Drivetrain

The train takes the rotational mechanical energy from the engine and transfers it to the wheels.

Outline:

• Gearing
  • gearbox, on bikes is internal but doest need to be discussed there
  • cvt
  • design of ratios
  • shifter
• Final Drive (chain/sprocket, gear, or direct drive)
• Differentials
• Tires?
• Validation

Gearing

Gearing determines crawl speed, top speed and torque availability at any vehicle speed in between.

Need to also be mindful of how much tractive for you will be generating in any given gear. This plays with tire selection and helps determine what happens when the driver firewalls the go pedal.

This also plays into forces on the differential and driveline components.

Motorcycle Gearboxes

Motorcycle engines have internal sequential gearboxes. This is means that the gearing is located inside the crankcase. The oiling is managed by the engine's oil system. Typically these are 5 (YZ450) or 6 speeds (CBR600RR).

Clutch

The clutch on motorcycles is a wet plate clutch. Unlike a car clutch, the motorcycle clutch uses a set of linear springs (some might use diaphram im not sure but ive never seen it). When engaged, the springs squeeze a series of clutch plates (explain what these are) tight enough to restrict relative motion. This mechanically links the engine output to the crankshaft. When disengaged, the plates are under no pressure and have the ability to rotate relative to one another. This allows the engine to spin without outputting a torque.
[we should get a simple diagram of how the torque flows through the engine here]

Continuously Variable Transmissions

These allow for an infinite combination of engine to wheel speeds. The benefits of this include allowing the engine to be run at peak power, peak efficiency, or peak torque at any vehicle speeds. The downsides are lower efficiency and a lower peak torque transfer.

Shifting

"stick"

electronic - solenoid

pneumatic

automatic (electronic or pneumatic)

not going to touch on driver controls (paddles or whatever)

Final Drive

• Chain Drive
• Belt Drive
• Driveshaft
• Gear Drive
• CVT

Differentials

this might warrant its own page. diffs are big bruh moment material

Validation

In vehicle simulations, including driveline affects become important the more detailed the vehicle model gets. The brake torque and horsepower are not what is seen by the tire's contact patch. A physical measurement of driveline forces should be undertaken at some point. It is not likely needed to do this every year however it should be done at least once to correlate model to reality.

This is typically a rotating measurement and typically involves the use of strain gauges. Wireless amplifiers are often needed. Several companies make them available such as Texense, Izze Racing and Lord Microstrain.

--Can talk more about the measurement in the electronics section. Maybe keep this higher level? You could right a whole section just on measurement techniques, uncertainty analysis, error influence coefficients.I think it is worth calling out a couple companies so teams at least have some direction. In the case of wireless strain gauge amps you can go down a real rabbit hole and not find what you need. As far as the gauge install itself, I think that is a lot easier to self research.