How Old can tyres be and still good ?

[blue al]

I have some 2017 tyres used for 3 months and then dry cold garaged stored on wheels flat stacked
Swapped on oz ultraleggeras and AD08r, at the time as 270hp fwd…

Have they an infinite shelf life if no visible damage or deterioration?

( A052 now on the car currently as summer toy, but it’s time to tax again ( only 16k miles)
so it made me think it’s time to use it over the winter months also)

[paintman]

blue al said:

I have some 2017 tyres used for 3 months and then dry cold garaged stored on wheels flat stacked
Swapped on oz ultraleggeras and AD08r, at the time as 270hp fwd

Have they an infinite shelf life if no visible damage or deterioration?

( A052 now on the car currently as summer toy, but it s time to tax again ( only 16k miles)
so it made me think it s time to use it over the winter months also)

No.
Worth a read: https://www.protyre.co.uk/car-help-advice/tyre-saf...

Having had a fair bit to do with caravan dealers as part of my business the main cause of tyre failure on caravans & trailers is due to aging & for one dealer it was standard practice to replace any tyre over 5 years of age on all used vans they sold.
Tread wise the tyres may look barely used due to the extremely low mileages but the compound has hardened & cracked.