old tyres

[wibble]

Does the rubber in old tyres go off after a while?
I have some 17 year old tyres and while they still have lots of tread, the front tyre some times will slip on wet tarmac. Its already caused me to fall off once Off road is okey so far...
Is it about time I got some new tyres?

 

[Johnsqual]

Re:

If you're riding MTB tyres on the road, they might be slipping because the profile is not suited for riding on the road. MTB tyres can slip because the knobbles on the tyres don't give enough surface area contact with the road. Maybe try slick (no knobbles) tyres?

Supposedly, the rubber in tyres is meant to get better with age, as long as they
are stored well (in the dark, at least partially pumped up). There are films of cycle teams with tyre cellars where they store tyres to age them.

Usually the biggest problems with old tyres is the side walls cracking and them losing shape because of being stored folded up.

 

[stesnape]

Re:

I don't know if this applies to bikes but most car tyre manufacturers recommend a max lifespan of 6 years. Apparently the vulcanising process continues and the rubber gets harder and more brittle, so it may well cause the front tyre to slip easier.

 

[jimo746]

I'd agree with stesnape, the black rubber tread often becomes harder and can crack.
Not so noticeable on the mud, but on tarmac .... Yeah.

Reminds me of having Jap import cars, often fitted with all season tyres, that were aged, rock hard compound, and slippery as buggery on UK roads. Always changed the tyres soon after getting the car.

 

[mattr]

The only tyres that get better with age are those which are on cotton or silk carcasses. Vulcanizing the rubber properly would make the cotton or silk disintegrate. So they sort of slightly vulcanize a little bit, then let it finish over time, slowly.
Any poly cotton or polyester/nylon cased tyre will have finished, and be as good as it gets by the time it's travelled from the factory to the shop, then sat on the shelf for a day or two.
They then start to go off, and harden up.

(There are a few exceptions, I've had a few, very few, polycotton tyres that weren't fully vulcanized, they were hand glued prototypes, and actually disintegrated in the bag I left them in for ~10 years, bloody brilliant while they lasted, not very durable!)

 

[wibble]

Sounds like I should have a look for new tyres for now especially as there seems to be a lot of warning for car tyres over 10 years old...

Is it no longer the fashion to have different design for the front and back tyres?

 

[jimo746]

Re:

you mean different tread patterns on the front & rear tyres? you can still get front or rear specific tyres, but most modern tyres work just as well on either end, plus when th rear starts to wear a bit you can easily swap the tyres around to get a bit more life out of them.