Test report acceleration

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Test report acceleration

Test report acceleration

Sock “n” roll

Speed ​​up the fact that it takes off your boots and your socks at the same time? only motorcycles can do that. What makes driving a lot of fun is worth a detailed report. How do different motorcycles behave when accelerating, how should the driver behave, what are the physical limits and which motorcycles are the fastest?

They still exist. Ambitious drivers who challenge a motorcyclist at the last traffic light before the end of the town. In the
the dusky red phase into provo-
decorating an eight-cylinder large sedan or a citizen’s cage turbodiesel. They want to instigate a tasty drag race, a nice win at the 100 mark. They think. And shortly afterwards look into the tube when the motorcycle scornfully disappears quickly.
It has a good traffic light start
the acceleration values ​​measured in MOTORRAD do not have too much in common, because these are determined by test professionals under ideal conditions. In real life there is no speed at 100 km / h
times more than a second. Extreme
Accelerating with the motorcycle is when the unity of man and machine suddenly seems tormented, the engine cheers in the highest tones, some clutches creak with a creak and the driver looks unfavorably grimacing from the tension.
Even experienced drivers can do this
Balance between falling into the speed drop and falling down at the back not
always equally good. Professionals minimize these fluctuations by practicing starts and getting into the Erin before the race-
Immerse yourself in particularly successful take-off maneuvers. If you want to accelerate five completely different machines in a row, you also need a full routine.
Despite some pitfalls, they are here
accelerated motorcycles halfway manageable. Because they at least enable a well-dosed coupling use. They neither hack like the anti-hopping unit of the Suzuki Hayabusa, nor do the discs suck on each other as beastly as with some dry clutches. The best example is the Honda Hornet 600. It has to be brought into motion at about 7000 rpm with a long slipping clutch. When the lever clicks beyond 60 km / h and the accelerator cable opens
The stop is taut, just a gentle jolt goes through the motorcycle, and the comfortable part begins.
Onions until just before the rev limiter, already the switch-
Pretension the lever, twitch the gas and load the next gear. And so on until the sixth. But always crouched down. Initially around the front wheel on the ground, later to keep the air resistance as low as possible. The even power delivery, the turning capacity of the 600 four-cylinder engine and the smooth shifting give you the security you need for an optimal test run.
The strongest and weakest motorcycle in the comparison, the Kawasaki ZX-10R with 167 hp and the KTM 660 SMC with 58 hp, demonstrate how it can get a little ticklish when accelerating optimally. An awful lot of power with the Kawasaki, a briefly translated first gear and a high center of gravity with the KTM
the two immediately with the front wheel in
snap lofty heights. It’s difficult-
It is easier to control, because the throttle and clutch still have to be coordinated and because of the dual task of the clutch hand: on the one hand, to hold on to the handlebars and, on the other, to control the clutch perfectly. It helps to hold the grip tightly with your thumb and at least one other finger and to control the situation with only fine corrections. And in an emergency, decided to stop the acceleration on the spot.
While at KTM in the further
All you have to do is reload gears quickly, the hell ride on the Kawasaki takes longer. Usually it starts with the complete opening of the throttle valve to the second wheelie wave, and that too is difficult to control. In second gear, which is only due at almost 150 km / h, it is a bit easier, in third the front tire dabs more often on the asphalt. It already goes over 200. It may be sobering, but the less spectacular the acceleration looks, the better it is usually.
The B.enelli TnT, however, tears the-
half as much because it is completely different. She snaps forward from a standing position
with a diabolical and un-
problematic efficiency. Thanks rich-
With the three-cylinder engine’s torque and a favorable weight distribution, no act on a knife’s edge, just medium speed, clutch in, and you’re 30 meters further. To the Kawasaki
ZX-10R only loses a little time up to 100 km / h because the gearshift is pending shortly before this mark, which takes two to three tenths of a second. However, it has to be set precisely because the three-cylinder limiter kicks in early.
What the Benelli shows, they lead
Triumph to the extreme. No, not because of
of the three-cylinder, but because of the way in which it converts its source of torque into propulsion. Weight is in and of itself a hindrance when accelerating, but here mass means class. Even with full thrust, there is nothing at the front and nothing spins at the rear. It goes single-
Lich about it, gently? important because of the
brute torque ?? engage the clutch and open the lock. Then shift through the five gears and that’s it. Amazingly, the acceleration curve is almost congruent with the Hornet line. The difference is in the
Feeling: relaxed and confident, but with
The Rocket roars away with fascinating dynamics, while the Hornet has to do a lot
accelerated aggressively.

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Test report acceleration

Test report acceleration
Sock “n” roll

…And off goes Luzie

Karsten Schwers, MOTORCYCLE test professional, says how to get the last tenths out when starting off. Optimal measured values ​​can only be achieved with a lot of routine, even more feeling and the right know-how.

From a standing start
The first meters are the most important-
ten. Most tenths will
immediately given away when driving off, either due to slow reaction time or poor co-ordination-
nation when engaging. First
once the clutch speed has to be correct. Large-displacement machines are relatively uncritical in this regard. You have so much power in the lower speed range that there is either a wheelie or slip on the rear wheel. The difficulty is rather to skillfully limit the pulling force. You can let the clutch come on quite quickly, after which you have to play with the gas carefully.
Low-displacement four-cylinder represent a greater challenge. In order to transfer the maximum tractive power to the rear wheel from a standing start, very high speeds ?? not infrequently over 8000 rpm? the clutch is slippingly engaged. If the clutch comes out too quickly-
is left, there are two possibilities-
possibilities: Either the front wheel comes up in a flash, or the
Motor falls into a torque hole. In both cases you can see them
Competition only from behind. However, such extreme loads put a lot of pressure on the clutch. Often you shouldn’t repeat these games, especially not one after the other.
Of course, it is crucial that the front wheel is just kept on the ground by constantly adjusting the clutch and throttle. With the MotoGP professionals be-
one often observes that when starting the front wheel up to the first corner five centimeters above the
Hold ground. That is true body control.

Switching operations
Without an automatic gearshift, as is the case with racing machines, there are three options:
1. Close the throttle, pull the clutch, then shift, disengage the clutch, open the throttle.
2. Let the gas stand still, pull the clutch slightly, shift, release the clutch.
3. Take the throttle back very briefly without pulling the clutch, shift gears and immediately open the throttle again.
With all three variants, you should pull the gear lever up with light pressure shortly before changing gear. Number one is the classic method. Not particularly fast, but gentle on the material. The second variant is the brutal one. I think the last option is the fastest. In the event of a poor switching process, 0.1 to 0.2 seconds can be wasted, which logically adds up with several switching processes. Long-geared motorcycles with a lot of power therefore have advantages. A Kawasaki ZX-10R, in which the first gear goes up to 150 km / h, the second up to 185 km / h, only needs two shifts up to 200 km / h. With machines with a shorter gear ratio, on the other hand, you have to shift more frequently.

Switching point
Most motorcycles only switch to the rev limiter shortly before the rev limiter. The driver must therefore know when the engine is reaching its limit. Please do not determine while standing, but under load in one
slightly higher gear. The limiter usually only sets in the red
Range of the tachometer. It gets tricky with motorcycles that firstly have no rev counter and secondly no rev limiter, like some single-cylinder machines. Singles are difficult to master anyway. The maximum torque is usually already available in the middle speed range. Therefore, an earlier upshift can lead to better values ​​than extreme loosening of the gears.

Sitting position
Basically, the driver should post as much weight as possible
Shift the front to prevent the front wheel from climbing. This not only applies to high-performance motorcycles, but also to short-geared motorcycles and those with a high center of gravity such as the KTM 660 SMC.

aerodynamics
Under 120 km / h on powerful motorcycles, maximum acceleration is rather limited by the tractive force that can be transmitted to the rear wheel. In addition, the driving resistance, i.e. rolling and air resistance, gain the upper hand. Then especially with Naked
Bikes can be made up for several tenths of a second by neatly folding them together.
The MOTORCYCLE values ​​are below optima on a closed area-
len conditions and without return-
determined view of the material. In the wild, however, the last tenths hardly play a role. Whether a Kawasaki ZX-10R in 7.2
Accelerating to 200 km / h in seconds or 8.9 seconds feels similarly brutal: in both
Cases are making great strides. So off to the next highway entrance and Gaaaaaas!!!

Show of strength

We have known since the time of Sir Isaac Newton, i.e. the 17th century: the apple usually does not fall far from the trunk, in any case it falls down. The acceleration can be derived from the law of gravity.

Anyone who paid attention in physics class has somewhere in the back of their mind: The acceleration is as
Change in speed defined in a certain period of time, a = Dv / Dt. So if a motorcycle sprints to 100 km / h in three seconds (corresponds to 27.77 m / s), after a little calculation you will get an average acceleration of 8.33 m / s2.

The law of gravity
However, this does not yet explain,
why an object is moving faster. This question was also answered in another physics lesson ?? as
It was about a basic equation of mechanics, which Mr. Newton is said to have come up with in 1666 during the midday meditation in his garden when he saw an apple falling from a tree: force = mass x acceleration (F = m x a). This discovery story is probably wrong, but the formula Isaac Newton used
founded modern physics. If you take the law of gravity around-
we get a = F / m. What do we learn from it? No acceleration without force. And on closer inspection it quickly becomes clear: if you want to achieve high acceleration, you should keep the mass as low as possible. What every driver of a heavy S-Class knows who has difficulty putting a Smart in its place for the first few meters after starting the traffic light.

The traction
In a motorcycle, the engine delivers the necessary torque. Unfortunately, this is not constant, but is derived from the torque curve. Depending on the engine, the maximum torque is therefore only available in a more or less narrow speed range. You need a gearbox to cover the entire speed range. The individual courses increase the rotation-
moment, first gear has the greatest drive force available. The torque delivered by the crankshaft is multiplied by the gear ratios of the primary drive, gearbox and secondary drive and the result is then multiplied by the radius of the outward-
terrads, that results in in every aisle
It has its own characteristic curve depending on the speed. The so-called tensile force diagram depicts these characteristics and provides a very good picture of the
at the respective speed for ver-
cohesive driving force.

Limits of physics
Let’s say we had limitless
Power available could be a motor-
rad then start infinitely fast? No, because the power has to be transferred somehow. If the motorcycle were catapulted by a rubber cord, there would be no problem with the transmission. In practice, however, the two-wheeler must
all of the driving force is applied to the tiny contact area of ​​the rear tire
bring the ground. And that only works up to the tire’s grip limit. Put simply, this is where physics comes in
with a coefficient of static friction of
µ = 1 the limit. The transferable driving force could therefore be at most as high as the normal force acting perpendicularly. Do we assume that all of the weight is on the rear wheel? and that is often the case when accelerating a motorcycle ??, the maximum weight that can be transmitted is. From which, according to the formula a = F / m, a
Acceleration of 9.81 m / s2, i.e. exactly
the acceleration due to gravity g results. Because for F the weight G must be used, which is calculated from m x g.
In reality, it is still a little faster. This is because there is no simple static friction on the contact surface of the tire, but because there are also interlocking effects and chemical aspects
Role-play. According to this, a top fuel dragster with huge sticky tires can accelerate several g, but a normal motorcycle has to be “content” with hardly more than one g.

The wheelie problem
The difference between dragsters and road machines is not just in the tire. Dragsters crouch as flat as possible on the road for good reason, and have wheelbases of several meters and wheelie bars: The inertial forces that act in the center of gravity of the structure of man and machine form one
Lever arm around the rear wheel contact point that wants to turn the motorcycle.
With the dragster, because of the low center of gravity and torque support, thousands of horsepower are not enough to relieve the front wheel. With the high center of gravity of an enduro, on the other hand, a few dozen horsepower are enough for a wheelie. Anyone who has ever ridden a children’s crosser knows that you can roll over backwards with just four horsepower. Simply because the center of gravity with an adult rider is almost above the rear wheel.

The driving resistances
The formula F = m x a only reflects part of the complex dynamics of a moving motorcycle. In addition to the driving force, other forces act, such as rolling and air resistance. Since the air resistance increases quadratically, the acceleration decreases more or less rapidly above 100 km / h. A KTM 660 SMC has to go at around 180 km / h-
tulate, then driving force and driving resistance are in balance. This means that the acceleration is zero at 180 km / h, while with a ZX-10R there is still a nice excess of tractive power left to propel the machine.

Actio = reactio
Not only does the motorcycle accelerate, but in response, the propulsive force affects the movement of the earth. Newton already formulated this in his third axiom. Thank God the mass of the earth is so great that it doesn’t really care if a Turbo-Hayabusa tries to throw it off track somewhere in the world.

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