BMW’s GS series gets serious
A couple of years ago Editorial Poobah Ken Hutchison and myself took an interesting road trip from SoCal up to Sonoma on a BMW R1150GS and a Triumph Tiger. We both knew riders who swore by their BMW GSs but we remained skeptical of what seemed to be an awkward compromise between a streetbike and a dirt bike.
Well, between pounding out highway miles, scratching in the canyons, rolling down two-track and tearing up Infineon Raceway, we gained a new appreciation for what an adventure-tourer can do for its rider. Still, it took just one arduous attempt to pick up the GS from a front-end washout on Pismo Beach to remind us that the GS is no XR.
But now, 25 years after the first GS hit the showrooms, BMW has redefined the definitive adventure-tourer with its 2005 R1200GS. We spent two full days playing in the hills around Las Vegas, much of it off-road, putting it to the test, and we came away with a new appreciation of what a well-engineered adventure-tourer is capable of.
Riders of BMW GS-series motorcycles are among the most devout in motorcycledom, exhibiting a fervor of enthusiasm for their mounts by literally looking down on other bikes as they rack up tens of thousands of miles, unconstrained by the boundaries of pavement. Odd and distinct in character, BMW’s GS (gelande/strasse or off-road/street) became a cult bike with a dedicated following.
The original, air-cooled, two-valve GS first debuted in 1980 as the 800cc R80GS, the first multi-cylinder enduro bike in production. The bike was simple, rugged, easy to work on and, with shaft-drive, didn’t require much maintenance. Rally ace Hubert Auriol won the Paris-Dakar rally twice on the R80, then the diminutive Gaston Rahier took a 1000cc version to two straight wins in 1984-85. A production version, the R100GS, followed in 1988 and continued in production until 1995.
One year prior, in 1994, BMW offered up its 4-valve “oilhead” R1100GS, a more powerful but larger and heavier enduro. GS purists hung on to their more off-road-capable two-valve bikes while the new 1100s began to build a loyal following of its own. The GS was revamped in 1999 as the R1150GS, and the off-road-oriented Adventure model came out in 2002.
Even though dual-purpose bikes have just a 3.2% share of the U.S. motorcycle market, the GS is hugely popular in BMW’s scale of production. BMW has sold more than 156,000 GSs since 1993, amounting to some serious coin for the German manufacturer. At, let’s say, $12K each, GS sales have rewarded BMW with revenues of nearly $2 billion!
Paying for these uber-tourers takes some deep pockets, so it’s no surprise to learn that the average GS owner is a male (98%) about 47 years-old with a household income of nearly $100K. Research shows that GS pilots clock up many more miles than the average rider and back it up with 28 years of riding experience. We knew this group was bright when we found out that they are internet savvy, with 90% dialing in to cyberspace on a regular basis (hello!). While BMW is happy appealing to rich older dudes, it also hopes the new GS will appeal to well-off younger riders, too.
Of course, at $15,100, the GS will suffer no paupers. However, those with the means to purchase Bee-Em’s biggest dirt bike are gonna be happy. So, too, will devoted GS fans, as the R1200GS combines the power (and then some) of the newer bike with the lightness of the original one. Comparative figures would have sportbike riders drooling in anticipation, as BMW claims the new engine cranks out nearly 18% more power and the big trailie’s weight has been reduced an incredible 66 pounds.
Part of the weight savings is attributed to the new Boxer motor that is claimed to be 8% lighter. Its crankshaft is shorter, for extra strength, which yields a weight reduction of 2.2 pounds (9%), and the crankcase uses new casting technology to optimize wall thickness, reducing weight by a further 3.1 pounds. Lighter pistons are of the same bore as last year, but they run an extra 2.5mm inside the cylinders to yield a displacement increase from 1130cc to 1170 cc.
BMW first used two plugs per cylinder in its 2004 Boxers, but already there’s an improvement in its design. The dual plugs now have revised locations for better efficiency, plus they can now fire independently by changing their relative timing. This process, called phase shift, works best at partial throttle openings to provide better response and greater fuel economy, the latter up a claimed 8%.
Getting instruction from off-road rally ace Jimmy Lewis: For the first time in 38 years, someone other than his mom told Duke to keep his wheelies low.
BMW has fitted an electronic knock sensor to the new GS, which allows the compression ratio to be boosted from 10.3:1 to a lofty 11.5:1. This sensor sends signals to the ECU when knock is detected, and the smarter new electronic brain retards the ignition timing to ward off the detrimental pre-ignition, no matter what grade of fuel is used. Of course, max performance can only be had by burning premium fuel. Separate oxygen sensors for each cylinder ensure the proper mixture gets burned before going back to the catalytic converter located in a pre-silencer below the transmission.
Some innovative valve technology has helped make the GS’s motor more robust in its power production. The intake and exhaust valves, still actuated by a chain-driven single camshaft located low inside each cylinder head, are 2mm larger for better breathing, and the exhaust valves employ a racing trick by being sodium-filled for improved heat dispersion.
Staying with the topic of valves, the GS marks BMW’s introduction of an exhaust valve in the muffler, much like the original Yamaha EXUP valve and other similar sportbike systems. The pressure-controlled valve stays closed at low to medium engine speeds for optimal backpressure and to deliver a quiet exhaust note. At higher engine speeds, the valve opens up to let the engine breathe easier, providing a fairly healthy exhaust bark for a Beemer. The stainless steel exhaust system weighs in at a reasonable 23.6 pounds, claimed to be 33% lighter than previous.
But the big news out of the BMW camp is the fitment of a balance shaft, a first for the Boxer engine. A flat- or opposed-Twin like BMW’s Boxer motor has perfect primary balance, much like a 90-degree V-Twin. But secondary forces from the engine’s rotational mass, called a rocking couple, causes unwanted vibration the creep through to the rider. BMW’s use of a counterbalancer reduces this effect, making for increased comfort for the rider and less stresses on reciprocating engine components, also allowing for a higher redline.
It all adds up to 100 horsepower at 7250 rpm and 85 lb-ft of torque at 5500 revs, according to BMW. That’s a significant bump in power from the R1150; it was rated at 85 hp and 71 lb-ft. BMW’s single-plate dry clutch has been enlarged to handle the greater power of the new engine.
Out on the road, the newfound power is immediately apparent. The Boxer pulls in a manner a significant step above the old bike, aided by the weight reduction that approximately equates to the ballast of an eight-year-old kid. While the motor doesn’t pull like a Ducati 999, there is an urgency to its acceleration that is unknown from any previous Boxer motor. We’re betting about 90 hp makes its way to the back wheel on a dyno.
Just as impressive as the newfound top end is the civility and perfect user-friendly throttle response from the new motor. The GS can be lugged way down to revs barely above triple digits and still pull smartly away at. This is simply one of the most flexible engines on two wheels, making a flat power curve that gives the rider accessible power at all engine speeds.
The motor’s endless powerband results in less shifting required, but you’ll want to play with the GS’s new six-speed transmission anyway. It now uses helical-cut transmission gears that reduce the gear noise endemic in past BMW Boxers while providing gear changes smoother than ever. And the too-tall sixth gear on the previous bike that was widely derided has now been lowered to be more naturally spaced with fifth gear. Top-gear acceleration is no longer doggy, and I never missed a shift during two full days of riding.
Owners of current GSs will be surprised when straddling the revised GS for the first time, as it is now much skinnier between the knees. The actual fuel tank extends far lower than its shell would lead you to believe, ending up just above the Boxer’s cylinders. This not only gives a rider more room to maneuver, it also has the beneficial effect of lowering the bike’s center of gravity, especially when the tank is filled. It also allows space for the larger airbox.
While BMW must be commended for making the new GS narrower, it comes at a price. At just 5.2 gallons, the tank is far from Paris-Dakar-worthy. I saw just 123 miles on the tripmeter on my first tankfull before the GS switched to its 1.0-gallon reserve. BMW optimistically claims a 210-mile range, but it would take a careful throttle hand to eke out that kind of mileage.
The GS’s new instrument panel includes a trip computer that, in addition to the typical oil temperature, fuel gauge, clock and gear position, also includes a handy display for estimated miles remaining under current riding conditions once the fuel level switches to its reserve position. It may, however, not be entirely accurate: Twice during my time aboard the display told me I was on reserve, only to be switched back to the overall tank level after several minutes.
On the other hand, we’re happy to report the GS has finally been given its second tripmeter, a virtual must on any machine called an adventure-tourer. The GS’s distinctive asymmetrical ovoid headlights are matched in the cockpit by similarly shaped analog dials for speed and revs. The key is equipped with an electronic immobilizer that prevents the ignition from operating without the proper key inserted.
The changes to the rider interface don’t stop there. BMW has switched from its familiar thick handgrips to ones with far less padding for a more direct feel from the handlebar, figuring the extra isolation provided by the old grips wasn’t needed with the new counterbalanced engine. But the new engine, with its slugs running up and down 2.5mm further, still emits noticeable vibration. I wasn’t the only rider who suffered a numb throttle hand after a long freeway stint, so those who don’t venture far off road might be tempted to fit a pair of the old grips.
The handlebar bend of the GS proves to be well chosen, offering a steady perch whether sitting (street) or standing (off road). Instead of lightweight aluminum as on pure motocross bikes, the handlebar is made of thin-wall steel. BMW says the slight weight penalty is worth the extra strength during a tip-over, offering better resistance to bending and easier roadside repairs.
The seat, now with a grippy cover, proved to be an excellent balance of comfort and support. The standard seat has two available positions, 33.1 inches and 33.8, both of them quite tall for dwarfs like me; my 32-inch inseam was able to tip-toe both feet at a stop when in the lower setting. BMW also offers two optional seats, one being 1.2 inches taller and one being 1.2 inches shorter, giving the GS an available span from an almost-low 31.9 inches to an inseam-stretching 35.0.