Bsi bs en 14764 2005 (2006)

16 Figure 6 — Method of fitting the gauge to the handbrake-lever and handlebar Minimum grip length is shown For the purposes of all braking tests in this standard the test force shall

Brake tests and strength tests – Special requirements

Definition of brake tests

Licensed Copy: AUB User, na, Mon Jun 25 14:15:56 GMT+00:00 2007, Uncontrolled Copy, (c) BSI

Definition of strength tests

Strength tests to which accuracy requirements apply, as in 4.1.4, are those involving static, impact or fatigue loading as specified in subclauses 4.7 to 4.14 inclusive and 4.20.2.

Numbers and condition of specimens for the strength tests

For static, impact, and fatigue tests, it is typically required to use a new test sample for each test However, if only one sample is available, all tests may be performed on that single sample, following the sequence of fatigue, static, and then impact testing.

When more than one test is conducted on the same sample, the test sequence shall be clearly recorded in the test report or record of testing

When multiple tests are performed on the same sample, earlier tests may affect the outcomes of later tests Additionally, if a sample fails after undergoing several tests, it becomes challenging to make a direct comparison with results from single testing.

In all strength tests, specimens shall be in the fully-finished condition

Accuracy tolerances of test conditions for brake tests and strength tests

Unless stated otherwise, accuracy tolerances based on the nominal values shall be as follows:

Sharp edges

Exposed edges that could come into contact with the rider's hands, legs, etc., during normal riding or normal handling and normal maintenance shall not be sharp.

Security and strength of safety-related fasteners

Security of screws

All screws involved in the assembly of suspension systems, as well as those securing generators, brake mechanisms, mud guards to the frame, fork, handlebar, and saddle to the seat pillar, must be equipped with appropriate locking devices such as lock washers, lock nuts, or stiff nuts.

NOTE Fasteners used to assemble hub and disc brakes should have heat-resistant locking devices.

Minimum failure torque

The minimum failure torque for bolted joints used in fastening handlebars, handlebar-stems, bar-ends, seats, and seat-pillars must exceed the manufacturer's recommended tightening torque by at least 50%.

Folding bicycles

Folding bicycles shall meet all test requirements

Folding mechanisms must be engineered to allow for easy, stable, and secure locking of the bicycle When folded, the design should ensure that no damage occurs to any cables Additionally, the locking mechanism must not make contact with the wheels or tires while riding, and it should be impossible to accidentally loosen or unlock the folding mechanisms during use.

Crack detection methods

Standardised methods should be used to emphasise the presence of cracks where visible cracks are specified as criteria of failure in tests specified in this standard

NOTE For example, suitable dye-penetrant methods are specified in ISO 3452.

Protrusions

Requirement

Any rigid exposed protrusion longer than 8 mm must terminate in a radius of at least 6.3 mm, except for specific components such as the front gear-change mechanism, rear gear-change mechanism, rim-brake mechanisms, lamp-brackets, reflectors, toe-clips, toe-straps, clipless attachment mechanisms, chain-wheels, sprockets, and water bottle cages Additionally, these protrusions should have a major end dimension of no less than 12.7 mm and a minor dimension of at least 3.2 mm.

4.5.1.2 Exclusion zone, protective devices and screw threads

The top tube of a bicycle frame must remain free of protrusions between the saddle and a point 300 mm forward, except for control cables with a maximum diameter of 6.4 mm and cable clamps that do not exceed a thickness of 4.8 mm.

Foam pads attached to the bicycle frame to act as protective cushions are permitted, provided that the bicycle meets the requirements for protrusions when the pads are removed

A screw thread that is an exposed protrusion shall be limited to a protrusion length of one major diameter of the screw beyond the internally threaded mating part

Test method

Conduct the test with a protrusion test cylinder (which simulates a limb) having the dimensions shown in Figure 2

To assess the bicycle's safety, maneuver the test cylinder in various positions towards any rigid protrusion If the central 75 mm section of the cylinder makes contact with the protrusion, it is classified as an exposed protrusion and must adhere to the standards outlined in section 4.5.1.1.

Examples of protrusions that need and do not need to comply with the requirements are shown in Figure 3

Figure 2 — Exposed protrusion test cylinder

Brakes

Braking-systems

A bicycle must have a minimum of two independent braking systems, with one system functioning on the front wheel and the other on the rear wheel These braking systems should operate smoothly without binding and must meet the braking performance standards outlined in section 4.6.8.

Brake-blocks containing asbestos shall not be permitted.

Hand-operated brakes

The positioning of hand-brake levers for front and rear brakes must comply with the legislation or customary practices of the country where the bicycle is sold Additionally, the bicycle manufacturer is required to specify in the user instruction manual which levers control the front and rear brakes.

The maximum grip dimension, denoted as \(d\), must be measured between the outer surfaces of the brake lever where it contacts the rider's fingers and the handlebar or any covering This measurement should span a minimum distance of 40 mm, as illustrated in Figure 4.

 on bicycles on which the minimum intended height of the saddle is less than 635 mm, d shall not exceed 75 mm

Conformance shall be established by the method detailed in 4.6.2.2.2

NOTE The range of adjustment on the brake-lever should permit these dimensions to be obtained

The dimension a, shown in Figure 4 which is used in 4.6.2.3 to establish the position for applying the test force, shall be established by the method detailed in 4.6.2.2.2

Key a Distance between the last part of the lever intended for contact with the rider's fingers and the end of the lever d Maximum grip dimension

Figure 4 — Handbrake-lever grip dimensions 4.6.2.2.2 Test method

To properly fit the gauge over the handlebar-grip or handlebar, position it so that face A contacts both the handlebar or grip and the side of the brake-lever Ensure that face B covers the area of the brake-lever meant for finger contact, without causing any movement of the brake-lever towards the handlebar or grip Finally, measure the distance \( a \), which is the space between the last part of the lever intended for finger contact and the end of the lever, as detailed in sections 4.6.2.2.1 and 4.6.2.3, along with Figures 4 and 5.

Figure 5 — Handbrake-lever grip dimension gauge

Figure 6 — Method of fitting the gauge to the handbrake-lever and handlebar (Minimum grip length is shown)

4.6.2.3 Handbrake levers — Position of applied force

In accordance with this standard, the test force for all braking tests must be applied at a distance, b, which is either equal to dimension a (refer to Figure 4) as specified in section 4.6.2.2.2 or 25 mm from the free end of the brake lever, depending on which distance is greater (see Figure 7).

Figure 7 — Position of applied force on the handbrake-lever

Attachment of brake assembly and cable requirements

NOTE See 4.3 in relation to fasteners

Cable pinch-bolts must be installed according to the manufacturer's instructions to avoid cutting any cable strands Additionally, if a cable fails, the brake mechanism should not unintentionally obstruct the wheel's rotation.

The cable end shall either be protected with a cap that shall withstand a removal force of 20 N or be otherwise treated to prevent unravelling

To prevent corrosion, the inner cable must be shielded by an appropriate impervious liner within the outer casing Additionally, either the inner cable should feature a low-friction coating or the outer casing should include a low-friction lining.

Brake-block and brake-pad assemblies — Security test

The friction material must be firmly attached to the holder, backing plate, or shoe, ensuring no assembly failure during testing as outlined in section 4.6.4.2 Additionally, the brake system must successfully pass the strength test in section 4.6.6 and meet the braking performance standards specified in section 4.8.4 after completing the tests in section 4.6.4.2.

To conduct the test, ensure the bicycle is fully assembled with properly adjusted brakes and a rider or equivalent mass seated on the saddle, totaling a combined weight of 100 kg.

To test the brake-lever, apply a force of 180 N at the specified point or a lesser force that brings the brake-lever into contact with the handlebar grip This force must be maintained while the bicycle undergoes five forward and five rearward movements, each covering a minimum distance of 75 mm.

Brake adjustment

Each brake must be adjustable without tools to ensure optimal performance until the friction material needs replacement, as advised by the manufacturer.

Also, when correctly adjusted, the friction material shall not contact anything other than the intended braking surface

Bicycle brake blocks with rod brakes must not touch the wheel rims when the handlebars are turned to a 60° angle Additionally, the rods should remain straight and not bend or twist when the handlebars are returned to the central position.

Hand-operated braking-system — Strength test

When tested by the method described in 4.6.6.2, there shall be no failure of the braking-system or of any component thereof

Test the fully-assembled bicycle by ensuring the braking system is adjusted per the manufacturer's instructions Apply a force of 450 N to the brake lever, or a lesser force if necessary, to achieve contact between the brake lever and the handlebar grip, or the handlebar itself if no grip is fitted Additionally, ensure that a brake extension lever is level with the handlebar surface or in contact with it.

Repeat the test for a total of 10 times on each hand-brake lever or extension lever

Back-pedal braking system

The brake is activated by the operator's foot pressing the pedal against the drive force It is designed to operate effectively regardless of the drive-gear settings Additionally, the angle difference between the drive and brake positions of the crank must not exceed 60°.

The measurement shall be taken with the crank held against each position with a pedal force of at least 250 N The force shall be maintained for 1 min in each position

When tested in accordance with 4.6.7.3 there shall be no failure of the brake system or any component thereof

To conduct the test on a fully-assembled bicycle, ensure the braking system is properly adjusted With the pedal cranks positioned horizontally, apply a downward force to the center of the left-hand pedal spindle, gradually increasing it to 1,500 N and maintaining this force for one minute.

4 Cycle chain-wheel and pedal crank

Braking performance

Braking performance is defined by the stopping distance, known as the braking distance Two testing methods are available, and both have proven effective, allowing for flexibility in their application.

One test method is the track test in which braking distance is measured directly with the progressive characteristics of the brakes being self-evident

The alternative testing method involves a machine test that measures braking force to calculate braking distance The linearity measurements determine the progressive characteristics of the brake, while a straightforward track test assesses the smoothness and safety of stopping performance.

Whichever method is used there shall be compliance with 4.6.8.2 and 4.6.8.3

Perform a braking-performance test on a fully-assembled bicycle after completing the strength tests outlined in sections 4.6.6 and 4.6.7 Prior to testing, ensure the tyres are inflated and the brakes are adjusted according to the manufacturer's guidelines, ensuring that rim-brakes are set to the maximum clearance specified.

When a bicycle is equipped with secondary brake levers connected to handbrake levers, bar ends, or aerodynamic extensions, it is essential to perform separate tests to evaluate the functionality of the secondary brake levers alongside the standard levers.

The bicycle shall fulfil the requirements shown in Table 1

Table 1 - Brake test velocities and braking distances

The bicycle shall show smooth, safe stop characteristics with regard to the intended use of the bicycle and the ability of the expected user of the bicycle

Safe-stop characteristics in track tests are defined by the ability to stop within required distances while avoiding issues such as excessive juddering, front wheel locking, bicycle overturning, loss of rider control, and excessive side-skid that forces the rider to put a foot down for stability.

Certain braking systems may lead to unavoidable rear wheel skidding during braking, which is acceptable as long as it does not result in conditions d) or e).

Back pedal-brakes shall additionally comply with linearity test of subclause 4.6.8.5.2

(ii) For the machine test, smooth, safe-stop characteristics are defined by compliance with the linearity requirements specified in subclause 4.6.8.5.3.4 and the simple track test described in 4.6.8.5.3.7 VIII)

4.6.8.4.3 Ratio between wet and dry braking performance

In order to ensure safety for both wet and dry braking, the ratio of braking performance wet:dry shall be greater than 4:10

The methods for calculating this ratio are given in 4.6.8.5.1.11 for the track test and in 4.6.8.5.3.7 VII) for the machine test

For optimal testing conditions, utilize an indoor test track whenever possible If an outdoor track is necessary, closely monitor ambient conditions during the test The track's gradient must not exceed 0.5%; if it is below 0.2%, all runs should be conducted in the same direction, while gradients between 0.2% and 0.5% require alternating runs in opposite directions The track surface should be hard, made of concrete or fine asphalt, and free from loose dirt or gravel, with a minimum friction coefficient of 0.75 between the dry surface and the bicycle tire Additionally, ensure the track is essentially dry at the start of testing.

4.6.8.5.1.6, the track shall remain dry throughout the tests; e) the wind speed on the track shall not exceed 3 m/s during the tests

The test bicycle or track must be equipped with essential instruments, including a calibrated speedometer or tachometer that is accurate to within ± 5% to inform the rider of the speed at the start of braking Additionally, a velocity recording device with an accuracy of ± 2% is required to document the velocity at the moment braking begins.

The braking system includes a distance recording system with an accuracy of ± 1% to measure braking distance, and a water spray system designed to wet the braking surface This system features a water reservoir connected by tubing to nozzles located at both the front and rear wheels, equipped with a quick-acting on/off valve for rider control Each nozzle is required to deliver a minimum flow of 4 ml/s of water at ambient temperature Detailed specifications for the positioning and direction of the nozzles for various brake types, including rim, hub, band, and disc brakes, are illustrated in Figures 9 to 14.

Figures 9 and 10 illustrate side-pull calipers for rim brakes, but the same configurations are applicable to center-pull calipers and cantilever brakes Additionally, a brake-actuation indicating system is included to independently record the activation of each lever or pedal.

4.6.8.5.1.3 Mass of bicycle, rider and instrumentation

The combined mass of the bicycle, the rider, and the instrumentation shall be 100 kg

During wet condition braking tests, the total mass may reduce due to water consumption; however, it must remain at least 99 kg by the conclusion of valid test runs.

Manufacturers must ensure that bicycles designed to carry a total mass exceeding 100 kg, including the bicycle's weight, are tested at this higher total mass These bicycles must also meet the required braking distance specifications.

Any extra weight shall be positioned above the rear wheel and in front of the rear axle

4.6.8.5.1.4 Force applied to the handbrake-levers

I) Magnitude and position of force on handbrake-levers

Apply a handgrip force not exceeding 180 N at the point as specified in 4.6.2.3 Check before and after each series of test runs to verify the lever force

II) Optional brake-force application device

A test mechanism may be utilized to operate the hand brake lever, provided it complies with the requirements of 4.6.8.5.1.4 I) This device must also regulate the application rate of the handbrake lever force, ensuring that 63% of the intended force is applied within a minimum time frame of 0.2 seconds.

4.6.8.5.1.5 Running-in the braking surfaces

A running-in process shall be conducted on every brake before performance testing is carried out

Apply the brakes for not less than three seconds to maintain steady deceleration whilst the bicycle is being ridden at a speed of approximately 16 km/h Repeat this operation 10 times

4.6.8.5.1.6 Test method – Test runs under dry conditions

Pedal the test bicycle until you reach the designated test velocity as outlined in Table 1 Once the speed is attained, cease pedaling and engage the brakes to bring the bicycle to a smooth and safe stop, following the guidelines in section 4.6.8.4.2 (i).

4.6.8.5.1.7 Test method – Test runs under wet conditions

The procedure outlined in section 4.6.8.5.1.6 requires that the wetting of the brake system(s) begins at least 25 meters before braking starts, as specified in section 3.12, and continues until the bicycle has come to a complete stop.

NOTE Excessive amounts of water may be swept from the test-track surface between runs

4.6.8.5.1.8 Number of valid test runs

Brakes - Heat-resistance test

Each brake on the bicycle shall be tested individually, but where the front and rear brakes are identical only one brake need be tested

During the test outlined in section 4.6.9.3, it is essential to maintain a minimum gap of 10 mm between the hand-brake lever and the handlebar grip Additionally, the operating force must not exceed 180 N, and the braking force should remain within the range of 60 N to 115 N.

After undergoing the test outlined in section 4.6.9.3, the brakes must attain a minimum of 60% of the braking performance recorded at the maximum operating force utilized during the performance tests specified in sections 4.6.8.5.3.7 III) a) and b).

Conduct the test by driving the wheel and tyre assembly with the brake engaged on a specified machine at a speed of 12.5 km/h ± 5% Simultaneously, maintain a rearward cooling air velocity of 12.5 km/h ± 10% to generate a total braking energy of 55 Wh ± 5% The test duration should be 15 minutes ± 2 minutes.

Allow the brake to cool to ambient temperature and then repeat the test cycle

A maximum of ten interruptions per test cycle is permitted, each with a maximum duration of ten seconds

Calculate the braking energy from the following formula:

FBr is the braking force (N);

VBr is the linear velocity of the periphery of the tyre (m/s) (i.e 12,5 km/h = 3,472 m/s)

T is the duration of each test cycle (h) (excluding interruptions) (i.e 15 min = 0,25 h)

Steering

Handlebar — Dimensions

The handlebar width must range from 350 mm to 1000 mm, unless specified otherwise by national regulations Additionally, the vertical distance from the top of the handlebar grips, when set to the highest riding position as per the manufacturer's guidelines, to the saddle's lowest seat surface must not exceed 400 mm.

Handlebar grips and plugs

The ends of the handlebar shall be fitted with handgrips or end plugs When tested by the method described in 4.7.2.2, the handgrips or plugs shall withstand a removal force of 70 N

To loosen the handlebar grips or plugs, first immerse the handlebar in room temperature water for one hour Next, place it in a freezing cabinet until it reaches a temperature below –5 °C Once removed, allow the handlebar to stabilize at –5 °C, then apply a force of 70 N in the loosening direction Maintain this force until the handlebar warms up to +5 °C.

Handlebar stem – Insertion-depth mark or positive stop

The handlebar-stem must feature one of two methods to ensure safe insertion depth into the fork-stem First, it should have a permanent transverse mark, at least equal to the external diameter of the stem, indicating the minimum insertion depth This mark must be positioned at least 2.5 times the external diameter of the handlebar-stem from the bottom, with a minimum of one stem diameter's length of continuous material below it Alternatively, the handlebar-stem can include a permanent stop to prevent it from being pulled out of the fork-stem, ensuring the insertion depth meets the specified requirements.

Handlebar stem-extension to fork-stem - Clamping requirements

The distance \( g \) between the upper external part of the handlebar stem clamp and the upper inner part of the fork-stem must not exceed 5 mm, as illustrated in Figure 18.

The upper part of the fork-stem to which the stem-extension is clamped shall not be threaded

The dimension g shall also ensure that the proper adjustment of the steering system can be achieved

NOTE For aluminium and carbon-fibre fork-stems the avoidance of any internal device that could damage the internal surface of the fork-stem is recommended

Key g Distance between the upper, external part of the handlebar-stem clamp and the upper, part of the fork-stem

6 Stem-extension to stem clamp

Figure 18 — Clamping between the handlebar-stem-extension and fork-stem

Steering stability

The steering must be able to rotate freely at least 60° in both directions from the straight-ahead position, without any tight spots, stiffness, or slackness in the bearings when properly adjusted.

When the rider is seated on the saddle and gripping the handlebars, at least 25% of the combined mass of the bicycle and rider must be applied to the front wheel, with both the saddle and rider positioned in their furthest rearward settings.

NOTE Recommendations for steering geometry are given in Annex B.

Steering assembly — Static strength and security tests

4.7.6.1 Handlebar-stem – Lateral bending test

This test is intended for stem manufacturers who do not produce handlebars

Testing according to the specified method must show that the stem exhibits no cracking or fractures, and the permanent set at the test force application point should not exceed 10 mm.

For stems with a quill designed for insertion into a fork-stem, securely clamp the quill to the minimum insertion depth For stem extensions that attach directly to an extended fork-stem, follow the manufacturer's instructions for attachment and securely clamp the fork-stem at the appropriate height Assemble a test-bar to the stem and apply a force of 600 N at a distance of 300 mm from the stem's axis, maintaining this force for 1 minute.

Key a) Combined stem and quill b) Stem extension

Figure 19 — Handlebar-stem: lateral bending test

4.7.6.2 Handlebar and stem assembly — Lateral bending test

This test is for manufacturers who produce handlebars and stems or for cycle manufacturers

Testing according to the specified method ensures that the handlebar, stem, and clamp-bolt exhibit no cracking or fractures, with a maximum allowable permanent set of 15 mm at the test force application point.

Assemble the handlebar and stem following the manufacturer's instructions, ensuring the grips of the handlebar are aligned perpendicular to the stem axis unless they are permanently connected For quill stems, securely clamp the quill at the minimum insertion depth, and for stem extensions, attach them according to the manufacturer's guidelines Apply a force of 600 N at a distance of 50 mm from the handlebar's free end and maintain this force for 1 minute.

When the distance between the center lines of the stem clamp and the handgrip exceeds 100 mm, it is essential to apply forces on the handgrips at a location 50 mm from the end of the handgrip.

Figure 20 — Adjustable handlebars: orientation for tests

Key a) Combined stem and quill b) Stem extension

4.7.6.3 Handlebar-stem — Forward bending test

Conduct the test in two stages on the same assembly as follows

When evaluated according to the specified method, there should be no visible cracks or fractures present Additionally, the permanent set measured at the point of force application, aligned with the direction of the test force, must not exceed the established limits.

To securely insert stems with a quill into a fork-stem, clamp the quill in a fixture at the minimum insertion depth For stem extensions that attach directly to an extended fork-stem, firmly secure the handlebar-stem extension onto a solid steel bar, ensuring the bar is clamped securely in a fixture, with the length of the bar being non-critical.

Apply a force of 1,600 N at a 45° angle downward through the handlebar attachment point, maintaining this force for one minute After releasing the force, measure any permanent deformation as specified in section 4.7.6.3.2.

If the handlebar-stem meets the requirement of 4.7.6.3.2, conduct Stage 2 of the test

Key a) Stem extension b) Combined stem and quill

Figure 22 — Handlebar stem: forward bending test

When tested by the method described in 4.7.6.3.5, there shall be no visible cracks or fractures

Apply a progressively increasing force on the handlebar-stem, as mounted in Stage 1 (4.7.6.3.3), in the same position and direction until the force reaches a maximum of 2,000 N or the handlebar-stem deflects 50 mm at the point of force application If the stem does not yield or continues to yield, maintain the force for 1 minute.

4.7.6.4 Handlebar to handlebar-stem — Torsional security test

When tested by the method described in 4.7.6.4.2, there shall be no movement of the handlebar relative to the handlebar-stem

Securely clamp the handlebar stem in a fixture at the minimum insertion depth with its axis positioned vertically Apply a torque of 60 Nm along the center-line of the stem-clamp Distribute the torque evenly by applying vertical downward forces on both sides of the handlebar, and maintain these forces for one minute.

NOTE The exact method of applying the torque will vary with the type of handlebar, and an example is shown in Figure 23

When bar-ends are installed by the manufacturer, test forces must be applied to them as illustrated in Figure 27 a) If the manufacturer's guidelines permit the use of bar-ends, simulated bar-ends, as depicted in Figure 27 b), should be utilized for testing.

Figure 23 — Handlebar to handlebar-stem: torsional security test 4.7.6.5 Handlebar-stem to fork-stem — Torsional security test

To properly assemble the fork-stem in the frame, securely attach the handlebar-stem to the fork-stem using the locking system as per the manufacturer's guidelines Ensure to apply a torque of 40 Nm in each possible rotational direction, maintaining this torque in a plane that is perpendicular to the axis of the fork and handlebar-stem.

NOTE The exact method of applying the torque may vary, and an example is shown in Figure 24

Figure 24 — Handlebar-stem to fork-stem: torsional security test 4.7.6.6 Bar-end to handlebar — Torsional security test

When tested by the method described in 4.7.6.6.2 there shall be no movement of the bar-end in relation to the handlebar

To properly install the bar-end on the handlebar, secure the handlebar in a suitable fixture and follow the manufacturer's instructions for tightening the fixings Additionally, apply a force of 300 N to the bar-end at a specified distance.

50 mm from the free end of the bar-end as shown in Figure 25 and maintain this force for 1 min

Figure 25 — Bar-end to handlebar: torsional security test

Handlebar and stem assembly — Fatigue test

Handlebar-stems can affect the testing outcomes of handlebars; therefore, handlebars must always be tested when mounted on a stem However, it is acceptable to test a stem using a solid bar that matches the dimensions of compatible handlebars and bar-ends.

For fatigue testing focused solely on the stem, the manufacturer must define the specific types and sizes of handlebars compatible with the stem, ensuring that the test is conducted using the most extreme combination of these components.

Conduct the test in two stages on the same assembly as follows

When tested by the method described in 4.7.7.1.2, there shall be no visible cracks or fractures in any part of the handlebar and stem assembly

For carbon-fibre handlebars or stems, the peak deflections during the test in either direction from the mean position shall not increase by more than 20 % of the initial values

Ensure that the grips of the handlebar are aligned in a plane perpendicular to the stem axis, unless they are permanently connected by welding or brazing Secure the handlebar to the stem following the manufacturer's instructions.

Securely clamp the handlebar stem in a fixture at the minimum insertion depth, or if using a stem extension for an extended fork-stem, follow the manufacturer's recommended tightening procedure to ensure proper attachment.

For handlebars not designed for bar-end use, apply reversed forces of 200 N at a distance of 50 mm from each free end for 100,000 cycles, ensuring the forces are out of phase and parallel to the handlebar-stem axis, as illustrated in Figure 26a The maximum testing frequency should be set at 25 Hz.

When installing bar-ends on a bicycle handlebar, ensure they are positioned according to the manufacturer's tightening instructions, with the bar-ends aligned perpendicular to the handlebar stem axis Additionally, apply out-of-phase forces to the bar-ends as illustrated in Figure 27a.

When a handlebar manufacturer indicates that their handlebars are compatible with bar-ends, it is essential to conduct tests using out-of-phase forces applied to simulated bar-ends, as illustrated in Figure 27b.

If the handlebar meets the requirement of 4.7.7.1.1, remove any bar-ends and conduct Stage 2 of the test with the assembly in the same mountings

Key a) Stage 1 — Out-of-phase loading

Key a) Test for handlebar fitted with bar-ends (Plan view) b) Test for handlebar intended for bar-ends (Plan view)

Figure 27 — Handlebar incorporating bar ends: out of phase fatigue tests 4.7.7.1.3 Requirement for Stage 2

When tested by the method described in 4.7.7.1.4, there shall be no visible cracks or fractures in any part of the handlebar and stem assembly

For carbon-fibre handlebars or stems, the peak deflections during the test in either direction from the mean position shall not increase by more than 20 % of the initial values

Apply opposing forces of 250 N at a distance of 50 mm from the free end on each side of the handlebar for 100,000 cycles, ensuring that the forces are in phase and parallel to the handlebar stem's axis, as illustrated in Figure 26b The maximum testing frequency should be set at 25 Hz.

Frames

Suspension-frames — Special requirements

The design must ensure that in the event of a spring or damper failure, the tyre does not make contact with any part of the frame, and the assembly holding the rear wheel remains securely attached to the frame.

Frame and front-fork assembly - Impact test (falling mass)

Bicycle manufacturers must perform tests on complete bicycles with the frame equipped with the correct front fork, ensuring that if a suspension fork is used, it is at its unloaded length.

Manufacturers of frames are permitted to conduct the test with a solid-steel bar fitted in place of a front fork

To ensure proper testing of a convertible frame for both male and female riders, remove the bar and conduct tests without it When a suspension fork is present, extend the fork to its unloaded free length for accurate assembly testing For frames with a rear suspension system, simulate the weight of an 80 kg rider by securing the suspension in a corresponding position If the suspension system cannot be locked, replace the spring/damper unit with a solid link of the appropriate size and compatible end fittings.

Testing according to the specified method in section 4.8.2.3 must show that the assembly is free from visible cracks or fractures, and that all components of the suspension system remain securely attached without any separation.

The wheel-base, defined as the permanent set between the axes of the wheel axles, must not exceed specific limits: 30 mm when a fork is installed and 10 mm when a solid-steel bar replaces the fork.

Assemble a roller with a mass of 1 kg or less, adhering to the dimensions specified in Figure 27, within the fork If substituting a steel bar for the fork, ensure the bar has a rounded end that matches the roller's shape Securely hold the frame-fork or frame-bar assembly in a vertical position by clamping it to a rigid fixture at the rear-axle attachment points, as illustrated in Figure 28.

To measure the wheel-base, place a striker weighing 22.5 kg on the roller in the fork drop-outs or on the rounded end of a solid bar Elevate the striker to a height of 180 mm above the low-mass roller and release it to strike the roller or steel bar at a point aligned with the wheel centers, opposing the fork rake or bar rake direction The striker will bounce upon impact, which is expected Once the striker has come to rest on the roller or solid bar, measure the wheel-base again.

5 Low mass roller (1 kg max.)

6 Rigid mounting for rear axle attachment point

Figure 28 — Frame and front fork assembly: impact test (falling mass)

Frame - Fatigue test with pedalling forces

All types of frame shall be subjected to this test

In testing suspension frames with pivoted joints, it is essential to adjust the spring, air pressure, or damper for maximum resistance If using a pneumatic damper with non-adjustable air pressure, replace the suspension unit with a rigid link that accurately simulates the original unit's end fixings and lateral rigidity For suspension frames with chain stays that flex instead of pivoting, ensure that dampers are set to provide minimal resistance to facilitate proper testing of the frame.

To optimize the performance of a bicycle suspension frame, it is essential to strategically position adjustable brackets or linkages These components should be arranged to effectively manage the resistance against ground-contact forces and to adjust the bicycle's attitude, ensuring that the frame can withstand maximum forces.

Testing under section 4.8.3.3 requires that the frame exhibits no visible cracks or fractures, and that all components of the suspension system remain intact without any separation.

For carbon-fibre frames, the peak deflections during the test at the points where the test forces are applied shall not increase by more than 20 % of the initial values

For testing, utilize a new frame and fork assembly equipped with standard head-tube bearings Alternatively, the front fork can be substituted with a dummy fork that matches the original fork's length and possesses equal or greater stiffness.

For optimal performance and safety, it is advisable to use a dummy fork that is stiffer and stronger than the genuine fork, as genuine forks may experience failures.

Where a frame is convertible for male and female riders by the removal of a bar, test it with the bar removed

Mount the frame assembly onto a base as illustrated in Figure 29, ensuring the fork or dummy fork is secured by its axle to a rigid mount with a height of \( R_w \) (the radius of the wheel/tyre assembly ± 30 mm) while allowing the hub to swivel freely on the axle Secure the rear drop-outs using the axle to a stiff, vertical link that matches the height of the front rigid mount, with the upper connection of the link able to swivel around the axle's axis, providing lateral rigidity, and the lower end of the link equipped with a ball-joint.

To install a crank, chain-wheel, and chain assembly, or a robust replacement assembly, follow the guidelines illustrated in Figure 29 If using a crank/chain-wheel assembly, position both cranks at a 45° angle downwards and forwards to the horizontal, securing the front end of the chain to the middle or smaller chain-wheel, and attach the rear end to the rear axle perpendicularly Alternatively, for an adaptor assembly, ensure it swivels around the bottom-bracket axis, with both replacement arms measuring 175 mm and inclined at a 45° angle Secure the crank replacement arms with a vertical arm, which replaces the chain-wheel, and a tie-rod with ball-joints attached to the rear axle perpendicularly The vertical arm should be 75 mm long, and the tie-rod axis must be parallel and 50 mm from the vertical plane through the frame's center-line.

Subject each pedal-spindle (or equivalent adaptor component) to a repeated downward force of 1 000 N at a posi-

The force exerted on a "pedal-spindle" decreases to 5% or less of the peak force prior to the application of the test force on the other "pedal-spindle."

Apply the test forces for 100 000 test cycles where one test cycle consists of the application and removal of the two test forces

R w Height of rigid mount and vertical link

R c Length of vertical arm (75 mm)

L Length of crank replacement (175 mm)

7 Centre-line of tie-rod

Frame - Fatigue test with a vertical force

All frame types must undergo testing unless the frame features a top-tube and seat-stays that connect to the seat-tube within a distance equal to twice the internal diameter of the seat-tube, measured from the upper end and parallel to the seat-tube axis, as illustrated in Figure 30 a).

When the face of the seat tube is not a flat section perpendicular to its axis, measurements from the top tube and seat stays (denoted as \(d_1\) and \(d_2\) in Figure 30) must be taken to the lowest part of the top edge of the seat tube, as illustrated in examples b) and c) in Figure 30.

Figure 30 — Frame dimensions for exemption from the fatigue test with a vertical force

Where a frame is convertible for male and female riders by the removal of a bar, remove the bar

To optimize the performance of a bicycle suspension frame with adjustable brackets or linkages, position these components strategically to maximize the frame's resistance against ground-contact forces and to adjust the bicycle's attitude Additionally, ensure the rear suspension is secured as outlined in section 4.8.3.1.

To optimize your suspension fork, lock it at a length that matches the weight of an 80 kg rider seated on the bicycle, which can be achieved by adjusting the spring/damper or using external methods.

Testing according to the specified method in section 4.8.4.3 must show that the frame is free from visible cracks or fractures, and that all components of the suspension system remain intact without any separation.

For carbon-fibre frames, the peak deflection shall not increase by more than 20 % of the initial value

Secure the frame in its normal position at the rear drop-outs, ideally using the rear axle to prevent any rotational restraint, as illustrated in Figure 31 Attach an appropriate roller to the front axle to allow the frame to flex forward and backward under the applied test forces.

Insert a tube equivalent to a seat-stem into the top of the seat-tube to a depth of 75 mm, and secure it according to the manufacturer's instructions using the standard clamp Additionally, firmly attach a horizontal, rearward extension as indicated in Figure 31.

Apply dynamic, vertically downward forces ranging from 0 to +1,000 N at a point located 70 mm behind the intersection of the axes of the solid steel bar and the extension piece, E, as illustrated in Figure 30, for a total of 50,000 test cycles, ensuring that the test frequency does not exceed 25 Hz.

3 Locked suspension unit or solid link for pivoted chain-stays

4 Rigid, pivoted mounting for rear axle attachment point

Front fork

General

Subclauses 4.9.1, 4.9.2, 4.9.4, 4.9.5 and 4.9.6, apply to all types of fork

In the strength tests, subclauses 4.9.4, 4.9.5, 4.9.6 and 4.9.7, a suspension-fork shall be tested in its free, uncom- pressed length condition.

Means of location of the axle and wheel retention

The design of the slots or other positioning methods for the wheel-axle within the front fork must ensure that when the axle or cones are securely pressed against the top surface of the slots, the front wheel stays centered within the fork.

The front fork and wheel shall also fulfil the requirements of 4.10.4 and 4.10.5.

Suspension-forks — Special requirements

The design must ensure that in the event of spring or damper failure, the tyre will not make contact with the crown of the fork, and the fork components will remain securely attached.

When tested by the method described in 4.9.3.2.2, the tyre shall not contact the crown of the fork

To test the wheel and tyre assembly on the fork, apply a force of 2,800 N directed towards the fork-crown and parallel to the fork stem axis, and sustain this force for one minute.

Testing according to section 4.9.3.3.2 must ensure that no parts of the assembly detach or loosen, and that the tubular, telescopic components of any fork-leg remain securely connected under the applied test force.

Securely mount the fork-stem in a rigid fixture, ensuring that clamping forces do not impact the fork-crown Apply a tensile force of 2,300 N evenly across both drop-outs, directed parallel to the fork-stem axis and away from the fork-crown Maintain this force for one minute.

Front fork — Static bending test

Testing according to section 4.9.4.2 must show that the fork is free from fractures or visible cracks Additionally, the permanent set, defined as the displacement of the wheel-axle or simulated axle relative to the fork-stem axis, should not exceed 5 mm for rigid forks and 10 mm for suspension forks.

Mount the fork in a fixture that simulates the head-tube, ensuring it is secured in the standard head-bearings Attach a loading device and swivel it on an axle positioned within the blade slots Place a deflection measuring device beneath the loading attachment to accurately measure both the deflection and permanent set of the fork, perpendicular to the stem axis and within the plane of the wheel.

1 Loading attachment swivel on axle

3 Rigid mount incorporating head bearings

To obtain consistent deflection readings, apply a static pre-loading force of 100 N to the roller, ensuring it is perpendicular to the stem axis and against the direction of travel within the wheel's plane Repeat this loading process until stable measurements are achieved, and then calibrate the deflection measuring device to zero.

Increase the static force to 1 000 N and maintain this force for 1 min, then reduce the force to 100 N and record any permanent set.

Front fork — Rearward impact test

4.9.5.1 Crown/stem joint assembled by welding or brazing

According to the testing method outlined in section 4.9.5.1.2, the fork must be free of fractures or visible cracks, and the permanent set, defined as the displacement of the wheel-axle or simulated axle relative to the fork-stem axis, must not exceed 45 mm.

If the fork is used in the frame impact test (falling-mass), 4.8.2, there is no need to perform this test

Mount the fork in a fixture representative of the head-tube and gripped in the normal bearings as shown in Figure

33 Assemble a roller of mass less than 1 kg and with dimensions conforming to those shown in Figure 28 in the fork

Place a striker weighing 22.5 kg on the roller within the fork drop-outs, ensuring it exerts a force opposite to the direction of travel and aligned with the wheel's plane Position a deflection measuring device beneath the roller to record its position perpendicular to the fork-stem axis and within the wheel's plane, while also noting the vertical position of the fork.

To conduct the measurement, first remove the deflection measuring device and elevate the striker to a height of 180 mm before releasing it to strike the roller against the rake of the fork It is normal for the striker to bounce upon impact Once the striker has settled on the roller, proceed to measure the permanent set beneath the roller.

1 Low-mass roller (1 kg max)

Figure 33 — Front fork: rearward impact test

4.9.5.2 Crown/stem joint assembled by press-fitting, bonding, or clamping

If a fork shows any fractures or visible cracks during testing, or if the permanent set exceeds 45 mm, it is deemed to have failed Should the fork pass these initial criteria, it will undergo a second test, where it must show no fractures or visible cracks Additionally, regardless of the permanent set amount, there must be no relative movement between the stem and the crown when subjected to a torque of 50 Nm for one minute in each rotational direction.

4.9.5.2.2 Test method a) This test is that described in 4.9.5.1.2 b) This test is similar to that described in 4.9.5.1.2 except that the dropping height shall be increased to 600 mm.

Front fork — Bending fatigue test

When tested by the method described in 4.9.6.2, there shall be no fractures or visible cracks in any part of the fork

For carbon-fibre forks, the peak defection during the test in either direction from the mean position shall not increase by more than 20 % of the initial values

Mount the fork in a fixture representative of the head-tube and gripped in the normal bearings as shown in Figure

Subject the loading attachment to cycles of fully-reversed dynamic forces of ± 450 N, applied in the plane of the wheel and perpendicular to the stem-tube This testing should be conducted for 100,000 cycles at a frequency not exceeding 25 Hz, utilizing an axle positioned in the axle-slots of the blades.

Forks intended for use with hub- or disc-brakes

When large discs are utilized, the caliper may be mounted on an extension rather than directly on the fork-blade's mounting point, and a practical assembly must be employed during all tests.

In tests outlined in sections 4.9.7.2 and 4.9.7.3, specific protocols must be followed for bicycles with multiple mounting points for hub or disc brakes When a complete bicycle is provided, the test adaptor must be attached to the mounting point utilized on the bicycle Additionally, if a fork with multiple mounting points is supplied as an accessory, individual tests must be performed on each mounting point across separate forks.

According to the testing method outlined in section 4.9.7.2.2, the fork must be free of fractures or visible cracks, and the permanent set, defined as the displacement of the axle location of either fork-blade perpendicular to the fork-stem axis, must not exceed 5 mm.

To properly set up the fork for testing, mount it in a fixture that simulates the head-tube and is secured with standard head-bearings Attach an axle to the fork and install a pivoted, L-shaped adaptor, as illustrated in Figure 35, which will create a torque-arm measuring 330 mm and serve as a mounting point for the brake Ensure that the fork is secured against rotation around the stem-axis while allowing for bending movement.

Position appropriate measuring devices on each fork blade at the axle location, as illustrated in Figure 35 a) Apply a force of 100 N to the torque arm, directed opposite to the travel direction Repeat the application and removal of this force until stable deflection readings are achieved, and document the vertical positions of both blades.

To test the fork's performance, first remove the measuring devices and apply a force of 1,000 N to the torque arm, directed parallel to the fork-stem axis and the wheel plane, as illustrated in Figure 35 b) Maintain this force for one minute, then remove it and, if applicable, allow the suspension-type fork to return to its normal length Afterward, reattach the deflection devices, reapply a 100 N force (refer to Figure 35 a)), and document any permanent deformation of the two blades.

Key a) Setting "zero" deflection b) Application of the test force

Figure 35 — Fork for hub/disc-brake: static brake-torque test

4.9.7.3 Fork for hub/disc-brake — Repeated brake-torque test

Testing according to section 4.9.7.3.2 must show that the fork is free from fractures or visible cracks, and for suspension forks, all components must remain intact without any separation.

Secure the fork in a fixture that simulates the head-tube, ensuring it is held by the standard head-bearings with the fork-stem axis positioned vertically Attach an axle to the fork and place a pivoted, straight adaptor on the axle as illustrated in the accompanying figure.

36 to provide a torque-arm of 330 mm in length and a suitable attachment for the brake mounting-point

Apply dynamic rearward forces of 600 N to the end of the torque-arm, parallel to the wheel plane, for 12,000 test cycles at a frequency not exceeding 25 Hz, as illustrated in Figure 36.

Figure 36 — Fork for hub/disc-brake: repeated brake-torque test

Wheels and wheel/tyre assembly

Rims, tyres and tubes

Mudguards

Pedals and pedal/crank drive system

Saddles and seat-pillar

Chainguard

Handling and operation of a fully-assembled bicycle

Lighting systems and reflectors

Durability test

Tiêu đề	City And Trekking Bicycles — Safety Requirements And Test Methods
Trường học	British Standards Institution
Chuyên ngành	Standards
Thể loại	British Standard
Năm xuất bản	2006
Thành phố	London

Định dạng
Số trang	90
Dung lượng	1,29 MB