There are mainly two methods of retreading the worn-out tires of your vehicles namely
Although named Cold retreading, this technique employs the use of heat. The tires are heated above 100 degrees (Celsius). No molds are used in this process as they are highly-priced.
The Hot retreading technique uses a mold in which they are heated above 150 degrees Celsius. This technique is used when you need to get the right shape of the tires. By vulcanizing tires at almost 150 degrees and upwards, it is possible to essentially change the threads and tire shape, and this is what Hot Retreading aims to do.
There are a couple of different processes for retreading a tire, which are referred to as “mold cure” and “pre cure.” No matter which process is used, it always has to start with a casing that’s in good shape and structurally sound. The casing is inspected thoroughly using non-destructive testing, looking for any embedded debris or other internal problems that could cause a tire to fail; some casings can be repaired before retreading while others will have to be scrapped. The old tread then has to be mechanically buffed off of the tire before anything else can happen.
In this process, a previously-prepared strip of tread rubber is cemented to the casing (using a special compound called cushion gum) after the old tread is removed. The new tread is already vulcanized (hardened), and the pre cure tire then goes to a chamber to complete the curing process. Pre cure retreads mean a much greater degree of flexibility in tire sizes, but it unavoidably leaves a slight seam where the two ends of the strip join up. Additionally, the bonding of a pre cure tire may not be as secure in the long run as a mold cured or remold tire.
This method is a lot closer to how a new tire is manufactured, with the original tread removed and raw, un-vulcanized rubber applied to the tire in one continuous piece. The tire and its new tread area then go to a rigid mold where they are cured, and the new tread pattern is applied into the rubber. Like new tire manufacturing, dedicated molds are used for each tire size and tread design .The higher pressure of the cure means a tighter, more secure bond and a cleaner, finished look.