N.Y. Comp. Codes R. & Regs. tit. 15 § 51.4
For the purposes of this section the following terms shall have the following meaning:
The worn tread rubber is rasped or buffed off the top of the tread and over the shoulders as far as the new rubber is to extend.
In top treading only the top of the old tread is rasped or buffed off. All the new rubber is applied just to the top of the tread.
Rubber between the base of the anti-skid design and buffed tire body.
The distance measured near the center-line of the tire from the base of the anti-skid design to the top of the tread.
Natural rubber shall include all forms and types of tree, vine, or shrub rubber.
Two types of synthetic rubber are commonly used in retreading. These are usually indentified as SBR synthetic rubber and BR synthetic rubber. The former is a butadine-styrene rubber and the latter a type called stereo synthetic rubber made from butadine and sometimes also called polybutadine or PBD.
Cold rubber is a type of synthetic rubber polymerized at approximately 41 degrees Fahrenheit, as distinguished from hot rubber polymerized at approximately 122 degrees Fahrenheit.
Reclaimed rubber is any rubber derived from the processing or treatment of vulcanized rubber or cured scrap rubber.
Tread rubber shall show whether it is natural rubber, cold rubber, or synthetic rubber and will also show rate of cure, such as, fast cure or regular cure on each box.
For the purpose of measuring the width and thickness of tread rubber, a cut should be made straight across the full width of the tread rubber with a sharp knife. The cut should be made not less than three or more than six feet from the outside end of the roll and also it must be away from the point where the weight of the roll or other pressure may have distorted the dimensions.
The padding stock shall be suitable for filling in worn (low) spots under tread rubber and made from a fast cure compound compatible with natural and synthetic rubber.
The filler strip stock shall be a minimum of 4/32 inch thickness at the center line. This stock shall be suitable for filling around the complete circumference of the tire being retreaded to insure the proper undertread, and shall be made from a fast cure compound compatible with natural and synthetic materials.
Vulcanizing cement used for adhesion of conventional tread rubber to the buffed tire shall be made with natural rubber and the necessary cement must be capable of being vulcanized and suitable for the use intended. Special cements made for the adhesion of particular compounds such as those used in extrusion application of tread stock must be specifically compounded to meet all necessary requirements as an adhesive and bonding agent-both before and after cure. It is not required that this type of cement be made of any specific rubber type, or that the solvent be a petroleum distillate alone.
The rubber solvent shall consist entirely of petroleum distillate, and shall be water-clear, free from foreign material, acid, water, or antiknock materials. When subjected to distillation in accordance with an applicable method, the solvent shall show an initial boiling point (I.B.P.) of 100 degrees to 140 degrees Fahrenheit, and an end point (E.P.) of 250 degrees to 300 degrees Fahrenheit, with no oily residue.
Tread rubber for pneumatic tires of all types, repair materials and unvulcanized accessories should be stored in a dry place, protected from the elements and direct exposure to sunlight and the temperature of the storage area should be kept below 80 degrees Fahrenheit. Under these conditions, tread rubber and repair materials should be expected to remain in a satisfactory condition for six months after date of receipt from the manufacturer. Colder storage conditions extend the shelf life, without harm to the product. Warmer storage conditions shorten the shelf life. Tread rubber and repair materials exposed to temperatures of 80 degrees to 95 degrees Fahrenheit, can be expected to have their shelf life reduced 25 percent and if stored at temperatures of 95 degrees to 110 degrees Fahrenheit, a reduction of 50 percent or more can be expected. Tread rubber and repair materials will not tolerate temperatures of over 110 degrees for more than a very short time without danger of vulcanization. If the tread rubber and repair materials are exposed to temperatures which cause freezing or hardening of the stock (which can occur at temperatures below 40 degrees Fahrenheit) the stock must be carefully restored to its original condition by warming it at a temperature between 70 degrees and 90 degrees Fahrenheit. Tread rubber, repair materials and all unvulcanized accessories are made to meet exacting standards and to perform under existing field conditions, and at the same time to be as satisfactory as possible for shelf aging. Because these materials are shipped to widely varied climates and are subjected to all types of storage the possibility of deterioration is always present. The storage period and conditions specified reflect general industry experience. Violation of these specifications may be reflected as an appreciable deterioration of a percentage of the material affected and does not mean that such material is unusable or subject to failure because of age.
Tires that have a known separation between the plies shall not be retreaded, and should be destroyed. No tires to be accepted for retreading may contain any of the following weaknesses or injuries.
All tires to be processed shall be thoroughly dry and all cords free of moisture.
All nail holes must be thoroughly cleaned and inspected for extent of casing injury. If casing is punctured only and does not require a full section repair or reinforcement, the nail hole may be filled and treated in the conventional manner so as to provide a sound tire body for processing.
The tire shall be uniformly buffed using a matrix template or other satisfactory system of measurement to insure proper matching of buffed crown contour with matrix tread contour and overall diameter. The buffed surface should be of a smooth texture and free from moisture, loose cords and foreign material which would affect adhesion properties between casing and tread rubber. Proper buffing dimensions for each matrix must be posted in the buffing room. These should include:
with minimum and maximum measurements.
The cementing process should begin within a reasonable time after the buffing operation is completed to avoid the hazards of an oxidized surface. Each container of cement shall be tested for freshness. If solvent is used as a thinner, this too must be tested for presence of oil or water. Tires to be cemented must be free from moisture and foreign material such as buffing dust, dirt, loose cords, etc. Extreme caution must be taken on air lines used to blow dust from the surface of a tire. Efficient moisture traps must be located as close as possible to the air release valve to prevent moisture from being blown onto the surface of the tread area.
After curing, the retreader shall make a final examination of the tire, checking inside to insure that nail holes and loose cords have been properly treated and that the tire is not buckled. The outside of the tire shall be checked to insure adequate moldings and curing. The tread shall be straight and not porous. Each tire shall be trimmed cleaned and/or painted.
The tread rubber used shall be of such thickness as to provide the following amount of undertread to adequately meet requirements. Undertread thickness should be gauged after the tire has been retreaded and does not necessarily reflect tread rubber thickness.
Tire size | Under tread | Skid depth |
| Passenger: Conventional Designs | ||
| Less than 7.003 cross section | 9/32 | 9/32 |
| 7.003 cross section and larger | 2/32 | 10/32 |
| Passenger: Mud and Snow Designs | ||
| Less than 7.003 cross section | 2/32 | 12/32 |
| 7.003 cross section and larger | 2/32 | 14/32 |
| Commercial Truck Tires | ||
| (Less than 203 bead diameter) | ||
| Less than 7.503 cross section | 3/32 | * |
| 7.503 cross section and larger | 4/32 | * |
| Large Truck Tires | ||
| (203 bead diameter and larger) | ||
| Less than 9.003 cross section | 4/32 | * |
| 9.003 cross section and larger | 5/32 | * |
*
Equal to that of new 100 level tire of same size and type-minus tolerance 2/32".
The effective use of time clocks, heat gauges, mold and/or matrix temperature gauges is required for the control of heat, time and air pressure. These gauges should be calibrated regularly to insure their accuracy.
In order that the consumer may know that the retreaded tire purchased actually complies with the specifications set forth in these standards, all tires must carry a guarantee against defects in workmanship and material as well as give satisfactory service under normal operating conditions.
No person, firm, association or corporation shall sell, offer or expose for sale, or having in his possession with intent to sell any motor vehicle tire or motorcycle tire which has been retreaded or recapped unless the fact that such tire has been retreaded or recapped and the name and address of the person, firm, association or corporation which has done the retreading or recapping is plainly shown by a mark or label in the English language on both side walls thereof. (General Business Law, § 391.)
Footnotes
* Equal to that of new 100 level tire of same size and type-minus tolerance 2/32".
N.Y. Comp. Codes R. & Regs. Tit. 15 § 51.4