Old tyres

[2manyoranges]

I’ve cosmetically rescued tyres with either spray-on or paste silicone clear furniture polish. Spray on, then use a stiff shoe brush then a soft one to finish. This actually does tend to increase the suppleness of the tyre too, but simply because you are handling it and bending it a bit, which puts energy in and loosens the polymer strings against one another.

 

[Dr Dremel]

Just use a rubber conditioner of your choice. Enough choices in the automotive realm (tire dressing or rubber seal protectant). I use generic silicon spray. I mean it´s not going to make existing damage go away, but it´s good for preserving a nice tire.