Carrera Nascar Tyres (Tires) Availability

At our club in the UK we race standard Carrera Classic Nascars on an irregular basis.
Oiling the tyres for extra grip is allowed, however as a consequence the rear tyres on several cars have become unusable due to degradation over time. Decent Decade has become a few months.
There don't seem to be any replacements available in the UK. Does anyone know of a US supplier with stock?
I know PG does urethane tyres to suit but at the moment they would not be allowed.
Thanks
Allan
Oiling the tyres for extra grip is allowed, however as a consequence the rear tyres on several cars have become unusable due to degradation over time. Decent Decade has become a few months.
There don't seem to be any replacements available in the UK. Does anyone know of a US supplier with stock?
I know PG does urethane tyres to suit but at the moment they would not be allowed.
Thanks
Allan