BIG BOXER FOR ON SALE SEPT BIG SPENDERS
BMW finally unveil the R18 and it’s a right good looker (but you’ll need to save up)
It’s been a long time coming but BMW have finally revealed the finished R18 and it’s really quite something. Taking visual cues from the classic R5 and tech cues from the school of ‘no replacement for displacement’, BMW have officially planted their flag into Harley-Davidson’s territory. The R18 is powered by a 1802cc air-cooled boxer twin, which is not only the largest and heaviest we have seen from the firm, but it also produces the most torque: a huge 116.5ftlb. More impressive still is that 110ft of go is available from just 2000rpm – why did they even bother with gears? But gears it has (six of them naturally) plus there’s an optional reverse, although that runs from the starter motor. This whopper is housed in a steel cradle chassis, akin to the classic machines, with a cantilevered softail rear-end. That means it looks like it has no suspension, but there’s 90mm of bounce at the back. The real pièce de résistance is the exposed, polished steel driveshaft that disappears into the fixed bevel box. Gorgeous! Despite its retro looks there’s plenty of modern tech hidden inside the big beast including switchable riding modes (Rain, Rock and Roll – don’t ask…), traction control, cruise control, hill hold control, drag-torque control for downshifts, ride-bywire throttle, keyless ignition, cornering lights and combinedABS. You can even spec heated grips and they definitely didn’t have those in the 1930s.
If the style of the machine isn’t quite for you, there will be plenty of accessories available at launch from various well-known brands such as Roland Sands Design and Vance & Hines. There’s an array of seats for the fussy bottomed and different handlebars for the Easy Riders – cleverly BMW have made the brake lines and wiring plug and play, so swapping a bar doesn’t turn into a £1000 workshop nightmare. The only downside to all this cleverness is that the bike weighs 345kg ready to roll, which is monstrous considering an equivalent Harley is a good 30kg less.
To begin with there are two models: a standard version plus the fancy First Edition, which is covered in chrome accessories and comes with a box full of ‘cool dad’ things including a trucker cap and a leather belt. It’s not confirmed if we’ll get the standard model just yet but we will get the FE, which will be a substantial £18,995 when it arrives in September. And you thought Harleys were expensive.
P‘Like BMW’s mid-1930s R51 it has twin cams’
oke around a classic bike engine, or HarleyDavidson, and you’ll spot tubes up the side of the cylinder from the crankcase to the cylinder head. These contain pushrods, the valve-operating tech common before the world went overhead-cam (OHC). A camshaft is carried in the cases, driven by the crank.
Its lobes move the pushrods – literally, rods that are pushed – which transfer movement to rockers in the head to open the inlet and exhaust valves, generally in an overhead valve (OHV) layout. The layout has advantages: the camshaft drive is short because the cam is next to the crank, which is good for timing accuracy; not having cams and cam-drive sprockets keeps the head narrow and low; and it’s lighter than a double overhead-cam (DOHC) engine. The layout suffers with valvetrain inertia, however. There’s lots of flailing metal to try to keep hold of and this can cause valve float, where the valve isn’t fully controlled by the return spring and doesn’t seat and seal correctly. The inertia also limits how fast an engine can rev before controlling the valvegear becomes an issue (most pushrod designs are also two valves per cylinder, so can’t flow enough air for high revs anyway). And there can be issues with pushrods expanding with heat and deflecting under load, so not giving the expected movement. Moving the cam into the head above the valves (OHC) and driving it by chain or belt makes an engine taller, but inertia is reduced and the improved control at speed allows more revs. It also allows two cams (DOHC) and four valves per cylinder. Power is essentially torque x revs, and we all love power, so it’s the default layout. Yet BMW’s new R18 (see page 5) uses pushrods as it’s the most authentic system for an aircooled motor inspired by black and white times. At 1802cc the ‘Big Boxer’ is huge and has so much torque that a restricted rev range isn’t a problem. It’s the trick Harley have used for decades – and the BMW has more grunt (and at lower revs) than H-D’s Milwaukee Eight V-twin. And BMW’s pushrod system isn’t conventional. Like the mid-1930s R51 it has twin cams, located left and right above the crank. This allows shorter pushrods, reducing mass and inertia, and limiting expansion and deflection. This means better valve control, good for emissions as well as torque and smooth running. The R18 also has four valves per cylinder, controlled by forked rockers, to give the flow required for the massive torque. Screw and locknut adjustment, too. Servicing will be a doddle.