New BWM S1000RR has a new effort to transcend Japanese inline 4 super sports. While BMW made the first model appear 10 years ago and also participating in the Superbike World Championship, I believe that this new model is the conclusion that BMW has studied the advantages and disadvantages of existing inline 4 machines and derived it.
It is innovative and innovative in that sense, before the specification of maximum output 207ps with a weight of 197kg.
In this article, let's focus on three of its technical policies.
Part 1, Frame that broke the existing common sense
For a period of time, the frame has increased handling performance by increasing the rigidity. But, I think that it is the theme how to supple today. When the rigidity of the frame is supple, it is crowded, it increases tolerance, and the degree of bending is also a source of information from the machine.
However, if the bending method is bad, it induces various problems including stability. One way to remedy that problem is to place the twisting center of the frame on the center connecting the head pipe and the pivot. It is because the core is unlikely to shake. Therefore, recent trend is to use the engine as a rigid member, weaken the frame itself.
As with the old twin tube type, if it depends on rigidity of the main tube with high rigidity, it twists around the main tube and the twist center becomes high position. Then, even if it is twisted by the same amount, the movement amount of the grounding point becomes large, which makes it easy to cause problems.
The frame of S1000RR is named Flex Frame, and it is truly delicate. Besides that, this frame seems to deviate from common sense of frame design.
Please imagine how the frame bends by breaking into the corner. The frame receives vertical bending in the direction to shorten the wheel base with brake force. Then, although the main member bent in the "L" shape resists bending, it can not withstand bending, but it may repeat the turning point of the inflection point in the left-right direction.
However, with this flex frame, the engine firmly presses on so that it does not become like that. That's why, the engine is mounted tightly at two points in front (usealy this is only one point) and at the back two points.
In other words, it can be expected that the amount of information due to the bending of the frame is sufficiently rich and, furthermore, it has rigidity and will not shake.
Part 2, Rear suspension that sufficiently communicates grounding feeling
The rear suspension is a link system similar to "full floater" developed by Suzuki more than 30 years ago and is named Full Floater · Pro · Kinematics.
It is said that the rear suspension feels the input from the rear shock transmitted to the rider as a sense of grounding. In that sense, Honda's unit pro link which receives the rear shock at the swing arm, and the Kawasaki system which puts the unit diagonally can also be viewed as inappropriate.
However, if the S1000RR method pushes the upper end of the shock with the bell crank and supports the lower end with the swing arm, the force from the shock and the force from the push rod both act on the bell crank support point and we are strong You can expect a sense of grounding. Moreover, since there is no lateral force applied to the rod support point and the pivot like a general bottom link type, it makes the contact feeling clearer.
Part 3, A variable valve system that realizes a trapezoidal torque curve
I think the ideal torque curve for super high performance model is a trapezoidal graph. It is because torque is linearly raised toward the peak area, acceleration increases with a certain degree, it is easy to grasp the traction, acceleration becomes constant in the peak area, and it becomes easy to make full use of the power.
The S1000RR is adopted a variable valve system and realizes rich low and medium speed torque and trapezoidal characteristics of the peak area. After all, the wide range of 6000 to 14000 rpm is a flat area covered with torque of more than 90% of the peak, so in that respect too, it transcends existing engines.
I am excited about expectation while writing this column on the day before going to Europe to travel to the test ride of S1000RR. Let's tell the opportunity to see how this actually did.
