Friday, Apr 03, 2020 at 16:00
It depends on how it's been stored. If it's been stored in the sun, then it probably needs replacing.
But if it's been stored under a vehicle or in a boot all that time, then I see no reason to scrap it.
I have tyres that are over 20 years old and still performing satisfactorily. But they haven't been in strong, direct, hot sunlight for lots of years.
And a spare that has never been on the road, has never been flexed, and never endured any road impacts.
The life of a tyre is dependent on the life it has led.
If the 15 yr old tyre has endured 15 yrs of road impacts and constant flexing - then yes, it's at the end of its life.
You would probably be surprised at the age of a lot of tyres coming towards you on the highways.
The manufacturers have a vested interest in selling new tyres, and therefore want you to scrap perfectly good tyres that are 15 yrs old.
A tyre with 100% tread is more capable of taking road shocks and impacts, than one with 20% tread.
I've never seen a satisfactory-looking tyre fall apart or blow up with age - unless it already showed very obvious signs of rubber ageing.
Those signs are tiny cracks in the rubber, that indicate perished rubber, or cracking circumferentially around the bead, or long cracks in the sidewall.
Most tyres fail because they have received a severe impact that has damaged the casing plies, or a crack or other tyre damage has uncovered steel plies, and the steel has rusted.
Tyres are built with enormous safety margins - if they weren't, we'd be seeing a vast amount of accidents caused by blown-out tyres.
Many truck tyres are retreaded at up to 6 or 7 yrs old. That means the retreader expects the tyre to perform satisfactorily for a number of years yet.
This is after the tyre has already been worn out once.
Interestingly, there are no regulations or guidelines for retreaders, as regards the age of the tyres they retread.
It's up to the individual retreader to choose whether they retread a tyre that is over 6 yrs old.
A tyre in good condition, that is 6 or 7 yrs old, will more than likely be retreaded.
And that same tyre will be alongside you on the highway, carrying a full load of up to around 4 tonnes, at 100kmh, at possibly 10 or 12 yrs of age.
Cheers, Ron.
AnswerID:
630856
Follow Up By: Lorne S1 - Friday, Apr 03, 2020 at 16:16
Friday, Apr 03, 2020 at 16:16
Thanks Ron, great response.
yeah my tyre has been under the car for its whole life, never seen sun in its life.
I never go outback or remote so its not life threatening, I might leave it until next tyre change
FollowupID:
906505
Follow Up By: Peter_n_Margaret - Friday, Apr 03, 2020 at 17:23
Friday, Apr 03, 2020 at 17:23
I suggest that ozone is responsible for tyre break down at least as much or even more than UV and keeping a tyre out of the sun has no effect on ozone exposure.
The best protection against UV attack in plastics (tyres) is to add carbon black. Tyres are absolutely loaded with carbon black.
Michelin says their tyres must not be retreaded at 10 years or more.
Personally, I would choose a 20% tread tyre that was 6 years old as a spare in preference to a tyre 15 years old, no matter what the tread level.
Cheers,
Peter
OKA196 motorhome
FollowupID:
906513
Follow Up By: Gronk - Friday, Apr 03, 2020 at 18:04
Friday, Apr 03, 2020 at 18:04
Hard question to answer based on facts ( or lack of ), but a good example of the advantage of rotating all 5 tyres.
Sure, you have to replace all 5, but the time frame is increased and you don't get any "stale" tyres.
FollowupID:
906517