S60 Wheels/Tyres: Tyres deflating

[JNMann]

My tyres go from 34 psi to 20 psi in a few days.

I had new Avon's fitted to front last year, fitter told me the tyres weren't sealing on the inside because of the state of my wheels. They do need a refurb but have been the same for 5 years, had several sets of tyres and never had this issue.

I took two better wheels down and paid to have swapped over. Still same issue but before they were going pretty much flat in 2/3 days, now they last a few days longer.

My intention is to either swap or refurb the wheels when I can but wondered if anyone had ever seen this issue? Not something I've ever come across and wondered if the type/fit of tyres could be causing this?

The tyres also rub on the inside which again is something I've never had happen.