. Always store bias ply tires laying flat on their sidewalls, not upright on the tread.
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I disagree with this statement .
My experience was ,I bought some tyres that I knew had been stored for several years , stacked flat as above , they were on my truck less than 2 months and I noticed cracking between the treads , at the tyre shop , the first thing the shop owner said was "stacked flat!"
FAIL !
I had to buy new ones .
I had the opposite experience: flat-spotted bias ply tires, had to have them shaved to make them round again. Tire store told me "Never store them upright or they'll flat spot."
So you had cracking from storing flat, I had flat spotting from storing upright. Bottom line evidently is that bias ply tires can't be stored very long in ANY DIRECTION or they will take a set.
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