tubless valves should they be replace when buying new tire

I believe it is good common practice to replace the tubeless valve stems when replacing tyres, but NOT mandatory.
I do check myself when having new tyres fitted, that new stems have been fitted.

Have never had them replaced in 40 years and never had a problem.
But why 'shocked'?

I know some people who religiously replace them every tyre replacement. Guess no harm.

I reckon wheel nuts take more stress. But I'm not 'shocked' they don't replace them.

They are subject to Ozone deterioration just like your tyres and if not changed can be the source of that hard to find slow leak due to micro cracking and splits as well as losing the flexibility needed to keep a seal in the mounting hole in the rim. They do flex a lot under centrifugal loading and of course they also suffer the odd stone and stick hit.

The guys I use always replace them, generally because they cut them off to deflate the tyre fully when dismantling.
Always been told that fitting new ones with new tyres is best practice. (Have to remind them about the TPMS!)

And then some people never have a problem with not changing them.

regards

A

Tubeless valves are only $2 each.
Every time I've bought tyres, the tyre fitter puts new valves in, and I'd be miffed if they didn't.

Most reputable tyre dealers will replace the tubeless valves as a matter of course when fitting new tyres on the basis that they do not last a lifetime and it is just good industry practice to replace them rather than have the customer return with a slow leak from that source. Unlike steel wheel nuts, being rubber they are susceptible to ozone, UV, heat and mechanical damage including cuts from ill fitting wheel covers. I got caught about a year ago when having 4 new LT tyres fitted to a tandem trailer and the dealer failed to repalce the tubeless valves (I didn't check) While travelling at night with a car on the trailer, about 2100kg all up, after about 600km I stopped for fuel and could smell hot rubber. One of the tyres had defelated to about 15 PSI because the T/L valve was leaking so I fitted the spare. After another 400Ks I stopped for the night and next morning another tyre was flat. When I went to re-inflate the tyre the brass insert in the T/L valve (which the valve screws in to) blew out and nearly took my eye out on the way past my head. Had I not noticed the first tyre losing pressure at best I may have wrecked the new tyre, at worse it could have caused a tyre fire (near impossible to extinguish) or caused a difficult to control situation. When I returned to the dealer and expressed my disappointment they did not believe they had not replaced the T/L valves until I showed them the valves still had blue over spray on them from when the trailer was painted some years prior. I would say this was a case of the tyre fitter forgot or lack of training but as this occurred within a few days of having the new tyres fitted rest assured if this incompetence had resulted in any tyre damage I would not be paying for their reaplacement.

As other posters have said, there is no good reason to not replace rubber tubless stems every time a tyre is fitted.

As for a tyre shop getting the tyre pressure right....don't make me laugh.

In over 30 years of driving and buying tyres I have not once come away from a tyre shop with the correct pressure in the tyres.

Some deliberately over inflate and say that they do, because it "helps seat the tyres on the bead" and advise adjusting the pressure after the vehicle has been driven on the tyres

Others just seem to have their own ideas on tyre pressures....almost always over inflated and considerably so.

Never, trust a tyre shop to correctly inflate your tyres and be very wary of any advice from a tyre shop concerning tyre pressures.

They should no better....but they mostly just don't.

cheers