Do tyres harden with age?

There was a post sometime in the past month about this.
Tyres apparently compress and harden with age and the wear rate slows.

I know with racing bikes, tires get hot when in use and the heat softens them. Then when they cool down, they go hard again, and if not used for a while, they go HARD... I mean HARD...

I would think this would happen to a point with car tires. Hot then cold constantly would have this affect on them.

A mechanic who did some work on my 4WD 10 years ago had two stacks of desert duelers on top of the office in his workshop. He said one pile was for him, the other for his business partner, they both had FJ40's with 350 chev engines. They recon the tyres would "go off" when stored for a long period which meant they would wear longer. But he did admit that grip in the wet was awfull, but they didn't care cos they mainly used the cars for tearing up the beach, not driving around town.

Yes they do, now, if only us guys would.....

Speak for yourself Wolfie!!

Is that why you are called "Lone Wolf"?

Time for the purple pill for by the sounds of it.

Dave L.

I think this another urban myth. Rubber compound doesn't 'harden' as it ages- in fact it goes brittle.

Apparently the life of a tyre is about 5 years.
I had a set of 2nd hand Olympic Steel Treks on the CT with heaps of tread left.
Thought one had a puncture and took it in for repairs. Was told it had died of old age and was unrepairable due to side wall failure. They also mentioned the 5 year approx life span.

I consider the crowd to be quite reputable, so have no call to doubt their point of view??

Cheers

signman,

INCORRECT mate.

It's a well known fact in the motor Racing industry that heat will have an effect on hardening, or curing of the tyre compound. How much, depends on the make up of the specific tyre compound.

A soft racing tyre is constructed so that heat will have a lesser impact on hardening as the intent is to keep the tyres "sticky" thus providing more grip.

A "controlled" racing tyre is manufactured so that heat generated when racing will have as little an impact on the rubber compound as possible, so that performance is consistent and "racing" life extended.

Back in my racing days, an "open" tyre had a noticeable performance drop after one days racing in that subsequent uses saw an increase in lap times when compared to a "fresh" tyre because they had become "less sticky".
The "controlled" tyres would last most of the racing season without a significant impact to performance. (lap times)

In a similar way, a normal road tyre would be manufactured with the intent of providing consistent performance over a prolonged period, once "cured".

Thus, a new tyre may wear quicker early in its life, if it hasn't had sufficient time for the rubber to cure. Once it has reached normal operating temperature a few times, the tyre will have reached its optimum performance level.
How well each brand and style of tyre performs and how long it lasts, is what keeps the "wheel Industry turning" so to speak.

Tyre manufacturers will tell you that tyres cure within 12 hours of manufacture. They may seem to become harder with age but that is due to compression. As previously stated soft tyres give more grip, harder tyres last longer.

Melissa,

I'm not sure of the reasons why, but I've had an almost identical experience to yours. My Cooper STT's wore fairly quickly to start with (after about 10,000 km, I too thought I'd only get about 50,000 out of them) but since then the wear rate has dropped considerably. I too reckon I'll get 80 to 90,000 out of them.

I don't know why this is so - maybe for some of the reasons discussed above - or maybe it's a different compound in the top few mm of tyre? I have no idea.

Cheers
Stephen J.

Hi
Ive always thought the aged principal was a good one, and leave a set of tyres out in the sun for a few months b4 using them if possible.
New tyres seem to be real slippery on the road....might be left overs from manufacture, dont know...but i do know that a set of Bridgestone muddies have almost worn out on my 80 series.
They were bought in 1990 as a second set of tyres for offroad, and used 10000kms in the first 5 years, then 10k per year since then...so i have got 110000kms from them with minimal tread left now. My Coopers are out the back sunbaking right now!
Andrew

I thought tyres gave more wear as they wear down due to less block squirm?

Seems to take for ever to wear that last 3mm off the tyres, from 4.5mm to 1.5mm tread depth of the wear bars!