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Bond gum / cushion gum / envelopes
What it is
The consumables that make cold retreading work. Cushion or bond gum is the uncured rubber layer between casing and precured tread that vulcanises into the bond; envelopes are reusable rubber covers that seal the assembly for curing under pressure
With tread rubber, they are the retreader's main purchased inputs
Impact on industries
- Input costs track natural and synthetic rubber, so a retreader carries the same commodity exposure as a tyre maker without comparable pricing power
- Consumable supply is a recurring, annuity-like business for the material suppliers, tied to retreading volume rather than to any single customer
- Bond quality determines whether the retread survives, so cheap consumables are the most common route to failures that discredit the category
- Envelopes are reusable with a finite life, so consumable cost per job depends on operating discipline as much as on purchase price