All four tyres slowly deflate - why?

My wife's X Type Estate loses air from all four tyres at a fairly rapid rate 10PSI in 3 weeks on one of them.

I could understand a slow puncture in one tyre, or possibly two, but all four deflating at varying rates suggests something else?

Asked on 8 May 2013 by HUNTER WRIGHT

Answered by Honest John
Porous alloys. Needs a new set of wheels.
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