Tyres

[timmsy]

Hi all we'll here is a question I can't seem to find anywhere on here (correct me if I am wrong)
But here goes at what age should I be looking at replacing the tyres on my spit 1500 irrespective of tyre tread as I recently heard that the rubber in the tyre degrades a lot over time and therefore becomes in danger of bursting
Is there a rule of thumb or is it dependant on where the car is kept and if the car is kept on stands ie tyres have no contact with the garage floor
Thanks for your time as always
Timmysy

[gfiandy]

Six to ten years.

Factors that reduce the time are uv exposure, high temperatures, being operated under pressure, an important one for a lot of classic cars, having only low usage. Yes if the tyres are under no load it is better for them.

If you tyres have any signs of side wall cracking it may be time to replace them.

[AndrewC]

I found that the tyres on my recently purchased Spitfire where from twelve to over twenty years old, and had been run grossly under inflated. All had plenty of tread and even wear, but changed all five as a safety precaution.

Andy

[Deleted User]

I have had my tyres (firestones) fitted for 7 years now, no cracking but as you would expect wearing a little low now. They tend not to blow out unless they are really knackered.

Rob

[timmsy]

Mine are Goodyear Grand Prix s can anyone remember when these were last produced

[npanne]

Tyres should be age stamped - see link for deciphering the code: http://www.123motor.ie/tyres-age/14

Older tyres (pre 1999) might not have these - but if they are that old they are prob due replacing anyway!

[timmsy]

Yeah npanne I was thinking that I would replace them I was more concerned about when I should replace the new ones

[Sheepy]

timmsy wrote:

Yeah npanne I was thinking that I would replace them I was more concerned about when I should replace the new ones

When they are worn out, damaged, or start to split! Difficult to give a time frame as said above, it all depends on usage, storage etc etc.

Just keep an eye on them and change when needed. But they should be good for a fair few years.

[gfiandy]

Older tyres blow outs would be rare without some pre warning if you check the tyres carefully for bulges or cracks or rumbling (as the side wall wears it starts to make a noise like a failing wheel bearing). However as the properties of the tyre degrade, the rubbers plasticising agents break down under UV and exposure to environmental contaminants oil etc and the internal structure can be damaged by under inflation or long periods of no use or over heating at high speeds (not that likely with a spit) the grip and structural integrity can degrade.

So your tyres may look fine may be safe from catastrophic failure but not provide the same level of grip and cornering stability as when new. My tyres are 8 years old for most of that time they were unused as the car was in restoration out of the sun and off the car, they look good and seem to perform well, they are Goodyear so a branded tyre, I plan to change them at 10 years unless I see visible damage. I only do about 1500 miles a year so there is no chance of them wearing out.

[rotoflex]

I had a dry-rotted tire that looked OK blow out at about 50 mph while driving my grandmother's station wagon.  While struggling to keep it in my lane, the tire diagonally opposite blew out.   I was lucky to maneuver into the ditch instead of going into oncoming traffic.  So I am sensitive to older, dry looking tires.

[junkuser]

That's interesting Bill.
    When I was working in my father-in-law's tyre (or tire if you prefer) service in 1959 I was intrigued that an old tyre I took off a large looking American imported car, was labelled as 4 ply "rated".  
This seemed a rather light tyre for such a heavy car, so cut it up to investigate further. There were only 2 plies.
Had not encountered  ply "rating" previous to this.

Later an American import was sent to us from a dealer to have all tyres retreaded.  The plies were already showing so we told the dealer we could not do them. (They were labelled 4ply rate also).
He insisted, so we sent them out for a full job to a re-treader who did not mind claims and they were done!

Frightening isn't it.  They would have had to buff through, at least, the ply that was showing, to retread them.

I trusted our retreads (we could not cope with the cost of claims, so were very thorough), but no other company's.