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Discussion Starter · #1 ·
I get back today from a local bike shop and I am in my driveway, get off the bike,lean it against my car and go to remove my water bottle. I hear a blast and had no idea what it was at first, it sounded like a shotgun blast. My rear tire tube had burst.

So, I change the tube, removing the bad tube but removing only one half of the tire bead.

I put roughly 30 psi in the tire and then mount the wheel back on. I go to pump it full and I finish. I screw the Presta knob tight thinking I am done and all of a sudden another blast. The tube burst again. This blast was in my face as I am screwing the cap back on.

I called it quits and will be taking the bike to a bike shop tomorrow to be looked at.

Any guess what could have caused this to happen?

1. Is it my tubes that could be bad? I use QTubes 700cx23-25mm Presta Valve 48mm. I had no problem with this brand in the past, maybe the tubes went bad?

2. I checked the first bad tube and it looks like the puncture is near the stem, but not on the stem.

If there is something sharp on the wheel that is causing the puncture, I figure the bike shop will find out for me and be able to fix it.

In the meantime I was wondering if anyone else had similar blasts with their tubes, this is the first time I ever experienced these loud blasts like this and back to back.

Could it be bad wheels? I'd like to have a rough idea what is going on before the bike shop looks at it. Last time I was at the shop the owner tried to sell me $700 wheels and I don't care to listen to that speech again.

Thanks for any thoughts.
 

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'brifter' is f'ing stupid
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99.9999999% of the time a tube goes "bang" it's operator error. The other .0000001% is when the tire actually gets shot by a shotgun. The tube explodes because it's been trapped between the tire and the rim. It can blow right when you inflated it or it can blow later...sometimes much later. When you take it back to the shop have them show you the proper way to install a tube...do NOT use levers when installing the tire.
 

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99.9999999% of the time a tube goes "bang" it's operator error. The other .0000001% is when the tire actually gets shot by a shotgun. The tube explodes because it's been trapped between the tire and the rim. It can blow right when you inflated it or it can blow later...sometimes much later. When you take it back to the shop have them show you the proper way to install a tube...do NOT use levers when installing the tire.
This part.

I've had many pains putting on tires of many different types. Tubeless road sucks the worst. However, I could always get the tire on withOUT a lever. It has taken a tad of soapy water before on the rim in the last spot, but they were on.
 

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Most of the time it's not the tube at all, the tire bead is not seated properly on the rim which causes the tube to ooze out under pressure..... BANG!
I had this happen in the middle of the night while in a deep slumber, Scared the crap out of me!
 

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I would love to know how to get a tube in without the lever, I can get it in about 90% but then I have to use the lever. When I pinch the tube it has never exploded, I don't use co2 though. I know it gets easier after a few tube changes after the tire is not so new, I am female with really pathetic arm strength. I don't have soapy water on the roadside. I probably have about an 80% success rate overall but the problem scenarios are always in the worst places to flat. I carry 2 tubes now and just ordered some co2. I have a direct fit pump and it seems to be really positional, so I have a lezyne hose pump on order too. I hate to be helpless.
 

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Most of the time it's not the tube at all, the tire bead is not seated properly on the rim which causes the tube to ooze out under pressure..... BANG!
I had this happen in the middle of the night while in a deep slumber, Scared the crap out of me!
Trust me, it's the tube. Really. The reason the bead wouldn't be seated properly (most of the time) is because the tube is caught between it and the rim. I've got a fair bit of experience w/ this whole tire-installing thing.

I would love to know how to get a tube in without the lever, I can get it in about 90% but then I have to use the lever. When I pinch the tube it has never exploded, I don't use co2 though. I know it gets easier after a few tube changes after the tire is not so new, I am female with really pathetic arm strength. I don't have soapy water on the roadside. I probably have about an 80% success rate overall but the problem scenarios are always in the worst places to flat. I carry 2 tubes now and just ordered some co2. I have a direct fit pump and it seems to be really positional, so I have a lezyne hose pump on order too. I hate to be helpless.
It doesn't matter whether you use a CO2 cartridge or a pump of some type to inflate your tire, if it's not done correctly, it will blow. Most of the time it's not shear hand strength that gets the tire on, it's knowing how to do it properly. Have your local shop help you w/ this, hopefully they know what they're doing.
And always...always...check to make sure the tube isn't pinched before inflating.
 

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If you have to resort to using levers to get that last bit of the tire on, inflate the tube to about 20 psi or so after your tire is almost on. This causes the tube to expand up into the bed of the tire, pulling it away from the rim edge. This lessens the chances of the tube pinching.

I've used this method with super tight tires on my carbon rims. Always go around the tire after its on, pinching the sidewalls with your fingers, inspecting for exposed or pinched tube.
 

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2. I checked the first bad tube and it looks like the puncture is near the stem, but not on the stem.
The last step in installing a tire before pumping it up is to push the valve into the tire to make sure the tube in that area is not caught under the tire bead. I agree with everyone else that the VERY most likely cause is that the tube was caught under the tire bead somewhere and when you pumped it up, the tube worked it's way under the tire and then popped like an overblown bubble gum (but MUCH louder).
 

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Discussion Starter · #11 ·
My gut feeling is CXWrench may be right about me having done something wrong when installing the tube. I got a few hundred miles since having to replace the rear tube yet likely did something wrong and it showed today. I replaced the tube and I am at a loss why it burst moments after unless I did something wrong again. The odd thing is I have replaced tubes before and they have lasted years.

I will try to get the bike mechanic to show me what I could have done wrong and will watch him carefully tomorrow. The shop I go to is friendly, hopefully they will pass on tips.

About installing the tires, I have Continental Grand Prix 4000S tires and it is impossible to mount the last few inches of the tire without a Kool Stop Tire Jack. The Tire Jack does not do anything other than pull the tire over the rim. I use the tire levers only to pull the tire off the rim when making room to remove the flat tube. Other than that, I do not use levers.

I will post what I find out tomorrow, if anything, after a visit to the shop.

Thanks for your replies, I appreciate it.
 

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'brifter' is f'ing stupid
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My gut feeling is CXWrench may be right about me having done something wrong when installing the tube. I got a few hundred miles since having to replace the rear tube yet likely did something wrong and it showed today. I replaced the tube and I am at a loss why it burst moments after unless I did something wrong again. The odd thing is I have replaced tubes before and they have lasted years.

I will try to get the bike mechanic to show me what I could have done wrong and will watch him carefully tomorrow. The shop I go to is friendly, hopefully they will pass on tips.

About installing the tires, I have Continental Grand Prix 4000S tires and it is impossible to mount the last few inches of the tire without a Kool Stop Tire Jack. The Tire Jack does not do anything other than pull the tire over the rim. I use the tire levers only to pull the tire off the rim when making room to remove the flat tube. Other than that, I do not use levers.

I will post what I find out tomorrow, if anything, after a visit to the shop.

Thanks for your replies, I appreciate it.
What kind of rims and rim tape do you have? I've never had a problem w/ getting GP 4000's on w/ just my hands. IME there are some tires that are a bit loose, but none that are really tight. If you have a tight tire and a badly designed rim it can be really hard to get them mounted, but proper technique makes it a bunch easier. The best advice i can give you is don't use your thumbs. Roll the last bit over w/ your inside knuckles, you know...right where you get callouses and blisters from doing hard work in the yard.
 

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Discussion Starter · #14 ·
What kind of rims and rim tape do you have? I've never had a problem w/ getting GP 4000's on w/ just my hands.
Here are the specs on my bike:

TrekBikes.com Bike Archive | 2010 Madone 4.5

The rims are the same as they came on the bike but the tires I replaced.

I am not the only one who has expressed extreme difficulty in mounting the Continental GP4000 tires on my rims. Others have too. I got around this issue by using a Kool Stop Tire Jack with the remaining few inches I could not finish when pulling the tire over the rim. It is a common problem with others who have the same tires and same rims.

If you are not experiencing the same difficulties, you must have different rims than the ones in the specs I provided in the above link.

My issue now is finding out what I may have done wrong in replacing my tubes. I hope to know tomorrow if the bike shop is helpful.
 

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'brifter' is f'ing stupid
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Here are the specs on my bike:

TrekBikes.com Bike Archive | 2010 Madone 4.5

The rims are the same as they came on the bike but the tires I replaced.

I am not the only one who has expressed extreme difficulty in mounting the Continental GP4000 tires on my rims. Others have too. I got around this issue by using a Kool Stop Tire Jack with the remaining few inches I could not finish when pulling the tire over the rim. It is a common problem with others who have the same tires and same rims.

If you are not experiencing the same difficulties, you must have different rims than the ones in the specs I provided in the above link.

My issue now is finding out what I may have done wrong in replacing my tubes. I hope to know tomorrow if the bike shop is helpful.
No, it's not that i'm working w/ different rims. I sell Trek at the shop and work for a team that rides Trek and uses Bontrager wheels for training. Conti tires are not that tight on these wheels. I show people how to mount tires all the time. I'm not trying to sound cocky, but you should see the looks i get when the tire they just couldn't get on goes right on w/ bare hands. If you use the proper technique, it's not that hard. I'm pretty sure after doing this for a living for 20 years i could show you a thing or 2 about mounting tires. Then again, maybe my perception of "tight" is different than yours. I probably install over 500 clinchers a year...i've seen tight.
 

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It's obvious that it's the tube that's bursting, but it's not a faulty tube.
You guys are kind of arguing about a small degree of difference in the frequency of two closely-related phenomena. The tube can only explode if it escapes from under a section of tire bead (everyone agrees). This can happen as a result of one of two kinds of error in tire installation: leaving a section of tube trapped under the bead (so it pushes out when inflated, and eventually bursts); or not evenly seating a section of bead (even though the tube is fully inside), so the inflated tube eventually pushes it off, escapes and explodes.

Some people have seen one more often, some people the other. Some tire/rim combinations are especially susceptible to poor seating if one is not attentive.

I've committed both typoes of error (not recently, however). And as for tire levers, they do perhaps make the trapped-tube scenario more likely, but you can have this sort of mess even if you install the tire by hand.
 

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Discussion Starter · #20 ·
99.9999999% of the time a tube goes "bang" it's operator error. The other .0000001% is when the tire actually gets shot by a shotgun.
The other .000000000000000000001 happened. I got back from the shop today and the tire was defective. I ride with Continental GP4000S and it was shredded. The shop told me they never saw a Conti do this after such a short time. I installed them in March and put on only 600 miles. There was nothing wrong with my installation of the tubes, the shop told me the tire is bad. I put tubes in many times and never had an issue.

If anyone has a sign of a tear or rip in the tire, best to immediately chuck them else your tubes will explode like mine did.

And to add to the aggravation I got a $35 parking ticket when I returned to my car. :mad:


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