Q: Is there a different speed limit for retreads than for new tires?

A: Tires have no bearing on legal speed limits in the United States. Some time ago, I rented a car in Germany and it had a red sticker on the windshield that limited the speed to 100 miles per hour (160 KPA) because it had retreads, but I do not know if it was a law or the rental car company policy.

Q: We recently experienced some failures at the bond line on a few mold cure light truck retreads. These tires failed after only a few miles, but only on one side. What could have caused this?

A: A close inspection revealed that all the failed tires were run in the same mold and the failure was always on the same side. A thermostat had failed on one side of the electrically heated mold causing the curing temperature to reach 350 degrees F. This caused the natural rubber cushion gum to revert at the buff liner causing the failure.

Q: We want to develop a high cut resistant compound for our mold cure truck retreads. Are there any drawbacks?

A: It depends a lot on how you use the retreads and how you develop the cut resistant compounds. The main concern is heat buildup on long distance, high speed hauls. I would suggest that you restrict the use of high cut resistant retreads to local applications.

Q: Will a retreaded tire fail from being run severely out of alignment or out of balance?

A: Any tire can fail due to excessive out of alignment or balance conditions. The greater the load speed and ambient temperature, the more likely the tire is to fail from heat buildup.

Q: Is it practical to save the buffing blades on the edge of the rasp hub that receive little wear to be used again?

A: For some people, it’s worth a try, but I would suggest that when the used blades are put back on the rasp hub for use that you sharpen them pretty aggressively before buffing the first tire. Some people use these blades to buff tires that have a lot of sand or small rocks or other debris lodged in the tread.

Q: We have noticed an occasional failure of a buzz-out in our truck retreads and we are concerned that the time lapse between uses of the handheld extruder could be the problem. What do you think?

A: It may be possible that you are letting your extruder gun set too long between uses or the temperature on the extruder gun is set too high. Check with your extruder rope supplier for the correct temperature setting. I would also suggest that if the extruder gun
sits more than 15 minutes that you throw away the first six inches when you start up again. I would also suspect that the preparation of the buzz-out is what is really causing your problem.