Wow: The Secret Hidden in the Parameters (Part 2)

What does cam lift mean?

How does the valve overlap angle affect different models?

How do large reach and trajectory correspond to handling performance?

What is the difference between the ergonomic triangle setting of a sports car and a station wagon?

What do you mean by curb weight, net weight, payload, gross weight?

...

Concepts and operations,

parameters and performance,

What is the causal relationship between them?

Motorcycles speak plainly about industrial products, quantitative indicator data, using a variety of concepts and parameters to define and describe performance, such as forward angle, towing distance, wheelbase, ergonomic triangle, net weight and curb weight, valve overlap angle, cam lift, power, torque... However, motorcycles are also a tool for riders, requiring richer feedback and more experience for riders, and the data is too blunt, too cold, too difficult to understand. After all, what function are these motorcycle concepts used to describe? What kind of performance do these parameters correspond to? Let's explore the story behind the important concepts and parameters of motorcycles through "Car Talk".

Turn geometry

The parameters directly related to the steering performance of the motorcycle are mainly the forward tilt angle, resistance distance and offset. The forward tilt angle is the angle formed by the extension of the steering column and the vertical line through the shaft of the front wheel. The greater the forward inclination angle, the blunter the steering, and the better the linear stability. The drag distance is the length of the steering column extension line that is projected on the ground after it intersects the vertical line that passes through the front wheel axis. The offset is the distance between the steering column extension and the parallel line that passes through the front wheel axis.

The steering geometry settings are different for each model. The typical difference is between a sports car and a cruiser, as the former is a high-speed model that tends to attack corners quickly and requires a keen steering response, while the latter is a casual model that excels at straight lines, focusing on rock-solid riding stability.

The Harley FXDR 114 is a classic American cruise model. Focus on calm acceleration, bold driving posture and comfortable riding experience. For this purpose, the FXDR 114 is equipped with a 114 cubic inch engine. Compared with the 107 cubic inch engine of the same class, the displacement has increased by 123mL to 1868mL, which is definitely "big". The V2 engine of the FXDR 114 features a bore and stroke of 102mm ×114mm and a compression ratio of 10.5:1. Under the servo of the latest generation of electronic fuel injection system, the maximum torque of 161N·m can be generated, and the speed at this time is only 3500r/min, and the low-speed torque is extremely powerful. Considering that the V-type twin engine is rigidly mounted on the frame and has a large displacement, in order to improve ride comfort, Harley engineers installed a double reverse balance shaft for this engine, which effectively reduces vibration during idling.

The FXDR 114 features a newly designed mild steel tube frame that reduces the height of the vehicle while lengthening the wheelbase. The swingarm is designed and assembled with aluminum alloy materials, which is 43% lighter than the steel swingarm of other models in its own house! Harley claims that the performance of the rear shock is improved due to a significant reduction in the under-spring mass. The saddle and tail are supported by a subframe. Unlike its other models, the subframe of the FXDR 114 is not made of steel, but is welded from aluminum steel tubes, further reducing weight.

With this characteristic frame setting corresponding to the move, Harley's engineers designed larger steering geometries with a focus on rock-solid linear line performance. The FXDR 114 has a backsloping angle of 34°, an increase of about 40% compared to the supercar; the drag distance is set to 119 mm, which also increases by about 20%. Such a large steering geometry setting makes the FXDR114 on a par with a supercar in the corners, but it has extremely stable straight-line driving performance, driving freely on the road, and the atmosphere is magnificent.

Human-machine triangle

The human-machine triangle actually refers to the driving posture. When a rider rides a motorcycle, there are three main parts of contact with the motorcycle, namely the handlebar, the foot pedal, and the hip pad. The connection of these three contact points forms a human-machine triangle. The human-machine triangle is directly related to the riding comfort and handling characteristics, and different types of motorcycles will be designed to adopt a human-machine triangle setting that meets the characteristics of the model.

For example, sports motorcycles, the primary consideration of the pursuit of speed and handling performance, riding comfort is secondary consideration of design. Therefore, in terms of human-machine triangle setting, this idea is also highlighted, and the Kawasaki ZX-10R is a typical example. As we all know, Kawasaki has been running smoothly in the Superbike Championship in recent years. Since 2015, it has held the WSB Championship for five consecutive years and is a double champion, including the Drivers' Championship and the Manufacturers' Championship. The Kawasaki ZX-10R has extraordinary energy. This liquid-cooled, dual overhead camshaft 16-valve side-by-side four-cylinder engine has a displacement of 998mL, a maximum torque of 114.9N·m (11200r/min), and a maximum power of 149.3kW (13500r/min), and when the forced air intake system is activated, the maximum power will soar further, up to 156.8kW (13500r/min), which is very exciting!

It is also important to increase the power to reduce the wind resistance. Air resistance is an obstacle that drains engine energy and prevents an increase in speed. When a rider reaches a certain speed, it becomes more and more difficult to increase the speed. Therefore, sports motorcycles will take measures such as reducing the windward area to achieve the purpose of reducing air resistance and increasing speed. The ZX-10R uses a low wind shield and windshield to optimize aerodynamic design. The rider's wind resistance can not be ignored. For this reason, Kawasaki engineers raised the pedal position and moved it backwards, mounting the handlebar position lower, along with the 835mm seat. Riders take a significantly forward-leaning riding posture, allocating more weight to the front end. Especially at high speeds, it is convenient for the rider to lie tightly on the fuel tank and curl up behind the windshield, effectively reducing the resistance of strong air currents.

The ergonomic triangle setting of the touring motorcycle is the opposite of that of the sport bike. Take the "Big Mac" Triumph Rocket 3 GT as an example.

As a heavy road wagon, comfort is the first priority, paying more attention to ergonomics and making driving more comfortable. The first is the wheelbase of 1677mm, which provides more sitting space for riders and passengers. Secondly, the seat height is only 750mm, the rider's feet can easily land on the ground; the rider's pedal is slightly forward and lowered to make room for the legs, making it comfortable and natural; the handlebar is installed in a higher position, and the man-machine triangle formed by the saddle, pedal and handlebar allows the rider to form a relatively upright driving posture, which is particularly comfortable and heroic to drive.

Curb weight and net weight

It should be said that among the various parameters of the motorcycle, the most popular concept is weight. Because this concept is used in our daily life. Contact at any time, in fact, we often say that weight is often quality. If you dig a little deeper, you'll see a lot of things hidden behind the weight. There are many ways to classify motorcycle weight, such as net weight, curb weight, curb weight, payload, gross weight, etc., and the specific classification methods used vary from country to country, and even the definition of the same classification method may be omitted. There are differences. In general, net weight refers to the weight of a motorcycle that does not contain liquids, that is, there is no gasoline in the tank, no oil in the crankcase, no radiator in the radiator, and no hydraulic oil in the braking system. It belongs to the lightest motorcycle. the weight. The curb weight is the opposite, that is, the weight of the motorcycle when it is filled with liquid, and the motorcycle can only be used in the curb weight state. Curb weight is usually another term for curb weight. Gross weight is the sum of the motorcycle's curb weight plus the rider, passenger and luggage weight. Payload refers to the rider, passenger and baggage weight that a motorcycle can handle.

The weight varies greatly from model to model. In general, motocross bikes are relatively light in quality among various models. In order to reduce weight, the EXC 250 SUV is extremely light, and KTM Engineering uses a lightweight chrome-molybdenum alloy steel tube frame to enhance lateral stiffness, longitudinal stiffness and torsional stiffness while reducing weight, and the subframe uses aluminum square tubes. The EXC 250 is one of the slimnest, lightest and most responsive steering arrays in its class. If there is no fuel in the tank, the EXC 250 weighs only more than 100 kilograms; when filled with gasoline, the weight of the vehicle is only about 110kg, which is 20kg lighter than the ordinary 125mL street car.

A first-class car that focuses on comfort and enjoyment can look bulky and bulky due to the welcome and various assistive devices. The Yamaha Star Venture is equipped with a large V2 engine with a displacement of up to 1854mL. It uses Yamaha's familiar dual spark plug, tilt-top combustion chamber, and 4-valve cylinder head technology. Exquisite technology, long-lasting and reliable operation. To keep the engine in perfect working condition, Yamaha also installed a mini oil radiator between the front and lower tubes of the Star Venture frame, given Star Venture's expeditionary mission.

The Star Venture travel equipment designers took great care of the fact that the Easy Parking system with electric motors makes it easier for riders to move the Star Venture's intercontinental cruise. Through the control button on the handlebar, it is possible to achieve safe slow or backward; Infotainment systems include vehicle control centers, communications equipment, advanced sound systems, etc., adding a lot of vitality to the journey; heating handlebars, heating rider's saddles and waist, heating passenger seats and backrests, so that you can feel warm during the journey, whether it is a cold and windy early winter, or a bleak and cold late autumn. As a result, Star Venture is robust and durable, with a curb weight of up to 434kg when the tank is fully loaded!

See you, wish the big guys and sisters a pleasant and safe ride.

Like don't skimp on your likes and comments, your support is the driving force for my constant updates