In-Depth: BMW's R18 Concept Bike

BMW shocked the world when they unveiled the R18 concept recently – a softail cruiser with the largest capacity motorcycle engine the Bavarians have ever built – because it was nothing like any bike they’ve produced in recent memory. But the idea has been brewing in the background for quite some time.

"You know we’ve always had the idea of entering the American cruiser segment," Karl Victor Schaller, Head of Engineering at BMW Motorrad, told MCN. "So the questions were ‘can we do it with the existing 1200 engine [from the R nineT]?’ and ‘what is the possibility to extend that engine?’ because there’s always a little bit of headroom in each engine."

Following investigation BMW realised they could perhaps take the engine out to a 1350 but, to compete with the big twins from Harley-Davidson and Indian, they knew they needed more.

"Then we thought well maybe we do a little like in the past like the very old concept R5 with a supercharger," Schaller added. "So we said maybe a 1350 with a compressor would fit and the marketing guys said ‘that’s much better’ but it’s still not an 1800.

"Half the volume for a bike like this is in the States and they’re not talking about horsepower, they are talking about cubic inches. After we settled on 1800 we decided we need to do a whole new engine. You might think it’s not complicated because we have lots of boxer engine history but designing a boxer engine of that displacement is not very easy."

The R18 also presented a production departure from the brand that normally takes an engine-first approach to design – they are called Bavarian Motor Works after all.

"Normally engineering takes the lead and creates a new set-up for the GS," said Schaller. "In this case the designers took the lead and we tried to fit the technology into the design idea. In this segment it’s all about styling – no one cares about power. We started with the looks and tried to make engineering parts fit. The real bike you will see is not very far away from the concept."

Even so, the engineers didn’t have an easy time of it, especially with the new Euro5 rules waiting around the corner which stipulate the mechanical noise of the engine.

"We don’t have Euro5B, so the noise we can still control. We are expecting about a 2dBreduction which can be done with an engine like this, but if it’s more we’ll have completely different motorbikes. It’s not only the big ones – every bike would be affected. If we see 5, 6 or more dB reduction in engine noise, it would change motorbikes completely as you would not have any open engines any more."

Although performance details  about the new engine are still thin on the ground, we do know it’s an air-cooled 1800cc boxer twin - not words that the chaps in white coats who draft emissions rules like to hear. Mercifully, BMW have come up with a solution that will see air-cooled engines sticking around for a little bit longer yet.

"The injector nozzles will move to the cylinder head, so they are no longer in the throttle butterfly body," revealed Schaller. "It’s still a port injection but it’s a completely different position. You’ll see this on all the models, we’ll move the injector nozzle closer to the valves."

The other issue is the sheer size of the pistons. Such a large capacity twin creates issues with the pressure and movement of engine oil in the crankcases.

"Oil control and oil foam control is not easy but we have a lot of experience with that, so we know what to do. This is maybe the biggest challenge on the engine."

BMW have already announced that a range of bikes with the new engine will be revealed later in the year and we’re expecting at least two distinct models – a softail and a full size bagger. As for the prices? We’d expect them to hover a few thousand each side of £20,000.

BMW have unveiled an all-new, stylish classic cruiser that looks set to take on Harley-Davidson in the near future. The R18 concept bike is a radical machine and shows that BMW are keen to woo cruiser and custom bike buyers.

Stripped down and raked out, the Concept R18 is not only a statement of BMW’s intentions, but also what their designers and engineers are capable of. From the total lack of switchgear, to the fishtail exhausts every single detail of the bike has been meticulously considered.

"This bike is not about being the fastest," says Edgar Heinrich, BMW Motorrad Head of Design. "This bike is about making an analogue statement in a digital age. BMW has a rich history of iconic motorcycles and they bear the same design characteristics. We believe that this can still work well today, together with current technology.

This isn’t the first time we’ve seen the R18 engine – BMW gave one to Custom Works Zon and another to Revival Cycles to get their take on it – but it’s the first time we’ve seen anything from the mothership.

BMW say that this bike is a tribute to the original 1936 R5 (below) and more recent R5 Concepts, but with a bit more meat in the engine department. The 21in (front) and 18in (rear) wheels give it a classic stance and the much-loved leaf-shaped saddle looks like it’s come straight of a 1950s Beemer.

The rest of the bike is dripping with stylish touches such as polished head covers, subtle shading and the teardrop tank. Even the pinstriping and Metzeler Rille tyres give it that cool custom vibe. Then there’s the completely open shaft drive, cantilever suspension, open carbs and a tiny LED light nestled between the fork legs. Even if you don’t like the style, you can appreciate the workmanship.

BMW have admitted that they are planning a whole range of cruisers later this year. Until now BMW’s heritage range has made do with engines from existing models, so to create a whole new engine platform for one bike seems unlikely.

We’ve already seen spy pics of a big bagger but it’s possible BMW will also present smaller, stripped-back bikes to compete with Harley-Davidson’s ever-popular Softail range as well as the likes of the Triumph Bobber.

BMW have said they will unveil the production bikes later this year, most likely at the EICMA motorcycle show in November but if this tantalising taste of what’s to come bears any resemblance to the finished articles, we’re going to be in for a treat...

https://www.motorcyclenews.com/news/new-bikes/bmw-concept-r18/