Originally Posted By: SteveSRT8
Hello Capri racer!
Can anyone explain why some tires sometimes seem to get better as they wear down while others get dramatically worse?
Virtually every 2nd tier cheaper type tire I have bough seems to dramatically lose performance as they wear down, can't recall a single one that didn't do this. The other side is it seems that my expensive name brands simply don't suffer this problem as severely.
I am speaking primarily about lateral traction not longitudinal, but the degradation affects all aspects of the tire's performance, just not equally.
Sorry to take so long to respond, but since the question was about differences, I wanted to think over what all might be going on - and I came up with 2 things:
1) Anitoxidants and antiozidants. - AO's for short. These are chemicals that attract oxygen and ozone so they don't attack the rubber. These are incredibly expensive and I would think that less costly tires would be inclined to use AO's more sparingly.
2) Sophisticated vulcanization techniques. I am not a rubber chemist so I am out of my element here, but I am aware that there are several techniques used to cross-link the long chain rubber molecules. One of them is using sulfur, but there are some more sophisticated ways - and I would think ways that are less prone to degradation over time. This, of course, requires research - and while the techniques would be transferable as chemists move from company to company, I would also think it would take time to re-develop the technology at a different locale.
Just an FYI. Each manufacturing plant seems to have its own set of parameters that influence what works and what doesn't. I am aware that differences in mixing machinery change the way the recipes need to be written in order to get similar results, but they are never exactly the same.
I am also aware that different companies approach rubber mixing in different ways and with different suppliers, so it shouldn't be a surprise to find that apparently simliar tires don't perform the same. I know that wet traction varies around the country and you can test different tires and get different rank orders.
I suspect this is why many tires on Asian car manufacturers have so much traction issues. They are not testing on pavement in the US - which seems to be different than in Asia.
