[AlanHo]

@ surferdude : A few months ago I discovered that some moron had stolen all my original KIA tyre valve caps. It was during covid lockdown so I took the easy route and bought some with the KIA logo on the end of each cap from Ebay.

The original KIA ones were plastic - the Ebay ones were metal - which I assumed was an improvement.

Over the week-end one of my tyres developed a slow leak so I popped into a local tyre workshop to get it seen to - it was a nail in the centre of the tread.

The foreman advised me that the metal valve caps were a bad idea - especially now that cars have TPMS. He has lost count of the number of owners who have snapped the valve stem trying to remove a seized metal cap and he replaced them with plastic ones.

You learn something every day.

[Surferdude]

Interesting.
I don't have any experience with the corrosion problems on your roads so I would have to accept what a local expert says.

In the real world (sans snow), metal caps are better in that they can hold pressure without a valve core in place.

And yeah. I get that TPMS reduces or negates the risk of a slow leak through a faulty valve core. Well, at least it lets you know if there's a problem.

    #metalvalvecapsforever
 

[Shambles]

I once fitted metal caps to one of our Rav4's and can confirm that they can be a bastard to break free when they corrode and bind.

[AlanHo]

The tyre guy explained that the problem is worse with cars having TPMS that uses pressure senders in the wheels which are integral with the valve. They contain a small 3v lithium ion battery. The miniscule current flow exacerbates electrolytic corrosion when the valve stem thread and metal valve cap are dissimilar metals. Thus resulting in them seizing.

He also added that when the batteries eventually die - typically in 4 to 10 years depending on mileage (The TPMS only used battery power when the car is moving) he suggested you can save significant cost by buying third party sensors that can be programmed to your car.  A sneaky advert for him no doubt.

[Lorian]

go back 8 or 9 years and there was quite a spate of members breaking the valves off when pumping air in. This was when the stems were aluminium and they didnt like acidic wheel cleaner. I still run with a very light smear of Vaseline on the threads to this day.

[Lakes]

Never had a problem using metal valve caps myself. must be your climate ? Or you could put smear of lubricant on the valve thread.