Commuting - I got *ANOTHER* flat on my bike today :(

Hi All,

I've been commuting to work for the past couple of weeks or so with a 1997 GT Ricochet that I bought off a guy so it is used, but in pretty good condtion.

Last week I got a flat from a piece of glass while I was in downtown and I had to take the bus back.

Last Monday I got a flat...this time I don't know how it happened... I looked at my tire (the same one that was flat the week before) and it was totally deflated! I changed the tire yet again.

Today I was riding my bike back and suddenly my bike tire started to deflate - rapidly. This was after a good 15 miles of riding. I don't get it. I don't think it was because of any glass, excessive force, or anything else...

Am I not changing the tire right? I am using tire irons and making sure the intertube isn't pinched. Oh, and also, I have been using new intertubes for each of the two times that I changed the tire - no patches.

Please help! Any suggestions would be great.

If the tires are badly worn, they might be more prone to punctures. Check the inside of the tire carefully for any foreign matter.

Is it possible the rim tape is defective or missing? This would allow the spokes and/or spoke nipples to come in contact with the tube and puncture it.

BTW, you should always inspect a punctured tube and determine the source of the puncture before you replace the tube (including whether the puncture was on the inside or outside). This will quickly allow you figure out whether you've had a pinch flat or whether you need to first look at the rim or the tire for the problem.

MItz Eclipse, I had a similar experience last week, I was riding to the library, everything seemed OK when I got there, locked up my bike , and when I came out the tire was as flat as a pancake, then I noticed there was a piece of broken beer bottle in the tire, I also had to take the bus home, and i took the bike to the LBS, and they told me that there was still glass in the tire that I had missed.

The rim tape is still there... so I don't think it's defective? How do I tell?

Also, what's a pinch flat? Where the intertube gets "pinched" between itself and the tire?

I checked the inside of the tire and the outside of the rim very carefully before replacing the new intertube after the last flat... no glass to be found.

Originally posted by MitzEclipse
The rim tape is still there... so I don't think it's defective? How do I tell?

Again, you check the old tube and see whether the hole is on the *inside* or *outside* of the tube as it would rest in the tire. Use the valve stem for reference. If it's on the inside, then you *know* that there's a problem there, whether it is obvious or not. Sometimes a burr on the rim can be the culprit. At high pressure, it doesn't take much of an imperfection to cause a problem.


Also, what's a pinch flat? Where the intertube gets "pinched" between itself and the tire?

Typically pinched between the rim and tire. There will usually be multiple small holes near each other. Assuming they are not already pinched during the install, they are caused by too-low pressure and/or running into a sharp edge at high speed (really bottoming out the tire). I am assuming you know how to install a tube that's not twisted or pinched.


I checked the inside of the tire and the outside of the rim very carefully before replacing the new intertube after the last flat... no glass to be found.

This is why you should use the old tube as a diagnostic tool - it eliminates some of the guesswork. You can also use the valve hole/valve stem as a reference of how far along you should look on the rim or tire (assuming you make note of how everything was aligned).

Perhaps you need to run greater tire pressure. Beyond that, I can't help.

I also had a couple of flats in a short amount of time. The first one was a puncture from the outside. I replaced the tube and two days later another flat. This one was on the inside so I suspected the spokes poking through. I said to hell with it and bought some good rim tape and self sealing tubes for both wheels. I hope the self sealers work as advertised.

I'll have to double check the rim tape.

Anyone know if there is a place or pictured-FAQ that shows how to change a tire exactly?

Thanks

No, but it's pretty straight forward. Inflate the tube a little to make it sort of round but not tight. Put one bead of the tire on the rim. Start the valve in it's hole first. You have to yank up on the overhanging tire bead to room to get the tube and valve in there. Then start working the tube into the tire and pusing the tire/tube towards the center of the rim but leave the bead off for now. Once it looks like the tube is into the rim good, start putting the bead on. I have to use a tire tool on the last bit of the bead although I think it is suggested to do that all by hand. I try to mostly use my hands but slide the tire tool along to add some pressure.