3 months ago I bought some kuhmo xs tires new in 295 35 17 becasue I got a great deal on them but I did not have wheels for them yet. THey are just sitting in my garage. THey will be used for auto x. My buddy is saying I don't want to be sitting on them more then 6 months without using them Cause they will harden up and not be as good for auto x. Is this true? I know tires harden up and it takes years for that but in 6 months time I don't see how they wouldn't be just as good for grip as when I first got them. I'm thinking at least a year sitting before it changes performance... Can anyone shed some light on this.

 

depends on light exposure, humidity, temperature. etc.
in a damp, hot environment in the sun, they will die quickly.
if dry, cool, dark - last a while.
anything in between will last between a while and quickly. Its unlikely to find much data on this.

 

Ya I wasn't able to that why I posted up. They are in a dry, cool, mostly dark area. My garage. Definetaly dry in Idaho and cool.