Why does my tyre keep deflating?

Q. My front tyre has only done 1300 miles, but it keeps deflating. When I took it to a local tyre dealer they said it was porous – is this normal?
PTMX1234, MCN forums

A. The majority of problems with ‘porous tyres’ turn out to be problems with the sealing of the bead against the rim.

Most tyre fitters will just strip the old tyre off, apply some soap and put the new tyre on. Good tyre fitters will clean the mating surface of the rim first with a soft wire brush to ensure a good seal.

If the tyre was really porous, and reasonably young in years as well as miles, then the manufacturers should have been contacted about it, and they would have probably offered a replacement.