[eye30]

Car is due its annual MOT end of July so checking the obvious things I noticed the 2 rear tyres are showing signs of cracking around the outside.

The tread is 3.5 mm on both and 5 years old.

In the past I've had an advisory on cracking between the tread but no evidence of such on outside.

Does anyone know what level of cracking is acceptable for MOT.

Ps
Did call into a tyre garage last week and they said ok but additional thoughts would be appreciated.

[Surferdude]

That's what I would have called ozone cracking.

Not normally an issue but that's more severe than normal and I also don't know how your MOT people would view it.

Ozone. Is an inert, heavy gas which tends to lie in the bottom of gutters in or around industrial areas. It has that effect on rubber.

A self proclaimed "expert" might suggest it's the beginning of belt edge separation but it's not. The belt edges are closer to the top of the tread blocks than that.

In the moulding process of a tyre, where those cracks are is the area where the tread rubber meets the sidewall rubber.

[Lorian]

Your going to get the MOT advisory for that for sure.

Pragmatically at 3.5mm left and a 5 year life its going to need to be replaced sooner or later anyway. personally I would replace it before the MOT somewhere I know I can get a good deal on the rubber rather than taking the chance on them failing it and  having to replace it a Inflated prices (you may groan)

[Surferdude]

Yeah. I missed the line with tread depth and age.
Probably worth getting some new ones.

[Surferdude]

BTW.  What's a MOT "advisory"?
Is that different to a "fail" and if so what does it require you to do?

[eye30]

The car passes the MOT as all items checked are ok.

The advisory is when an item although at time of the test passes but will require looking at  before the next test.

[eye30]

Thanks for replies.

I like to have the MOT around 2 to 3 weeks before actual expiry date so will call into the garage to make appointment and ask their opinion.

That will give me time to replace if they deem them to be a fail.

However, I'll be checking prices in the meantime and depending on deals may just go for it.

[PGN I30]

Mine came with cooper tyres on which have cracks down the tread line and are only 3 years old, swapped them for Yoko blu earth's, £60 a tyre.

[wbm00]

Sou

Thanks for replies.

I like to have the MOT around 2 to 3 weeks before actual expiry date so will call into the garage to make appointment and ask their opinion.

That will give me time to replace if they deem them to be a fail.

However, I'll be checking prices in the meantime and depending on deals may just go for it.

Mine had an advisory for cracking on the original Kumho tyres and that was less visible than in your pic, so would be surprised if it doesn't get noted at all in the MOT. If you don't replace before the MOT, it'd be interesting to know whether it did get recorded as an advisory.

I found the most competitive option for tyres was calling the smaller local tyre places where the owner is a mechanic. Got a bit fed up with the national chains recently... it seems using a torque wrench to tighten the wheel nuts appropriately is beyond them

[eye30]

Been to a few small indi tyre shops today.

All said 50/50 as depends on tester and how the rest of the car performs.

If only thing then probably get away with an advisory.
But if a few faults which means fail then it will just be added to the list.

Got prices so will mull over them.

One gave me a good price for all 4 as fronts are 2.5mm so will need new before autumn.

[Surferdude]

Just came across this story.

Covid pandemic blamed for UK rise in cracked tyres | Motoring | The Guardian

[eye30]

Think what said has contributed to my cracking.

This company do MOT's and their core business is tyre sales all usually in the same building.

[Surferdude]

Think what said has contributed to my cracking.

This company do MOT's and their core business is tyre sales all usually in the same building.

Yeah. Over the years they've had close ties to Goodyear.
At one stage, maybe back in the late 90s, early 2000s we were actually making some of their home brand tyres here in Australia and shipping them to the UK.

[TerryT]

Just came across this story.

Covid pandemic blamed for UK rise in cracked tyres | Motoring | The Guardian

Surferdude, thanks for the link, interesting article.  Your earlier post that eye30's tyre problem was due to ozone cracking was educational (along with your: "Ozone is an inert, heavy gas which tends to lie in the bottom of gutters in or around industrial areas.  It has that effect on rubber".   I must have been asleep during science lessons that day.

I have copied part of an article I read on the subject: "Sun and ozone cause a reaction to the tyre’s rubber that causes them to crack. Tyre manufacturers use a chemical additive to rubber called “antiozonant” to protect from harmful UV rays and ozone.   The catch is that antiozonant only works if the tyres are being driven, going through their normal heating and cooling cycles.  As a rule, the less you drive, the more likely your tyres will crack".  The COVD-19 pandemic made sure we drove much less than normal.

I believe tyre manufacturers (used to) say, as a rule-of-thumb, replace your tyres after 6 years.  My car, 5+ years old, done less than a measly 11,000kms, has original Hankook tyres with no signs of cracks of any kind, anywhere.  Probably helped by spending about 90% of its time in a garage or under cover out of the elements.