Constantly-deflating tyres

[downstairs]

My tyres keep going down. It's not punctures, because even new tyres go down if I put new tyres on. I put air in, and within a week or two they're half flat again.

I can only imagine my wheels have somehow become porous or something. Is that a thing? One wheel is a bit buckled from a pothole but that tyre doesn't go down as much as the others. Do alloys eventually lose their "airtightness"? or are my garage constantly just putting the tyres on a bit wrong?

If it's the wheels themselves, can they be fixed? Skimmed or sealed or something? Or might I need to replace the wheels? My car is just over ten years old, and so are its wheels.

[alangla]

Yes - older alloys can become porous.
Best option is to ring up your local powdercoater/alloy wheel refurb shop & get the offending wheels refurbished.
My mum's 18 year old Citroen ZX had this problem, £50 a corner to fix and the wheels were in factory condition when they came back.
Also, if you ever fancied different coloured wheels, this is your chance - they had a variety of different finishes available.

[kambites]

I think the most likely problem is corrosion on the bead causing it to leak.

[Emeye]

Could be a rim leak. A good tyre place should be able diagnose and clean up your rim (OO-er missus).

[downstairs]

Will corrosion be fixed by a refurb as suggested?

[kambites]

Yes; or just the application of a bit of elbow grease on your part.

[sparkythecat]

I had this problem on an old car a few years ago. Painting the painting the inside of the wheels with 2 coats of hammerite cured it. Don't forget to use the special primer.

[mark.c]

All of the above, you could also ask the tyre fitter to put a bit extra splurge around the rim whem they fit them. Refurb/wire brush is your best long term solution though.

[anonymous-user]

King Herald will be along in a minute to lecture you on the need for valve caps

[hornetrider]

kambites said:

I think the most likely problem is corrosion on the bead causing it to leak.

^^ First port of call.

Get the wheels off and soak with water, you'll probably see bubbles from where the air is escaping. Then it'll be tyre off, wire brush on the bumpy bits and tyres back on, job done.

[Drive Blind]

try and find a friendly tyre fitter who will take the time to trace where the fault is if you can.

I had an occasion where after getting 2 new tyres the tyre fitter just announced 'the new valves probably wont seal due to corrosion thanks bye' and then said I needed new wheels, etc, etc.

sure enough they lost about 10 psi per week. I went to another tyre fitter who took the time to look at the problem and ensured the valves seated properly with no leaks.

obviously I haven't used tyre fitter 1 again.

[007 VXR]

Take the wheel off and put it in the bath and watch bubbles ?

[Monkeylegend]

007 VXR said:

Take the wheel off and put it in the bath and watch bubbles ?

Don't forget to add water.

[007 VXR]

Monkeylegend said:

007 VXR said:

Take the wheel off and put it in the bath and watch bubbles ?

Don't forget to add water.

[jimi]

My dad had a high mileage car a while back which was running on the original wheels. They were slightly out of shape and had this issue.

The other thing I have had before is a crack in the wheel rim itself which you cant see - the water and bubble idea should show any leak..

[downstairs]

jimi said:

My dad had a high mileage car a while back which was running on the original wheels. They were slightly out of shape and had this issue.

Interesting. Mine certainly counts as high mileage I think.

[paintman]

Very common issue with alloys is, as said, corrosion where the tyre meets the rim.
If you want to take them off to check then just lay the wheel flat on the ground & pour soapy water where the tyre meets the rim - then turn over & repeat on the other side. Do the same to the valve.
Tyre place I use wire brushes the corrosion & if the surface is pitted use a black sticky stuff before refitting the tyre. Never had any issues subsequently.

Edited by paintman on Monday 30th March 11:54

[r11co]

Question - do your wheels have stainless steel valve stems? Electrolytic corrosion between the mating surfaces of the valve stems and the wheels can cause air leaks.

[jimmyVX]

I had a similar situation with a Volvo V50. I assumed it was a slow puncture only to find it still going down once I had the tyres replaced. It went back to the tyre fitters a couple of times where they tried various things, changed valves/removed tyres and cleaned up the rim etc. After a couple of visits he spotted a very small hairline crack in the alloy that was barely visible. It was just enough to let the tyre pressure drop around 50% over the course of a week.

[downstairs]

r11co said:

Question - do your wheels have stainless steel valve stems? Electrolytic corrosion between the mating surfaces of the valve stems and the wheels can cause air leaks.

I think so. I hadn't considered galvanic corrosion.