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Im no rocket scientist, and I dont know if you could even compare G's to a motorcycle. But if someone knows a little something.....how many G's could a 600-1k sportbike pull...whether that be accelerating out of a turn or flat out balls to the wall accleration in a straight line.
 

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I doubt it's going to be overly impressive since it would just flip over or lose traction if the G's became overwhelming. Throw on a wheelie bar and the limits are greatly increased.
 

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Maximum straight-line acceleration of a stock sportbike is about 1g, and the limit is the tendency to wheelie. That's why so much improvement is possible at the drag strip with an extended swingarm and lowered front end--longer and lower increases the wheelie limit.

Without suspension mods, engine improvements can't increase peak acceleration due to the wheelie limit. But they can increase acceleration at higher speeds, where a stock bike can't reach the wheelie limit.
 

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It may not be that much but I dont think its really an accurate comparison of abilities vs 4 wheeled counterparts
 

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A GSXR-1000 can do 0-100-0 in 10.7 seconds.
A Bugatti Veyron can do it in 9.9 seconds.

I think the acceleration/deceleration G forces can be pretty comperable.
 

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Subliminal said:
I don't even want to begin thinking about that. Do we pull more G's slowing down, or do we pull more G's speeding up.
Peak, probably about the same. Sustained, slowing down. Virtually every bike out there can brake at the point of incipient lockup from their maximum speed to zero. None can accelerate at the point of incipient wheelspin from zero to their maximum speed.

KeS
 

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More speeding up is my guess. There is more weight on the front of the bike, more acceleration before it starts to loop.
 

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maybe I'm confused, but isn't 1g the effect of gravity on a stationary object? as in... standing in my room I have 1g acting on me?

or is 0g the standard? Because I thought 0g would be a weightless environment?
 

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I think standing stationary is 1g. One times the force of gravity.
When we are talking about g forces in performance terms we are really discussing positive or negative g's. So a high performance car can be said to corner at around +1g.


This is really a good thread, and it brings up an area not often discussed in motorcycling.

I believe a motorcycle achieves more g forces from braking than accelerating. It is a time to distance thing. How quickly and how far does it take to go from 0-60, or 0-100 as opposed to 60-0, or 100-0?
I believe under braking bikes do these in shorter times and distances, hence higher g force loads.

As far as lateral or cornering g's, think about this... If a bike leans through a turn at an included angle (bike and rider) of 45 degrees, is that not equal to +1g lateral force?

I don't know, that's why I'm asking... I do know that obviously many bikes can lean far beyond 45 degrees.


 

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if i remember correctly, Michelin says the PP will hold about 52 degrees (with respect to the verical of course) of lean in a corner. if the rider has any sense, then he's hanging off quite a bit, so the center of gravity is even lower. as was already stated, at 45 degrees gravity is equal to centripetal (centrifugal is an imaginary force) force so a bike is pulling well over 1g cornering. braking and acceleration are probably both over 1g also. since maximum straight line acceleration is determined by tires, i imagine you could achieve more g's braking since it is possible to have maximum braking w/o looping it whereas wheeling is a huge problem on stock bikes.
 

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Yes, we normally have 1g acting on us, but it's pointed downward. When accelerating in a straight line at 1g, you also have 1g acting horizontally in the direction of travel. In normal discussions about g-force under acceleration, deceleration, or cornering, it's usually just horizontal g's that are of interest. But if you're solving a physics problem or something like that, you may have to consider the vertical acceleration of gravity as well.

Most motorcycles--even some cruisers and sport-tourers--can brake from 60-0mph with average deceleration of 1g or better (1g = 120ft), but only the fastest sportbikes can accelerate 0-60mph at an average of 1g (= 2.73sec). But those are averages. Peak acceleration is a different thing. I don't know whether sportbikes achieve higher peak acceleration under thrust or braking. The limit in both cases is the tendency to lift a wheel off the ground, and it depends on static weight distribution (measured at rest). More weight on the front than the rear for better acceleration; more on the rear than the front for better braking.

The reason most vehicles can brake at greater average g's than they accelerate is that brakes allow you to apply the same force at the wheels regardless of speed. The same force at the lever is required to apply 600lb (about 1g for most sportbikes) at the front tire whether you're going 100mph or 10mph. So if you decelerate at an average of 1g, you may be decelerating at an actual rate of 1g throughout.

But thrust applied by the engine at the rear wheel is different. If a bike can just manage 600lb of thrust (about 1g acceleration) at 50mph, it will be able to produce only 300lb of thrust at 100mph. So a time-to-speed chart gradually flattens out at higher speed, and average acceleration is just that--an average of higher acceleration at low speed and lower acceleration at high speed.
 
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