Rubber does not always fail because it reaches its maximum tensile strength.
A small cut, damaged edge, sharp corner, or local stress concentration can start a tear long before the entire component is uniformly overloaded. Once that tear begins, the next question is how strongly the material resists further propagation.
ASTM D624 is used to evaluate this behavior in conventional vulcanized rubber and thermoplastic elastomers.
But specifying “ASTM D624” does not completely define the test system.
The specimen type affects the test speed and result calculation. Thickness affects the reported tear strength. Soft elastomers can slip or become damaged in poorly selected grips. And because many tear tests generate relatively low forces, the most important force specification may be the load cell range—not the maximum capacity printed on the testing machine.
For equipment selection, a better sequence is:
Material → Specimen Type → Thickness → Expected Tear Force → Load Cell → Grip → Testing Machine
This guide follows that sequence.
Quick Answer: What Is ASTM D624?
ASTM D624 is a standardized method for measuring the tear strength of conventional vulcanized rubber and thermoplastic elastomers (TPE).
As of August 2026, ASTM lists ASTM D624-00(2020) as the active edition.
Tear-strength results can be influenced by stress distribution, strain rate, specimen dimensions, material orientation, and test conditions. For this reason, ASTM D624 data should be understood as material behavior under controlled test conditions rather than as a direct prediction of finished-product service life.
That distinction matters.
If an automotive rubber seal tears in service, ASTM D624 can help characterize the tear resistance of the material used in that seal. It does not reproduce every contact force, temperature, geometry, aging condition, and stress concentration experienced by the finished component.
In practical terms:
ASTM D624 is a controlled material test—not a complete simulation of product failure.
What Materials and Products Are Relevant to ASTM D624?
ASTM D624 primarily applies to vulcanized rubber and thermoplastic elastomers.
Typical users include rubber manufacturers, automotive suppliers, elastomer material developers, sealing-material manufacturers, and laboratories working with flexible molded materials.
| Application | Typical Examples |
|---|---|
| Automotive | Rubber seals, boots, flexible sealing materials, elastomer components |
| Rubber Manufacturing | Rubber sheets, compounds, molded specimens, formulation comparison |
| Industrial | Flexible seals, protective rubber components, molded parts |
| Medical / Healthcare | Selected elastomeric components and materials |
| Electronics | Silicone or elastomer sealing and protective materials |
| Material R&D | Vulcanized rubber, synthetic rubber, TPE and silicone formulations |
A useful distinction for buyers is that ASTM D624 normally evaluates a prepared material specimen.
If the requirement is to pull an entire finished rubber seal, cable boot, gasket, or molded component until it tears, that test may still be useful for product evaluation—but it is not automatically an ASTM D624 test.
How Does the ASTM D624 Tear Test Work?
A prepared specimen is mounted between the upper and lower grips of a universal testing machine.
The grips separate at the required test speed. Because of the specimen geometry, cut, or notch, stress becomes concentrated in a defined area and tearing begins or propagates.
The machine continuously records force as the specimen tears.
A practical test sequence is:
Prepare Specimen → Measure Thickness → Install & Align → Set Test Method → Apply Load → Record Tear Force → Calculate Tear Strength
The mechanics are straightforward.
The difficult part is making sure the force curve actually represents the material.
If the specimen slips, the cut geometry is inconsistent, or one grip pulls the specimen off-axis, a very accurate testing machine can still produce poor data.
ASTM D624 Specimen Types: A, B, C, T and CP
ASTM D624 defines five acceptable specimen types:
Type A · Type B · Type C · Type T · Type CP
They are not simply five cosmetic variations of the same test.
Their geometry changes the stress concentration, tear initiation, propagation behavior, required speed, and result evaluation.
For Types A, B and C, tear strength is determined from the maximum force divided by specimen thickness.
For Types T and CP, the relevant average or median force from the tearing section of the curve is used, depending on the curve behavior, and divided by specimen thickness.
This has a practical software implication:
The test method should know which specimen type is being used before the result is calculated.
A saved “ASTM D624” method with one calculation rule should not automatically be reused for every specimen geometry.
Why Specimen Type Also Changes the Equipment Setup
Specimen geometry is normally discussed as a standard requirement.
For a testing-machine buyer, it also affects equipment selection.
Different D624 specimen types can change:
- Grip separation
- Required crosshead travel
- Test speed
- Force-curve behavior
- Result-analysis method
That means the question:
“Can this machine perform ASTM D624?”
is less useful than:
“Can this machine perform the D624 specimen types we actually use, at the correct speeds, with suitable grips and force measurement?”
That is a much better equipment specification.
ASTM D624 Test Speed: One Speed Does Not Fit Every Specimen
One of the easiest mistakes is copying an existing rubber test method and changing only the standard name.
Typical ASTM D624 test speeds are:
| Specimen Type | Test Speed |
| Type A / B / C | 500 ± 50 mm/min |
| Type T / CP | 50 ± 5 mm/min |
That is a 10× difference in nominal speed between the two groups.
Rubber and elastomers are rate-sensitive materials, so test speed can influence tear behavior.
One saved speed should therefore not be reused across every D624 specimen geometry.
For equipment selection, maximum speed is only part of the specification.
The machine also needs stable and repeatable control at the speeds actually required by the test.
Specimen Preparation Can Affect the Result Before the Machine Starts Moving
Types A, B, C, and T are prepared using the required cutting geometry, while Type CP is molded.
Tear testing intentionally creates a stress concentration.
That makes cutting and notch quality especially important.
An unintended nick, rough edge, damaged surface, or inconsistent notch can change where the tear starts and how it propagates.
If one batch produces unusually scattered results, inspect the specimens before changing machine calibration.
Do not investigate machine repeatability while ignoring specimen repeatability.
A useful troubleshooting order is:
Cutting → Notch → Thickness → Material Direction → Grip → Alignment → Test Settings → Machine
Why Thickness Matters in ASTM D624
For ASTM D624, force alone is not tear strength.
The basic relationship can be understood as:
Tear Strength = Tear Force / Specimen Thickness
Suppose:
Relevant Tear Force = 150 N
and:
Specimen Thickness = 2.0 mm
Then:
150 N / 2.0 mm = 75 N/mm
Therefore:
Tear Strength = 75 N/mm
For Types A/B/C, the applicable force is the maximum force.
For T/CP, the appropriate average or median force from the tearing region is used according to the specified evaluation procedure.
So two specimens that both reach 150 N do not necessarily have the same tear strength if their thicknesses differ.
Engineer Note: Measure Soft Elastomers Carefully
Thickness measurement sounds simple until the specimen is soft.
If the measuring instrument applies excessive contact force, the elastomer can compress during measurement.
That smaller thickness value then goes directly into the tear-strength calculation.
The measurement process should therefore be controlled just like the mechanical test itself.
A repeatable workflow is:
Prepare → Condition → Measure → Test → Calculate
not five unrelated operations.
How Much Force Does ASTM D624 Require?
There is no universal ASTM D624 machine capacity.
The standard tells us how the test is performed.
It does not tell us whether your specimen will tear at:
60 N
250 N
or:
900 N
Actual force depends on:
Material + Specimen Type + Thickness + Tear Resistance + Test Conditions
This distinction is particularly important because rubber tear tests often operate at relatively low forces compared with high-force materials testing.
Buying equipment only from the maximum machine capacity therefore misses an important part of the selection process.
A 5 kN Machine Does Not Mean You Need a 5 kN Load Cell
Suppose the testing-machine frame has a maximum capacity of:
5 kN
but the actual specimen normally tears at:
70–100 N
The fact that the machine can produce 5,000 N does not answer the important measurement question:
Which load-cell range best matches the force we actually need to measure?
Consider three illustrative applications:
| Expected Tear Force | Selection Focus |
| 40–80 N | Low-force measurement capability |
| 150–300 N | Load cell suited to a few hundred newtons |
| 700–1000 N | Higher low-force measurement range |
These are selection examples, not prescribed ASTM load-cell capacities.
The useful rule is:
Select the load cell around the expected tear force—not around the maximum frame capacity.
For an 80 N tear test, the words “5 kN machine” tell us much less than many buyers expect.
Grip Selection Matters More Than Many Buyers Expect
With rigid materials, buyers often start by comparing machine capacity.
With rubber, grip behavior can be just as important.
A poor grip can create three problems before the material's real tear behavior has even been measured.
Specimen Slippage
If the specimen moves inside the grip, part of the crosshead travel comes from grip movement rather than specimen deformation.
Misalignment
If the upper and lower gripping points are not correctly aligned, the specimen may experience unintended off-axis loading.
Grip-Induced Damage
Excessive or poorly distributed clamping pressure may damage a soft elastomer before the intended tear develops.
For grip selection, we therefore ask three simple questions:
Will it slip?
Will the grip damage it?
Will it stay aligned?
The machine supplies the motion.
The grip determines whether the specimen stays where you put it.
Use the Actual Specimen to Select the Grip
A grip that works well for one rubber formulation may behave differently with another.
Hardness, surface texture, specimen width, thickness, and elasticity all influence gripping.
This is why a specimen drawing, material description, or physical sample is much more useful than simply requesting:
“Please quote a rubber grip.”
ITM-LAB offers material-testing fixture configurations suitable for rubber and elastomer applications.
The final fixture should be selected around the specimen and expected force rather than assuming every elastomer uses the same jaws.
Why the RS-8010A Is a Practical Starting Platform for ASTM D624
For conventional rubber and TPE tear specimens, measurement range, grip behavior, travel, and speed control generally deserve more attention than very high frame capacity.
Within the ITM-LAB range, this makes the 【ANCHOR → RS-8010A】RS-8010A Universal Testing Machine a practical starting platform for typical ASTM D624 applications.
Key specifications include:
Capacity Range: 50 N–5 kN
Force Accuracy: ±0.25%
Test Speed: 0.001–500 mm/min
The 500 mm/min upper speed is particularly relevant to Type A/B/C D624 testing.
A typical test configuration can therefore be:
RS-8010A
Appropriate Load Cell
Suitable Rubber / Tear Grip
ASTM D624 Test Method
The important phrase is:
Appropriate Load Cell
The value of the platform is not simply that the frame reaches 5 kN.
It is that the system can be configured around the actual specimen and force range.
Why We Would Not Normally Start With a 50 kN or 300 kN Machine
ASTM D624 is different from a high-force plastic compression test.
For ordinary rubber tear specimens, jumping immediately to a 50 kN or 300 kN frame normally does not solve the main measurement problem.
If a customer's expected D624 force genuinely exceeded the RS-8010A configuration, we would review the application.
But the first response should not automatically be:
“Use a larger machine.”
It should be:
“Show us the specimen, expected force, grip requirement and test method.”
That keeps the equipment selection tied to the test rather than the product catalog.
When ASTM D624 Is Not the Test You Need
Knowing where the standard stops is as important as knowing what it covers.
If You Need Tensile Strength or Elongation
ASTM D624 measures tear strength.
If the objective is tensile strength, tensile stress, or elongation of rubber and thermoplastic elastomers, ASTM D412 is the more relevant test method.
If Your Customer Specifies ISO Tear Testing
ISO 34 addresses tear resistance of rubber and elastomeric materials using its own specimen and procedural requirements.
ASTM D624 and ISO 34 should not simply be treated as interchangeable result sets.
If You Need Finished-Product Tear Performance
ASTM D624 evaluates material behavior under controlled specimen conditions.
A finished component may have different:
- Geometry
- Stress concentrations
- Aging history
- Temperature exposure
- Installation conditions
ASTM D624 data can support product engineering, but it does not replace every product-level tear test.
ASTM D624 vs ASTM D412
These two standards often appear in the same rubber laboratory, but they answer different questions.
| Item | ASTM D624 | ASTM D412 |
| Main Property | Tear Strength | Tensile Properties |
| Typical Material | Rubber / TPE | Rubber / TPE |
| Loading Purpose | Initiate / propagate tear | Stretch specimen in tension |
| Typical Result | N/mm | Tensile strength, elongation, related properties |
| Specimen | Tear geometry | Tensile specimen |
| Testing Platform | Universal Testing Machine | Universal Testing Machine |
| Fixture | Suitable tear / rubber grip | Rubber tensile grip |
This creates a useful equipment strategy.
You may need two test methods, but you may not need two testing machines.
A properly configured RS-8010A can support different rubber tests by changing:
Specimen + Grip + Load Cell + Test Method
ASTM D624 vs ISO 34
ASTM D624 and ISO 34 both address elastomer tear resistance, so buyers sometimes place them together in an equipment requirement.
The same universal testing machine may be capable of supporting both methods.
That does not mean the procedures or results should be mixed.
ASTM D624 uses its own specimen geometries, including Types A, B, C, T, and CP. ISO 34 follows its own specimen and method definitions.
A better equipment requirement is:
Machine capable of ASTM D624 and ISO 34 test configurations
rather than:
ASTM D624 = ISO 34
The first describes equipment flexibility.
The second incorrectly implies identical testing.
Common ASTM D624 Test Problems—and What to Check First
When a laboratory sees inconsistent tear results, it is tempting to start with machine calibration.
That should not always be the first step.
A practical troubleshooting order is:
Specimen Cutting
↓
Notch Condition
↓
Thickness
↓
Material Direction
↓
Grip Slip
↓
Alignment
↓
Test Speed
↓
Machine
Why this order?
Because tear testing is intentionally sensitive to geometry and stress concentration.
A poorly prepared specimen can produce a perfectly accurate measurement of the wrong physical condition.
Similarly, a specimen slipping several millimeters in the grips can change the force-displacement behavior even though the testing frame itself is functioning correctly.
Machine accuracy matters.
But it cannot compensate for uncontrolled specimen preparation.
Environmental Conditions Can Change Rubber Tear Behavior
Rubber and elastomers are sensitive to temperature and conditioning.
For routine incoming inspection, testing under specified laboratory conditions may be sufficient.
For applications involving:
- Automotive sealing
- Low-temperature elastomers
- High-temperature rubber
- Material development
the question may become:
Do you need ASTM D624 at room temperature only, or under controlled temperature conditions?
That question should be answered before ordering the final system because environmental accessories can affect grip selection, test space, and installation.
Three Typical ASTM D624 Equipment Scenarios
The following are illustrative selection examples rather than claimed customer cases.
Scenario A — Low-Force Soft Elastomer
The specimen produces tear forces below approximately 100 N.
The main concern is not obtaining a stronger frame.
It is selecting an appropriate low-force measurement range and preventing grip slippage.
Starting configuration:
RS-8010A + Suitable Low-Force Load Cell + Elastomer Grip
Scenario B — Tougher Rubber Material
The specimen generates several hundred newtons.
The same RS-8010A platform may remain suitable, but the load-cell range should now be selected around the higher working force.
The frame did not need to change.
The measurement configuration changed.
Scenario C — Laboratory Also Performs ASTM D412
Now the laboratory needs:
ASTM D624 Tear
ASTM D412 Tensile
The better question is no longer:
“Which tear tester should we buy?”
It becomes:
“How should we configure one universal testing machine to cover both methods?”
That may involve different grips, specimen methods, and load-cell ranges while retaining the same machine platform.
This is where a universal testing machine becomes more valuable than a single-purpose tear tester.
Before We Recommend an ASTM D624 Testing System
A useful equipment inquiry should tell the supplier more than the standard number.
For ASTM D624, we would want to know:
Material
Natural rubber, synthetic rubber, silicone, TPE, or another elastomer?
Specimen Type
A, B, C, T, or CP?
Specimen Thickness
What is the normal thickness range?
Expected Tear Force
Do you have previous test data?
Other Standards
Will the same machine also perform ASTM D412, ISO 34, peel, or other low-force tests?
Test Environment
Room temperature only, or controlled temperature?
If previous test data are available, even one force-displacement curve can help with load-cell selection.
The equipment can then be configured in the right order:
Specimen first. Sensor second. Grip third. Machine last.
ASTM D624 Testing Machine Selection Checklist
| Question | Why It Matters |
| Which D624 specimen type? | Changes speed and evaluation method |
| What is the specimen thickness? | Directly affects tear-strength calculation |
| What tear force is expected? | Determines useful load-cell range |
| Will the specimen slip? | Influences grip selection |
| Can alignment be reproduced? | Affects tear path and repeatability |
| Is 500 mm/min required? | Relevant for A/B/C specimens |
| Are T/CP specimens tested? | Different speed and force evaluation |
| Is ASTM D412 also required? | Supports multi-fixture UTM planning |
| Is temperature-controlled testing required? | May affect accessories and test space |
This checklist is more useful than asking only:
“Is the machine ASTM D624 compliant?”
A complete testing system has to match the actual application.
FAQ
What does ASTM D624 test?
ASTM D624 measures the tear strength of conventional vulcanized rubber and thermoplastic elastomers under defined test conditions.
What ASTM D624 specimen types are available?
The standard defines five specimen types:
A, B, C, T and CP.
What is the ASTM D624 test speed?
Typical test speeds are:
Type A/B/C: 500 ± 50 mm/min
Type T/CP: 50 ± 5 mm/min
How is ASTM D624 tear strength calculated?
For Types A/B/C, tear strength is based on maximum force divided by specimen thickness.
For Types T/CP, the applicable average or median force from the tearing region is divided by thickness.
What unit is used for ASTM D624 tear strength?
A commonly used SI unit is:
N/mm
Does ASTM D624 require a 5 kN machine?
No single machine capacity is specified for every D624 application.
Machine and load-cell selection should be based on the actual force generated by the specimen.
Do I need a 5 kN load cell if the testing machine is rated to 5 kN?
Not necessarily.
If the specimen tears at a much lower force, a load cell better matched to that force range may be more appropriate.
Which ITM-LAB machine is suitable for ASTM D624?
For typical low-to-medium-force rubber and elastomer tear testing, the RS-8010A is the primary ITM-LAB platform to evaluate.
The final load-cell and grip configuration should be selected according to the specimen and expected force.
Can one machine perform ASTM D624 and ASTM D412?
Yes, provided the machine's force range, speed, travel, grips, load cells, and test-method capabilities meet both applications.
Is ASTM D624 the same as ASTM D412?
No.
ASTM D624 = Tear Strength
ASTM D412 = Tensile Properties
Is ASTM D624 the same as ISO 34?
No.
Both address tear resistance of elastomeric materials, but specimen geometry and test procedures differ. Results should not automatically be treated as directly interchangeable.
Final Selection Rule: Start With the Tear Force, Not the Maximum Machine Capacity
ASTM D624 looks like a simple tensile movement applied to a shaped rubber specimen.
Useful data, however, depend on an entire measurement chain:
Material
↓
Specimen Type
↓
Cut / Notch Quality
↓
Thickness
↓
Expected Tear Force
↓
Load Cell
↓
Grip
↓
Test Speed
↓
Universal Testing Machine
For many conventional rubber and TPE applications, the ITM-LAB RS-8010A provides a practical starting platform because its low-force capacity range and speed capability can be configured around ASTM D624 testing.
But the final equipment decision should never come from the assumption:
“ASTM D624 = 5 kN machine.”
A better rule is:
The standard defines the method. The specimen defines the measurement range.
If the specimen tears at 80 N, measure 80 N well.
If it tears at 800 N, configure the system around 800 N.
And if the laboratory also needs ASTM D412 tensile testing, configure the same platform with the appropriate fixtures and load-cell ranges instead of buying another machine simply because the standard number changed.
That is the difference between selecting a testing machine and designing a testing solution.
