Tyre cracking

  1. My model of MX-5 is: __3 nc
  2. I’m based near: __Bradford
  3. I’m looking for technical help or recommendations on: __Tyre recommendations
    Hello , the Toyo tyres on my 5 are showing fine cracks on the shoulders which seems to always happen on this make of tyre. To avoid this my local tyre shop recommend not fitting premium tyres which are hard
    but using a mid range product . I’m happy to take their advice but would be interested in other club members

A few suggestions below, you’ll find my favourite there…:+1:

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How old are the tyres?

Tyres are about 4 years old with about 7 mm tread.

Tyre shops advice doesn’t add up for me, premium tyres tend to be softer (for more grip, albeit with sometimes faster wear), not harder. Toyo are very much NOT premium anyway, they are a mid-range tyre.

you say they are four years old is that when you bought them or when they were manufactured. I think they have had their day and it’s time to replace them.

They’ve moved upmarket now and are on most new Mazdas. It’s many years since I bought any Toyos for an existing car but I’ve had them on a couple of new cars (CX-5 and Mazda 3). No complaints.

7mm can be the starting tread depth for a brand new tyre. Have you done many miles with them? It sounds like a case of them not being used all that much and starting to perish.

I’d say that happening wouldn’t be unique to any one tyre manufacturer, nor that a tyre from a ‘premium’ manufacturer would be immune to this issue.

Tyres should have a date mark on them - this varies by make as to where this is, and all old tyres will crack/perish/fail eventually.
We used to supply tyres for motor sport. I still have some left but they are now being used as planters because they are out of date - although some look brand new. They would never be fitted if out of date!

It is very easy to have perfect looking tyres, but they could be out of date!
Just a thought.


I had the same happen on my 5 year Avons (advisory on the MOT)… they had only covered 4000 miles!
So have had them all replaced with Michelins as there is a special offer at the moment with ATS. As it worked out cheaper than most midranges when you include the Voucher you receive back worth looking at if you want a premium tyre.

Last year I was very, very happy when I got rid of the Toyo Nano Energy set that came new on my Mazda3.

The Continentals are so much better in every department; more comfort, better grip, better stability on cornering, better mpg, less noise, much less random wander, etc.

Today I had another set of Kumho 195/50/15 HS52 82V fitted to my
'94 Laguna Blue S Special (the third set of Kumhos since 2012 when I bought the Eunos)
Yesterday I treated my 2014 3.75 Sport Tech Recaro to another set of
Kumho 215/45/17 PS71 91Y
8 tyres & £656 less in my account but I know I have tyres that suit my MX5s


Check the date code on the tyres. Different sources will say replace tyres that are between five and ten years old. Maybe somewhere around seven to eight years is a good figure to work to.

The date code is a four digit number. First two the week, followed by year. So 1723 would be the 17th week of 2023.

Tyres can be sold as new up to five years from date of production. So it is possible that you were sold tyres which only have two to three years of useful life. This may not be a major problem with a company car doing 15k miles a year but to the average MX-5 owner who just goes for a few jaunts in the summer they will need replacing way before the tread wears down.

Cracking on a tyre is due to the rubber hardening. Hard rubber doesn’t grip however deep the tread may be.


Some of the online tyre places push that 5 year sales limit to the max. If in doubt, buy a new model of tyre, then you know it will be fresh.

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If you are buying online then why not ask the seller the date code of the tyre they are supplying. If you are buying from a fitting centre then it’s easy to check them before they go on the car.

Also a set of four wants to be a set of four. If they have put set together from odd tyres and different sources they will be different batches, maybe sifferent compounds and could be different factories.

There was one report a while ago of an brand new MX-5 destroying two LSDs. Turned out that on arrival in the UK a rear tyre was found to be damaged and replaced with a ‘matching’ Bridgestone tyre. However both fronts and one rear were Japanese manufactured and the other rear was EU sourced. Treads had minor differences and compounds were not the same. The slight differences were causing damage to the differential.

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Sidewall and shoulder edge cracking are usually caused by oxygen or ozone attack and can be present in tyres as young as 4 years old. Providing that they are very shallow, no problem.
Groove cracking, i.e. in the deep tread groves is also an aging problem.
Tyre manufacturing dates are wwyy that is 1823 means week 18 of 2023. This system replaced the 3 digit system in 1998 or so. My knowledge comes from 20+ years of lab based tyre testing and work as a rubber compoind developer

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For info: One of the most common causes of older tyres cracking is when a vehicle is unused for several months (often during winter). The tyres develop flat spots - due to the weight of the vehicle - which causes additional stress to the tyre structure weakened by UV light etc.,

Classic cars are often stored on axle stands to avoid this. I had a friend with a classic Jag who ended up shelling out 4 x £200 for new tyres due to this!

Although if it’s in axle stands for long periods, that can place undue stress on suspension components. As they’re not designed to be suspended for long periods.

Basically, just drive the thing! That tends to resolve both issues :smiley: