Tyre Hardness

shibuichi said:
Same, even when the guy at the tyre shop says "#$&@! These haven't been made in more than ten years!" 😲
The old Pirelli still had good even tread, keeps pressure, and in the event of emergency only needs to get me a short conservatively travelled distance.
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i am not having a dig here, because I do the same or worse, but I always think it’s funny when the majority of people go on and on and on some more about space saver tyres, when it is no better or worse than the pos spare I carry.
My perspective is, I have never had to change a tyre in my koleos and most likely never will.
to me a spare tire is something that stops the sub speaker rattling around!
 
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I have not read all this but will address the safety issue of old tyres failing only due to age.

A few years ago now on the way home from a military vehicle show in Corowa a gent in a restored Landrover was killed when the vehicle rolled owing to an aged front tyre failure.

Most don't know an old tyre that looks perfect can be a ticking time bomb.

All old tyres take on a certain set thru rotation in one direction. Cross rotating tyres [whether bias or radial ply] is definitely not recommended, no matter what manufacturer's manuals suggest.

Doing so tries to reverse that initial set & can lead to re-flexing the wall ply & separation failure.
 
On rotation:

Yes, these is a tendency for a tyre to take a structural "set". And yes, with an old tyre, that "set" being reversed increases the likelihood of strain in crucial places as a result of newly focused stresses. But:

A tyre used for ten years or less from manufacture should remain resilient enough to cope with such minor increased stresses. More is gained, safety-wise (& wallet-wise), by employing an X-pattern rotation schedule to even wear & shift the direction of surface engagement of the tread elements wear patterns.
 
4cvgordini said:
On rotation:

Yes, these is a tendency for a tyre to take a structural "set". And yes, with an old tyre, that "set" being reversed increases the likelihood of strain in crucial places as a result of newly focused stresses. But:

A tyre used for ten years or less from manufacture should remain resilient enough to cope with such minor increased stresses. More is gained, safety-wise (& wallet-wise), by employing an X-pattern rotation schedule to even wear & shift the direction of surface engagement of the tread elements wear patterns.
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There is also the thought that you shouldn't change sides (and therefore direction of rotation), even with tyres without a designated rotation direction. Equal wear may not always result in maximum life. Does anybody know of any credible published work on this?
 
I am anti - tyre rotation.
Not an expert tyre technician.
But I believe a new tyre becomes set in how it rolls and how the
steel belts and surrounding bonded rubber settle onto each other.
I will move a front to the rear on the same side if I need to get 2 new tyres.
Always preferable to get 4 at a time.
Even moving front to rear has disadvantages since the drive and braking
forces are changed.
Also, rotating theory is that it evens out wear patterns.
Maybe on a "dinosaur" with primitive suspension.
But I think it just ends up scrubbing the tread until it adopts a different wear pattern.

So folks, just kick your tyres before a long trip, and spend more time and effort
looking out for potholes that disgrace our roads....
 
Cross rotation is definitely not recommended no matter the tyre age.
Once a front tyre's wear pattern is established it is usually permanent even after a corrective wheel alignment.
The tyre will keep wearing in line with the original wear pattern.
Only new tyres will wear correctly & get things back on track.
If not mentioned earlier in this thread here is how to read the manufacturing date code & all tyres are marked:
E.G. 4820 means 48th week of 2020
Ref: https://www.michelin.com.au/auto/advice/tyre-basics/tyre-markings-explained#:~:text=The date code appears at,week of the year 2014.
 
Four tyres going onto a Scenic as we speak. I find they wear remarkably evenly on this model. This car has a bit of a mixture from a previous owner and it finally has worn them enough to change the lot and get it right! So, if it is say $800 every 5-10 years at our mileages, say $100 per year, that is less than one pint of Guinness per month. A manageable expense. the best of the old ones will be replacing the (much) older spare.
 
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