Single Motor vs Dual Motor BMW EVs: What's the Difference?

Photo by Eren Goldman on Unsplash

One of the easiest ways to get lost in BMW's electric range is to start comparing power figures. An i4 eDrive40 has one motor. An i4 M60 has two. The new iX3 comes as a single-motor 40 or a twin-motor 50 xDrive. Then there are different batteries, wheel sizes and equipment levels to consider. It can all look rather complicated on paper. The basic idea is actually quite simple. A single-motor BMW sends its power through one axle, while a dual-motor car has an electric motor at each end. In BMW's current range, that usually means rear-wheel drive for the single-motor cars and xDrive for the twin-motor versions. But the interesting bit is what BMW does with that extra motor.

One motor is plenty

A single-motor electric BMW isn't the stripped-back version that the name might suggest. Take the i4 eDrive40. It has a rear-mounted BMW electric motor and rear-wheel drive, but it is still a properly quick car. There is no waiting for the engine to build boost and no gearbox working through several ratios. Press the accelerator, and the response is immediate. There is also something familiar about the layout. BMW has spent decades building rear-wheel-drive cars, and the i4 keeps that basic philosophy even though its power comes from a battery rather than a petrol engine. The other advantage is weight. You aren't carrying another electric motor, inverter and associated hardware at the front of the car. That doesn't make a single-motor BMW slow. It simply means BMW hasn't added hardware that you may not actually need.

What changes when you add a second motor?

Quite a lot. Put an electric motor on the front axle as well, and BMW can drive all four wheels. There is no conventional propshaft running between the axles; the two motors are controlled electronically. That gives BMW a lot of freedom. The front motor can provide extra drive when the rear tyres are approaching their limit, and both motors can work together when maximum acceleration is required. The response is extremely quick, which is one reason electric xDrive cars can feel almost absurdly effortless when you put your foot down. The downside is less mysterious. The second motor weighs, takes up space and consumes energy. So you are not getting something for nothing.

The BMW i4 shows the difference particularly well

The i4 is a useful example because the basic car hasn't changed dramatically, but the drivetrain can. The eDrive35 and eDrive40 use a single rear motor. The M60 xDrive has two motors, one on each axle. The current M60 is a very different proposition from the eDrive40. BMW quotes 593bhp in Boost mode and a 0-62mph time of 3.7 seconds. That's serious performance by any standard, let alone for a practical four-door EV. 

But there is an interesting trade-off here. The M60's extra performance doesn't come free. It's heavier, and if you actually use all that power regularly, the range disappears rather more quickly than the brochure figures might suggest. Autocar's road test makes much the same point: the M60 is extremely quick, but the simpler i4 versions can feel more natural and engaging when you're not chasing outright acceleration. That's something worth remembering when buying an electric BMW. More motors and more power don't automatically make the car more enjoyable.

BMW iX3: single motor or dual motor?

The iX3 makes things slightly more confusing because the new car is very different from the original. The previous-generation iX3 used a single rear-mounted electric motor. The new-generation car gives buyers a choice. The BMW iX3 40 is rear-wheel drive and uses a single motor. The iX3 50 xDrive has a motor at each axle and four-wheel drive. The difference isn't just about acceleration. The 50 xDrive has a much larger battery and a substantial amount of power, while the 40 is positioned as the simpler entry point into the range. BMW has therefore used the single- and dual-motor versions to create genuinely different propositions rather than simply offering two power outputs of the same car. That is important if you're shopping for a used iX3. “BMW iX3” isn't enough information. Check the generation and exact version.

Does a second motor mean better range?

Not necessarily. In fact, you might expect the opposite, and in many cases you would be right. A second drive unit adds weight, and there is more hardware involved in moving the car. But this is where BMW's current EVs become interesting. The new iX3 50 xDrive has a much larger battery than the iX3 40, so you can't simply look at motor count and predict which one will travel further. BMW quotes up to around 500 miles for the 50 xDrive, while the newer 40 has an official range of around 395 miles in UK specification. The battery, motor efficiency, software, aerodynamics, wheels and tyres all matter. So if somebody tells you that a single-motor BMW always has more range than a dual-motor one, that's too simplistic.

Where dual motor really earns its keep

Traction is probably the most useful reason to have two motors if you're not interested in drag-race figures. Consider a wet roundabout or a greasy B-road. A rear-wheel-drive BMW has to put all its available drive through the rear tyres. A twin-motor car can bring the front axle into play as well. The electronics can make those adjustments extremely quickly. It's one of those things you might not notice during a normal drive. The car simply feels planted and gets on with it. And in poor weather, that can be more useful than another 100bhp on a specification sheet. It still doesn't mean xDrive makes tyres irrelevant. It doesn't. Good tyres remain fundamental to how any BMW behaves in the wet or cold.

So why would anyone choose the single motor?

Because you might not need the other one. If most of your driving consists of commuting, motorway journeys and normal use, a single-motor BMW already gives you plenty of performance. There is also something to be said for having less weight. The eDrive40 is a good example. It isn't an entry-level car in the traditional sense. It is a fast, refined BMW that happens to use one electric motor rather than two. And if you enjoy driving, the rear-wheel-drive layout can be more interesting than simply having four driven wheels and a huge power figure. That's why the choice isn't really about “better” and “worse”. It's about what you want the car to do.

What about winter driving?

This is probably the strongest argument for choosing a dual-motor in the UK. We don't get Scandinavian winters, but wet roads, standing water, frost and occasional snow are hardly unusual. A twin-motor BMW has an obvious advantage when the available grip is poor. The car has another axle it can use to put its power down. But don't make the mistake of buying xDrive and then fitting poor tyres. A single-motor BMW on a good set of appropriate tyres can be remarkably capable. Four-wheel drive helps you use available grip; it doesn't create grip where there isn't any.

What does this mean when buying a used BMW EV?

This is where the distinction becomes more important than it first appears. If you're looking at a used i4 or iX3, check the exact drivetrain before comparing cars. A single-motor and dual-motor BMW may share much of the same bodywork and interior, but underneath there are important differences. The motor, drive unit, cooling system and associated electrical components are not necessarily interchangeable. This also matters when buying replacement parts.

BMW breakers are increasingly dealing with electric models, so there is a growing supply of used genuine BMW electric parts from cars that have been dismantled. Body panels, lights, wheels, interior parts and trim can all be sensible candidates for the used market.

At MT Auto Parts, customers can provide their BMW registration or VIN so the vehicle specification can be checked before a part is supplied. That is particularly useful with newer BMWs, where the same model name can cover several drivetrain configurations. High-voltage components are a different matter. Battery packs, high-voltage cabling and electric drive units should be handled by appropriately qualified technicians rather than treated like an ordinary used BMW spare.

Single motor or dual motor BMW: which makes more sense?

For an everyday BMW EV, a single motor is more than enough for most drivers. You get strong acceleration, rear-wheel drive and, depending on the model, very competitive range. There is no need to carry a second motor simply because the specification sheet says you can.

The dual-motor cars have a different appeal. They bring xDrive, stronger traction and, usually, considerably more performance. The i4 demonstrates the difference particularly well. The eDrive40 is a quick and efficient electric BMW; the M60 turns the same basic idea into a 593bhp performance car. The new iX3 takes a similar approach, with the single-motor 40 sitting alongside the considerably more powerful 50 xDrive.

So when comparing BMW EVs, don't just ask how many motors they have. Look at the whole car. Battery size, motor output, drivetrain, weight, wheels, range and the way you actually intend to use the BMW all matter. Once you look at it that way, the single-motor versus dual-motor decision becomes considerably easier.

Disclaimer: This article is for general information only and is not a substitute for professional automotive advice. BMW specifications can vary by model year, market, equipment and individual vehicle. Always check the exact VIN and vehicle specification before purchasing a BMW or ordering replacement parts. High-voltage systems and components should only be inspected, diagnosed or repaired by suitably qualified professionals. MT Auto Parts is an independent BMW parts specialist and is not affiliated with BMW AG.