Retreading replaces the worn tread of a sound tire casing with new tread rubber. For trucks, buses and aircraft it is standard practice: a good casing can be retreaded several times, cutting tire cost per kilometre and saving a lot of rubber and oil.
Before either process
Every casing is inspected first — visually, and often with shearography or x-ray. Casings with cuts into the belts, separations or too many repairs are rejected. The old tread is then buffed off to a precise profile.
Hot retreading (mold cure)
Uncured rubber is applied to the buffed casing, and the tire is placed in a mold that forms the new tread pattern while the rubber is vulcanised at roughly 150 °C.
- The tread pattern can cover the shoulders ("top cap" or "bead to bead").
- Good for patterns that match the original tire and for passenger and light-truck tires.
- Higher temperature puts more heat into the casing; each mold suits one size and pattern.
Cold retreading (pre-cure)
The tread is vulcanised in advance as a flat strip with the pattern already formed. It is bonded to the casing with a thin cushion gum layer in an autoclave at about 100–125 °C.
- Lower temperature, gentler on the casing.
- One autoclave handles many sizes; a wide choice of tread patterns.
- The most common method for truck and bus tires.
Which is better?
Both give reliable results when the casing is good and the shop follows the process. Fleets usually choose pre-cure (cold) for truck tires because of pattern choice and casing care, and mold cure (hot) where an original-looking pattern or full shoulder coverage matters.
Tips for fleets
- Keep pressures correct — under-inflation is the main reason casings are rejected.
- Pull tires for retreading before the tread is worn to the belts.
- Track the casing history: how many retreads, which positions, which failures.
See also: inner tubes for commercial trucks.