Mickey Thompson ET Streets

[cudabob496]

My ET Streets are 15 yrs old. MT tech guy says we should replace tires
after 6 years, because the rubber ages and the tires woun't have as good
of traction.

[70chall440]

Is this a question or a statement? If you are asking, I'd say 15 yo tires may not be the best traction device available, but then it does depend slightly on how they have been stored and taken care of.

[cudabob496]

Is this a question or a statement? If you are asking, I'd say 15 yo tires may not be the best traction device available, but then it does depend slightly on how they have been stored and taken care of.

A statement. Car is always garaged, driven about 3000 miles a year. My fingernails don't seem
to sink into the rubber like they use to. It does make sense that the rubber would age and
some of its qualities would deteriorate. I'll put on the ET Street R's and see if it feels different.
The R's and S/Ss have the same R2 compound.

[73440]

https://www.nhtsa.gov/sites/nhtsa.dot.gov/files/811885_tireagingtestdevelopmentprojectphase2evallab.pdf

A long read, look for small cracks along the sidewall, I know I should replace mine.

[cudabob496]

I got the new ET Streets. The rubber is much softer than the hard rubber
on my 15 yr old ET Streets, even though they are the same R2 material. I'm sure
traction will be better.

[cudabob496]

https://www.nhtsa.gov/sites/nhtsa.dot.gov/files/811885_tireagingtestdevelopmentprojectphase2evallab.pdf

A long read, look for small cracks along the sidewall, I know I should replace mine.

The below sums up the report. Basically, as tires age, their perfromance deteriorates.

"Canonical correlation of the properties showed that the properties of the components tended to change in the same direction with increased time in service in Phoenix or increased time of laboratory aging on each candidate method. Particularly, the hardness, modulus, cross-link density, and oxygen content tended to increase; and the tensile, ultimate elongation, peel adhesion, and flex properties tended to decrease over time. All of these changes are consistent with the proposed mechanism of thermo-oxidative aging."