Bicycle Frame Vertical & Horizontal Fatigue Test Machine (FH-CJ052)

One machine. Two axes. Nine national standards.

The FH-CJ052 tests bicycle frames for both vertical seat-tube fatigue (ISO 4210-6.4.5 / EN 15194) and horizontal front fork dropout fatigue (ISO 4210-6.4.4) on a single servo-actuated test bench — with independent servo cylinders for each axis, a 5,000N disc-type force sensor, closed-loop force control, and a test frequency up to 5Hz. Covers all major bicycle frame categories including city, mountain, racing, and EPAC (electric pedal-assist) frames across nine international standards: EN 15194, ISO 4210, EN 14781, EN 14766, EN 14764, CNS, JIS, DIN, NF, CPSC, CSA, AS, and BS.

Quick Specs

• Standards: EN 15194, ISO 4210-6 (6.4.4 & 6.4.5), EN 14764, EN 14766, EN 14781 + CNS / JIS / DIN / NF / CPSC / CSA / AS / BS

• Servo cylinders: 2 independent (1 horizontal + 1 vertical)

• Force sensor: 5,000N disc-type

• Horizontal stroke: ±75mm | Vertical stroke: ±50mm

• Test frequency: 0–5Hz

• Vertical test load: F10 = 1,100N / 50,000 cycles

• Horizontal test load: F8 / F9 = 600N (EPAC) or 500N (other) / 100,000 cycles

• Displacement sensor accuracy: ±1% (±0.5% static calibration)

• Dynamic force control accuracy: ±5%

• Power: AC 220V, 2.5kW

• Bench dimensions: 2430 × 810 × 1700mm

Table of Contents

1. Why Bicycle Frames Need Both Vertical and Horizontal Fatigue Testing

2. Overview of the FH-CJ052 Test Machine

3. Standards Covered: ISO 4210-6, EN 15194, EN 14764 / 14766 / 14781 and More

4. Test Methods, Load Conditions, and Setup

5. Design Features of the FH-CJ052

6. Technical Specifications

7. How the FH-CJ052 Testing Process Works

8. Benefits for Frame Manufacturers and Testing Labs

9. Choosing the Right Dual-Axis Frame Fatigue Tester

10. Real-World Application Scenarios

11. FAQs for the FH-CJ052

12. Related Testing Equipment

13. Get a Quote from Feihong Machine

Why Bicycle Frames Need Both Vertical and Horizontal Fatigue Testing {#section-1}

A bicycle frame in real-world use is never loaded in just one direction. A rider's weight bears down through the seat tube — vertical compression cycling with every pedal stroke and road bump. At the same time, braking, acceleration, and cornering forces transmit into the frame horizontally through the front fork dropouts — alternating forward and rearward loads that stress the rear triangle and head tube region in a fundamentally different loading plane.

These two load cases produce different stress distributions in the frame, propagate fatigue at different locations, and are governed by different clauses in the applicable standards. ISO 4210-6 addresses them in two separate test clauses — 6.4.4 for horizontal fork dropout fatigue and 6.4.5 for vertical seat tube fatigue — precisely because one test does not substitute for the other.

For manufacturers certifying bicycle frames against ISO 4210-6, EN 15194, or any of the European category standards (EN 14764 city, EN 14766 mountain, EN 14781 racing), both tests are mandatory. Running them on separate single-axis machines doubles fixture setup time, doubles calibration overhead, and often doubles the floor space requirement. A dual-axis frame fatigue test machine that covers both clauses on a single bench solves this — provided both axes genuinely meet the force, stroke, frequency, and control accuracy requirements of the respective test methods.

Overview of the FH-CJ052 Test Machine {#section-2}

The FH-CJ052 is a dual-servo bicycle frame fatigue tester with independent horizontal and vertical actuation axes, designed for full compliance testing of bicycle and EPAC frames against ISO 4210-6 clauses 6.4.4 and 6.4.5 and the equivalent clauses in EN 15194, EN 14764, EN 14766, EN 14781, and eight other national standards.

Two independent servo cylinders — one horizontal, one vertical — each apply the force, stroke, and frequency specified by the respective test clause. A 5,000N disc-type force sensor with closed-loop force control ensures that the applied load tracks the programmed setpoint throughout the test, compensating automatically for frame compliance and fixture variation that would cause an open-loop system to drift from the required load amplitude.

The machine tests one axis at a time (single-axis mode per test clause), with the fixture configured for the axis being tested. Frame mounting geometry is adjustable with ~300mm spacing, accommodating the range of frame types covered by the nine referenced standards — from compact urban e-bike frames to mountain bike and racing geometries.

Standards Covered: ISO 4210-6, EN 15194, EN 14764 / 14766 / 14781 and More {#section-3}

Primary International Standards

Additional National Standards

The FH-CJ052 also covers frame fatigue test methods defined in:

This nine-standard coverage makes the FH-CJ052 practical for manufacturers supplying frames to multiple international markets — a single machine covers the frame fatigue requirements across every major bicycle import market.

Force and Cycle Requirements by Test and Frame Category

Horizontal Frame Fatigue Test (ISO 4210-6.4.4 — Front Fork Dropouts)

Per Table 14 of ISO 4210-6 (Forces and cycles on front fork drop-outs):

Forces are applied alternately at the front fork dropouts — forward (F8) and rearward (F9) — simulating the braking and acceleration loads transmitted through the front axle interface during normal use.

Vertical Frame Fatigue Test (ISO 4210-6.4.5 — Seat Tube)

Per Table 15 of ISO 4210-6 (Forces on seat-stem):

The 1,100N vertical force is applied downward at a point 70mm behind the axis-intersection point E on the horizontal rearward extension fitted to the seat tube steel bar — per the geometry defined in Figure 23 of ISO 4210-6. The steel bar is inserted 75mm into the seat tube at the maximum saddle height position (point H), with the extension bar's mounting height h3 corresponding to the saddle clamp center at maximum adjustment.

Test Methods, Load Conditions, and Setup {#section-4}

Horizontal Fatigue Test Setup (ISO 4210-6.4.4)

The frame is mounted with the front fork dropouts at test point 1 (front) and point 2 (rear). The horizontal servo cylinder applies alternating forward (F8) and rearward (F9) forces at the front fork dropout — simulating the reaction forces that occur at the wheel-ground contact point during braking and acceleration.

For EPAC frames (front-wheel-driven systems), both F8 and F9 are set at 600N, reflecting the higher axle forces generated by hub-motor torque reaction. For conventionally driven frames, the load is 500N in each direction. All configurations run for 100,000 cycles at frequencies up to 5Hz.

Pass criteria (per ISO 4210-6 / EN 15194): No fracture, crack, or permanent deformation after the full cycle count. The frame is inspected under dye penetrant or visual methods at the dropout, weld, and surrounding tube areas.

Vertical Fatigue Test Setup (ISO 4210-6.4.5)

The frame is repositioned for vertical testing, per Figure 23 of ISO 4210-6:

• Front axle: mounted on a free-running roller (point 1) — allows the frame to rotate slightly as it deflects under load, preventing artificial constraint forces

• Rear axle: connected to a rigid pivot support (point 4) — holds the rear of the frame while allowing rotation

• Bottom bracket: secured via a locked suspension device or solid chain link (point 3) — prevents rotation of the chain stay under load

A steel bar is inserted 75mm into the seat tube (point 2), clamped at the assembly limit mark. A horizontal rearward extension is fitted to the bar at height H (corresponding to maximum saddle height center). The vertical servo cylinder applies force F10 = 1,100N downward at a point 70mm behind the axis-intersection E on the extension — the precise loading geometry specified in Figure 23.

The test runs for 50,000 cycles at up to 5Hz. This load and geometry produces the seat tube bending stress distribution that correlates most closely with the fatigue failure modes seen in service.

Pass criteria: No fracture, crack, or permanent deformation visible after 50,000 cycles at the seat tube, top tube junction, seat stay welds, and surrounding regions.

Design Features of the FH-CJ052 {#section-5}

Two Independent Servo Cylinders

One horizontal servo cylinder (±75mm stroke) and one vertical servo cylinder (±50mm stroke) each operate independently — sized to the stroke and force requirements of their respective ISO 4210-6 test clauses. The horizontal cylinder performs bidirectional (push/pull) actuation, replicating the alternating forward/rearward forces at the dropout. The vertical cylinder applies downward dynamic loading at the calculated seat-tube extension point.

5,000N Disc-Type Force Sensor with Closed-Loop Control

A 5,000N disc-type load cell provides continuous force feedback throughout the test. Closed-loop force control automatically adjusts the servo command to maintain the programmed load amplitude — essential for fatigue testing, where frame compliance and temperature drift would otherwise cause the actual applied force to deviate from the setpoint over a 50,000–100,000 cycle run. Dynamic control accuracy is ±5%; static calibration accuracy is ±0.5%.

Adjustable Frame Spacing (~300mm)

The mounting plate spacing is adjustable to approximately 300mm, accommodating the range of frame widths covered by the nine referenced standards without fixture replacement. Joint plates are locked manually via screws — straightforward to reconfigure between horizontal and vertical test modes.

Full Steel Rigid Structure

The bench frame is all-steel welded construction, providing the structural rigidity needed to ensure that machine deformation under cyclic loading does not contribute to measurement error or load instability over long test runs.

Standard-Compliant Test Fixtures Included

The machine ships with the fixture set for both vertical and horizontal frame testing — saddle tube steel bar assembly, rearward extension piece, free-running front roller, and dropout force application tooling — eliminating the fixture sourcing step before first use.

Single-Test-per-Run Operation

The machine is designed for single-axis testing per run — consistent with the ISO 4210-6 test sequence, which specifies horizontal and vertical tests as independent procedures. This simplifies test control logic and ensures that the load conditions for each test clause are cleanly separated.

Technical Specifications of the FH-CJ052 {#section-6}

Test Parameters

Servo System

Physical

Standards Coverage

Why These Specifications Matter

• 5,000N sensor capacity with closed-loop control is the specification that distinguishes compliance-grade fatigue testing from indicative testing. An open-loop system applies a displacement, not a verified force — the actual load depends on frame stiffness, which varies between frame materials and geometries. Closed-loop force control guarantees that every test, on every frame design, sees the same 1,100N or 600N regardless of how stiff or compliant that particular frame is.

• ±75mm horizontal stroke is sized to accommodate the deflection range of frames across the nine standard categories at the specified 600N load without reaching actuator end-of-travel — important because stroke saturation during a fatigue test destroys the sinusoidal force waveform and invalidates results.

• 0–5Hz test frequency matches the upper frequency limit specified in ISO 4210-6.4.5 for vertical testing, ensuring the machine does not introduce dynamic amplification effects that would make the applied force exceed the static programmed value.

• 1,100N vertical force at 70mm offset produces a bending moment of 77N·m at the seat tube wall — the specific moment arm geometry in ISO 4210-6 Figure 23 is not arbitrary; it is calibrated to produce the stress distribution that correlates with observed fatigue failure modes in the seat tube / top tube junction area.

How the FH-CJ052 Testing Process Works {#section-7}

Step 1: Configure for the Target Test Clause

The fixture is set up for either the horizontal test (ISO 4210-6.4.4 — dropout loading) or the vertical test (ISO 4210-6.4.5 — seat tube loading), per the applicable standard. Frame spacing is adjusted to fit the test frame geometry.

Step 2: Mount and Align the Frame

For horizontal testing: The frame is mounted with front fork dropouts at the horizontal servo load points (front and rear). For vertical testing: Front axle on the free-running roller; rear axle on the rigid pivot support; bottom bracket on the locked chain-link support; steel bar inserted 75mm into the seat tube at maximum saddle height and clamped; rearward extension fitted at height H; force application point located 70mm behind intersection E.

Step 3: Set Test Parameters

Load amplitude (F8/F9 for horizontal; F10 for vertical), test frequency (0–5Hz), and cycle count are entered. The closed-loop force controller is enabled.

Step 4: Automated Test Execution

The servo cylinder applies the programmed cyclic force at the set frequency. The closed-loop controller monitors the load cell output and adjusts the actuator command in real time to maintain the target force amplitude throughout the run.

Step 5: Completion and Inspection

The machine stops automatically at the programmed cycle count. The frame is removed and inspected for fracture, crack initiation, or permanent deformation at all critical locations — seat tube welds, dropout regions, and surrounding tube junctions.

Benefits for Frame Manufacturers and Testing Labs {#section-8}

Dual-Clause Coverage in One Setup

ISO 4210-6.4.4 and 6.4.5 are both required for full frame certification. Running them on one machine — without procuring, calibrating, and maintaining two separate single-axis testers — cuts capital cost and floor space for any manufacturer or lab certifying multiple frame models per year.

Verified Force Control for Defensible Data

EPAC and Conventional Frame Coverage

The machine's 600N horizontal force capacity covers EPAC (front-wheel-driven) frames — which ISO 4210-6 and EN 15194 load at higher force than conventional frames due to hub motor reaction torque. Many older or lower-spec horizontal fatigue testers are sized for 500N conventional loads only; the FH-CJ052 covers both in the same fixture configuration.

Nine-Standard Global Market Reach

A single machine that covers JIS (Japan), CPSC (US), CSA (Canada), AS (Australia), and the full EN/ISO suite means manufacturers don't need to qualify separate test equipment for each export market's standard — the FH-CJ052's force and geometry specifications meet all nine simultaneously.

Choosing the Right Dual-Axis Bicycle Frame Fatigue Tester {#section-9}

Verify Closed-Loop vs. Open-Loop Force Control

This is the most important technical question to ask. An open-loop machine controls displacement, not force — acceptable for some component tests but not for ISO 4210-6 frame fatigue, where the standard specifies force (600N, 500N, 1,100N) and frame stiffness variation between models would cause significant load variation without feedback control. Confirm the tester has a load cell and genuine closed-loop force control, not a displacement-controlled system with estimated force.

Check Horizontal Stroke Adequacy

±75mm horizontal stroke is the specification that matches the deflection envelope of frames tested at 600N across the categories covered by ISO 4210-6. Some lower-cost machines rate ±50mm — adequate for stiffer frames, but potentially reaching end-of-travel on more compliant carbon or thin-wall aluminum frames and destroying the test waveform.

Confirm EPAC Load Capacity

If your product range includes front-wheel-driven EPAC frames, the horizontal force requirement is 600N — 20% higher than the 500N required for conventional frames. Verify the machine is rated for the 600N EPAC specification, not just 500N.

Single-Axis vs. Dual-Axis

A machine that tests only vertical or only horizontal fatigue cannot complete both ISO 4210-6 clause requirements without a second machine. For a lab or factory regularly certifying frames, the total cost and floor space of two separate single-axis machines typically exceeds the cost of a dual-axis machine within the first product cycle.

Real-World Application Scenarios {#section-10}

An EPAC frame manufacturer preparing for EN 15194 type approval used the FH-CJ052 to run both the horizontal dropout test at 600N and the vertical seat-tube test at 1,100N on the same frame design in the same week — identifying a crack initiation site at the seat tube / top tube weld after the vertical test and correcting the weld bead profile before the certification submission, avoiding a failed test and an eight-week resubmission delay.

A Taiwanese OEM supplying frames to European distributors under both ISO 4210 and EN 14766 mountain bike specifications used the FH-CJ052's nine-standard coverage to run a single machine qualification across both standards, satisfying both buyers' incoming QC requirements without separate test equipment purchases or external lab engagement.

A Japanese manufacturer certifying frames under JIS D9416 used the machine's JIS-aligned force and geometry parameters to run compliance tests in-house, reducing certification lab turnaround time from six weeks to under ten days by pre-qualifying each frame design before external submission.

FAQs for the FH-CJ052 Frame Fatigue Test Machine {#section-11}

What are the two test axes and which standard clauses do they cover?

The horizontal axis covers ISO 4210-6.4.4 — alternating forward/rearward forces at the front fork dropouts (600N EPAC / 500N other, 100,000 cycles). The vertical axis covers ISO 4210-6.4.5 — downward force at the seat tube extension point (1,100N, 50,000 cycles).

Why is the vertical force applied 70mm behind point E, not directly at the seat tube?

This is the geometry specified in ISO 4210-6 Figure 23. The 70mm offset from the axis intersection E on the rearward extension produces the bending moment at the seat tube wall (77N·m at 1,100N) that correlates with the fatigue stress distribution observed in field failure investigations. Applying force directly at E would produce a different stress distribution and a non-representative test.

What is the difference in horizontal load for EPAC vs. conventional frames?

EPAC frames with front-wheel-driven hub motors are loaded at F8 = F9 = 600N per ISO 4210-6 / EN 15194 — 20% higher than the 500N specified for non-EPAC frames — because hub motor reaction torque increases the force at the front dropout during both acceleration and braking. Both load levels run for 100,000 cycles.

Can the machine test both axes on the same frame without remounting?

The machine performs one axis per test run (single-axis mode). To test both horizontal and vertical fatigue on the same frame, the frame is remounted between runs — consistent with the ISO 4210-6 test sequence, which specifies the two tests as independent procedures.

What is closed-loop force control, and why does it matter for fatigue testing?

Closed-loop force control means the machine continuously measures the actual force applied (via the load cell) and adjusts the servo actuator command to keep applied force at the programmed setpoint. For fatigue testing, this is critical because frame compliance — how much the frame deflects under load — varies between designs and materials. Without force feedback, a displacement-controlled machine would apply different actual forces to different frames, making results non-comparable and potentially non-compliant with the standard.

Does it cover CPSC requirements for the US market?

Yes. CPSC bicycle frame fatigue requirements are within the force and geometry envelope of the FH-CJ052's test capability. Manufacturers targeting the US market should confirm the specific CPSC clause requirements against the machine's test parameters at the time of purchase, as CPSC regulatory guidance can be updated independently of ISO/EN standard revision cycles.

What is the steel bar insertion depth for the vertical test?

75mm, as specified in ISO 4210-6.4.5 and the test method description — the bar is inserted to this depth, clamped at the assembly limit mark, and the extension is fitted at height H corresponding to maximum saddle height center position.

Related Testing Equipment {#section-12}

• Bicycle Frame Vertical Vibration Fatigue Test Machine (FH-S2989) — dual-motor vertical vibration tester per ISO 4210-6, JIS D9401, GB 17761; 6–10Hz, 85kg load

• Bicycle Fork Impact Test Machine — drop-weight front fork impact testing per ISO 4210-6 and EN 14764

• Bicycle Handlebar and Stem Fatigue Tester — fatigue testing for handlebar assemblies per ISO 4210-5

• Electric Bicycle Comprehensive Test Machine (FH-ZD2988) — max speed, dry/wet braking, range testing per EN 15194, ISO 4210, GB 17761

Get a Quote from Feihong Machine {#section-13}

Feihong Machine (Dongguan Feihong Instrument and Equipment Co., Ltd.) designs and manufactures bicycle frame and component testing equipment for manufacturers and testing laboratories worldwide.

To get started:

• Request a Quote — share your frame type, target standards, and test volume

• Request Technical Datasheet — full dimensional drawings and calibration data

• Schedule a Demo — see the FH-CJ052 run a live ISO 4210-6.4.5 vertical fatigue test

Request a Quote →