Neometrix / Fatigue Test Rigs / Wheel Fatigue Test Rig / NMX-WFT-65

NMX-WFT-65 · ENGINEERED-TO-ORDER CLASS — SPECIFY · MOUNT · SET · RUN · INSPECT · PROVE

Wheel Fatigue Test Rig. A wheel needs two fatigue tests.

Name: Wheel Fatigue Test Rig
Brand: Neometrix
SKU: NMX-WFT-65

A wheel fatigue test asks whether a wheel will go on turning, under load, for as long as it is meant to last. The answer depends on which part of the wheel is loaded, and on how truly it is loaded.

So the rig is built around three things: two tests, because the disc and the rim fail apart, a load that is proved before the run, and a crack that is looked for as well as a stiffness read.

Discuss a test rig Capability note (PDF)

A single wheel radial fatigue test rig on a plain white studio background: a welded grey steel frame with a large smooth steel drum on a horizontal shaft in two bearing blocks, a bare five-spoke alloy wheel without a tyre bolted to a heavy steel hub on a sliding carriage that a stout hydraulic cylinder presses toward the drum, and a grey electric motor with a guarded belt drive, and no people

Fig · 01 — A radial wheel fatigue rig: a wheel on a sliding hydraulic carriage pressed against a heavy drum that a motor turns. The tyre that the test fits is left off so that the wheel can be seen — illustrative render.

The tests

cornering and radialeach aimed at its own part

The load

proved before the runchecked against a reference

The stop

stiffness and the eyea crack is looked for

The verdict

a sample, not one wheelthe record covers the run

Status

engineered to orderno test rig claimed

ISO 9001ISO 14001SAE J328 · SAE J267 · SAE J1204 reference standards

Overview

Why the whole job is two tests and a true load.

Because a wheel is two parts that fail in different places, and a rig that loads only one of them, or loads it wrongly, will pass a wheel that it should not.

Fig · 02 — The rig in one picture: the wheel is mounted as it is used, the load is put on and proved, and the rig watches, counting turns, reading stiffness and looking for the crack.

A wheel needs two fatigue tests.

What the rig is for

It turns a wheel under a repeated load for long enough to find out where and when it cracks. It suits passenger car, truck, bus and trailer wheels, in alloy or in steel, and it is built around the wheel the customer supplies.

Why a wheel needs two tests

In use a wheel is loaded two ways. It rolls under the weight on it, which pushes on the rim once each turn, and it is bent by the sideways force of a turn, which pushes and pulls on the disc once each turn. The cornering test is aimed at the disc. The radial test also loads the rim and the way the wheel is fixed. A wheel that passes one has not been shown to pass the other.

Why the load must be proved

Fatigue life falls as a steep power of the load, so a small error in the load becomes a large error in the life. A load that is set once and never checked is an assumption. The rig measures its load against a reference before the run, and keeps measuring it while the wheel turns.

Why a sample, not one wheel

The life of nominally identical wheels scatters. One wheel is therefore not a verdict, and a design is judged on a sample of wheels, as the public standards do. The rig is built for a run of wheels, and the record is built for the whole run.

Why stiffness alone is not enough

A wheel gets softer as a crack grows, and a rule can stop the test on that. But a crack can start well before the stiffness moves. A stop rule on stiffness alone can miss it, so the wheel is also examined on a schedule, and the test plan says what counts as a crack.

Why the mounting matters

The wheel is clamped the way it is clamped in use: the same seat, the same bolt pattern and a bolt torque that is written down. A fixture that clamps it differently tests the fixture, not the wheel.

The method

Specify, mount, set, run, inspect, and prove.

Six steps in a fixed order. The two shaded steps are the ones a quick order skips.

FIG · 02WHEEL FATIGUE TEST RIG · SPECIFY / MOUNT / SET / RUN / INSPECT / PROVE — A WHEEL NEEDS TWO FATIGUE TESTS

The step people underrate is the proof of the load. A rig that never checks its own load cannot say whether its result means anything.

Fig · 03 — Three ways a wheel test misleads: the load is taken on trust, one test is made to do for two parts, and a crack is judged by stiffness alone — a drawing of the idea, with no values.

1 · Specify

The wheel, the loads and the standard are stated by the customer, and the rig is sized to the wheel and the loads.

2 · Mount

The wheel is fixed to the hub the way it is fixed in use: the same seat, the same bolt pattern, and a bolt torque that is written down.

3 · Set

The load is checked against a reference and then set, so the rig proves its load before the first turn.

4 · Run

The turns are counted, the load is logged throughout, and the checks are made on a schedule.

5 · Inspect

The wheel is looked at for cracks on a schedule and its stiffness is read, because neither alone tells the whole story.

6 · Prove

The record is kept, and handed over with the rig.

Work content

What the rig contains, element by element.

Read it as a checklist: a rig missing a row will give a life it cannot defend.

A single wheel cornering fatigue fixture on a plain white studio background: a grey steel base plate and an upright steel column holding a bare five-spoke alloy wheel without a tyre, bolted to a thick steel hub plate, with a long rigid loading arm reaching sideways from the hub to a hydraulic cylinder and a thin pair of black strain gauge leads running from one spoke, and no people

Fig · 04 — A cornering fatigue fixture: a wheel bolted to a hub plate, a long loading arm with a hydraulic cylinder at its end, and a strain gauge lead on one spoke — illustrative render.

Element	What it does	What matters
Frame and bedplate	carries the loads	a stiff welded frame whose own flexing does not change the load the wheel sees
Hub and mounting	holds the wheel	a hub and clamp that fix the wheel as it is fixed in use, with the bolt torque written down
Drum and drive	rolls the wheel under load	for the radial test, a heavy drum on a driven shaft, with the wheel pressed on it by a hydraulic carriage
Loading arm	bends the disc	for the cornering test, a rigid arm from the hub with a hydraulic cylinder at its end, so that a rotating moment passes through the wheel
Hydraulic loading	puts the load on	a cylinder, a power unit and a valve that holds the load steady as the wheel turns
Load measurement	proves the load	a load cell in the load path, checked against a reference before the run and kept in the record
Strain gauging	shows where the stress is	gauges on the disc and the rim, used to prove the load path on a sample wheel before the run
Stiffness check	reads the wheel	a periodic reading of deflection under a reference load through the test
Counter and controller	runs the test	counts the turns, holds the load, logs everything and stops the run on a rule written in the test plan
Crack inspection	looks for the crack	an examination of the disc, the rim and the hub seat on a schedule, by dye penetrant or another method the customer names, with the crack rule written down
Guarding and safeties	protect the rig and the room	a guard round the turning parts, an over-load cut-out and an emergency stop
Procedure	fixes the sequence	specify, mount, set, run, inspect and prove, the same for every wheel
Testing & documentation	prove the rig first	a check of the load cell and the counter, a run on a reference wheel, and a record the customer can inspect

The element that decides whether the rig tells the truth is the proof of the load, because a rig that sets its load by calculation alone can be wrong by the whole error in the load and never show it.

Fig · 05 — What the rig loads: a wheel pressed on a drum in the radial test, and a wheel bent by a loading arm in the cornering test — a drawing of the idea, not to scale and with no values.

Full specification — expand

System	A stiff welded frame; a hub and clamp that fix the wheel as it is fixed in use; for the radial test a heavy drum on a driven shaft with the wheel pressed on it by a hydraulic carriage, and for the cornering test a rigid loading arm from the hub with a hydraulic cylinder at its end; a hydraulic power unit and a valve that holds the load steady; a load cell in the load path, checked against a reference; strain gauges to prove the load path on a sample wheel; a turn counter and a controller that holds the load, logs everything and stops the run on a written rule; a periodic stiffness reading; a crack inspection on a schedule; guarding and safeties; a written test plan; and testing and documentation before handover
The One Idea	A wheel needs two fatigue tests.
Why Two Tests	A wheel is loaded two ways in use and fails in two places: rolling under the weight on it pushes on the rim once each turn, and the sideways force of a turn pushes and pulls on the disc once each turn, so the cornering test is aimed at the disc, the radial test also loads the rim and its fixing, and a wheel that passes one has not been shown to pass the other
Why The Load Must Be Proved	Fatigue life falls as a steep power of the load, so a small error in the load becomes a large error in the life, and the rig measures its load against a reference before the run and keeps measuring it while the wheel turns
Why A Sample Not One Wheel	The life of nominally identical wheels scatters, so a design is judged on a sample of wheels, and the rig and its record are built for a run of wheels
Why Stiffness Alone Is Not Enough	A wheel gets softer as a crack grows, but a crack can start well before the stiffness moves, so a stop rule on stiffness alone can miss it and the wheel is also examined on a schedule by a rule written in the test plan
Why The Mounting Matters	A wheel is clamped to the rig the way it is clamped in use, with the same seat, the same bolt pattern and a written bolt torque, because a fixture that clamps it differently tests the fixture
Standards	SAE J328 is the public reference for passenger car and light truck wheels, SAE J267 for truck and bus wheels and SAE J1204 for trailer wheels. They describe fatigue tests of wheels, including a cornering test and a radial test, and judge a design on a sample of wheels. This page prints none of their loads, speeds or cycle counts, and no edition year: those come from the standard the customer names and from the wheel. Approval of a wheel or a test for use rests with the customer and the authority they name; none is claimed here
Configurations	A radial fatigue rig, a cornering fatigue rig and a rim torsion rig
Scope Boundary	This page is the wheel fatigue test rig. It is not a general servo-hydraulic fatigue machine for coupons and structures (see servo-hydraulic fatigue and structural test system), not a torsion fatigue machine for a shaft at temperature (see LP shaft torsion fatigue testing machine) and not an axle noise and endurance rig (see axle test rig with acoustic enclosure). A tyre test, a wheel balance machine, or a rolling endurance test of running gear where heat build-up governs, is a different test again. No certification is claimed here
Status	Neometrix has quoted against successive wheel fatigue test rig requirements, and no delivered wheel fatigue test rig is claimed.

Configurations

One method, three ways to build the rig.

The method, the load proof and the crack inspection are shared. What changes is how the wheel is loaded.

Radial fatigue rig

Drum, wheel and load

A wheel pressed on a rotating drum under a radial load, so that the rim and its fixing feel a push once each turn.

Cornering fatigue rig

Arm, wheel and hub

A wheel bolted to a hub with a long loading arm, so that a rotating moment bends the disc, a push and a pull once each turn.

Rim torsion rig

Actuator, fixture and rim

A twist applied to the rim and its fixing through a fixture, where a torque test of the rim is called for.

Fig · 06 — Three ways to build the rig, one method: a radial fatigue rig, a cornering fatigue rig, or a rim torsion rig.

And the part that is not equipment at all, yet decides all three: the test plan. It fixes the loads, the length of the run, the stiffness reading, the crack rule and the size of the sample, and it is written from the wheel and the standard, not from the rig.

Where it is used

Wherever a wheel carries a load for years, and a crack is not an option.

The common thread is a wheel whose life is a promise, and a test that has to keep it.

Passenger and light truck wheels

Where a new wheel design is proved against the public standard before it goes into production.

Truck and bus wheels

Where a heavier wheel is tested for its disc and its rim, in both tests.

Trailer wheels

Where a wheel on a trailer axle is tested as the standard for trailer wheels asks.

Design change and batch checks

Where a change of material, casting or heat treatment must be shown not to have made the wheel worse.

Watch

See it in motion.

A short walkthrough video of the wheel fatigue test rig.

FAQ

Common questions.

Longer answers, for readers who want the reasoning.

Q · 01 What does a wheel fatigue test rig actually do?

It mounts a wheel and loads it again and again, either by rolling it against a drum or by bending it through a loading arm, until the wheel cracks or the run reaches its planned length. It proves the load, counts the turns, reads the stiffness, looks for cracks and keeps the record. It does not design the wheel.

Q · 02 Why does a wheel need two fatigue tests?

Because a wheel is loaded two ways and fails in two places. The cornering test bends the disc with a moment, a push and a pull once each turn, and it is aimed at the disc. The radial test presses the rim on a drum, a push once each turn, and it also loads the rim and the way the wheel is fixed. A wheel that passes one test has not been shown to pass the other, so a wheel is tested both ways and the rig can be built for either.

Q · 03 Why is the load proved rather than simply set?

Because fatigue life follows a steep power of the load: a small error in the load becomes a large error in the life. So before the run the rig measures its load against a reference, through the load path, and then sets it, and it goes on measuring while the wheel turns. A load that is only calculated is an assumption, and the whole result stands on it.

Q · 04 Why is the wheel inspected as well as measured for stiffness?

Because stiffness is a good sign but not a complete one. As a crack grows the wheel gets softer, and a rule can stop the test on that. But a crack can start long before the stiffness moves, and a stop rule on stiffness alone can miss it. So the wheel is also examined on a schedule, and the test plan says what counts as a crack, so that the rule can be defended.

Q · 05 Is this the same as the servo-hydraulic fatigue machine, the shaft torsion machine or the axle rig?

No, and the differences are worth stating precisely. The servo-hydraulic fatigue and structural test system page covers a general dynamic testing machine for coupons, components and structures. The LP shaft torsion fatigue testing machine page covers a machine that cycles a shaft in torsion at temperature. The axle test rig with acoustic enclosure page covers a rig that listens to and endures a drive axle. This page is the wheel fatigue test rig. A rolling endurance test of running gear, where heat build-up governs, is a different test again. It does not replace any of them, and it does not claim what they claim a second time.

Q · 06 Has Neometrix built one of these?

We would rather answer this plainly than let a page imply otherwise. Neometrix has quoted against successive wheel fatigue test rig requirements, and no delivered wheel fatigue test rig is claimed. What stands behind the offer is adjacent: Neometrix engineers a servo-hydraulic fatigue and structural test system (see the servo-hydraulic fatigue and structural test system page), a torsion fatigue machine for shafts (see the LP shaft torsion fatigue testing machine page) and an axle test rig (see the axle test rig with acoustic enclosure page). The motors, load cells, strain gauges, encoders and controller hardware are catalogue items, bought in, not invented. What Neometrix engineers is the rig around them: the frame, the hub and the mounting, the hydraulic loading and its control, the load proof and the record, the procedure and the test plan. So the honest position is that the rig is engineered to order, the neighbouring disciplines are in the building, and the first rig of this exact kind will be built around the customer's own wheel and standard rather than taken off a shelf.

Q · 07 Which standards apply, and what can the rig not do?

SAE J328 is the public reference for passenger car and light truck wheels, SAE J267 for truck and bus wheels and SAE J1204 for trailer wheels. They describe fatigue tests of wheels, including a cornering test and a radial test, and judge a design on a sample of wheels. This page prints none of their loads, speeds or cycle counts, and no edition year: those come from the standard the customer names and from the wheel. The rig loads, counts and keeps a record. It does not certify a wheel: this page claims no certification or accreditation. No load, speed, life or count figure is printed here, and approval for use rests with the customer and the authority they name; none is claimed here.

Q · 08 What do you need from us to quote?

Six things, and most of them describe your wheel rather than the rig. First, the wheel: its kind, size and material, and the way it is fixed to the hub. Second, the standard: which test or tests are to be run. Third, the loads: how they are specified and how they are to be proved. Fourth, the stop rule: how the rig decides that a wheel has failed, by stiffness, by the eye or by both. Fifth, the sample: how many wheels, and how often they are inspected. Sixth, the record: what you want kept with each wheel. From that we come back with a rig concept, a written test plan you can check, and a budgetary price.

The neighbouring test pages, and how they differ from this one.

Three neighbours: one is a general fatigue machine, one cycles a shaft, one tests an axle.

↗ A general fatigue machine

Servo-Hydraulic Fatigue & Structural Test System

A dynamic testing machine for coupons, components and structures - a general machine, where this page is a rig built around one part, the wheel.

↗ A shaft fatigue machine

LP Shaft Torsion Fatigue Testing Machine

A machine that cycles a shaft in torsion and tension at temperature - another turning-part fatigue test, where this page loads a wheel.

↗ An axle rig

Axle Test Rig with Acoustic Enclosure

A rig that listens to and endures a drive axle - a test of noise and endurance, where this page tests a wheel for cracks.

Browse all Neometrix product lines.

Get a quotation

Tell us the wheel, the standard,
and the loads.

The projects desk replies within two working days with a rig concept, a written test plan you can check, and a budgetary quotation. Write to [email protected] or use the form.

Enquire — wheel fatigue rig Capability sheet (PDF) +91 7777 876 876

ISO 9001 / 14001 ENGINEERED-TO-ORDER CLASS — WHEEL FATIGUE TEST RIG SPECIFY · MOUNT · SET · RUN · INSPECT · PROVE — A WHEEL NEEDS TWO FATIGUE TESTS ENGINEERED IN NOIDA · INDIA