How long can new tyres last?

So I have a set of brand new west without the plastic covers that have been sitting around for around a year and will for around another 6 months, have they lost any performance? They are the leconts.

Store them somewhere out of the sun and not too hot and i would think they’d last quite a while. Worst case scenario you can use them for practice if you’re worried about race performance

Brand new tires hold oils pretty well. No issues running them. Worst case, the first cycle might take a second to come in, but you will be fine.