Michelin tire blow out!!
On a recent trip to the Western end of the Florida panhandle, we had a blowout on the right rear inside tire. Luckily it was on a straight section of Interstate Hwy with very wide and flat shoulders a...
Forum Discussion
To help everyone that is having problems understand the complex nature of what they think is just some rubber, string and steel cured in an oven here are a few facts from personal experience.
When designing a tire there are a variety of tests that the tire must pass. Wear, High Speed, endurance etc. One is a "burst" test where high pressure water is pumped into a tire until some part lets go.
There are three types of failure when doing a burst test. Note the "Pass" level is normally 3 to 5 times the rated pressure of the tire and this is usually higher than the burst pressure for standard wheels.
In the tire:
1. The steel belts break (wire fails under tension confirmed with microscopic examination for presence of "cup/cone" configuration i.e. proof of tensile failure of steel cord.
or
2. The sidewall breaks out but the belt does not break
or
3. The bead wire breaks and neither the sidewall or belt breaks.
Now in more than one case I was asked to write a spec for an LT tire of a higher Load Range than currently in production. Lets say it was make a Load Range D and a LR-E just like the current Load Range C tire except the LR-D & LR-E had to pass the the appropriate High Speed, Durability etc testing and the higher pressure required to pass the LR-D or LR-E specs
We found in more than one case the existing LR-C construction pass all the tests except Burst where the failure of the LR-C was in the Bead bundle not the belt or sidewall when running the burst test.
Sometimes there were other differences between the LR-C & LR-D but then we learned the LR-D construction might pass every test for a LR-E except that burst test.
If I increased the number of strands of wire in the bead bundle I could then pass the LR-E test requirement before the bead wire broke. The rest of the spec for the LR-D and LR-E version were identical in all respects and other times the LR-C & LR-D were identical except for bead but the LR-E needed different belt design. Each tire is different.
Now this is not always the case but this is what was required in more than one instance.
So people can choose to go with their gut feeling or with scientific facts. I do know that many people want to go with feelings as science don't always support their per-conceived notions but I prefer facts, evidence and repeatable test results over gut feel and wishful thinking.
When designing a tire there are a variety of tests that the tire must pass. Wear, High Speed, endurance etc. One is a "burst" test where high pressure water is pumped into a tire until some part lets go.
There are three types of failure when doing a burst test. Note the "Pass" level is normally 3 to 5 times the rated pressure of the tire and this is usually higher than the burst pressure for standard wheels.
In the tire:
1. The steel belts break (wire fails under tension confirmed with microscopic examination for presence of "cup/cone" configuration i.e. proof of tensile failure of steel cord.
or
2. The sidewall breaks out but the belt does not break
or
3. The bead wire breaks and neither the sidewall or belt breaks.
Now in more than one case I was asked to write a spec for an LT tire of a higher Load Range than currently in production. Lets say it was make a Load Range D and a LR-E just like the current Load Range C tire except the LR-D & LR-E had to pass the the appropriate High Speed, Durability etc testing and the higher pressure required to pass the LR-D or LR-E specs
We found in more than one case the existing LR-C construction pass all the tests except Burst where the failure of the LR-C was in the Bead bundle not the belt or sidewall when running the burst test.
Sometimes there were other differences between the LR-C & LR-D but then we learned the LR-D construction might pass every test for a LR-E except that burst test.
If I increased the number of strands of wire in the bead bundle I could then pass the LR-E test requirement before the bead wire broke. The rest of the spec for the LR-D and LR-E version were identical in all respects and other times the LR-C & LR-D were identical except for bead but the LR-E needed different belt design. Each tire is different.
Now this is not always the case but this is what was required in more than one instance.
So people can choose to go with their gut feeling or with scientific facts. I do know that many people want to go with feelings as science don't always support their per-conceived notions but I prefer facts, evidence and repeatable test results over gut feel and wishful thinking.
