Topic: Bulge in sidewall

[Subarugrl]

Two questions:

1. Does a bulge in the sidewall mean a tire is toast? (hit a pothole)

2. Do all 4 tires need to be replaced when one tire blows on an all-wheel drive car, and an exact replacement cannot be found? (original tires aren't sold anymore but the other 3 are 'like new').

Thanks!

[ovr50]

Not a tire expert but:

1. I would say very, very likely is ruined.

2. Not sure you HAVE to, but likely is preferable to change all four.

Others can be more helpful. 

[rrocket]

1) You should replace it. The next time you hit a bump might be the sidewall blowing out.
2) Get the new version of the current tire on the car and you should be fine.  Anybody disagree with this?

[wing]

If the other tires are like new, and you can find a similar tire in size / compound / company that should work.

Or replace 2 on the same axle if you have to.

[Squishy]

1 - yep, toast

2 - My advice is to sell your three used tyres on Kijiji or Craigslist.  How old are they?  The last four numbers of the DOT code should tell you (e.g., '1205' means it was made in 2005; '128' means it was built in 1998).  If they are over five years old, recycle them instead.

To add to rrocket's post, the new version of an old tyre is probably fine, although there is the odd case where a new version is a drastic change from the old - that, coupled with the old tread/rubber vs. new, would upset the handling characteristics of your car in an emergency manoeuvre.  If you have regular non-directional all-season tyres, I wouldn't worry about it, but I wouldn't do it with a performance-oriented set.

[inco]

What about your spare tire? Is it full size and if so I would be putting it on. If not you could check Kiijiji or Buy & Sell for a used tire or even try the dealers because sometimes they get trades.

The bulge has to go - it means the cords in the tire have separated and that isn't a good thing.

[Subarugrl]

Thanx for the replies!

They're Nokian Hakka1's, bought in 2004. Barely used over 4 winters and best tires ever. Contacted Kaltire a while back but they don't have any Hakka1's kicking around in the system and they didn't offer any other options. Talked with another guy in the same boat earlier in the season (who posted an ad on Kijiji), but he already sold his 3 Hakka1's and bought a whole new set (Hakka5's) by the time I contacted him. $$$!!! I want to check out all my options before selling them, 'cause the tires are so awesome. I appreciate the feedback.

[Trainman]

I see you have a Subaru.  There is a lot of debate and internet myth around tires with the Subaru AWD.  A lot of people say tires need to be within 1/8" of an inch in actual circumference although there is nothing in my owners manual about that (but its an 09, check yours).

I would say you would be fine if the replacement tire had a similar diameter.  What do I man by similar?  That is the question!  My three tires are as such:

The spare is one of the original 16" Bridgestone's mounted on an OEM steel wheel. Actual diameter is 68.6 cm.

The road tires are General Grabber AT2 mounted on the factory alloys. Actual diameter is 68.5 cm.

The Blizzacks are also 68.6 cm on OEM steel wheels.

So I think I am good to go, however some on Subaru forums would disagree 

Anyway, to keep the AWD happy, make sure you get a tire with an actual diameter (or circumference) that is as close to what is on there right now as possible.  And measure it, do not rely on what fact sheets say.  Then the AWD will be happy but don't sweat it if you are off a bit.  Tire pressure can make even a bit of difference in diameter too.

[Squishy]

I don't think the biggest problem will be in matching the diameter.  As you said, inflation pressure can make a big difference in itself.

The issue to focus on here is to not upset the handling characteristics, especially since you drive at the edge of your car's performance a lot more often in the winter than you do in the summer.  At six+ years old, they're about ready to expire anyways, so I would not waste money on a brand new tyre to complete the set.  Get a matching used tyre if you can, then use it for one or two more winters.  You should notice a drop in performance from the tyres by that time, as the rubber ages.

[johngenx]

I don't think the biggest problem will be in matching the diameter.

Subaru's AWD system relies on having all four tires very close in diameter for proper operation.  Some people are fanatical about it, but there is truth behind having them as close as possible.

[tortoise]

Your tires are 5-6 years old.  Regardless of the mileage on them the rubber will dry out over time.  Were it me, I would replace them all.  Winter tire technology has progressed a lot in the last 5 years.

[Trainman]

Your tires are 5-6 years old.  Regardless of the mileage on them the rubber will dry out over time.  Were it me, I would replace them all.  Winter tire technology has progressed a lot in the last 5 years.

This is also an excellent point.  We will be getting new snowies for the Sienna this winter for just that reason.  They are 5 years old and my wife has remarked on a noted decrease in performance this past winter.  When I try to dig into them with my nail, they are very hard.  Much, much harder than the Blizzacks I have on the Forester, even harder that the Grabbers.  But they have a decent amount of tread left so that makes it harder to swallow but we will do it anyway.

[johngenx]

This is also an excellent point.  We will be getting new snowies for the Sienna this winter for just that reason.  They are 5 years old and my wife has remarked on a noted decrease in performance this past winter.  When I try to dig into them with my nail, they are very hard.  Much, much harder than the Blizzacks I have on the Forester, even harder that the Grabbers.  But they have a decent amount of tread left so that makes it harder to swallow but we will do it anyway.

If they have lots of tread left, sell them.  It seems kinda cruel to sell tires you don't think are any good anymore, but I sold an older set of snowies that were going a little hard but still had lots of tread depth on them, and for super cheap.  Why?  The guy that bought them would never have been able to afford ANY new snow tires, and my old tires were MILES better than the crappy A/S tires he was running.  I got rid of my old tires, the guy got a big winter improvement, and the landfill won't see the tires until later.

[Squishy]

An old tire presents more than just the danger of reduced traction.  Oxidation and rubber deterioration lead to separation of the steel belt, which can then cause a loss of control from tread separation.  You can't tell that this is about to happen without destructive testing.  A 3-year-old all-season is still safer than a 7-year-old winter tire.

I keep tires for 10 years from date of manufacture, which is what the RMA recommended back in 2003, but that is because I store my tires in a controlled environment and away from ozone.  I think the general guideline for a tire with an unknown or questionable history is five or six years.

[mrthompson]

Where's capriracer when you need him?

[Squishy]

http://www.nhtsa.gov/staticfiles/DOT/NHTSA/NRD/Multimedia/PDFs/Crashworthiness/CongReptTireAgingFinal080907.pdf

...we do know that tire aging is a significant factor in tire related safety.

...aging is a phenomenon that is affected by the heat generated in tires and the degradation that occurs due to the chemical reaction within the rubber components due to oxidation.

Later studies showed this aging phenomenon to be a thermo-oxidative degradation process (i.e., degradation due to their heat and oxygen exposure over time). The agency determined that this thermo-oxidative degradation is accelerated with higher temperatures and is a contributing factor for tire failures, such as tread separations.

[weebl]

This reminds me...  I visited my brother a while back, and he had just put on his summers.  I heard an awful racket, kind of like a groaning, and asked if it was his car.  He said yep, he heard the noise last fall, when his winter set came on, the noise disappeared, and now it was back.

I had a quick look, noticed 2 tires had tiny spots, which looked a little like bulges, but were small enough that they could have just been an imperfection in the tire mold.  Both spots were in exactly the same spot in the 2 different tires, almost exactly in the middle of the "/" where the tire size was molded.

Any thoughts?  I suspect these may not be bulges, but perhaps some other issue going on, like possibly cord separation?