What would cause a tire to fail on the sidewall?

[Nirmala]

I recently had the rear tire on my new Magnum Ui5 fail catastrophically with a bang. Fortunately, I was going slow at the time, but once I stopped, I found that the tire (not just the tube) had a 2-3 inch long tear in it. I was riding on smooth pavement at the time, and had just pumped the tire up to about 45 psi. This was a Schwalbe Big Ben 26 x 2.15 inch tire that had a grand total of 6 miles on it.

Does anyone have any idea why the tire failed so dramatically? Is it a case of underinflation or overinflation? I read here that I should be riding these tires at more like 35-40 psi: http://interdependentscience.blogsp...howComment=1446680783613#c7270798928866337750

But somehow, I am leery now of lowering the pressure more, and have even been riding them at higher psi. Does anyone know how tire pressure would affect a sidewall failure like that? Or did I just end up with a defective tire?

 

[KenM.]

You did not hit a curb or pothole?
Under inflation could cause a pinch if you hit something .
Or it could be a bad tire. Even the best have some times have trouble .(Firestone )
That would mess up your day, glad you were going slow when it bad. Hope you find out what caused it and let us know.
Keep looking up! Ken.

 

[Nirmala]

I am going to go back to the spot where it happened and investigate. I was riding along on smooth pavement in a dedicated bike lane. But it was right where I started to cross a bridge, and the other day as I rode by the same spot in my car, it looked like a piece of the joint between the road and the bridge was sticking up very slightly. I will have to see if that thing was sharp enough to slice my sidewall as I rode by. I will report back here. Definitely no curbs or potholes as this highway was recently completely rebuilt and paved.

 

[KenM.]

Yes a pice of medal would do it. Would not even have to be that sharp either. Good hunting ! Ken.

 

[KenM.]

I was just thinking , if you did hit that pice of medal, you better check your rim too. I could have got bent too. Ken.

 

[JoePah]

What does the sidewall say about max tire pressure? Cause it should handle 55 psig no probem.

Unless the sidewall separated probably not a defect. Tires are cheap, so you got lucking with the blow out not doing more damage.

 

[Nirmala]

What does the sidewall say about max tire pressure? Cause it should handle 55 psig no probem.

Unless the sidewall separated probably not a defect. Tires are cheap, so you got lucking with the blow out not doing more damage.

The sidewall says 30-55 psi. I saw that piece of metal when I drove the same route in my car, and so I am thinking it hit the side of my tire. Once it warms up a bit here, I will ride out there and take a closer look. I also just recently discovered that the guage on my Schwinn floor pump shows a psi that is about 5 psi lower than the actual pressure. So the tire was probably near the maximum inflation. The steep learning curve with my new bike continues

Fortunately, it was a slight uphill and so I was not going very fast. It was quite startling as it sounded like a gun going off. I would hate to have that happen on my front wheel.

As I mentioned on another thread, it has me thinking about the Tannus flat free tires: http://www.tannus.com/#intro Any slight increase in rolling resistance might be worth the piece of mind of knowing my tires will never fail that way. I may make the switch when these tires which came with my bike start showing their age. In the meantime, I will avoid that particular obstacle, as it will be easy to stay to one side of where the metal is protuding.

 

[Nirmala]

I was just thinking , if you did hit that pice of medal, you better check your rim too. I could have got bent too. Ken.

No damage to the rim as far as I can tell. The piece of metal was only about an inch higher than the road, so it was not big enough to hit the rim, even if I ran right over it. I am thinking I caught the edge of the metal with the sidewall of my tire.

 

[Nirmala]

I went back out where this happened, and the piece that was sticking up from the road a little bit was some soft rubbery stuff that is part of the expansion joint between the road and the bridge, so it was not metal, and probably did not damage my tire. I think maybe it was just a defective tire.

 

[KenM.]

Take it back to your dealer( if you bought it at a shop by you) and see if the will replace it. Can't hurt to try.
Keep looking up! Ken.