I happened to notice an asymptomatic bubble in the sidewall of one of my tires. It is small, about 1 inch in diameter, 1/2 in depth. Do I need to replace the tire?
Probably. It strongly suggests that the rubber is weak there, and sidewall cuts cannot be repaired, AFAIK. Why risk a blow-out?
Depends. Do you do a lot of driving at highway speeds? If it were me I’d just keep a close eye on it, like at least daily, for a while and check the tire pressure a couple of times a week. If it gets bigger, or you’re losing air, best to replace it. How’s the tread wear? If you’re going to need new tires in a few months and the bubble stays small, you can probably squeak by. If it makes you nervous, do it now. Tires should be replaced in, at least, pairs, so you may need to buy a pair.
Yes.
It may be a production flaw. Take it back to where you got the last set of tires and, if it wasn’t a long time/lotta miles ago, they may at least credit you with something in the purchse of the next set when they see this. It has worked for me…twice.
If you can’t get it the tire replaced right away, at least move it to the rear axle if it’s not already there.
The only acceptable manufacturing sidewall flaws that I’ve ever seen were more like a slight depression or bulge which ran the length of the sidewall, perpendicular to the tread.
If you’re short on $ and have a good jack and spare, let it be. If it going south could leave you or another driver in the family stranded, mebbe it’s bullet biting time.
Good luck.
You are aware of Murphy’s laws as related to tire failure, right?
It will be night.
It will be raining.
There will be no place to pull over.
You will already be late.
You will be wearing nice clothes.
One nut will not loosen.
The spare will be flat.
You will swear. A lot. 
Sorry, but I must disagree. Blowouts are rare, but if one occurs it’s better to have it on a steer axle than a rear axle. A blowout on the rear will result in oversteer and be more difficult to control, than a blowout on a steer axle, i.e: Loss of traction on the rear will most likely result in the car slewing sideways, which will cause the driver to overcompensate, resulting in loss of contol, a possible side skid and potential rollover. Loss of a front tire will cause the car to pull toward that side, much easier to compensate for w/o losing control.
I’ve driven on tires w/ a minor tire bubble, not a problem as long as you keep an eye on it and it doesn’t get worse.
The suggestion of returning it to the dealer is a good one, especially if it has more than 50% tread.
A bubble is a defect, and it is dangerous. Get a replacement. Unless you have a lot of wear, a new one should be prorated at the place of purchase. Make sure your spare is inflated to full pressure. Use a gauge not your eye.
It’s a danger, and should be replaced ASAP. It could be a defect, but I’ve also caused the problem myself by bumping against curbs and such.
I must disagree with the “keep on truckin’” folks. Get a new tire ASAP.
Blowouts are not fun. Not fun at all.
Yes indeed. If you can’t afford a new tire go to a tire store and see about a good used one.
In the meantime I would install the spare.
I wonder if there have been studies on this? A front tire blowing during a corner would be a very bad thing for a lot of drivers. On a straight line, I think most drivers would still prefer a rear tire blowing as it would cause less feedback to the wheel and less panic. RogueGF, who sadly is not a very good driver, had zero problems with her flat left rear tire. I know anecdotes are not equal to data though, which is why I wonder if there have been studies done.
To put a different spin on things, as an oval racer (always turning left) cut tires are rare going straight, more frequent in the corners when cars tend to rub on each other. If a tire is going flat (not blown), the problem doesn’t show itself until we’re in a corner. So looking at the corners, if I lose the left front I should be ok getting the car slowed down and into the pits. If I lose the left rear, I may spin out, but not always. If I lose the right rear, I’m spinning out. If I lose the right front, I’m going into the wall. Guess which tire I don’t want to blow?
In regards to the OP, I would side with getting it replaced ASAP or at least looked at by a tire shop.
Keep in mind the speed and torgue difference between an oval, and a street car. The weight is distributed differently as well to assist (You could probably speak to this better than I could, as I am just a NASCAR nerd) in the left turn. The turns are also not as sharp on main roads, therefore it would be easier to compensate for the sudden ‘push’ you would get from the right front. (Vice versa for a right turn with a left blowout)
When I had a catostrophic right rear blowout, in a slight left turn at 45 mph, I got a BIG wiggle, but was able to maintain due to the slow(ish) speed. I would not have wanted that happenning at 70mph on the interstate. One thing worthy of mention is that I was driving a rear wheel drive car at the time- I wouldn’t think a rear blow would be as bad in a FWD car. YM(or lack thereof)MV.
You forgot…
You’ll be out of petrol and no garage for miles.
Incidentally, If caught driving with a bubble on a tyre in the UK the cops will not let you proceed with your journey until it is changed.
No spare?, tough shit, get walking
I agree that it’s hard to compare conditions on the street versus the track. Mostly I was just trying to make a point that in a turn bad things can happen either way depending on what the edge of the road looks like. Since there is a wall at the edge of my road surface, I would much rather spin then go straight into it.
Keep in mind that most cars these days are front wheel drive. The front tires are doing a lot of work already. Also in my experience, most of these cars are designed to have an understeer (or tight/push) condition. If that’s incorrect, I’m sure the car experts like Rick can set me straight. Adding a flat front tire to a car that’s already understeering seems worse than having a flat rear. About the only thing I see worse with a flat rear tire is that if you do lose it, you run the risk of a roll over.
Again, I would be very curious about any studies done on this.
RogueRacer- It appears the IEEE has a study on just this subject, but I am not a member so I can’t access. (Although they say guests can view documents- I don’t have a lot of time to investigate while I’m at work)
It is certainly something I am interested in as well. I love vehicle physics! (I would like to pick your brain about racing sometime Rogue)
It seems to me that we would need to have road data as well to be able to say which would truly be worse. As you stated, (on a track) the front right is the worst type of blowout in a turn, due to it being the tire under the most load at that point. Assuming we had a perfectly level/straight/smooth surface, it seems to me that either rear tire would be worse than the front, regardless of RWD/FWD. (The “wiggle” I referred to earlier)
Again, a computer model or paper showing effect would be pretty cool.
I just want to know what an “asymptomatic bubble” is. :dubious: