Reviving an old post!Hawkeye wrote: ↑Sat Sep 07, 2019 10:44 pmSo week 7 in 2018. That they are showing cracks in the treads is totally and utterly unacceptable. Do send off those pictures to the manufacturer and ask for their feedback, will be interesting to hear what they say and what they propose to resolve the issue.
Sat on this a while but sent a couple of emails to bridgestone UK, here is their response.
The tyres are obviously worse than the original post particularly the front right.
Thank you for the detailed close up photographs of the Bridgestone tyres fitted to your car.
Concerning the ‘cracking’ in the tyre shoulder grooves; this we have seen many times in the past (across many products, and most brands) where the top layer of surface rubber begins to oxidise and appears perished. We refer to this as ‘crazing’, as ‘cracking’ generally relates to splitting after force or trauma during operation.
The visible surface rubber crazing on your tyres is very minor and will pose no detriment to the vehicles safety of tyres performance.
It is worth noting that as part of tyre manufacturers’ compliance to environmental responsibility legislation, there are increased restrictions on the materials used in tyre construction.
‘Crazing’ can also be caused by other factors:
• Extended exposure to sunlight. (UV light dries out the anti-aging oils in the rubber which give a tyre it’s tackiness and elasticity).
• The application of ‘Tyre Dressing’. - Used by dealer forecourts and carwash companies mainly to make the sidewalls/shoulders of the tyres look ‘more black’. These can be quite strong and some are even mildly corrosive if used consistently over time.
• Poor pressure maintenance during the tyre’s life. This causes over flexing in the tyre casing eventually causing tyres to prematurely age.
• Exposure to contaminates. - Petrol, anti-freeze, motor oil, tyre ‘dressing’ (used on the sidewalls to appear more “black”).
• Regular, but short frequent trips in the vehicle (lack of use), where the tyres are heating up, then cooling down over a short period of time. (essentially preventing the aforementioned oils from percolating/migrating throughout the tyre fully). We add anti-aging oils into the rubber compound, however for these oils to be released the tyres need to get to an operating temperature. If the tyres are not used regularly then the releasing agents in the anti-aging oils are unable to percolate through the casing and ensure the tyre stays subtle.
The upside to this phenomenon is that ‘crazing’ only affects the top cap layer of rubber, so is only cosmetic in nature. - This type of appearance does not have any effect on the tyres handling or performance, and based on the appearance in the image provided we would advise that these tyres are ok to continue running. However as with any appearance-based condition reported in the market, we always advise to monitor the tyres regularly.
Please note that we take safety very seriously and we would never recommend you to continue using tyres that we thought were unsafe to use.
In their current conditions the tyres will not cause any detriment to the tyres serviceability or affect the cars dynamic performance abilities. If the tyres are well serviced and the correct tyre pressure is maintained the tyres will continue to provide an excellent service life.
We hope this info has helped, please let us know if there is any more info you require on this subject to assist with your enquiry.