Cautionary tale on older tyres

[SlimJim]

My two rear tyres were the original tyres, made 6 years ago, although car is 5 yr old. Last week noticed a significant drop in pressure after a good run previous day. Significant pressure drop every second day during the week. Bought 2 new Michelin PS4 and had them fitted this morning. I was intending to change them within next 2 months, prior to service / MOT.

Tyre fitter showed me the reason for pressure drop. All around the inner face, was 25-30mm cracks. Probably due to a mixture of ageing and low mileage. Other tyre had similar but not as many cracks.

Worth noting for older, low mileage tyres to have them checked.

I guess the recommendation to change at 5 yr old is not without reason.

 

[markjay]

Not arguing with a professional tyre fitter and I would also replace any tyres that show signs of cracking... but it is not clear to me how the cracks can cause pressure loss? The tyre is made of several different layers glued together, you would have thought that the cracks only affect the outer layer (that is exposed to UV light, chemicals, etc), but not the inner layers? I.e. the cracks would have to go through several layers for air to escape. Tyres losing pressure through poor rim fitting (corrosion etc) or via a slow puncture are common, but can tyres lose pressure through cracks (in the outer layer)? I really don't know the answer.

Either way, it's just to satisfy my interest, the point is academic anyway given that I think we all agree that badly cracked tyres should be replaced (regardless of any pressure loss).

 

[markjay]

BTW, as far as I know, the guidelines are that new tyres should not be sold if they are more than 6 years old at the time of sale, and should not be used on any vehicle if they are more than 10 years old (regardless of condition).

 

[whitenemesis]

Also noted that the cracks were on the inner edges? So not directly exposed to sunlight?
IIRC tyres depend a lot on use, that is flexing during driving, to release lubricants held within the compounds making up the various layers, to provide protection against premature ageing. It's not just UV but ozone and other pollutants that can degrade the tyre.

 

[W1ghty]

My 2 rears on the E class are 2010 , no cracking yet . But this is their last season

 

[SlimJim]

BTW, as far as I know, the guidelines are that new tyres should not be sold if they are more than 6 years old at the time of sale, and should not be used on any vehicle if they are more than 10 years old (regardless of condition).

I got them replaced in Kwik Fit, the manager advised they don’t sell tyres older than 4 years.

note, only the inner faces of the tyre were cracked.

 

[markjay]

Found an interesting explanation here...:

Stop the Rot: What You Need to Know About Tire Dry Rot - Evans Tire & Service Centers

As a long-time vehicle owner, you understand the importance of replacing your tires when they become too worn out to provide adequate traction. But your tires can become compromised even before they begin to bald. One of the most common … Read More →

evanstire.com

Apparently, the cracks are just a symptom of a bigger problem.

 

[flowrider]

I only buy current year or late previous year tyres.

 

[OneForTheRoad]

I only buy current year or late previous year tyres.

You should try 5 year old rotalla race.

 

[190]

It's not at all normal that tyres dry rot in 6 years. It happens sometimes but it could mean they were defective in some way when new. I'd feel aggrieved if a tyre showed signs of dry rot under 10 years old.

I've cross sectioned a 28 year old tyre just out of curiosity. The outside did show extensive dry rot but the inner layers were absolutely solid and it didn't lose air.

 

[SlimJim]

Found an interesting explanation here...:

Stop the Rot: What You Need to Know About Tire Dry Rot - Evans Tire & Service Centers

As a long-time vehicle owner, you understand the importance of replacing your tires when they become too worn out to provide adequate traction. But your tires can become compromised even before they begin to bald. One of the most common … Read More →

evanstire.com

Apparently, the cracks are just a symptom of a bigger problem.

Yep, that’s what the tyre fitter was suggesting. Very interesting article.
The article also suggests that budget tyres are more susceptible to dry rot. One for the budget champions to ponder.

 

[markjay]

Interesting:

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Brakes must of course ensure vehicle safety, that’s their main job... but ATE brakes can do more than that.

www.ate-brakes.com

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