Other than visible tyre damage like sidewall punctures and metal/nylon plies exposed to ambient, according to tyre manufacturers across the world ONLY 10 year tyre age AND tyre wear touching ' tyre wear indicator of standard 1.6 mm height' are (mainly) the criteria of discontinuing service of said tyres.

Other incidences like loud tyre noise/hardened rubber compound/so-called slippery/so-called handling/tyre botak/so-called scratches and roughened patches/rubber compound surface cracks etc etc does not fall under the criteria of tyre manufacturer requiring service termination/replacement of tyres.

This post has been edited by zeng: Jul 29 2023, 12:51 PM

Yes, 10 years for aftermarket like Continental brand etc.

You may google in lowyat for screenshots (I uploaded 2-3 years back) of tyre manufacturer manuals saying so.

Socalled 'cracks' on external surfaces of sidewall rubber or tread compound rubber (as natural part of rubber hardening/oxidation/aging) in itself is not a structural problem leading to tyre burst and hence safe for continuing service.

You may want to identify and watch for exposure or puncture of tyre structural members in the form of nylon/fibre/steel plies or belts, which rarely occurs in the real world.

Rubber compound materials, be it on sidewall or treads is NOT a structural member.Period.

This post has been edited by zeng: Aug 6 2023, 01:31 PM

Tyre tread area puncture repair by external plug method has been prevalent, common and low cost for decades has proven to be effective and often times easily last till the tyre end of life at standard 1.6 mm tyre wear indicator level/mark.

However, tyre manufacturers recommends the other alternative method of 'patching' from inside surface of tyre after separating rim from tyres. This method is more time consuming and costs slightly more.

In either case, a tread puncture repair should last till a tyre's end of life generally.

Note: Tyre manufacturers recommend against repairing a punctured sidewall.

This post has been edited by zeng: Aug 6 2023, 10:22 PM