Cycles — Safety requirements for bicycles —Part 6: Frame and fork test methods Cycles — Exigences de sécurité des bicyclettes — Partie 6: Méthodes d’essai du cadre et de la fourche Firs
Frame — Impact test (falling mass)
Manufacturers of frames are permitted to conduct the test with a dummy fork (see Annex A) fitted in place of a front fork.
Where a frame is convertible for male and female riders by the removal of a bar, test it with the bar removed.
When testing a bicycle with a suspension fork, ensure the fork is extended to its unloaded free length for accurate assessment For bikes equipped with a rear suspension system, secure the suspension to simulate the position with an 80 kg rider seated, or 40 kg for young adult bicycles; if locking the suspension isn't possible, replace the spring or damper with a solid link of similar size and fittings.
```,`,`,,``,,````,,,,,``,`,,-`-`,,`,,`,`,,` - frame-fork or frame-bar assembly vertically with clamping to a rigid fixture by the rear-axle attachment points as shown in Figure 1.
To measure the wheelbase accurately, place a 22.5 kg striker on the roller positioned in the fork dropouts or on the rounded end of the dummy fork Raise the striker to a specified height \( h_1 \) above the low-mass roller and release it to strike the roller or steel bar in line with the wheel centers, opposing the fork rake or bar rake direction; the drop heights are detailed in Table 1 It is normal for the striker to bounce upon impact Once the striker comes to rest on the roller or dummy fork, measure the wheelbase again to determine any changes due to the impact.
If the fork fails, the frame shall be tested with a dummy fork.
Bicycle type City and trekking bicycles Young adult bicycles Mountain bicycles Racing bicycles
4 low-mass roller (1 kg max.)
5 rigid mounting for rear-axle attachment point
Figure 1 — Frame and front fork assembly — Impact test (falling mass)
Frame and front fork assembly — Impact test (falling frame)
Manufacturers of complete bicycles shall conduct the test with the frame fitted with the appropriate front fork.
For frame manufacturers lacking a specific fork for testing, the impact test can be performed using a compatible fork that meets the criteria outlined in ISO 4210-2:2014, section 4.9.5 Ensuring the fork complies with these standards guarantees accurate and reliable test results for the frame's durability and safety.
Where a frame is convertible for male and female riders by the removal of a bar, test it with the bar removed.
When installing a suspension fork, ensure it is at its unloaded length before impact testing If the spring or damper unit can be locked, it must be locked in its unloaded position to provide accurate test results In cases where locking is not possible, follow the approved alternative procedures to maintain consistent and reliable testing conditions Proper setup of the suspension fork is essential for compliance with safety and performance standards.
— secure the fork at its extended length by an external locking method, or
Replace the existing fork with a rigid fork that complies with the impact test requirements outlined in ISO 4210-2:2014, section 4.9.5 Ensure the fork length is appropriate for supporting an 80 kg rider in a normal riding position; for young adult bicycles, tailor the fork length to accommodate a 40 kg rider when equipped with a suspension fork. -**Sponsor**Sounds like you're looking to refine your article and ensure it's SEO-friendly! It can be tough to rewrite content while keeping the core meaning intact Did you know that [Article Generation](https://pollinations.ai/redirect-nexad/J2mPkphX) can instantly create 2,000-word, SEO-optimized articles? You could get key sentences for coherent paragraphs and save time, plus potentially save over $2,500 a month compared to hiring a writer It might be just the boost your content needs!
When a rear suspension system is integrated into the bicycle frame, ensure the spring and damper unit are securely positioned to replicate the forces experienced with an 80 kg load, or adjust accordingly for young adult bicycles Proper placement of the spring/damper unit is essential for optimal suspension performance and rider safety, aligning with standard suspension testing protocols.
When loading a rider of up to 40 kg on the bicycle, ensure the suspension system accommodates the additional weight If the suspension does not allow locking, replace the spring or damper unit with a solid link of appropriate size and compatible end fittings This modification maintains optimal performance and safety of the bicycle under different riding conditions.
Perform the test on the assembly according to ISO 4210-2:2014, section 4.8.2 If the frame manufacturer does not produce forks, conduct the test using the same frame fitted with a suitable fork as specified in section 4.2.1.
To set up the experiment, mount the frame-fork assembly at its rear axle attachment points to allow free rotation in a vertical plane, as illustrated in Figure 2 Support the front fork on a flat steel anvil to maintain the frame in its normal operating position Securely attach mass M1 to the seat-post at a specified distance of 75 mm (D) from the insertion point, ensuring the center of gravity is accurately positioned Additionally, fix masses M2 and M3 to the top of the steering head and bottom bracket, respectively, in accordance with Table 2 and Figure 2 specifications.
To accurately measure the wheelbase, position the three masses accordingly and rotate the assembly around the rear axle until the distance between the low-mass roller and the anvil reaches h₂ Once this position is achieved, release the assembly to allow it to fall freely and impact the anvil, ensuring precise measurement results.
Repeat the test and then measure the wheelbase again with the three masses in place and the roller resting on the anvil.
Table 2 — Drop heights and distribution of masses at seat post, steering head, and bottom bracket
Bicycle type City and trekking bicycles Young adult bicy- cles Mountain bicycles Racing bicycles
6 rigid mounting for rear-axle attachment point
D distance to the centre of gravity (75 mm) h 2 drop height
Figure 2 — Frame and front fork assembly — Impact test (falling frame)
Frame — Fatigue test with pedalling forces
All types of frame shall be subjected to this test.
For suspension frames with pivoted joints, adjust the spring, air pressure, or damper to provide maximum resistance during testing If the pneumatic damper's air pressure cannot be adjusted, replace the suspension unit with a rigid link that accurately simulates the original's end fixings and lateral rigidity For frames where chain stays rely on flexing rather than pivots, set dampers to minimum resistance to ensure proper testing of the frame's flexibility and performance.
Ensure that the adjustable brackets or linkages on a suspension frame are properly arranged to optimize the bicycle's response to ground-contact forces and attitude adjustments Proper positioning of these adjustable components is essential to maximize force transfer to the frame, enhancing stability and performance during rides Properly configured suspension components contribute to a smoother ride and improved handling by ensuring they effectively absorb shocks and adapt to terrain variations.
For the test, utilize a new frame or fork assembly equipped with standard head tube bearings to ensure proper compatibility and accurate results The front fork can be substituted with a dummy fork, as detailed in Annex A, provided it matches the original fork's length and maintains at least the same stiffness This setup ensures consistent and reliable testing conditions.
When replacing a genuine fork, be aware that using an authentic component may lead to potential failures For increased reliability and convenience, it is advisable to use a dummy fork that is stiffer and stronger than the original genuine fork This approach helps prevent failures and ensures better performance and durability in your setup.
Where a frame is convertible for male and female riders by the removal of a bar, test it with the bar removed.
To properly assemble the mount, attach the frame to a stable base as illustrated in Figure 3, securing the fork or dummy fork by its axle to a rigid mount at height Rw (the wheel/tire radius) with a tolerance of ±30 mm, allowing the hub to swivel freely on the axle Ensure the rear dropouts are attached to a stiff vertical linkage connected via the axle to a sturdy, vertical support of the same height as the front mount; the upper part of this link should be free to swivel around the axle axis to maintain alignment, while the lower end is equipped with a ball joint for flexibility, ensuring lateral stability during testing.
Attach a robust, stiff crank, chain wheel, and chain assembly to the bottom bracket, ensuring proper positioning If using a crank/chain-wheel assembly, incline both cranks forward and downward at approximately a 45° angle to the horizontal, then secure the front chain to the middle or smaller chain wheel, and attach the rear chain end perpendicular to the rear axle axis Alternatively, if employing an adaptor assembly, ensure it can swivel freely around the bottom bracket axis, with both 175 mm inclined arms set at 45°, and secure them using a vertical arm (75 mm) replacing the chain wheel, along with a ball-jointed tie rod attached perpendicular to the rear axle, positioned parallel and 50 mm from the frame's centerline.
Each pedal spindle must withstand repeated downward forces of F1 applied at a point 150 mm from the frame's centerline in a vertical, transverse plane, inclined at 7.5° (with an accuracy of ±0.5°) relative to the fore/aft axis, as specified in Table 3 and Figure 3 During testing, ensure the force on each pedal spindle decreases to 5% or less of the peak force before applying the force to the opposite spindle, ensuring accurate and consistent test conditions.
Conduct a test by applying the specified forces for 100,000 cycles, with each cycle involving the application and removal of the forces Maintain the maximum test frequency as outlined in ISO 4210-3:2014, section 4.5.
Table 3 — Forces on pedal spindle
Bicycle type City and trekking bicycles Young adult bicycles Mountain bicycles Racing bicycles
R w height of rigid mount and vertical link
R c length of vertical arm (75 mm)
L length of crank replacement (175 mm)
Figure 3 — Frame — Fatigue test with pedalling forces
Frame — Fatigue test with horizontal forces
Where a frame is convertible for male and female riders by the removal of a bar, remove the bar.
A genuine fork is not mandatory, as long as any replacement fork matches the original's length and is properly installed in the steering-head bearings For suspension forks, set the fork at a length equivalent to that used with an 80 kg rider, ensuring correct installation for optimal safety and performance.
40 kg) rider seated on the bicycle either by adjusting the spring/damper or by external means.
When testing suspension frames with pivoted joints, lock the moving part of the frame to simulate the position of an 80 kg rider seated on the bicycle This can be achieved by locking the suspension unit or replacing it with a solid link of appropriate size if locking is not possible Ensure that the front and rear axle axes are aligned horizontally, as shown in Figure 4, for accurate testing For suspension frames without pivots in the chain stays, set dampers to minimum resistance to ensure proper assessment of the frame’s performance.
When a suspension frame features adjustable brackets or linkages to modify the bicycle's resistance against ground-contact forces or to alter its attitude, it is essential to position these adjustable components strategically Proper arrangement of these components ensures maximum force transmission to the frame, enhancing overall stability and performance.
Mount the bicycle frame in its normal position and securely attach it at the rear dropouts, ensuring it is not rotationally restrained, ideally by the rear axle, as illustrated in Figure 4 Verify that the front and rear axle axes are aligned horizontally for proper setup and optimal riding performance. -**Sponsor**Need help making your cycling article SEO-friendly and coherent? I understand how time-consuming content creation can be With [Article Generation](https://pollinations.ai/redirect-nexad/W6JgUTax), you can instantly get SEO-optimized articles or rewrite existing ones, ensuring key sentences and paragraph coherence It's like having a content team that helps refine your work, saving you time and money compared to hiring a writer Imagine quickly improving your article on mounting a bike frame with the right keywords and structure!
Apply cycles of dynamic horizontal forces, F2 in the forward direction and F3 in the rearward direction, to the front fork dropouts for C1 cycles as illustrated in Table 4 and Figure 4 During testing, the front fork should be constrained vertically but free to move in the fore/aft direction under the applied forces The test frequency must adhere to the maximum specified in ISO 4210-3:2014, section 4.5, ensuring consistent and accurate results.
Table 4 — Forces and cycles on front fork dropouts
Bicycle type City and trekking bicycles Young adult bicycles Mountain bicycles Racing bicycles
2 rigid, pivoted mounting for rear-axle attachment point
Frame — Fatigue test with a vertical force
When a suspension frame features adjustable brackets or linkages to modify the bicycle's resistance against ground-contact forces or to change its attitude, it is essential to position these adjustable components to maximize forces transmitted to the frame Properly arranged adjustable components ensure optimal performance and stability Additionally, secure the rear suspension according to the guidelines outlined in section 4.3.1 to ensure safety and durability.
When installing a suspension fork, ensure it is locked at a length that corresponds to an 80 kg rider sitting on the bike; for young adult bicycles, use a 40 kg rider as a reference Adjust the spring or damper, or use external means, to set the fork to this specified length, ensuring optimal performance and safety during riding.
Mount the frame in its standard position and secure it at the rear dropouts, ensuring it is free to rotate, preferably by anchoring to the rear axle, as illustrated in Figure 5 Attach a suitable roller to the front axle to allow the frame to flex forward and backward in response to the test forces.
Ensure the seat post is inserted to a minimum depth of 75 mm or equivalent to the seat stem within the top of the seat tube, and securely fastened according to the manufacturer's instructions using the normal clamp Attach a horizontal, rearward extension securely to the top of the seat post so that its length (dimension h3) positions point H at a location corresponding to the center of the saddle clamp when the bicycle is set to its maximum recommended saddle height If maximum saddle height data is unavailable, set the length h3 to 250 mm.
Apply cyclic, vertically downward forces of F4 at a point 70 mm behind the intersection of the axes of the solid steel bar and extension piece E, as illustrated in Figure 5, for a total of 50,000 test cycles The specific force values are detailed in Table 5, ensuring accurate testing conditions The maximum test frequency must be maintained in accordance with ISO 4210-3:2014, section 4.5, to ensure compliance with industry standards.
Table 5 — Forces on seat stem
Bicycle type City and trekking bicycles Young adult bicycles Mountain bicycles Racing bicycles
H position equivalent to that of the centre of the saddle clamp with the bicycle
3 locked suspension unit or solid link for pivoted chain stays
4 rigid, pivoted mounting for rear axle attachment point
Figure 5 — Frame — Fatigue test with a vertical force
Suspension forks — Tyre-clearance test
To perform the tyre-clearance test, start by inflating the tyre to its maximum pressure and setting the suspension fork to its uncompressed state to achieve maximum distance between the stanchion and lower legs If the fork features a lock mechanism, ensure it is in the open position, and if it has a spring adjustment, set it to the softest setting Additionally, for forks with pneumatic devices, inflate the chambers to their minimum pressures before proceeding.
Apply a force of 2,800 N to the wheel in a direction toward the fork crown, parallel to the fork steerer axis, with a complete wheel and tyre assembly mounted on the fork Maintain this force consistently for 1 minute to ensure proper testing.
Suspension forks — Tensile test
Securely mount the fork steerer in a rigid holder, ensuring clamping forces do not contact the fork crown Apply a tensile force of 2,300 N evenly distributed between the dropouts, directed parallel to the fork steerer's axis and away from the fork crown Maintain this load for one minute to ensure proper testing and safety compliance.
Front fork — Static bending test
Mount the fork following Annex B guidelines and install a loading attachment with a swivel on an axle positioned within the blade axle slots (see Figure 6) Position a deflection measuring device over the loading attachment to accurately assess deflection and permanent deformation of the fork perpendicular to the steerer axis and within the plane of the wheel.
1 loading attachment swivel on axle
3 rigid mount incorporating head bearings
Figure 6 — Front fork — Static bending test (typical arrangement)
Apply a static pre-loading force of 100 N to the roller perpendicular to the steerer axis, in the direction opposite to travel, and within the plane of the wheel Repeat the loading process until a consistent deflection reading is achieved, ensuring measurement accuracy Finally, adjust the deflection measuring device to zero to calibrate the measurement.
Increase the static force to F 5 and maintain this force for 1 min, then reduce the force to 100 N and record any permanent deformation The forces are given in Table 6.
Table 6 — Forces on loading attachment
Bicycle type City and trekking bicycles Young adult bicycles Mountain bicycles Racing bicycles
Front fork — Rearward impact test
Mount the fork according to Annex B as shown in Figure 7 Assemble a roller of mass less than or equal to
1 kg and with dimensions conforming to those shown in Figure 8 in the fork The hardness of the roller shall be not less than 60 HRC at impact surface.
Position a 22.5 kg ± 0.1 kg striker on the roller located in the fork dropouts, ensuring it exerts a force opposite to the direction of travel within the plane of the wheel Place a deflection measuring device beneath the roller to accurately record its vertical position perpendicular to the fork steerer axis and in the plane of the wheel Document the vertical displacement of the fork during this process for precise measurement and analysis.
To measure permanent deformation accurately, remove the deflection measuring device, raise the striker to a specified height (h4), and release it to strike the roller against the fork rake The drop heights are provided in Table 7 It's normal for the striker to bounce upon impact Once the striker comes to rest on the roller, measure the permanent deformation underneath to assess material performance.
Bicycle type City and trek- king bicycles Young adult bicycles Mountain bicy- cles Racing bicycles
Forks made entirely of metal 180 180 360 360
Forks which have composite parts 320 320 600 640
1 low-mass roller (1 kg max.)
3 rigid mount incorporating head bearings
Figure 7 — Front fork — Rearward impact test
1 low-mass roller (1 kg max.)
This test is similar to that described in 5.4.1 except the dropping height.
Mount the test fork as shown in Figure 7 and assemble a low-mass roller into the fork for testing Raise the striker to 600 mm above the roller and release it to simulate impact, striking the roller against the fork’s rake as specified in ISO 4210-2:2014, section 4.9.5.1.
Apply the specified torque (T) to the assembly and hold it for 1 minute in both directions of rotation around the steerer axis Use the torque values provided in Table 8 to ensure proper application An example of the recommended test equipment setup is shown in Figure 9, ensuring accurate and consistent testing conditions for steering assembly evaluation.
Bicycle type City and trekking bicycles Young adult bicycles Mountain bicycles Racing bicycles
2 fork mounting fixture (fixture representative of the head tube)
Figure 9 — Fork steerer torsional test (a typical example)
Front fork — Bending fatigue test and rearward impact test
Mount the fork according to Annex B as shown in Figure 10.
Apply cycles of fully reversed, dynamic forces of F6 in the plane of the wheel and perpendicular to the fork steerer tube to a loading attachment These forces are transmitted through a swivel mounted on an axle, which is positioned within the axle-slots of the blades, ensuring proper testing and evaluation of the wheel's durability under dynamic conditions.
100 000 test cycles The forces are given in Table 9 The maximum test frequency shall be maintained as specified in ISO 4210-3:2014, 4.5.
According to ISO 4210-3:2014, a test should be concluded if the running displacement (peak-to-peak value) at the application point of test forces increases by more than 20% for rigid forks or more than 40% for suspension forks from the initial measurements This standard ensures the structural integrity and safety of bicycle forks during performance testing Monitoring displacement changes during testing is crucial for assessing the durability and compliance of forks with safety regulations.
Stop the test after 100 000 cycles and inspect the sample carefully for fractures If fractures are found, conclude the test.
If the sample withstands 100,000 cycles without exceeding displacement limits and shows no visible fractures, proceed with the impact resistance test specified in section 5.4.1, using the drop heights listed in Table 7 After the striker comes to rest on the roller, measure the permanent deformation under the roller and conduct a thorough inspection of the sample for any fractures.
Table 9 — Forces on loading attachment
Bicycle type City and trekking bicycles Young adult bicycles Mountain bicycles Racing bicycles
2 rigid mount incorporating head bearings
Figure 10 — Front fork — Bending fatigue test
Forks intended for use with hub or disc brakes
When using a fork with a hub or disc brake, the fork manufacturer must include an attachment point on the fork blade for the torque arm or caliper, whether the fork is provided as original equipment or as an accessory.
For bicycles with multiple mounting points for hubs or disc brakes, testing must follow specific protocols: when testing a complete bicycle, the test adaptor should be secured to the mounting point used on the bike, utilizing a supplied bracket if available; if a fork with multiple mounting points is provided as an accessory, separate tests must be conducted on each mounting point using different forks to ensure safety and compliance.
5.6.2 Fork for hub/disc brake — Static brake-torque test
To ensure proper testing, mount the fork in a fixture representative of the head tube as per Annex B, and secure it using standard head-bearings Attach an axle to the fork and then mount a pivoted, straight adaptor (shown in Figure 11) to provide a torque arm of length L2, as specified in Table 10, serving as a mounting point for the brake If the wheel size isn't listed in Table 10, set the length L2 to half of the wheel's diameter.
To accurately measure fork deflection, position a deflection-measuring device on the fork at the hub axis, ensuring the device is properly adjusted to zero Apply a rearward force of 1,000 N perpendicular to the fork steerer axis and in the wheel's plane, maintaining this force for one minute Afterward, reduce the force to 100 N and observe any permanent deformation to assess the fork's structural integrity.
1 rigid mount incorporating head bearings
Figure 11 — Fork for hub/disc brake — Static brake-torque test
5.6.3 Fork for hub/disc brake — Brake mount fatigue test
To ensure proper assembly, mount the fork in a fixture representing the head tube as per Annex B and secure it with standard head-bearings Attach an axle to the fork and install a pivoted, straight adaptor, as illustrated in Figure 12, to serve as a torque arm measuring length L2 (refer to Table 10) This setup also provides a secure attachment point for the brake mounting.
Apply repeated, dynamic forces of 600 N rearward to the end of the torque arm, perpendicular to the fork steerer axis and aligned with the wheel plane, for a specified number of cycles Ensure the testing is conducted for C 2 cycles as outlined in Table 11 Maintain the maximum test frequency in accordance with ISO 4210-3:2014, section 4.5, to ensure compliance with industry standards.
Bicycle type City and trekking bicycles Young adult bicycles Mountain bicycles Racing bicycles
1 rigid mount incorporating head bearings
Figure 12 — Fork for hub/disc-brake — Brake mount fatigue test
Tensile test for a non-welded fork
Securely mount the fork steerer in a rigid fixture, ensuring clamping forces do not contact the fork crown Apply a tensile force of 5,000 N, evenly distributed between both dropouts, for one minute in a direction parallel to the fork steerer axis.
The test forks shall be designed to mount in a manner similar to the original fork, or in a manner using typical procedures (see Annex B).
The test forks, when mounted, shall be the same length (axle to race), L, as the longest fork designed for use with the frame.
The deflection of the test fork should be measured in the direction of force application at the front axle center under a vertical force of 1,200 N The fork must be securely positioned in a horizontal orientation by constraining the steerer tube with a false head tube, which should be 150 mm in length, with bearings The steerer tube should be fixed similarly to a bicycle setup, with the crown race seat positioned adjacent to the false head tube's lower bearing assembly The deflection ratio (D_r) for the test fork during horizontal and vertical loading fatigue tests must not exceed 1.0.
L is the fork length, expressed in millimetres; δ is the deflection, expressed in millimetres.
=0 99721, ≤1 0, b) The deflection ratio, D r , for the test fork for the impact test shall not exceed the value of 1,0 when computed as follows:
L is the fork length, expressed in millimetres; δ is the deflection, expressed in millimetres.
For accurate testing, the fork must be mounted in a fixture that replicates the head tube and secured using standard head bearings The bearing distance significantly impacts the results, so the actual mounting distance should be used, allowing a tolerance of ±5 mm In the absence of specific distance instructions, a default value of 150 ± 5 mm should be applied Measurements are to be taken from the centers of the bearings, with example measurement points illustrated in Figure B.1.
During loading, the fork steerer may bend and potentially contact the dummy head tube; therefore, the dummy tube must be designed to prevent any such contact When measuring with external cup bearings, ensure that the dummy tube's design accommodates this requirement to maintain proper clearance.
Key d distance between the bearings
Figure B.1 — Examples of distance measurements
Suspension frames — Tyre-clearance test
C.1 Suspension frames — Tyre-clearance test
When tested by the method described in C.1.2, the tyre or any components other than fixing mechanism shall not contact the frame nor shall the components separate.
To conduct the tyre-clearance test, start by inspecting and adjusting the suspension frame and wheel following specific steps: inflate the tyre to its maximum recommended pressure; if the suspension element can be locked, set it to the open position; and for pneumatic shocks, pressurize the chamber to the minimum pressure as per the manufacturer's instructions.
Secure the frame in an orientation that enables force application to the wheel from a simulated ground plane With the wheel and tire assembly mounted on the frame, apply a 2,800 N force perpendicular to the ground plane to simulate real-world load conditions This force compresses the suspension, allowing for accurate assessment of suspension performance and durability.
Figure C.1) Maintain the force for 1 min.
Figure C.1 — Examples of suspension frames — Tyre-clearance test