Gyroscopic forces in motorbikes.

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In summary, a person is asking whether the reduction in stroke and diameter of the crank in a dirt bike engine has a significant impact on the bike's handling due to reduced gyroscopic forces or if it is a perceptual effect caused by changes in power output. However, it is unlikely to have a significant effect on the bike's rate of lean due to the engine's location and size. More measurements would be needed for a proper assessment.
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Foss
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Just a quick problem for you guys that goes a little bit further than my high school physics education.

In recent years dirt bike manufactures have been trying to negate the effects that the crankshaft, through gyroscopic effect has over the motorbike. To take one example; the 2010 KTM 400exc. This bike is exactly the same as the 450exc apart from the engine. They have reduced the displacement from 449.3 to 393.4. They have done this by reducing the stroke of the engine.

They have reduced the stroke (and therefore the diameter of the crank) from 63.4mm to 55.5mm. Now my question is would this have a large impact on the bikes handling through reducing the gyroscopic forces or would it be a perceptive effect by reducing and changing the power output of the engine and making it more ‘manageable’.
I know that to figure out this properly you would need more weights and measurements but I don’t have access to them. I have tried but not luck. Any light that you guys could shed on this topic would be GREATLY appreciated.


MK
 
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Considering the engine is centrally located near the roll axis of the bike and rider, and that it is a 400cc single cylnder engine, I doubt it would have much effect on the rate of lean on a dirt bike.
 
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What causes gyroscopic forces in motorbikes?

Gyroscopic forces in motorbikes are caused by the rotation of the wheels. As the wheels spin, they create a gyroscopic effect that helps to stabilize the bike and keep it balanced.

How do gyroscopic forces affect the handling of a motorbike?

Gyroscopic forces play a crucial role in the handling of a motorbike. They provide stability and help the bike to maintain its balance while turning, accelerating, and braking. This makes it easier for the rider to control the bike and maintain its direction.

Do all motorbikes experience the same amount of gyroscopic forces?

No, the amount of gyroscopic forces experienced by a motorbike depends on several factors, including the speed of the bike, the weight distribution, and the size and weight of the wheels. A heavier and faster bike will experience greater gyroscopic forces.

Can gyroscopic forces be used to steer a motorbike?

While gyroscopic forces do play a role in steering a motorbike, they are not the primary means of steering. The rider must still use handlebars and body positioning to steer the bike, but gyroscopic forces help to stabilize the bike and make steering more precise.

Are there any disadvantages to gyroscopic forces in motorbikes?

Although gyroscopic forces play a crucial role in the handling of motorbikes, they can also make the bike more difficult to turn or maneuver at low speeds. This is because the gyroscopic effect is stronger when the wheels are spinning faster. However, this can be overcome with proper training and technique.

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