Tire Retreading

Tire Retreading

Retread services are offered to State Agencies only.

PI’s retread division carefully inspects tires with special electronic and high pressure testing equipment to ensure you receive a safe product and one that should provide service equal to that of a new tire. After testing, any defects are repaired and then the remaining old tread is buffed away. The new tread is applied to the casing and the tire is “shrink sealed” for baking in the heat chamber. When it comes out, it is inspected again for your safety and satisfaction. 

Economy

Successful fleet managers know that retreaded tires significantly reduce operating costs. A new truck tire will deliver up to 200,000 miles and by recycling the casing, as many as 600,000 additional miles may be added to the life of the tire. Of course, mileage will vary based on the tire application and care. A sound casing can be expected to be safely retreaded three times and each retread should equal or exceed original wear and deliver the same performance. Tires, old or new, require some maintenance, proper mounting, matching, demounting and appropriate inflation. 

Ecology

Retreaded tires contain 75 percent post consumer recycled materials, one of the highest percentages of all recycled products. Since the casing already has undergone one life cycle, the only new material used to retread a tire is the raw material used to manufacture the tread. In 1992, 33 million tires were retreaded in North America and placed back in service rather than further contributing to the solid waste stream. Once a tire can no longer be retreaded, it may be broken down and used in the construction of interstate and secondary roads.*

*Source: The Retreading/Repair Journal, E.J. Wagner. 

Resource Conservation

It takes about 22 gallons of oil to produce one truck tire and just 7 gallons to retread the same tire. This means 15 gallons of oil are saved each time a truck tire is recycled. Retreading conserves 400 million gallons of oil annually in the United States and Canada.**

**Source: The Retread Information Bureau, Pacific Grove, CA 93950.

 

Facts About Retreads

1) PI retreads tires for most types of heavy equipment or fleet vehicles. Radial tires are available in sizes from 750/R16 to 425/R/65/22.5 and bias ply tires in sizes from 750 x 16 to 1200 x 20. PI does not offer retreading of automobile tires.

2) Nearly 100 percent of the world’s airlines use retread tires! The Navy’s famous Blue Angel jet precision flying team lands on retread tires. Over 50 percent of the tires used on military aircraft are retreads**

3) The performance of a retread is greatly determined upon the the original quality of hte new tire.

4) More than nine out of every 10 fleet vehicles ride on retreads. Retreads are being used by school buses, emergency vehicles, race cars, taxis, trucks and many other vehicles.**

5) There is no evidence showing retreads to be less safe than new tires.

6) There is a misconception that rubber found on the side of the road is the result of retread failure. Rubber on the road side has a 50/50 chance of being retread. Most tire failure, new and retread, is caused by abuse like overloading, under inflation and mismatching of dual axle tires.

7) Retreads generally carry a warranty comparable to new tire warranties. 

When Can a Tire Be Retreaded or Repaired?

Features

1) Recognized “A” rating with National Tire Dealers and Retreaders Association.

2) All tires must pass a 12 step PI quality assurance and testing program.

3) All radial tires are high pressure tested.

4) Rereading of radial and bias ply tires for most vehicles.

5) Nationally recognized tread supplier.

6) PI’s tire staff and workers are professionally trained by factory representatives.

7) Electronic pre-treatment exams.

8) All rims are steam cleaned at no charge and painted upon request, for a nominal charge.

9) Tires carry DOT and PI identification code along with manufacturing completion date.

10) Customer ID/Logo stenciled or branded at no charge. 

Benefits

1) Our standards are reached by only 30 percent of the tire retreading facilities in North America.

2) Ensures the highest manufacturing quality and tire safety possible.

3) Fleet service is not interrupted and the tire inventories can be reduced.

4) Our technicians have a broad base of experience in fleet vehicles, including highway maintenance, sanitation and school busses.

5) Only the highest quality compounds are used in the retreading procedure.

6) All the latest technologies and industry applications are used.

7) We evaluate tire soundness to avoid unnecessary processing.

8) Better safety and appearance.

9) Identification markings allow casing to be tracked throughout manufacturing.

10) Improves customer satisfaction while identifying specific customer needs. 

 Retreading Process

Initial Inspection

 

Each tyre received in a retread plant is subjected to a rigorous visual inspection. Inspectors are assisted by the use of non-destructive sophisticated inspection equipment.

We also purchase a new machine (Inspection Spreader).This Inspection Spreader designed to detect pinholes, nail holes, cuts, cracks, porosity,etc,Automatic tyre rotation stop when penetration detected with sparks.

Buffing

 

The tyre’s old tread is mechanically removed on high speed buffers. Today’s buffers are extremely accurate and will remove the proper amount of old rubber while turning the tyre to an exact specified diameter and radius.

Skiving & Repairing

 

With advances in state-of-the-art repair materials and repair methods, many of these tyres can be routinely repaired and in most cases can be retreaded when the original tread is worn off. The repair station is where any surface injury is treated using effective material and tools for grinding and patching.

Cementing & Filling

 

Even in small injuries it is critical that the injury is cleaned and filled. If this is not done, severe rust, separation and steel cable looseness could take tyre out of service. The injury should be inspected, and then cleaned out with a carbide cutter. After cementing the injury, a vulcanizing rubber stem should be applied to “fill” the injury. This would create a permanent repair that maximizes tyre life.

Building

 

In the pre-cure system, the tread rubber has already been vulcanized with the new tread pattern design. The buffed tyre needs a thin layer of cushion gum to be wrapped around its crown area. The pre-cured tread rubber is then applied with the building machine. This is called the building process.

Enveloping, Rim Mounting & Double Envelope System

  

a) The built tyres are then mounted with envelops and rims to prepare them for curing.

b) For enveloping, tyres are first fitted an outer envelope at the envelope-mounting table before the inner envelope is fitted into them. The enveloped tyres are then vacuumed out for preparation prior to curing. Modern plants have their casings hoisted by monorail systems.

Curing by Chamber (Precure)

 

The Precure Tread system is a process by which a tread pattern is fully cured or vulcanized into the tread by using a press. The tread is then vulcanized onto a tire casing using a bonding layer of uncured natural rubber. The tyre is vulcanized with heat, time and pressure in a curing chamber that bonds the tread to the casing. This thin layer called precure cushion or bonding gum. Cold retreading was then a term used to describe a process in which the final curing of retread is done at temperature lower than 115c.

Hot Process (Hotcure)

This system is similar to the technology of new tyre manufacturing.

Hot retreading is the term used to describe the retreading process in which the curing of retread is done at a temperature of above 140c. It employs a steel or aluminum mold with a tread design cast or machined into it.

Final Inspection (Presure Test) & Painting

• Tyre inflation pre-set at 2, 4 & 8 bar (max) for a better QC inspection.
• Enclosed by steel cage as safety protection.
• Testing cycle ended automatically to reduce supervision work.
• Well lighted within the cage for better visual inspection.

The retreaded tyre is subjected to a final inspection. This inspection insures that only tyres that meet industry quality standards are allowed to leave the retread plant.
All retreaded tyres are encouraged to be returned with the sidewalls painted using a light coat of black tyre paint.