August 18, 2004

Touring a Goodyear tire plant
by Jim Kerr

The dark grey skies and high, barb wire-topped security fence looked ominous. The remote controlled gate slowly opened. Thankfully, we were greeted by the friendly staff of Goodyear's Napanee, Ontario tire manufacturing plant. Located out in the middle of the Ontario countryside two hours from Toronto, we were there to see Goodyear's new Assurance line of tires and tour their manufacturing plant.

Materials trucked into Goodyear's Napanee tire plant include natural rubber from Indonesia, synthetic rubber, carbon black, special fibreglass for the Assurance TripleTred tire compound and sulphur to harden the rubber. As each material enters the plant it is placed on a pallet and identified by bar code. The bar code enables this material to be tracked by computer throughout the complete manufacturing process. By reading the code on the finished tire, they can trace exactly everything that went into that individual tire and every machine or process it went through. Before the mixing can occur, the lab tests each pallet of material for quality.

There are hundreds of recipes for the rubber compounds used in different parts of a tire and for different types of tires. There are four crews with 19 members each who are responsible for mixing the 21,000 pounds per hour of rubber compounds. The Napanee plant crews are proud to have set a Goodyear world record by mixing an incredible 1,035,000 pounds in one day.

Mixing occurs in several stages. The first stages are called "non productive" mixes. Additional materials are added each time that it is mixed. For example, the Assurance TripleTred tire uses three non-productive mixes and the final "productive" mix. Each batch is cooked for a specific time and temperature and finally passes though an extruder where it comes out in long ribbons of rubber shaped for the specific part of a tire. The rubber is rolled onto spools before being transported to the tire assembly area. A roll of tread holds enough material for 35 to 40 tires. Again, each batch is tested in the lab for quality before it moves on.

Assembly takes place in a temperature and humidity controlled part of the plant. Huge G3 (3rd generation) tire machines spin rollers where the tires are put together. First, the inner liner rolls on. Then an overlay layer of rubber. Two strips for the sidewalls roll on next followed by apex strips for the bead. The wire bead reinforcements are installed automatically during the process.

Each time a new layer of rubber is rolled on, the machine stops so the operator can inspect the splice and reposition it by hand if necessary. The rubber at this stage has the consistency a little drier than bubble gum so it can be repositioned easily yet sticks together. The tread is simultaneously being assembled with the layers of belts and cords on a second machine. When completed, the tread assembly slides over the tire casing and is "stitched" together with rollers that push the tread against the casing. Finally, air pressure pops the assembled tire off the rollers and it is transported to the curing area.

Until now, the tire is a non-descript bowl-shaped circle of soft rubber. During the curing process, the tire is placed in a large metal moulding press with all the sidewall and tread patterns engraved in the mould. It is baked under pressure at about 300 degrees Fahrenheit for 11 to 13 minutes to cure the rubber. There are over 150 presses at the Napanee plant and they operate 24 hours a day, seven days a week. When the tire is popped out of the mould, it looks like what you have on your car, but the process is far from finished.

Every tire is now inspected for 161 potential faults. Some of them pass onto the sidewall grinder where the black rubber is removed off the whitewalls and white raised lettering. Now the tire looks finished.

Then, each and every tire goes on a force machine. There are 13 force machines in the Napanee plant, each one costing between $750,000 and $1 million dollars. The force machine spins the inflated tire under loads and pressure equal to the loads it would find on a vehicle. Strict quality control sees less than 100 tires a day rejected and scrapped from the 19,000 tires a day produced here. The final production step is inspecting the tire for balance. The tires with the best balance go to the auto manufacturers for new vehicles while tires that may need slightly more balance weights go off to retail stores.

We give very little thought to those bands of rubber that support and allow us to control our vehicles. After watching the fascinating manufacturing process and seeing all the quality controls, I know that the Goodyear staff has quality and safety of their tires as a priority so I don't have to worry.

Jim Kerr is a master automotive mechanic and teaches automotive technology. He has been writing automotive articles for fifteen years for newspapers and magazines in Canada and the United States, and is a member of the Automotive Journalist's Association of Canada (AJAC).

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