only option. And not surprisingly, the i3 is a no-tow zone. 

As a sports coupe, it's hardly a practical all-rounder but it's not a squishy 2+2 either. The rear seats are sculpted for maximum headroom and have the added bonus of holding onto rear passengers. 

Six footers won't be super-comfortable but it's bearable for short trips. There are two ISOFIX points back there, too. 

The front seats electrically fold out of the way for ingress and egress, but it's not an elegant process.

Front-seat passengers score two cupholders and bottle holders in the doors and a black hole for your phone and its wireless charging pad.

The boot takes an impressive 440 litres and the rear seats split and fold like good little soldiers.

The 420i starts at $71,900. That's a fair bit of money, I think you'll agree.

You get 19-inch wheels, a 10-speaker stereo, LED headlights with auto high beam, head-up display, power front seats, lighting package, auto-parking with reverse assistant, synthetic leather and Alcantara interior, 'Live Cockpit Professional' (fully digital dash), wireless phone charging and digital radio.

The massive 10.25-inch touchscreen may be smaller than the 12.3-inch digital dashboard, but it still looks huge. BMW's Operating System 7.0. is a cracking set-up, and you can control it via either touch or the 'iDrive' rotary dial on the console. It also has Apple CarPlay and Android Auto. Both of them, wireless. You don't read that every day.

You also get 'BMW ConnectedDrive', with some remote services that last for three years. The subscription includes things like the endearingly weird 'Caring Car' and the far less weird real-time traffic information.

The 4 Series is available in eight colours. 'Alpine White' is the only freebie while 'Black Sapphire', 'Arctic Race Blue', 'Portimao Blue', 'San Remo Green' and 'Mineral White' are $1538 each (or part of the 'Visibility Package'). 'Tanzanite Blue' and 'Dravit Grey' are a hefty $2962.

My car for the week had the $6300 Visibility Package (metallic paintwork, sunroof, BMW Laserlight, Ambient Light, which is worth it for the amazing Laserlights alone), the $2860 'Comfort Package' (lumbar support, electric boot, heated front seats, 'Comfort Access' with 'BMW Digital Key') and an $800 black pack. All this took the price to $81,860.

The i3s is powered by BMW’s ‘eDrive’ hybrid synchronous electric motor, producing 135kW at 7000rpm, and 270Nm from 0-4500rpm. Yep, that’s right, maximum torque is delivered the instant you depress the right-hand pedal, and we’ll get to what that brings to the driving experience a little later.

The unit incorporates a charging and generator function for braking energy recuperation, the latter delivering up to 50kW.

Drive goes to the rear wheels via a single-speed (fixed-ratio) automatic transmission.

The battery powering the whole show is a 352-volt/120 amp-hour (Ah) Lithium-ion unit with a (gross) energy rating of 42.2kWh.

The 420i’s 2.0-litre turbocharged four-cylinder, codenamed B48, spins up 135kW/300Nm. Driving the rear wheels through an eight-speed ZF automatic transmission, you'll go from zip to the 100km/h mark in 7.5 seconds, which is brisk, if not staggering.

When it comes to an electric car’s energy use and projected range, there are two main things to consider - the motor’s power consumption and the battery’s capacity.

And according to BMW, the i3s’s power consumption for the combined (urban/extra-urban) cycle is 14.6–14.0kWh/100km.

Over a week, and roughly 250km of urban driving (with some brief freeway runs thrown in) we saw 19.3kWh/100km staring back at us from the on-board computer.

When BMW launched the i3 in Australia in 2014, the pure EV version came with a 60Ah battery pack delivering a claimed 130 kilometre range (a range extender model featuring the addition of a two-cylinder petrol motorcycle engine was also offered). 

In 2016 a 94Ah version arrived to boost range up to 183km, and the i3s launched in 2018, with its 120Ah battery pushing range out to BMW’s current, real-world estimate of 260km.

Then, there’s charging time, which is like asking how long is an electric piece of string.

According to BMW, for a 0–80 per cent charge from a (50 kW DC) fast-charging station, you’re looking at 45min.

From a (11kW/16A/380V) high-output home/office wall unit, that pushes out to 3.10h, and using a (3.7kW/16A/240V) low-output home/office unit stretches the wait time to 9.40h.

BMW offers the ‘WallBox plus’ charging suite as a dealer accessory priced from $1990 (not including GST or install costs).

Plug into a domestic (2.4kW/10A/240V) socket, and you’re staring down the barrel of 15.00h. But at least you can use low-cost, off-peak energy overnight, right? Nah, I don’t buy that line either.

BMW's official combined-cycle figures seem to be slowly moving towards reality. The 420i's sticker figure of 6.4L/100km was met with an indicated 6.8L/100km, which was excellent going for almost exclusively suburban and urban running. 

It's a solid result, but being a BMW, it's premium unleaded only for its 59-litre tank.

With my generally unsympathetic (but not psychopathic) right foot, that means a real-world range of over 800km between fills.

It might not look like a conventional sports car, but the BMW i3s certainly accelerates like one, with a claimed 0-100km/h time of 6.9sec. The i3s is a smile-inducing hoot to drive.

Every one of this little hatch’s 270 newton metres of torque is available from the minute you hit the accelerator pedal, and remain in service until 4500rpm, at which point torque delivery drops off a cliff.

But peak power steps in at exactly 7000rpm, so if you’re determined to make that overtaking move you won’t be left in the lurch. In fact, BMW says it only takes the i3s 4.3 seconds to surge from 80km/h to 120km/h.

However, the i3’s forte is 100 per cent the city, rather than the open road. Its ‘point and squirt’ ability making it the perfect partner for the cut and thrust of the urban jungle.

The i3s features an upgraded ‘Sports Suspension’ incorporating firmer dampers, re-tuned springs and revised anti-roll bars. It’s also lowered 10mm, the track is widened (+21mm front / +2.0mm rear) and the wheels go plus one inch to 20-inch alloys.

The standard i3 (no longer offered in Australia) rolls on 19-inch rims shod with 155/70 rubber all around. And while the i3s’s 175/55 front and 190/50 rear tyres are still exceptionally narrow, from the side the low-profile Bridgestone Ecopias look like fan belts wrapped around pulleys rather than tyres around wheels..

No surprise then that ride comfort isn’t exactly cushy, and in signing on for the i3s experience you’ll need to be ready for more than occasional bumps and thumps.

But the pay-off is super-sharp dynamics, Suspension is by alloy struts at the front, and a five-link alloy set-up at the rear..The steering responds to inputs quickly yet smoothly, and with 48/52 front to rear weight distribution, the car always feels balanced, eager, and taut.

And if you really want to dial things up the ‘driving experience control’ allows a switch to Sport mode for a further tweak of the suspension, steering, and traction control set-ups.

A tight 10.3m turning circle makes for easy parking and stress-free U-turns. But if things get too tight, rapid three-point turns are assisted by the gear shift controller bring mounted on a chunky stalk on the right-hand side of the steering column. Too easy.   

Braking is by vented discs front and rear, but they’re tiny. That’s because the ‘Brake Energy Regeneration’ system does most of the work. 

Effectively turning the motor into a generator, the system not only slows the car dramatically but feeds energy to the battery in the process. It takes a while to get used to the sensation, but soon becomes a fun, and surprisingly easy game to use the brake pedal as little as possible… often not at all, for long periods.

One of the main things that sets a BMW sedan or sedan-based coupe apart is that they're good everywhere, except perhaps in quicksand. 

As the platform has matured and BMW's persistence with run-flat tyres has yielded improvements in tyre construction, the 3/4 Series platform (and many others - the internal name for the platform is CLAR) has once again become the benchmark for ride and handling.

For some people reading this, that's a lot of blah blah blah but the main point is, it's a terrific thing to drive whether you're dawdling along in traffic, dealing with traffic calming or bombing down your favourite deserted road.

The Bridgestone tyres on the 420i aren't as ultimately grippy and sticky as the alternative rubber on the 430i but they work well in town and are quiet on the 80km/h roads so prevalent in Sydney. 

The steering is absolutely lovely, providing just the right weight at any given speed and throwing in the road feel to inspire confidence.

Ride around town is compliant but with the whiff of fun if you decide to push things outside of the city. 

Its capabilities are still more than worthwhile day-to-day, however, because the way it handles the need to duck in and out of spaces in traffic is extremely handy.

The 2.0-litre four-cylinder is as smooth as rival Audi's. It doesn't sound like much (with a few vestigial pops in Sport mode) but it's certainly got the power to get you out of sticky situations and a transmission that's willing to play ball, whether in Sport or Normal.

Without the adaptive suspension of its 430i and M 440i brethren, this is a very smooth, easygoing sports coupe, with just enough sportiness to keep you interested, if you're that way inclined.

The 4 Series comes with six airbags, ABS, stability and traction controls, forward AEB, forward collision warning, lane-departure warning, reverse cross-traffic alert and reversing camera.

The 4 Series hasn't been tested by ANCAP or Euro NCAP and the 3's five-star rating can only be a guide because of the very different structure of the 4. 

Sports cars rarely fare well in the sometimes complex rules so carmakers tend to keep them away from the clutches of crash testers.

BMW offers a three year/unlimited km warranty, which is off the pace given the majority of mainstream brands have stepped up to five-year cover, with some at seven. And the pressure is on with Mercedes-Benz recently announcing its shift to five years/unlimited km.

That said, the BMW's body is warranted against rust (perforation) for 12 years/unlimited km, and roadside assistance is provided free-of-charge for three years/unlimited km.

Maintenance is 'condition based' with sensors and on-board algorithms (mileage, time since last service, driving style) determining whether an annual vehicle inspection is required.

The 'BMW Service Inclusive' package, offering a single, one-off advance payment to cover selected service and maintenance costs, is available in two levels - 'Basic' ($850) or 'Plus' (dealer quote)

BMW offers a ho-hum length of three years and 100,000km of warranty coverage. Mercedes has gone to five years so one wonders why BMW (and Audi) hasn't joined its German rival.

Servicing is entirely reasonable at $1650 for a five-year/80,000km package that covers the 12 month/16,000km servicing regime. 

At $330 per service, it includes things many carmakers don't, such as brake fluid and spark plugs. 

You can go full noise with the 'Plus Package', which costs $4500 and chucks in brake pads, rotors and even windscreen-wiper replacement. That doesn't seem like terribly good value to me unless you drive like a lunatic.