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-   -   Weird pattern developing on the sidewalls of all 4 tyres of my car - What is it? (https://www.team-bhp.com/forum/tyre-alloy-wheel-section/240036-weird-pattern-developing-sidewalls-all-4-tyres-my-car-what.html)

Noticing this weird pattern on my Pirelli Centurato P7 235 55 R17 tires (S class). No other issue other than this visual patch all around circumference on all four tires. The tires are 4 years old and may have run about 20K km. It may have happened after a long highway drive but I couldn't be sure. No bad roads involved. It doesn't look like any structural damage to me but some oils coming out - any idea what this could be?




I am thinking of changing the tires as a precaution and have the option of Michelin Primacy 4 ST. These would be imports from Thailand I guess. How do they compare to Michelin tires imported from Europe (with which I have had very good experience)? I used Michelin Energy (made in Thailand) on smaller cars and they didn't particularly stand out.

You may want to look up 'tire blooming'.

Tyre blooming is a discovery for me, I had never heard or come across this in all these years. Thanks Chetan_Rao for this knowledge.

I found out that tyre blooming is formation of brown deposits because of antiozonants in the rubber getting exposed to oxygen. But in none of the pictures about blooming, I could see the swirl marks like those in androdev's pics. The pics from the Google search showed uniform brown deposits on the blooming tyres. Is this blooming or some other chemicals coming to the surface?


As mentioned above, the swirl marks are surprising. Did the sidewalls rub against some steps (like footpath)?

Blooming is just one possibility. He did say it's happened to all 4 tires which makes curb-rash unlikely, and he also didn't drive on bad roads before noticing this so it's a curious phenomenon.

These marks are clearly curb scuffs. Nothing wrong with the tyres but driving style. They look like they have been rubbed against a curb and the marks go around the whole tyre.

Had the curb been high enough, you would have damaged the alloys. You dont need new tyres. Just inspect for damage to the cords and look for bulging.

From the images the marks on the tire appear to me as scuff marks. But on all four tires!? That's quite bizarre. I can only think of one reason, albeit a wild guess. Underinflated tires carrying decent to heavy loads may cause scuff marks on tire side walls. Long ago once it had happened so in my slow moving load carrier, I vaguely remember. I noticed such scuff marks on under-inflated rear tires of my vehicle after a few trips of load hauling back then.

I am 100% certain they are not curb scuffs even though it looks like that in the first picture. The pattern is there on all the wheels and all around the tires - I just took a pic of a small portion for better image resolution.

It seems as if some oils in the rubber compound squeezed out as the car went over undulation of the road at high speed. Lack of use during lockdown may have contributed to this. I wrote to Pirelli, let me see if they care to get back.

I always maintain recommended tire pressure of about 34 psi, no different in this case also. I check pressure before every long trip and the car has TPMS. Under inflation usually results in a circular band of discolouring in the middle of the sidewall due to excessive flex. The pattern is observed on all four tires. Some variation of "blooming" is the only plausible explanation I can think of.

During the installation of this tire if any sealant (against puncture) is applied on the inside of the tire, it will gradually make its way out.

You can wash it away and apply a silicone emulsion, wait for a while and wipe off to get a new tire look.

Maybe you drove through some wet / mildly waterlogged roads which had a thin layer of oil deposits floating on it. That probably got stuck and dried off.

Probably some local eateries discarding their used oil in the drains, which came floating when the roads became waterlogged.

Just another theory to consider.

Did you do any drive recently on broken roads with lots of rocks and pebbles? Or on some under construction road where a rock bed is prepared before finer layers are prepared? These look like scuff marks caused by rocks rubbing on the tyres when they go over them. Do you apply tyre polish? Tyre polish + rain causes these scuff marks to look like this. Give your tyres a good wash and scrub with a tyre washing brush like this one and most of the marks will go away. I don't think it has anything to do with tyre chemical compound going wrong.

Do you mean to ask if I drive in Bangalore? ;-) Jokes apart, I may have gone through such patches. Makes sense when I think about it. Let me get the tires cleaned and check - too much rain and slush at the moment.

Androdev, moving your very unique query to a new thread :thumbs up

This looks like a result of many factors. The marks look like scrub marks which are usually done to clean the tyres. Frequent use of tyre cleaners can also result in these marks since the abrasives are harsh and are bad against the ozone protection and anti oxidation layers of the tyre. These marks can also be the result of infrequent use during the lockdown and in the process, the chemicals which can result in Ozone cracks ooze out somewhat. The marks are also visibly in line with the circular motion which is usually done while applying polishes and cleaners.

Going by the marking, it does look like scrubbing marks to me with tyre cleaners and which has now resulted in the anti-oxidant layer damage on the outside of the tyres. These are not curb scuffs for sure since it happened on all the tyres.The tyres might have already lost their anti-ageing properties and hence the marks !!

Nothing wrong with your tyres mate. Just give them a good scrubbing and you’ll find them as good as new.

It’s a combination of potholes, stones, dirt and possibly some oil / grease on the road that have contributed to it.

Enjoy your car! :thumbs up

Have you had the tyres cleaned and polished recently?

I had similar marks from the use of a rather stiff brush and weird tyre dressing compound at the local detailer years ago. I was on MRF ZVTS then, which kept rolling for another 16k km before I switched out to XM Energy.