Slipper Clutch
The S1000RR clutch only allows power to go from the engine to the gearbox. When the throttle is shut, the bike pushes against the engine braking produced by the motor, the clutch slips and absorbs some of the energy coming from the rear wheel. This slippage is mechanical on the S1000RR, so that this slippage effort is set to work well at higher rpm, i.e. when engine braking (erroneously referred to as “Compression” is at a maximum.
A slipper clutch also contributes greatly to rider safety on the street, by preventing rear wheel lockup from engine braking when the rear wheel goes over a slippery surface, such as oil, sand or standing water.
Shift Assist
When the rider’s boot moves the shift lever a few millimetres as part of an upshift, fuel and ignition are cut ease the engagement of the gears (Actually dog clutches). This means full throttle gear upshifts and no significant interruption in acceleration.
Downshifts still require the use of the clutch, and blipping the throttle to ease the life of the slipper clutch and help it prevent blocking or skipping of the rear wheel from engine braking.
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You can see the cover of the swingarm pivot axle, which can be raised or lowered to compensate for changes in ride height and to optimize weight transfer on corner exits. |
How it all works together
The four Mode setting allow a rider to select a set of variables according to riding conditions, preferences and skill level (aka bravery).
Mode |
Power/ Throttle Response
|
DTC/ABS
Settings |
Power Freeze
Lean Angle
|
Wheelie Control |
Rain |
153 hp, 5%
throttle
dampening |
High DTC
intervention
Anti rear wheel lift ABS |
38º |
5 sec before throttle is reduced |
Sport |
193hp, 5%
throttle
dampening |
Medium DTC
Anti rear wheel lift ABS |
45º |
5 sec before throttle is reduced |
Race |
193hp, no
throttle
dampening |
Light DTC |
48º |
None |
Slick
|
193hp, no
throttle
dampening |
Very Light or no DTC |
53º |
None |
The ABS and DTC can be disabled independently by the rider at any time.
The various limits in angles, dampening and other variable were arrived at during exhaustive testing, and worked well when I rode the bike.
BMW can always reset some of these values over time, as knowledge about the bike and how it works grows with the number of bikes on the road or track.
Computational Fluid Dynamics (CFD) simulation
Every major manufacturer and race teams in F1, NASCAR and Endurance racing use CFD simulation to accelerate the development and optimisation of the vehicles.
In the case of the S1000RR, BMW used CFD to optimise the circulation of water, oil, air and fuel in the engine, as well as the air around the fairing. In this last example, CFD helped with the evacuation of heat, protection from the elements, and reduction of turbulence.
Photo Credit : Kevin Wing/BMW