Tyres: rim not sealing

David Balfour ( snipped-for-privacy@bal4.fsnet.co.uk) gurgled happily, sounding much like they were saying :

They've gone porous.

You might get away with cleaning and relacquering the inside of the rims.

May be worth inflating them underwater, so you can see exactly where the air's coming out.

The usual problem I have is air coming out between the rim and the bead, especially where clip-on balance weights have been used. Rather than use a large tank you can just run a little soapy water or leak detector around the rim with the wheel horizontal and you should be able to see where the bubbles are appearing. It only takes a small leak to flatten a tyre overnight.

The answer is to clean up the rims on the inside with a softish wire brush to remove any oxides and apply a tyre sealant. Tyre fitting places will usually do this for you. Then get them to use stick-on weights if possible.

Remove the tyres, clean and paint the inside of the wheels. Make sure you use a suitable primer.

Thanks for your input guys. I took them down to the local tyre place who cleaned up the inside of the rim with a wire-brush as Richard suggested. They said the wheels were probably ok, there was just a bad seal around the bead where the rim had corroded whilst the tyre was flat.

I'll see if they hold their pressure for a few days before fitting them.

Thanks again, David.

They will do, but this is only a *very* short term fix. The alloy will corrode again very quickly now it has no protection. The only long term answer is to re-paint properly.

Alloy wheels are buggers for corrosion along the bead. My wife's Previa usually gets a flat every couple of years through this - remove tyre, clean the bead area thoroughly, refit, sorted.

Yup - all four on my SD1 used to lose pressure. Been there about wire brushing the rim - it simply doesn't last. Nor did sealing gunge.

Then again after cleaning them up you could always fit tubes!

Check that your tyres can be used with tubes, the finish to the inside surface of many is not sufficiently smooth and will abrade the tubes. Check with the tyre manufacturer if in doubt, Cheers, Bill.