The steering wheel on a bicycle turns without a wheel

Bike geometry

From geometry. from angles and sizes. a lot depends on the behavior of the bike. Depends on stability, handling, cross-country ability (in a good way), acceleration dynamics, effective braking, descent and ascent from a mountain, passing sharp turns and the ability to engage in steep extreme sports. In ancient times, the geometry of a bicycle was rigidly and unambiguously determined by the geometry of the frame. This is no longer the case. There are suspensions, front and rear. This means that the geometry and behavior of the bike depends on the characteristics of the suspensions (travel, stiffness, damping), and on their settings. In order not to delve into the jungle, but simply, look around, a dense forest, with a casual eye of an expert, consider the main points.

In many ways, it sets the fit of the biker and the convenience of pedaling. if the pipe sticks out vertically and the carriage is exactly under the saddle, then it is inconvenient to pedal, there is nowhere to put your hips. It also determines the weight distribution of the bike, that is, the distribution of the load on the front and rear wheels. The smaller the angle of inclination (it is measured from the horizontal) and the higher the biker, the greater the load on the rear wheel and, naturally, less on the front. On steep inclines, if the biker is in the saddle, the front wheel can be completely unloaded and lose contact with the road. And the biker runs the risk of falling onto his back. And on steep slopes, everything is exactly the opposite. The front wheel is loaded, and the further back the biker is moved, the more stable the bike is and the less likely it is to fall over the handlebars. The seat tube angle of 73 ° (plus, minus 1 °, 2 °) is considered to provide a correct, comfortable fit and load distribution. This angle is precisely tailored for the ideal biker with a 32 ” (813mm) thigh length. To further correct this angle and fit the bike to the actual dimensions of the raider (height, arm and leg length.), You can replace the straight seatpost with a curved one (Thomson). And, even easier, you can slide the saddle forward or backward. With the saddle in place, the leg is almost fully extended in the down position. 2. Carriage height

Determines the ride height of the bike. clearance between the pedal and the road when the connecting rod is lowered vertically. Too low ground clearance does not allow the bike to tilt too much when cornering at high speed. you can catch the pedal on a stone, bump, root, accelerating at the exit from the bend. Or hit the stars of the system for a bump. Therefore, bikes for different riding styles have different bottom bracket heights above the ground. for DH and freeriding, the carriage is raised higher, up to 34.36 cm. As a specific material, there is a table that was kindly provided by Alexey Madzhuga and, where, using the example of KONA bicycles, it is shown how the dimensions change from the purpose of the bike and the riding style.

K-country hardtails K-country double suspension Back Country Bikes (Trail) Mid travel freeride bikes Downhill Bikes
Shock absorber travel 100mm 100mm / 100mm 130mm / 130mm 150mm / 150mm 200mm / 203mm
Bottom bracket height 31cm 31.5cm 31.5cm 34.8cm 35.8cm
Head tube angle, degrees 69 68.5 68 66 64.5
Wheelbase length 106.4cm 108.2cm 110.7cm 111.8cm 114cm

Note. Due to the clear progress in the design and operation of suspension forks and rear shock absorbers and the creation of “stable platforms”, shock absorbers travel has increased in recent years and, quite possibly, will increase even more. In addition, the higher the carriage is, the higher the saddle should be lifted and, the higher the height of the bike becomes and the higher the center of gravity of the bike system is. Which undoubtedly affects stability and controllability. On a high bike, it is easier to maintain balance, and when entering a bend, the angle of inclination required to compensate for the force of gravity, the centrifugal force arising from movement in a circle (radius) will be less. than a low bike. Which follows from the most elementary geometry. Consequently, on a high bike it is easier to ride on narrow forest singletracks and it is easier to “stack” it in tight turns. That is, once again, in order to corner at a given speed and along a given radius, a tall bike must be tilted sideways at a smaller angle than a low one. But when braking and descending, the picture is reversed. On steep climbs, descents and heavy front brake braking, a tall bike is more likely to lose balance. tip over backward or over the handlebars. To reduce this harmful effect, increase the base of the bike. the distance between the axles of the wheels. At the same time, they get more softness and smoothness of the ride, the bike bounces less on potholes, roots and bumps. But a long wheelbase bike has greater directional stability and fits worse into sharp turns, which again follows from the simple geometry. To improve handling and maneuverability, you have to “play” with the angle of the steering tube and reduce the Trail (front wheel rollout).

Tilt angle of the steering tube (measured from the horizontal)

We only note the following. The larger this angle, the closer the fork stays to the vertical, the faster the bike accelerates and the better the fork fulfills small bumps and bumps on the road. Conversely, if the angle is smaller, and the fork stays are more shallow (sharper) to the surface, the worse the dynamics and controllability, but the fork easily swallows large potholes and bumps and they less affect the movement of the bike. In XC, the head angle is typically 71.69 degrees and the wheelbase is long. 100.107 cm, then in DH. 64.65 degrees and 110.117 cm. See table The low tilt angle of the front fork, combined with the long stays that are common on bike choppers, result in poor maneuverability. efficiency (sharpness) of control: an increase in the minimum bend radius and the need to turn the steering wheel to a greater angle.

Front Fork Geometry and Trail (Front Wheel Rollout)

A little experiment. If you put the correct bike vertically on both wheels, holding the frame and tilting to the side, then the handlebar itself will turn in the same direction. The reason for this behavior lies in the design of the front fork and steering column. It is they who determine the relative position of two important points. Point A. of the place of contact of the front wheel with the road and point B. of intersection of the steering column axis with the same road. The relative position of these points sets not only the direction where the handlebars will turn when the bike is tilted, but also its directional stability, handling, control severity, cornering stability and much more. All bicycles can be divided into two types: BA and AB. AB type. in which the point of contact of the front wheel with the road is located in front of point B (Fig. a). VA type. Point A lies behind point B (Fig. B).

The options shown in Fig., A) and b). give us too much distance between points B and A, which leads to “over-stability” of the bike. The greater the distance between these points, the greater the moment of force that turns the front wheel and, of course, the handlebars in the direction of the inclination of the bicycle. The result is clear, directional and vertical stability is very good, and handling “below the plinth”. Therefore, to reduce the distance between these points, the fork is bent forward on bicycles, Fig., C). But, even if the fork is straight, then its inclination is changed, relative to the axis of the steering column, or the roosters, in which the front wheel is attached, are shifted forward. Fig. The distance between the axle of the steering column and the axle of the front wheel hub is called differently, both Rake and Fork Offset, but here you can encounter a coast, offset or fork offset. The R fork overhang is usually between 30mm and 50mm. Knowing the fork reach, the tilt angle of the steering column axis and the real diameter (taking into account the thickness and deformation of the tire) of the wheel, you can easily calculate the distance between points A and B. This distance is called Trail or roll-out (runout) of the front wheel, sometimes it can be found in catalogs So, knowing the Trail, the stability (handling) coefficient (Ku) is considered, which is equal to: Trail (T), divided by the sum consisting of the length of the bike base (G) plus Trail (T), the result of division is multiplied by 100%. Now the formula is: Ku = (T / [GT]) 100% (1). everything is very simple. In modern bicycles, the Ku lies in the range from 5% to 7.5% and is usually chosen a value close to the stability limit, for a very transparent reason. such a bike is easier to handle.

The geometry of the bike changes when the damping is applied

At the moment of braking, when the bike “nods” when the suspension fork is compressed, the base decreases, but Trail decreases even more, and, consequently, Ku also decreases. It turns out that when braking, the bike becomes more controllable, but also less stable. The same happens when pedaling while standing, when the biker brings the body closer to the handlebars and when descending a slope, especially if the front wheel is braking intensively. If you now load the trunk with a heavy load (pretty girl) or reduce the travel of the rear suspension (put a shorter shock absorber) at the double suspension, then the situation will change to the exact opposite. The trail will increase, the Q will increase, the bike will become more stable, but it will be more difficult to control it. This is probably familiar to many leading tourists. With a well-loaded trunk, the bike rushes like a tank, especially when accelerated well. But turning or driving along a winding path at low speed, oh, how difficult it is. Many extreme bikes nowadays have long chainstay dropouts that allow wider rear axle shifts or smaller wheel sizes than 26 inches. Not surprisingly, this changes the stability and handling of the bike. The first trail bikes have appeared, the geometry of which can be changed directly on the go over a wide range. For example, the novelty of the season, the BIONICON EDISON bike. With the help of an industrial valve that is used in pneumatic devices and pneumatic lines, the frame geometry can be changed by 6 degrees! Head tube inclination angle 67.5 °. 73.5 °. Seat tube angle 71 °. 77 °. Fork travel 69mm. 147mm, 142mm rear travel with 1056mm wheelbase. The same bike can now be ridden in XC and downhill spectacularly. 6. Upgrade

Replacing the suspension fork and rear shock with longer or shorter ones will affect the stability and handling of the bike. This should be taken into account.

Top tube length is defined as the distance from the centerline of the head tube to the centerline of the seat post. This distance, together with the stem length, largely determines the rider’s position. And besides, it also affects the weight distribution of the bike. The long tube helps relieve stress on the front wheel. slippage when cornering. Shorter. may cause your knees to brush against the steering wheel when pedaling in a dancer fashion. XC lovers choose a long tube and a long stem (100.130mm) for a low, extended fit. This makes cornering and tricky sections difficult, but the main struggle usually occurs on the climbs. For downhill and freeride use a slightly shortened top tube with a short stem. Therefore, on a slope, the raider moves far back and ensures the correct load distribution between the wheels. In addition, the additional loading of the front wheel when the rider moves slightly forward helps to navigate the technical sections.

First of all, it sets the height of the standover. a safe distance from the vital organs of the biker to the top tube of the frame. This is very important in extreme sports. In addition, the height of the frame decreases and, as a result, its rigidity and strength increases, which plays a role in jumping disciplines and hard freeriding. Recently, the lowered top tube has been used in road and cross-country bikes. This allows you to reduce the number of sizes of the produced frames and their weight.

It is identified by the line parallel to the ground from the carriage axis to the rear hub axis. Chainstays length affects the weight distribution and dynamics of the bike. And, it doesn’t matter if the biker is sitting in the saddle or standing on the pedals, this is the difference between the influence of the length of the feathers on the weight distribution, from the inclination of the seat tube. After all, when the biker gets off the saddle, the inclination of the seat tube no longer affects the distribution of the load between the wheels. The short stubs load the rear wheel and increase traction, and also make the rear triangle more compact, taut and stiff. The bike climbs uphill more easily, passes faster, turns and accelerates. On touring bikes and touring bikes, the base is usually increased and the rear triangle is stretched. This worsens the dynamics and requires more energy to climb the mountain. But you have to go for it in order to place a large and voluminous cycling backpack (pants) on the trunk and not touch it with your heels when pedaling.

And a few more words about the difference in bike geometry for different riding styles. The sharper the bike is “sharpened” for downhill and hard freeriding, the longer the stroke of its shock absorbers, the sharper the angle of the head tube, the larger the wheelbase and the higher the bottom bracket. The dirt bike has a shortened seat tube, a low standover (distance from the ground to the middle of the seat tube) and a short stem. This is useful for the safety and comfort of the raider when performing jumps and tricks and for greater frame strength.

Bicycle instruction manual. Check before every ride.

Checking the condition of the bicycle wheels

Check the condition of the front and rear wheels before each ride.

  • Bushings
  • Rear wheel hub cassettes
  • Brake disc (if fitted)
  • Spokes and nipples
  • Rims
  • Tires with a tube inside, protective tape.

Some models of bicycles are equipped with special wheels with tubeless tires. In this case, the camera may not be mounted on the wheel.

Checking the correct fit of the bicycle wheels.

Scroll each wheel of the bike in the direction of travel, while:

  • Wheels should not “dangle” in the attachment points on the fork and on the frame;
  • The eccentrics must be clamped;
  • There should be no rattling or crackling sound;

If you find any problems in the wheels, please contact your dealer.

Checking the condition of bicycle rims.

Damaged rims can cause a fall, injury to the rider, or damage to the bike. The worn out rim must be replaced, the found figure eight must be straightened. Dirt on the rim will impair the braking of the bike, so the rim needs to be cleaned.

READ  Bicycle Rear Brake Does Not Brake

To assess the degree of wear on a bicycle rim, it is necessary to visually inspect the condition of the condition indicator of the rim itself. On an unworn rim, the indicator is clearly visible without scuffing. (as shown in the pictures)

In the event that your rim is technologically not provided for the presence of a rim wear status indicator, then it is necessary:

  • carry out a visual inspection
  • run your fingernail along the sides of the rim. The surface must be smooth, no cracks, potholes.

If the status indicator is worn out or you feel a crack to the touch, the rim needs to be replaced.

  • lift the bike and rotate the front and rear wheels in turn in the direction of travel
  • with V-brakes fitted, pay attention to the distance between the rim and the brake pads. The distance should not vary over the entire circumference of the wheel. The maximum permissible deviation is 2 mm.; If your bike has disc brakes, look at the distance between the rim and the fork leg, or between the rim and the stays. Maximum permissible deviation 2 mm.

Even the smallest oil or dirt spots must be removed from the rim.

Melanie Martinez. Training Wheels

Checking the condition of tires.

An improperly installed bicycle tube or tube nipple can rupture the tube itself, resulting in a fall and injury to the rider.

Checking the correct position of the bicycle tube nipple:

The nipple of the bicycle tube must be directed strictly towards the center of the wheel

The nipple is directed strictly to the center of the wheel (correct position)

Nipple not pointing in the center of the wheel (wrong position)

Checking the pressure in the bicycle wheels:

Please note that each type of bike has a corresponding type of tire.

For a mountain bike, the width of the tire must be greater than 40 mm; recommended inflation pressure of wheels 2.5-3.5 bar.

For city and cross-country bicycles, the tire width should be 28-40 mm; recommended inflation pressure of wheels 3.5-5.0 bar.

For a road bike. the width of the tire must be less than 28 mm; recommended inflation pressure of wheels 6,0-10,0 bar.

For types of bicycles not listed in the specified list, you must follow the recommendations for the degree of inflation, indicated directly on the tire itself.

Some tires have recommended pressures in psi:

Check the tire pressure with a monometer and bring it in accordance with the recommended standards indicated above.

There are 3 types of bicycle tube nipples.

After inflating chambers with Schraeder (Auto) or Dunlop valve types, the nipple must be screwed on top with a cap.

If the camera of your bike has a French type nipple, before inflation, you must remove the nipple cap, unscrew the upper nipple head, pump up the tube, then you must return the nipple head to its original twisted state.

The tire tread should be clearly defined. The top layer of the tire should be even without blisters and cracks, the structure of the tire should be dense without protruding fibers.

Checking the condition of the seatpost and post

If the seat post is not deep enough, it will not be possible to secure the seat post, which will lead to the cyclist to fall or damage the frame.

To check that the seatpost and saddle are securely attached:

  • twist the saddle in different directions. The saddle and seatpost must not rotate.
  • Pull the saddle up with both hands, then press down firmly. The saddle must be stationary.
  • If the saddle moves or rotates, tighten the corresponding bolt (see the instructions for securing the saddle)

Checking the condition of the bicycle handlebars and stem

The handlebars and stems are very important components of your safe cycling. Damage or improper installation of these components can result in serious injury to the rider.

If you find that the handlebars or stem of your bike are damaged or you are not sure of their absolute integrity, the use of the bike is FORBIDDEN until the damage is repaired. In this case, contact your dealer immediately.

To verify proper installation of a bicycle handlebar and stem, make sure that:

  • The stem is in the same plane as the front wheel rim of the bike
  • The angle between stem and rudder is 90 °
  • The handlebars and stem of your bike are securely locked. To do this, follow the steps as shown in the figures below.
  • The handlebars and stem must not roll.
  • No extraneous grinding sounds.

Checking the condition of the brake levers and shifters

To check the reliability of the fastening of the brake levers, gearshift paddles, as well as steering wheel grips, you must:

  • Clamp the front wheel between your legs
  • Try to turn the brake levers up and down
  • Do the same with the gearshift paddles.
  • The fixation of all components must be absolutely reliable
  • Make sure there are no extraneous sounds.

Checking the steering column

Check your bike’s steering column. With the correct setting of the steering column, the front wheel should turn freely left-right without backlash.

To correctly adjust the steering column, you must:

  • Grip the steering wheel with both hands by the grips.
  • Apply and hold the brake on the front wheel of the bike.
  • Try to jerk the bike back and forth while there should be no backlash in the steering column and grinding extraneous sounds.
  • Raise the bike so that the rear wheel is higher than the front wheel, holding it by the frame.
  • Continuing to hold the bike by the frame and not holding the handlebars, turn the bike left and right. The front wheel should freely (without biting) repeat the turns of the bike.

Checking the front fork and rear shock absorber

To check the serviceability of the front fork, you must:

  • Squeeze the front brake lever and hold it down, push the handlebar so that the fork compresses
  • Return the plug to its original position by removing the load. The fork should be easy to open and close without a rattling sound.

To check the serviceability of the rear shock absorber, you must:

  • Press down on the saddle so that the shock absorber compresses
  • Return the shock absorber to its original state by removing the load. Rear shock should be easy to compress and unclench without rattling sound.

Checking bike brakes

Malfunctioning brakes will result in serious injury to the cyclist and damage to the bike. Take extra care when checking the brake system on your bike.

During a multi-day bike ride, there is significant wear on the brake discs, brake blocks and brake pads. It is highly recommended to have spare brake pads. Self-replacement of brake pads can only be done if you have the appropriate skills. Otherwise, you need to contact a specialized bicycle workshop.

To check the correct functioning of the bicycle brake system, you must:

  • Compress the brake levers fully to the limit
  • Remember that when squeezing the brake levers, the minimum distance between the brake levers and the handlebar grips must be at least 35 mm
  • Attempt to set the bike in motion with the brake levers fully engaged. In this case, both wheels must remain locked.

Checking road bike brakes:

  • When checking the brake cables and brake mounts, there must be no mechanical or corrosive damage.
  • The brake cable must be firmly clamped to the brakes.

Checking the correct attachment of the front and rear brakes:

  • Try to pull the brake away from the fork (front) or frame (rear) with your hand. The brakes must be completely secured.

Checking the correct installation of the brake pads:

  • When the brake is in the clamped state, the brake pads should be in contact with the side of the rim with almost their entire surface.
  • The brake pads must not come into contact with the tire in any condition (clamped or not clamped)

Checking the degree of wear of the brake pads:

  • Brake pads must not be worn below the wear indicator
  • The brake pads must be at the same distance from the rim of the bicycle wheel.

Checking the mechanical rim brake for mountain and city bikes:

  • When checking the brake cables and brake mounts, there must be no mechanical or corrosive damage.
  • The brake cable must be firmly clamped to the brakes.

Steering Wheel Instead of Bars On My Bike!

Checking the correct attachment of the front and rear brakes:

  • Try to pull the brake with your hand. The brakes must be completely secured. Small backlash is acceptable.

Checking the correct installation of the brake pads:

  • When the brake is in the clamped state, the brake pads should be in contact with the side of the rim with almost their entire surface.
  • The brake pads must not come into contact with the tire in any condition (clamped or not clamped)

Checking the degree of wear of the brake pads:

    To check the brake pads, release the brake levers as shown in the illustrations.

  • Brake pads must not be worn below the wear indicator
  • The brake pads must be at the same distance from the rim of the bicycle wheel.

Mountain and City Bike Hydraulic Rim Brake Test:

Checking the correct attachment of the front and rear brakes:

  • Try to pull the brake with your hand. The brakes must be completely secured. Small backlash is acceptable.
  • The brake must be secured in such a way that it would not be possible to freely remove it by hand. Small backlash is acceptable.

Checking the brake system for leaks:

  • Press the brake lever to the limit and hold
  • Check the braking system of your bike from brake lever to brake along the entire length of the brake hose
  • Leaks of brake fluid are not allowed
  • When the brake is applied, the brake pads should be in contact with the sides of the bicycle rim with almost the entire surface.
  • In any position, even when the brake is not pressed, the pads should not come into contact with the tires

Checking the brake pad wear indicator:

  • Brake pads must not be worn below the wear indicator
  • The brake pads must be at the same distance from the bicycle rim

Mountain and City Bike Hydraulic Disc Brake Test:

Disc brake performance is significantly impaired if the disc is dirty.

  • The caliper must be stationary when trying to turn it with your hands in any direction.

Checking the brake system for leaks:

  • Press the brake lever to the limit and hold
  • Check the braking system of your bike from brake lever to brake along the entire length of the brake hose
  • Leaks of brake fluid are not allowed
  • The brake disc of the bicycle must not be bent or cracked; there should be no deep scratches or other mechanical damage

Checking the correct installation of the brake disc:

  • Raise the front wheel of the bike and turn the wheel, while the disc should not touch the brake pads. Minimal touch allowed.

We recommend installing and testing disc brakes and brake pads in specialized workshops.

Controlled skid on a bike: 4 tips

There is such a scientific, however, not understandable concept for everyone: “skid”. In principle, it means the displacement of a wheel (or two wheels at once), which does not coincide with their rolling.

There are controlled and uncontrolled drifts. It is necessary to be able to correctly use a controlled skid, since this maneuver is very difficult and dangerous. In turn, uncontrollable drifts almost always lead to falls.

Skidding can be caused by: steep descent, slippery or uneven road, wheel blockages.

Skidding while cycling can occur at almost any time, as the bike itself never travels straight. And it is especially important to remember that a front wheel skid is much more dangerous than a rear skid, and if you do not take the necessary measures, a fall is inevitable. To be able to safely take turns, certain skills are needed, which we will now talk about.

Landing

The most global mistake of all beginners and even some experienced Catalans is that their body is extremely enslaved in the shoulder girdle and elbow joints, this prevents easy and relaxed taxiing.

The problem is that in the process of driving we lean on the steering wheel, transferring 30 percent of the weight of the whole body to it. as a result, it becomes difficult to operate with what is also the fulcrum.

Therefore, the first thing to analyze in yourself is the position of the body at the moment of active taxiing, most likely you will feel how tight your shoulders and elbows are. this prevents easy handling of the steering wheel, you interfere with yourself.

Now tense your back and abdominal muscles a little to relieve the pressure on the handlebars. stop leaning on it, keep your torso above the bike using mainly your back and abs. The lower your bike’s riding position, the more difficult it is, but in the end, this is only needed during the active steering phase, and then you can lean on the steering wheel again.

Bend your elbows slightly so that the vector of force applied to the rudder grips is parallel to the ground, and not from top to bottom. In other words, you should pull-push the steering wheel with only one hands and forearms, and not with the whole body on outstretched arms.

So, your body is held above the bike by the muscles of your torso, your hands are free to hold the handlebars without leaning on it. Relax your elbows, lower your shoulders. Move the steering wheel. you no longer have to fight the strength of your own hands, which grabbed onto it in order to keep the carcass on the bike, now the steering wheel moves freely to the right and to the left.

steering, wheel, bicycle, turns

Constantly reinforce this skill. check how relaxed your arms and shoulders are, the fact is that with increasing stress levels, our body tends to involuntarily become enslaved.

What taxiing is made of

The most important factors affecting the handling of any two-wheeled vehicle are the position of the body and hands (landing in the active phase of taxiing), the direction of view and position of the head, as well as traction control (constant pedaling).

Correct posture

For the successful implementation of the skid maneuver, the technique must be honed, otherwise there is a high probability of an accident. During skidding, an even distribution of body weight between the wheels is necessary. When the rear wheel skids, you need to unload it by slightly moving forward.

When turning, you need to lock the rear wheel and abduct the knee to the side. At the same time, the steering wheel is directed in the direction of travel. Elbows, knees and body are used for additional adjustment and cushioning, but under no circumstances should the handlebars be used.

How to take turns on a bike

The technique of passing the turning radius depends on the speed and grip of the tires. At low speed, the cyclist turns by simply tilting the handlebars at a large angle and practically without leaning the bike. At high speeds, in order to compensate for the centrifugal force, the bicycle is deflected in the direction of the turn, and the handlebar turns at a small angle. Steering the wheel at a large angle can cause the wheel to roll out perpendicular to the direction of travel or skid, resulting in a guaranteed fall. At high speed, due to the high angle of inclination, the bicycle may start to slide sideways, which will also lead to a fall. If the road surface does not inspire confidence, and the tires are not “toothy”, then it is advisable to reduce the speed, and even before entering the turn.

READ  How To Remove A Reflector From A Bicycle Wheel

There are three main “styles” of high-speed flat cornering with the bike.

The first, it is also classic, when the cyclist deviates in the direction of the turn at the same angle as the bicycle. That is, if you continue mentally with the line of the seat tube up, it will pass axially through the spine and helmet. Thus, the center of gravity of the bike and the biker is deflected inward of the turn, compensating for the centrifugal force. To the “main course” there is also an inevitable, but healthy “side dish”. The bike slides backward, transferring the load to the rear wheel and preventing the possibility of slipping and skidding and creating favorable conditions for braking. Braking with the front wheel on a bend is unwise and dangerous. You can brake with the rear wheel, but very carefully, avoiding skidding, which will quickly lead to skidding. It makes sense to take into account that during braking on a bend, the bike changes its trajectory, and the more, the more the rear brake is applied. You don’t have to fit into a narrow path. And when the rear wheel is skidding, the bike will move almost in a straight line. If sharp turns follow one another, then it is useful to sharply tilt the bike in the direction of the turn, resting your foot on the pedal, which is in the lower position from the outside. To do this, it is sometimes convenient to crank the pedals in the opposite direction and take a turn in a sporty style, with vertically positioned cranks.

It is advantageous to make a turn at high speed along the maximum possible radius. To do this, you can start the turn at the outer edge of the track, then go near the inner edge and end the turn again at the outer edge. This is permissible if you are not driving on a road. Otherwise, this maneuver is a double violation of traffic rules, and even about your safety, especially if the turn is closed, and there is nothing to say. Other cornering trajectories may be beneficial depending on the specific conditions.

The second option is cornering to shorten the time if the grip of the tires, determined, in particular, by the coefficient of friction (K), is large enough. For example, you are driving on dry clean asphalt (K = 0.7), concrete (K = 0.9), soft ground where the tread spikes are imprinted, leaving a clear mark, etc. In order to take full advantage of the great traction. it is advantageous to tilt the bicycle in the direction of the turn at a greater angle than in the first version. Then, to balance the forces, the body remains almost vertical, and its center of gravity shifts slightly to the outside of the turn. You can stay in the saddle, but it is convenient to slightly rise above the saddle, but only a little, since the main idea of ​​this technique is to lower the center of gravity (more precisely “CM”. the center of mass) of the biker-bike system. This allows you to take a turn faster: on a smaller radius and / or at a higher speed. The extra tilt angle and upright position of the bike increase the mobility of the bike and make it easier to deal with skids. The connecting rods should be vertical with the outer connecting rod at the bottom. Another technique: if you press on the top tube of the bike with your “outer” thigh, you can additionally and very accurately control the trajectory without changing the position of the steering wheel. The inner thigh helps turn and maintain balance. the bent leg is pulled back towards the turn and slightly reduces the lean of the bike. This technique can be used in the first variant of the turn.

The third option is cornering on wet, slippery and wintry roads with low grip. Then the bike remains almost upright, the cyclist’s body shifts inward of the bend, the “inside” leg is retracted toward the corner for a finer balance, and the “outside” thigh, if necessary, presses on the top tube of the frame. For steep turns along narrow and slippery (wet loam, clay soil, dry sandy soil) paths, when cornering on slopes, an extreme version of the third option is used:

  • for belaying on a tight turn, the “inside” leg is released from the pins or toe clips and unloaded from the weight of the body. the “empty leg” position. If necessary, it quickly straightens and extends to the side of the turn, preventing a fall.
  • for faster cornering, the “inner, empty leg” is removed from the pedal and lowered down, touching the ground with the heel. At this moment, the body moves forward, and the biker sits on the upper tube of the frame, as it were, and his hands rest on the steering wheel. The “outer” leg supports the body, and the “inner” leg, only touching the ground, creates a third fulcrum. It makes sense to lift the toe of the “inner” leg up to avoid injury to the ankle.

A slope corner is ideal for turning when the ground or road surface is sloped in the middle of the corner and the angle between the ground and the bike is about 90 °. But such conditions are most often encountered on specially prepared tracks. Something can be found in natural conditions. for example, the outer edge of a dirt road, a deep and wide enough track, a trace from a tractor.

Correct speed

It is possible to enter any skid only at a sufficiently high speed, so if your speed is above average, you always need to be prepared for a sharp turn. You must first practice on a dusty road, since on a slippery track it is easier to break the bike into a skid.

Suicide-no-hander

To learn this trick, you first need to “fly” and squeeze the saddle between your legs during the flight. When you feel that the bike is flying smoothly, and without the impact of your hands on it, first try to release your hands one at a time, then do not completely release the steering wheel, but just open your palms.

When all of this is easy to do, release both hands. Know: you are fully no-hander if you can clap your hands behind your back.

Bar-spin

As one of the foundational and simplest tricks in bmx street, the bar spin is a very complex dumb trick. When flying out, clamp the saddle with your feet, turn the handlebars and catch it.

It is usually performed on a bmx, but if desired, it can be done on a bike with a narrow handlebar.

Kick out

Medium trick, but very beautiful. From the takeoff, you need to turn the body and the steering wheel to the right, and throw the rear wheel with legs to the right (you can also to the left, as it is more convenient for you). Thus, the bike flies like a crease, only with a large turn of the steering wheel.

X-up

Steering wheel 180 degrees. Quite a strange trick is dying, for some it is given easily, for someone on the contrary. It is done something like this: the bike must be moved forward so as not to hook the leg with the steering wheel and turn the steering wheel 180 degrees. It will take a long time to learn, with each jump turning the steering wheel a fraction of a degree further.

Nothing

Aerobatics. Beautiful, difficult, dangerous. Pull the steering wheel towards you, as with no-hander, and the bike will fly almost vertically. First let go of your legs, then, slightly pulling on the steering wheel, let go of your hands. Ideally at the same time. The main thing is for the bike to fly smoothly and you have time to grab it.

Hall

In fact, not a trick on the bike, but a way to land more conveniently. To break or lay down means to turn in the air and land at an angle. It is usually used in cases where the takeoff and landing are not parallel, but the flight looks spectacular with them. You can do both with the help of the steering wheel (turn the steering wheel, the body turns after it by inertia), and vice versa. throw the body to the side, turning the steering wheel if necessary. to land softer.

One-footer

Another one of the easiest tricks to get rid of. From the takeoff, apply the rear brake and at the hovering point, leaving the chocolate foot on the pedal, raise and then lower the other. After it is easy to get it, take your leg not up, but sideways or back.

The best thing about learning this trick is that if you did not have time to put your foot in place, then nothing will happen from landing with one leg, the maximum. the connecting rod will bend, and then it is unlikely.

Optimal handlebar width for a bicycle

Optimal handlebar width for a bicycle

Hello dear readers, I haven’t contacted you in writing for a long time. Today we will talk about a very important parameter of the bicycle. the width of the handlebars. I recently tested a light freeride bike with a narrower handlebar than my street park bike, something like 640mm. So what’s the deal, you ask? Maybe it’s more convenient for the owner. And the fact is that for each discipline, there is a minimum safe steering wheel width, even not so. the minimum comfortable one. I just came up with this concept 🙂 The size of the handlebars is chosen depending on the type of bike, riding style, terrain and shoulder width of a particular cyclist.

For cyclists riding on road hybrids and road bikes, the optimal handlebar width is equal to the shoulder width for free breathing.

Mountain bike enthusiasts choose the size of the handlebars depending on the style and the intended terrain. It is believed that rudders with a width exceeding 2.5-6 cm shoulder width are well suited for rough terrain. A narrow handlebar on a freeride bike is good only if you have a bad eye, the sense of size is junk, and the track is filled with trees, and yes, you think that the brakes were invented for cowards. In all other cases, front bicycles require a wide handlebar, at least 700 mm wide. Yes, yes, I know what you are thinking about the rider’s shoulder width right now. I agree that everyone has their own and a guy with narrow shoulders will be uncomfortable on a wide steering wheel, but if you take an average person 170 cm tall, he will get used to a width of 700 mm in one day. For a girl, you can cut off the steering wheel a little, because their hands are shorter than those of guys. It’s definitely not worth putting your children on a fr bike.

So, back to the question of why you need a wide steering wheel for freeriding. everything is simple, just turn on the logic. Fr means high speeds, which means you need precise steering, every degree of wheel turn significantly affects the trajectory of movement, safety and comfort depend on it. It is more comfortable to hold on to a wide stick than a narrow one. The wider the steering wheel, the more accurately you can steer and the stronger and more comfortable it is to keep the weight on the steering wheel, resting your hands on it. Of course, if you are narrow-shouldered, then the prohibitively wide handlebars will cause discomfort. It is also safer to pass narrow forest tracks with a moderate steering width.

Cross-country skiing is typical for forests and parks, where trees are much more common and they grow more densely. For this and several other reasons, cross country handlebars are mainly 580-620 mm. Less often they take wider handlebars, up to 720 mm, but this is an amateur and more often for allmountain and enduro. In pure sight, for racing they take narrow handlebars. Have you seen how in road racing or cross country competition, riders stand on the pedals and pedal powerfully, while rocking the bike left and right? So doing such a power acceleration with a wide steering wheel is very inconvenient.

Stunt disciplines such as MTB / BMX Street, Dirt, Park are mainly characterized by small and medium-width handlebars, although in recent years wide “steering wheels” have also invaded freestyle disciplines. Since the age of riders starts as early as 12 years old (or even less), the degree of impact on the audience in the video industry is very high. Here is a 13-year-old boy watching a video with Garrett Reynolds and sees how he wets tricks on a wide 730 mm wide handlebars and thinks that if he has the same, he will ride like Garrett. This leads to the fact that the guy does not properly distribute the load on his shoulders, hands, back and he cannot ride normally.

The handlebars need to be cut to a width that is comfortable for YOU! Those who believe that the sawn-off steering wheel loses its virginity. keep your statements away from children, it will not give them anything. My advice is to grab the steering wheel so that the hands are slightly further than your shoulder width, this will be a comfortable width.

As for the tricks with the steering wheel twist. yes, you can turn the barspins at least 800 mm on the steering wheel, but to whom and what are you trying to prove with this? Personally, it’s convenient for me to make bars on handlebars up to 720 mm, this does not mean that I cannot make a bar on 800 mm handlebars, but why should I make myself problems :)?

Why do the wheels turn at a different angle when turning the steering wheel??

If you turn the steering wheel all the way, get out of the car and look at it from the front, you will notice that the wheels are turned at different angles: one is turned out more than the other. But this is not a malfunction, but on the contrary, an exact engineering calculation, which celebrates its anniversary this year. it turns exactly 200 years old. Why steering is designed this way, and why it couldn’t have been done otherwise?

The answer to this question lies on the surface: imagine that the car is moving in a clockwise circle. in this case, the circle along which the front right wheel will move will be less than the circle described by the left. Accordingly, at a constant speed of the car, the wheels on the same axle will rotate at different speeds. If the wheels were turned at the same angle, then the inner wheel, trying to move in the same way as the outer one, would constantly slip and cause slipping of the outer one. while the car’s behavior in the corner would be unpredictable, and tire wear would be catastrophic. This can be clearly seen on multi-axle bogies of trucks and trailers: non-turning wheels move with slippage in a corner, and tires wear out quickly and unevenly. Accordingly, to solve these problems and ensure the correct movement of the steered wheels along their trajectory, they turn at different angles.

READ  How To Match A Tire To A Bicycle Rim

The very problem of slipping the inner wheel in a turn was relevant long before the mass distribution of cars. after all, horse carts had the same problems. Actually, it was on the horse-drawn carriage that the steering, which solves this problem, made its debut: in 1817 it was invented by Georg Lankensperger, and in 1918 it was patented in England by his agent Rudolf Ackermann. Since then, the principle of turning the steering wheels at different angles in a turn is called the Ackermann principle.

To ensure the required angles of rotation of the wheels, the geometry of the steering linkage is calculated according to a single conventional scheme. In it, the track rod is shorter than the steering axle and is offset behind it, and the steering control arms lie on the mowing line between the steering axis of the front wheels and the center of the rear axle of the vehicle. To make it easier to understand this seemingly complicated explanation, just look at the simple diagram below.

Accordingly, when turning the wheels in such a scheme, they turn out to be turned at different angles. the inner one turns more, and the outer one turns less. In this case, the centers of the circles along which the wheels move coincide, and the radius of the circle for the outer wheel is actually the turning radius of the car “from curb to curb” adjusted for the width of the tire.

It is worth noting that the image above is schematic, and the steering of the car is, of course, more complex than what is shown in the diagram. However, the general geometry is valid for all “civilian” cars.

In motorsport, the approach can change: for example, on some racing cars, the situation with wheel angles may even be reversed to compensate for lateral wheel slip in high-speed corners, and in drift, the front wheels try to be parallel even in corners in order to reduce front tire wear at constant driving in a controlled drift. But these are extremes that are not relevant for ordinary serial cars.

By the way, at the very beginning, it was not in vain that we mentioned not only the different paths that pass in the turn of the wheel, but also the different speeds of their rotation. In order to provide the ability to rotate the wheels on the same axle at different speeds, as we have already said, a differential is needed.

Adjusting the height of the steering wheel

The most efficient way to make cycling more comfortable. adjust the stem and handlebar height. Often, a bike with a handlebar that cannot be adjusted in height is less controllable and not comfortable enough. Cyclists experiment with saddle heights, tire pressures, and suspension settings, but not everyone is aware of the benefits of setting the height of the handlebars correctly. Read our detailed guide on how to adjust the handlebar height yourself. The height of the handlebars is measured relative to the height of the saddle. So, riders often set the handlebars lower than the saddle, on the contrary, lovers of comfortable riding try to raise the handlebars higher.

Note that a low handlebar lowers the bike’s center of gravity. You put more stress on the front wheel, you increase traction. In addition, the low position of the handlebars more evenly distributes the rider’s weight between the wheels, which is especially important during uphill climbs. These features are even more noticeable on bikes with large wheels (29er).

But it is worth making a reservation: too low a position of the steering wheel impairs control over the bike. Luckily, you can easily experiment with handlebar heights on your own for free. We bring you a detailed guide to adjusting the height of the handlebars on modern mountain and road bikes using a threadless stem. If your stem is bolted to the fork stem. then most likely you have just such a system, which we will discuss below.

We have described in detail all the actions on the photos.

Time: 15 minutes Skill Assessment: Easy Cost: Free

Tools you need to adjust the handlebar height:

– Hex Socket Set. If you are working with lightweight components or carbon fiber we recommend using a strain relief to avoid ripping off the threads. Some stems will need T20 or T25 torxes

The easiest way to adjust the handlebar height. this is the use of special spacer rings, which are usually found on every bike.

This bike is equipped with two rings and a tapered ring for increased handlebar height. If you want to set the stem lower. the tapered ring can be replaced with a short spacer.

Spacer rings are usually fitted on all bikes (20mm to 30mm) so that stem and handlebar heights can be quickly changed by simply moving the rings above or below the stem. Bolts used are standard, hex head.

Start by securing your bike wheel and then loosen the stem bolts to the fork head tube.

Remove the steering column cover. Typically a 5mm or 4mm wrench.

Remove the stem from the fork head tube.

Decide for yourself to what height to lower the stem and remove the appropriate number of rings.

Place the stem back on the head tube and slide on the rings that you removed from under the stem.

Make sure there is a 3-5mm clearance from the top of the ring to the head tube after installing the rings. This will indicate that you have enough space left to tighten the steering column without play. If this gap is not there, then make sure that you have installed all the rings from those that were removed from under the stem or add more wheels (in case you are changing the stem and it has a lower mounting height).

6. Now install the steering column cover and tighten the bolt until you feel sufficient resistance. Hang up the front wheel by holding the bike by the top tube of the frame and check how smoothly the handlebars turn. This cap is required to pre-tighten the steering column. Tightening too loose will leave play that can ruin bearings and cups. Tightening too tight can impair handling due to insufficient steering. Perfect tightening. when, in the absence of backlash, the wheel suspended at an angle turns under its own weight.

Then align the stem so that it is flush with the wheel (the stem is straight)

Once the handlebars are aligned. tighten the stem mount to the fork head tube. Usually a tension of 5-8 Nm is used for this.

Check the steering column play again. It is very simple to do this: put the bike on the wheels, apply the front brake and rock the bike back and forth. If you do not feel free play (play), as well as when hanging the wheel on one side, the steering wheel turns under its own weight of the wheel. everything is done correctly. If play is found, carefully tighten the stem mounting bolts, then tighten the steering column cover a little more, align the handlebar and retighten the stem bolts.

Now test the new handlebar height, ride the bike.

TURNING THE STEERING WHEEL

If the height of the spacers is not enough for you, you can simply flip the stem. Most mountain bikes come with low-lift stems. You can easily lower the handlebars by simply flipping the stem. It is very simple and how to do it is described by the steps above. But in order to flip the stem, you also need to unscrew the handlebar (usually 2 or 4 bolts on the front of the stem)

The bike must be securely in place. Remove the stem bolts that secure the handlebars (usually two or four bolts).

Free the stem from the handlebars, then follow steps 1-4 above.

Remove the stem from the head tube and turn it over. Reattach the bike upside down.

Now attach the handlebars to the opposite stem. Use a torque of 4 to 8 Nm to tighten the bolts. Make sure all bolts are evenly tightened and the stem cover clearances are the same at both the top and bottom (see image).

Follow steps 3 to 7 (above) to properly tighten the steering column and stem.

You can now test the new rudder position in action. Handlebar adjustments are individual and may take a long time to determine the ideal fit. But when you get what you want. your bike handling skills will improve significantly.

Bicycle movement physics.

To keep the two-wheeled bike from falling, you need to constantly maintain balance. Since the support area of ​​a bicycle is very small (in the case of a two-wheeled bicycle, it is just a straight line drawn through two points at which the wheels touch the ground), such a bicycle can only be in dynamic equilibrium. This is achieved by steering: if the bike tilts, the cyclist tilts the handlebars in the same direction. As a result, the bike begins to turn and centrifugal force returns the bike to an upright position. This process occurs continuously, so a two-wheeled bicycle cannot go strictly straight; if the handlebars are secured, the bike will fall. The higher the speed, the greater the centrifugal force and the less you need to tilt the steering wheel to maintain balance.

When turning, you need to tilt the bike in the direction of the turn so that the sum of the force of gravity and centrifugal force passes through the line of the support. Otherwise, centrifugal force will tip the bike in the opposite direction. As well as when driving in a straight line, ideally it is impossible to maintain such an inclination, and steering is carried out in the same way, only the position of dynamic balance is shifted taking into account the centrifugal force that has arisen.

The bike’s steering design makes it easier to maintain balance. The steering axis is not vertical, but tilted back. It also runs below the front wheel’s pivot point and in front of the point where the wheel touches the ground. This design achieves two goals:

  • In case of accidental deviation of the front wheel of a moving bicycle from the neutral position, a frictional moment occurs about the steering axle, which returns the wheel back to the neutral position.
  • When the bike is tilted, a moment of force is generated that turns the front wheel towards the tilt. This moment is caused by the reaction force of the support. It is attached to the point at which the wheel touches the ground and is directed upward. Because the steering axle does not pass through this point, when the bike is tilted, the reaction force of the support shifts relative to the steering axle.

Thus, automatic steering is carried out. helping to maintain balance. If the bike accidentally tilts, then the front wheel turns in the same direction, the bike begins to turn, centrifugal force returns it to the vertical position, and friction forces the front wheel back to the neutral position. Thanks to this, you can ride a bike “hands-free”. The bike itself maintains balance. By shifting the center of gravity to the side, you can maintain a constant tilt of the bike and make a turn.

It can be seen that the ability of a bicycle to maintain dynamic balance on its own depends on the design of the steering fork. The defining shoulder is the reaction arm of the wheel support, that is, the length of the perpendicular lowered from the point of contact of the wheel to the ground on the axis of rotation of the fork; or, equivalently, but easier to measure, the distance from the point of contact of the wheel to the point of intersection of the axis of rotation of the fork with the ground. Thus, for the same wheel, the resulting torque will be the higher, the greater the inclination of the fork axis of rotation. However, to achieve optimal dynamic characteristics, not a maximum torque is needed, but a strictly defined one: if too small a torque will lead to the difficulty of maintaining balance, then too large. to oscillatory instability, in particular. “shimmy” (see below). Therefore, the position of the wheel axle relative to the fork axis is carefully chosen during design; many bicycle forks are bent or simply biased forward to reduce excess torque.

The widespread opinion about the significant influence of the gyroscopic moment of rotating wheels on the maintenance of balance is incorrect.

At high speeds (starting at approx. 30 km / h), the front wheel may experience so-called speed wobbles, or shimmies, are well known in aviation. With this phenomenon, the wheel spontaneously wags to the right and to the left. High-speed wobbling is most dangerous when riding without hands (that is, when the cyclist rides without holding the wheel). High-speed wobbling is not due to poor build or loose front wheel attachment, it is caused by resonance. High-speed wobbles are easy to suppress by slowing down or changing posture, but if not done, they can be deadly.

Cycling is more efficient (in terms of energy consumption per kilometer) than walking and driving. Cycling at a speed of 30 km / h burns 15 kcal / km (kilocalories per kilometer), or 450 kcal / h (kilocalories per hour). Walking at a speed of 5 km / h burns 60 kcal / km or 300 kcal / h, that is, cycling is four times more efficient than walking in terms of energy consumption per unit distance. Because cycling consumes more calories per hour, it is also the best athletic activity. When running, the cost of calories per hour is even higher. Please note that shock loads while running, as well as improper cycling (for example, riding uphill in high gears, hypothermia of the knees, lack of sufficient fluid, etc.) can injure the knees and ankle joint. A trained man who is not a professional athlete can develop a power of 250 watts, or 1/3 hp, for a long time. from. This corresponds to a speed of 30-50 km / h on a flat road. A woman can develop less absolute power, but more power per unit of weight. Since on a flat road almost all power is spent on overcoming air resistance, and when driving uphill, the main costs are to overcome gravity, women, all other things being equal, go slower on a level place and faster uphill.

Views count: 18482