BMW’s touring boxer gets even better.

By Bruno dePrato, cycleworld.com

When it appeared in 1976, the BMW R100RT model was the relaxed sister of the elegant and much sleeker R100RS. The R100RT was a fully dressed touring bike and featured a protective fairing derived from that of the R100RS, built fatter and fitted with a large straight-up windshield. The R100RS faded away by 1984, but the R100RT held on, as it was highly functional and fulfilled the needs of a good percentage of motorcyclists.

When the new 1996 R1100 boxer twin replaced the last of the classics, the /7, the R1100RT was the flagship of the R1100 models range. It offered the same comfort and weather protection that made the original R100RT a success, but with a much more aerodynamic shape that bridged the designs of the previous RT and the R100RS. The RT model evolved steadily from there until the latest GS models took over the role of company flagship, but its unmatched efficiency and wonderful road manners meant it never faded into the background.

The 2018 adoption of the 136 hp, 1,250cc, DOHC, four-valve boxer gave new credibility to the RT’s performance potential. Now BMW Motorrad has further enhanced the model’s appeal, offering an attractive 2021 edition with state-of-the-art technological advances. The new R 1250 RT is an absolute technological wonder, perhaps the most advanced motorcycle in the touring domain, and most importantly, it’s extremely easy to use.

The R 1250 RT is equipped with two electronics suites, one to manage the bike’s dynamic functions and one managing the sophisticated engine. The two are fully interconnected, but I still rate them as two separate units given the multitude of functions they perform, both independently and cooperatively. The dynamic function suite is based on the latest Bosch six-axis inertial platform, the most advanced unit available, dedicated to ensuring safety and comfort levels never before offered.

The evolution of the antilock brakes provides a good example. With the new Full Integral ABS Pro system, the rider can activate the entire braking system with either the right-hand lever or the pedal. Both dual 320mm front rotors and their Hayes four-piston calipers and the rear 276mm rotor and two-piston floating caliper apply braking force from rider input, but also take into account the lean angle of the bike (cornering ABS) to automatically calibrate the amount of decelerative force applied to each wheel, calculating weight transfer in consequence of the braking force applied. This global ability to modulate the brakes frees the rider from the additional stress of worrying about lock-up or running wide.

The renewed Dynamic Traction Control is further improved to ensure maximum control under all riding conditions. Dynamic Traction Control includes hill start control and can be integrated with the addition of the optional Riding Modes Pro, which offers four riding modes including Dynamic mode for a more spirited riding style and engine drag torque control under deceleration. There is also Eco mode, conceived to optimize fuel consumption when riding on open roads or highways.

The new Dynamic Cruise Control is standard equipment and acts not only on the throttle but also on the braking system in order to ensure that a selected speed will not be exceeded going downhill. Active Cruise Control, available as an option, offers the ability to modulate the R 1250 RT’s speed in relation to that of the preceding vehicle to maintain a constant following distance as selected by the rider. This is achieved by a forward-looking radar that talks to the engine ECU. A set of dedicated cruise-control switches is located on the left grip, and an icon indicating the precise following distance appears on the bike’s 10.25-inch TFT display. This screen also gives access to the connectivity apps, the navigation system, various assistance and safety apps, and bike management electronics.

The new TFT display ensures perfect readability in all lighting conditions and integrates navigation as well as smartphone connectivity, allowing the phone to be stored in a separate compartment where its battery can be recharged by an inductive system or by a USB connection. The massive electronics suite includes an optional audio system and adaptive LED headlights.

The latest edition of BMW’s boxer twin has achieved Euro 5 homologation thanks to a highly advanced ECU allowing the motor to maintain the previous model’s 136 hp at 7,750 rpm and 105 pound-feet of peak torque at 6,250 rpm while still reducing emissions. That torque number is impressive, approaching the 100 pound-feet per liter mark, and the torque curve as a whole is generous from 2,000 rpm on, with 88.5 pound-feet available at just 3,500 rpm.

This motor retains the same bore and stroke measurements of its forbear, 102.5mm and 76mm respectively, and runs at a 12.5:1 compression ratio. The combustion chamber features an extremely compact profile with valves set at 18-degree included angle, 8 degrees for the intake valves, and 10 degrees for the exhaust. Valve diameters are 40mm for the intake and 34mm for the exhaust. Each cylinder breathes through 52mm throttle bodies equipped with twin injectors.

The BMW technical team continues to evolve their legendary boxer twin to meet modern levels of sophistication. A variable timing and lift valve train modulates these two fundamental factors to adjust the engine response in relation to the demand of power and torque. Meanwhile, combustion is rigorously optimized to control emissions under all riding conditions. This highly complex process features the mechanical ability to shift from moderate to high-lift cam lobes and to reconfigure the camshafts in order to vary cam overlap. The valve train operates via finger-type cam followers. In addition, the inlet valves follow asynchronous opening timings in order to induce a high swirl turbulence and induce optimal combustion of the intake charge.

The combination of clean emissions and abundant power characteristics starts with the valve train, but an advanced sequential injection system and a large-capacity catalytic converter finish the job. The fundamental digital management functions are performed by a BMS-O ECU. The final touch of efficiency comes via the air/liquid-cooling system, which concentrates cooling fluid in the cylinder heads and the upper sections of the cylinders, where it brings the most benefits.

The chassis structure centers on the massive engine block, which is employed as a stressed member with bolted frame elements front and rear. The fully adjustable ESA suspension units use a front Telelever and rear paralever unit, with fully electronically managed Dynamic ESA “Next Generation” available as option. The chassis spans a relatively short 58.5-inch wheelbase. Steering geometry is set at 25.9 degrees of rake (though with the Telelever suspension that varies with the wheel travel) and 4.6 inches of trail. The R 1250 RT rolls on 120/70-17 front and 180/55-17 rear radials, and the standard seat is set at 32.5 inches above the ground, though its position can be lowered to 31.7 inches. BMW claims a curb weight of 615 pounds, but weight distribution front to rear has not been disclosed.

The profile of the new R 1250 RT is elegant, almost sleek, particularly in the brilliant metallic blue Sport version, but the front view shows a massive frontal area. This is fairly logical, given the bike’s mission of delivering maximum high-speed comfort in any weather. Wind tunnel research was used to develop airflow that diverts turbulence away from the rider, and the windshield is adjustable to prevent buffeting on the rider’s shoulders and helmet. On the highway section of our test, the R 1250 RT delivered incredible and almost total aerodynamic comfort at 100 mph on the Italian autobahn. In case of riding in low temperatures, heated grips and seats can be employed.

The engine is simply superb, with instant meaty throttle response at any speed, with supreme engine torque delivery assisting magnificently in both city and backroad duty. A balance shaft kills all vibrations coming from the boxer twin’s offset cylinders. Speaking of throttle response, I started the ride in Road mode which makes the throttle less direct and not as impressive. But switch to Dynamic mode and the engine’s response is connected and direct—as if the engine is connected to your wrist. Spot-on. Period.

The steering is firm, precise, and stable even past the 120 mph mark on smoother and flowing roads. Off the highway, the R 1250 RT remained smooth and agile in medium to fast sweepers, with a front wheel that feels light but solidly in contact with the ground, allowing easy and instinctive control. On narrow and twisting Apennines mountain roads, badly deformed by roots growing underneath the surface of the road, the R 1250 RT was not as impressive, feeling top-heavy and less composed, with a bit of unpredictability.

The R 1250 RT offers extra security at night with a powerful LED headlight system, even in standard, nonadaptive trim. But upgrade to the adaptive headlight system and it’s simply terrific with the ability to project a powerful volume of light on the inside of a curve without disturbing the drivers of oncoming vehicles.

The 2021 BMW R 1250 RT has been painstakingly conceived, designed, and honed to offer a satisfying ride on almost any road. Its engine is a superb piece of engineering that connects a pleasing traditional design with contemporary technology. And does it all with supreme class and composure. A proper continuation of the RT’s touring excellence.

2021 BMW R 1250 RT Specifications

MSRP:	$20,190
Engine:	1,254cc, DOHC, air/liquid-cooled flat twin w/ BMW ShiftCam
Bore x Stroke:	102.5 x 76.0mm
Transmission/Final Drive:	6-speed/shaft
Claimed Horsepower:	136 hp @ 7,750 rpm
Claimed Torque:	105 lb.-ft. @ 6,250 rpm
Fuel System:	EFI w/ ride-by-wire
Clutch:	Wet, multiplate; hydraulic actuation
Frame:	Two-section w/ load-bearing engine
Front Suspension:	37mm BMW Telelever, central spring strut; 4.7 in. travel
Rear Suspension:	BMW paralever, WAD strut, spring preload, rebound damping adjustable; 5.4 in. travel
Front Brakes:	4-piston fixed calipers, 320mm floating discs w/ BMW Motorrad Integral ABS
Rear Brake:	2-piston floating caliper, 276mm disc w/ BMW Motorrad Integral ABS
Wheels, Front/Rear:	Cast aluminum; 17 x 3.50 in. / 17 x 5.50 in.
Tires, Front/Rear:	120/70ZR-17 / 180/55ZR-17
Rake/Trail:	25.9°/4.6 in.
Wheelbase:	58.5 in.
Seat Height:	31.7/32.5 in.
Fuel Capacity:	6.6 gal.
Claimed Curb Weight:	615 lb.
Contact:	bmwmotorcycles.com