Tyres - do they go off???

[wibbleone]

Looking at some alloys with unused tyres that have been stored for 5 years as a cheaper alternative to replacing them at a tyre shop - but then I thought does the rubber go off and are these likely to be dangerous??

I think some manufacturers say 5 years - other internet posts have said should be safe for 10 years - they'll probably be on my car for a maximum of 2 years - so is there any disadvantage / risk to doing this??

Thanks :-)

[mrmr96]

Yes, rubber does go off.

Best bet would be to go and inspect them. If they've been stored out of reach of sunlight they have a better chance.

For the sake of saving money I would tend to buy new tyres though, even if that means going for a less premium brand or saving money elsewhere.

[Crusoe]

Depends what they are for, they tend to get harder and crack as it ages so on a high performance car with sticky summer rubber the old tires wouldn't have as much grip and might fail under load if there are a lot of cracks in the side walls and could ruin the ride if they are low profile. For a eco friendly hard wearing tire on a hatch back if they looked ok I would expect them to be fine.

[wibbleone]

thanks - i think that makes my mind up - probably not worth the risk!

[agent006]

It's light that does the damage to tyres. If they've been stored properly then there's no reason they would be dodgy. Look for cracks and crazing on the sidewalls and between the tread blocks.

[philoldsmobile]

they do go off, but not like they used to.

a lot of it depends on the compound, and how much natural rubber v synthetic rubber is used (synthetic rubber is the main reason tyres dont loose pressure like they used to)

even without cracks, if the rubber has gone hard and greasy, they will be utterly gripless. a blue tinge to the colour of the tread can be a giveaway there. 5 years isn't that long though..

[volvoforlife]

Don't say things like that! I've had the same set of tires on my car since 2002 and they still have about 4mm left!

[flemke]

A quick and dirty test can be done with your thumbnail.
Of course there is great variability across compounds, but you can adjust for that somewhat by looking at the wear rating on the sidewall, and comparing the sample tyre with a newer tyre of similar wear rate. (Nb: Each tyre manufacturer seems to use its own scale, so a Mich. 160 will not necessarily be the same as a Goodyear 160).
Allowing for the above, you should be able to put your thumbnail into it and feel some compliance, with the rubber moving around a bit as your modulate the force you're applying.
Think of it this way: much of the grip that the tyre achieves is the result of the rubber momentarily changing its shape and digging into the tiny fissures and irregularities in the cement or stones in the asphalt. The less that the rubber is capable of changing shape into the road surface, the less grip it can offer.

[Red Cabbage]

I have known certain tyres to go off due to age and I have replaced them despite the amount of tread remaining. As commented above my understanding is that the rate of decay is largely dependant on how they are stored and the compound.

Tyres are not a component I am prepared to take chances with.

[anonymous-user]

Yes tyres degrade but it depends on how you are going to use the car as to whether its worth worrying about. An old snotter that goes to the shops, no. Something that you will load up and/or use hard, probably. Anything going near the limit, definately.

Check the date stamp and look for obvious cracks and as suggested dig your nail in them when next to something that has newer tyres to see the difference.