True.. the keyword “dangerous” was enough for me to think again and actually replace it. I dont want to live on hope even if it wasn’t dangerous. Better be safe than sorry.
Tire looks funny at the line. Safe?
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JHZR2
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Had a sidewalk bulge on the OE run flats on my 135i. Took it to a local Goodyear shop and they replaced it free on warranty.
I'm quite late to the party - sorry. And I see the OP has made a decision. Nevertheless, this might be a good learning experience.
I'm not sure but I can think of 3 things it could be. Oh and it has nothing to do with the belt. The belt is under the tread, not in the sidewall.
1) A cured lump. Nothing to worry about. During the manufacturing process, sometimes a bit of rubber gets cured before it's supposed to. When it goes into a tire, it causes a lump. When the tire is inflated, that lump is pushed out.
2) A broken cord or 2. Caused by impacting an object. A good reason to replace the tire. In a RunFlat tire, the sidewall has a stiff insert that somewhat hides any sidewall condition. In a normal tire, a couple of broken cords would cause a bulge.
3) Open ply splice. Another good reason to replace the tire. In a normal tire, this would be a bulge, but a RunFlat would somewhat hide the bulge.
So to the OP: Mark the spot of the tire. When you get the tire replaced, make a circumferential cut with a box cutter just below the lump - not between the tread and the lump. Just a bit lower down the sidewall. Cut away from you. It's going to require quite a bit of force! It's easiest if you position the tire such that you will be cutting downwards. Look at the cords in the sidewall.
An open ply splice will have missing cords.
Broken cords will have the cut ends of the broken cords look different than the rest of the cords in the sidewall.
A cured lump can be seen as an extra bit of rubber (the lump) in the cut.
I'm not sure but I can think of 3 things it could be. Oh and it has nothing to do with the belt. The belt is under the tread, not in the sidewall.
1) A cured lump. Nothing to worry about. During the manufacturing process, sometimes a bit of rubber gets cured before it's supposed to. When it goes into a tire, it causes a lump. When the tire is inflated, that lump is pushed out.
2) A broken cord or 2. Caused by impacting an object. A good reason to replace the tire. In a RunFlat tire, the sidewall has a stiff insert that somewhat hides any sidewall condition. In a normal tire, a couple of broken cords would cause a bulge.
3) Open ply splice. Another good reason to replace the tire. In a normal tire, this would be a bulge, but a RunFlat would somewhat hide the bulge.
So to the OP: Mark the spot of the tire. When you get the tire replaced, make a circumferential cut with a box cutter just below the lump - not between the tread and the lump. Just a bit lower down the sidewall. Cut away from you. It's going to require quite a bit of force! It's easiest if you position the tire such that you will be cutting downwards. Look at the cords in the sidewall.
An open ply splice will have missing cords.
Broken cords will have the cut ends of the broken cords look different than the rest of the cords in the sidewall.
A cured lump can be seen as an extra bit of rubber (the lump) in the cut.
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Hi @CapriRacer and others, Im just back from Pirelli showroom (EU) ready to replace both tries, only to be told by their employee that it is NOT a bulge and only the surface layer is deformed and I should not really replace the tire!! They believe the issue is absolutely a shallow one and no bulge or effect on the structure of the tire (its actually smooth to touch).
I left (after the comments above) wondering if I should trust Pirelli employee who gave a neutral advice although he knows that am here to buy, or just force buy the tire? In anyway, I’ll keep my eye on it everyday and drive only inside the city and update the discussion here in couple of weeks.
Ps the tire hit by stone is an old one according to Pirelli and not a new one.
I left (after the comments above) wondering if I should trust Pirelli employee who gave a neutral advice although he knows that am here to buy, or just force buy the tire? In anyway, I’ll keep my eye on it everyday and drive only inside the city and update the discussion here in couple of weeks.
Ps the tire hit by stone is an old one according to Pirelli and not a new one.
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Scrap the car immediately, it's a death trap. 
Most sidewall bulges are much larger that that... But they can be hidden a bit more with run-flats.
If it was my car, I would probably just run it for a few more weeks and keep an eye on it. If it doesn't get any larger you will be ok.
If it was my car, I would probably just run it for a few more weeks and keep an eye on it. If it doesn't get any larger you will be ok.
Reading through all comments on the discussion, and still trying to laugh, but couldnt.. do you have British roots by any chance?Scrap the car immediately, it's a death trap.
Have some British cars but not aware of any roots.
Now thats the one that made me laugh
He didn't say 1mm, he said 1%.
The thing is it was not a bulge (not even raised surface).. its a pulled surface caused by loose object (smooth stones where I park my car usually)
I know. I said 1mm, which is roughly about how much a tire wears in 7000 miles.
I'm not sure what you mean by that. But for a small stone to damage this tire is very unlikely.
Almost certainly this is a defect where plies in the sidewall of the tire overlap. There are many layers of construction in the sidewall/shoulder of a run-flat tire. The question is whether or not that defect is dangerous. It is almost certainly not, but I would keep an eye on it regardless.
Certainly would be 1mm, not 1%. Couldn't even really measure 1% accurately.
See stones:
I was so excited to move on and buy the tires directly from Pirelli, until their employee told me that I dont need one
somehow I wished that he would have told me that I must replace it. I kept insisting on “are you sure” and 2 others confirmed its fine - one gone extra mile and said, well, you still can move it to back to reduce future impacts and avoid wearing the tire prematurely because it’s obvious that both of my front tires are so beaten and scratched from bad parking habit..
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Just saw this - I'll get you some pictures this week.
See stones:
I was so excited to move on and buy the tires directly from Pirelli, until their employee told me that I dont need one
I kept insisting on “are you sure” and 2 others confirmed its fine - one gone extra mile and said, well, you still can move it to back to reduce future impacts and avoid wearing the tire prematurely because it’s obvious that both of my front tires are so beaten and scratched from bad parking habit..
That is just superficial. Going over rocks like that at low speed will not hurt the tire. Maybe in a 1/10,000 bizarre circumstance.
Some areas in the parking lot has a mix of bigger stone (not sharp) size of a big potato. I can hear them shooting away when I drive over them.. i drive very slowly and still.. by the way, they found its 2.1 bar and raised it to 2.6 (all of them due to lack of use of this car.. last time I used was in April so we couldnt know how old the impact is but they say its not a yesterday or last week impact )
OK, I thought of one more possibility: a bubble of air trapped in the rubber. You can tell if it's a bubble if you push on it. A bubble will be very obvious and soft.
Come to think of it, if you push on it, both broken cords and an open ply splice will be softer than the rest of the tire, but not as soft as an air buble.
By contrast a lump will be as hard as the test of the tire.
Come to think of it, if you push on it, both broken cords and an open ply splice will be softer than the rest of the tire, but not as soft as an air buble.
By contrast a lump will be as hard as the test of the tire.
Its actually very hard and not a bubble at all (no bulging inner or outer).. it feels like the surface shifted up but the photo give a feeling that the shifting upward is like something bulging out.
How old is the tire? What kind of warranty do they have where you are anyway? Maybe try a different shop and see if they will warranty out the tire because it's either a cosmetic defect or a tire defect, but either way see if you can force them to cover it under warranty.