Rubber components used in industrial, automotive, and outdoor environments are constantly exposed to temperature swings — sometimes from sub-zero mornings to scorching operating temperatures within minutes. These repeated changes, known as temperature cycling, cause rubber to expand, contract, harden, soften, and eventually break down. If your rubber parts are failing earlier than expected, temperature cycling is often a major contributor.

In this post, we’ll break down why temperature cycling affects rubber so strongly, what symptoms to look out for, and how smart material selection and design can greatly extend part lifespan.

Why Temperature Cycling Damages Rubber

Rubber is a viscoelastic material, meaning it behaves partly like a solid and partly like a fluid. This is great for sealing and flexibility — but challenging when temperatures fluctuate rapidly. Here are the key effects:

1. Repeated Expansion and Contraction

Each temperature cycle causes rubber to expand when heated and shrink when cooled. Over thousands of cycles, this mechanical strain leads to:

  • Micro-cracking
  • Surface hardening
  • Loss of elasticity
  • Distortion or warping

Materials like EPDM and silicone handle this better than nitrile or natural rubber.

2. Hardening at Low Temperatures

At low temperatures, rubber becomes stiff and brittle. When the material is flexed or compressed while cold, it can:

  • Crack
  • Tear around high-stress regions
  • Lose sealing force
  • Fail prematurely under vibration

This is especially common in outdoor gaskets and seals exposed to winter conditions.

3. Softening and Degradation at High Temperatures

Elevated temperatures accelerate chemical reactions inside the rubber:

  • Oxidation
  • Crosslink breakdown
  • Outgassing of plasticizers
  • Surface embrittlement

High heat is especially damaging for NBR, SBR, and polyurethane but is well-tolerated by FKM (Viton), silicone, and fluorosilicone.

4. Compression Set Worsens With Temperature Cycles

Compression set is when a rubber part doesn’t fully spring back after being squeezed. Temperature swings multiply this effect because:

  • Heat accelerates permanent deformation
  • Cold reduces the rebound ability

This leads to leaking seals, loose gaskets, and vibration mounts that lose preload.

Common Failure Symptoms Caused by Temperature Cycling

If you’re seeing any of these, temperature cycling may be the root issue:

  • Cracks around edges or thin regions
  • A hardened, shiny, or brittle surface
  • Loss of sealing pressure
  • Gaps forming between mating surfaces
  • Rubber shrinking or deforming
  • A “flattened” gasket that doesn’t rebound
  • Bond failure in rubber-to-metal assemblies

These failures often appear well before the rubber’s expected lifetime.

How to Design Rubber Parts to Withstand Temperature Cycling

Fortunately, the right design and material selection can significantly increase lifespan.

1. Choose a Material Rated for Your Full Temperature Range

Every rubber compound has a minimum and maximum working range. General guidelines:

  • Silicone: -80°C to +200°C
  • EPDM: -50°C to +150°C (excellent weather resistance)
  • FKM (Viton): -20°C to +250°C (fuel + heat environments)
  • NBR: -30°C to +120°C

Selecting the wrong compound is the #1 cause of temperature-related failures.

2. Avoid Sharp Corners and Thin Sections

Sharp transitions concentrate stress during expansion/contraction. For long life:

  • Use generous radii
  • Maintain consistent wall thickness
  • Avoid “knife edges” or thin lips

This reduces crack initiation points.

3. Include Design Features That Reduce Stress

Features such as:

  • Compression limiters
  • Support ribs
  • Flexible hinge regions
  • Reinforced inserts

can significantly improve durability under temperature cycling.

4. Account for Compression Set in High-Temperature Applications

To reduce compression set:

  • Choose low-CS compounds
  • Increase gasket cross-section
  • Avoid constant over-compression
  • Use the right curing system for the part’s intended environment

5. Test Using Accelerated Aging

Before committing to a full production run, you can simulate years of use by:

  • Cycling temperature chambers
  • Measuring durometer drift
  • Checking for cracking, shrinkage, or bond failure

This is especially important for automotive, energy, and industrial equipment.

Why Temperature-Resistant Design Matters

Poor performance under temperature cycling can lead to:

  • Costly downtime
  • Leaks and contamination
  • Mechanical noise or vibration
  • Premature component replacement
  • Warranty failures

Designing for temperature extremes is almost always cheaper than fixing repeated part failures later.

Primo Rubber Co: Your Partner for High-Performance Rubber Parts

Whether you’re developing new equipment or troubleshooting a recurring failure, our team can guide you to the right solution — and produce parts built to last, cycle after cycle. Contact Primo Rubber Co. today to learn more about our custom rubber molding capabilities and material options.