[unclebilly]

From ChatGPT

Mounting 60-year-old NOS motorcycle tires is possible, but treating them to “soften” the rubber is not something modern tire science generally recommends—because the compounds that keep a tire flexible chemically break down over time, and no topical product can truly restore them.
But since you’re using the bike for shows/parades (low speed, low load, low heat), you can take some careful steps to mount them safely and protect them during installation.

Below is the safest, most practical approach.

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✅ Realistic Goals With Old NOS Tires

For 60-year-old tire rubber:
• You cannot chemically restore flexibility to original condition.
• You can temporarily improve workability for mounting.
• You can preserve appearance and prevent cracking during and after installation.

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✅ Before Doing Anything: Inspect Carefully

Even if stored perfectly, look for:
• Micro-cracks when flexing the sidewall
• Hard spots
• Bead cracking
• Casing distortion
• Chalkiness on the surface

Even tiny cracks at the bead area can cause trouble during mounting.

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✅ Safe Ways to Make the Rubber More Workable for Mounting

1. Warm the tires — safest and most effective

Old rubber becomes more pliable when warmed, not when coated with chemicals.

Best method:
• Put the tires in a warm room at 85–100°F (29–38°C) for several hours.
• Or leave them near (not on) a baseboard heater or a space heater from a safe distance.

This softens the casing enough to ease mounting without damaging historic rubber.

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2. Use proper mounting lubrication — crucial

Use a dedicated tire mounting lube, not WD-40, not dish soap.

Best options:
• Ru-Glyde (rubber-safe, water-based, dries without residue)
• Commercial tire paste/lube
• A 50/50 mix of glycerin + water

Lubricate:
• The bead
• The rim edge
• A few inches of the sidewall for slip

This prevents tearing the bead or leaving spoon marks.

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3. Nylon or plastic-tipped irons

Regular steel tire irons will mark old rubber.
Use:
• Nylon rim protectors
• Plastic-tipped irons
• Or wrap your irons with heat-shrink or heavy tape

A small manual bead expander can also help reduce spooning force.

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❌ What NOT to Use

These products either damage old rubber or only make it look “wet”:
• Silicone spray – surface shine only, no softening
• Armor All – can accelerate cracking on vintage rubber
• Brake fluid – old bikers used it, but it destroys tire compounds
• ATF – petroleum-based, causes swelling and bead failure
• Diesel/kerosene – destroys rubber chemistry
• “Tire restore” solvents – mostly snake oil

None of these can restore lost plasticizers.

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✅ Post-Install Preservation

Once mounted:

1. Treat with a protectant that actually works

You want an anti-ozonant, not a shine product.

Best options:
• 303 Aerospace Protectant (UV and ozone protection, non-silicone)
• Griot’s Garage Rubber Prep/Protect

Apply sparingly and reapply a few times a year if the bike sits on display.

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2. Keep tires inflated, but not at max

Store around 75–80% of operating pressure to reduce casing stress.

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3. Keep away from:
• Electric motors (ozone)
• Furnace ducts
• Sunlight
• Welders
• Air compressors and generators

These are ozone sources that accelerate sidewall cracking.

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❗ Important Safety Note

Even with perfect storage, NOS tires over 20 years old are not recommended for highway speeds.
For parades, shows, slow riding, they’re typically fine if the carcass is structurally sound.

If you ever want to ride the bike at highway speeds, swap to new reproduction tires.

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�� If you’d like, I can also help with:
• Tips for mounting vintage clincher or bead-edge tires
• What to look for to assess structural integrity
• Recommendations for reproduction tires that match original tread patterns (if you change your mind)

Just let me know!