Lately, I have been going through inner tubes like a madman! I don't understand why; I'm not riding any differently, not going anywhere unfamiliar, no really rough terrain... I primarily ride around my neighborhood and typically within a 20mi radius of my house, mostly on pavement. Occasionally I will ride through some "rough" patches, like an empty field or where rain has made little gullies in the dirt. I occasionally will "bunny hop" to clear curbs as well...

Today I replaced a popped Slime tube from a week ago and went for a ride. I was probably 8mi into it, when I realized that this BRAND NEW Slime tube had apparently popped too! I made it home, took the wheel and tire off and checked for sharp points but didn't find anything. I submerged the tubes in the bath and did not see any sign of bubbles or a leak...

So what is the deal!? This is very frustrating... I've never had this happen to me before. I'm inflating to 60-65psi as the tire sidewall gives a range of 40-65psi and I'm riding mostly on pavement. I'm 5'10", I weigh 175lbs at the moment..... Any other info you want just ask.

So your tube popped, but still holds air when you put it under water ? Does it have a very slow leak ? Some more details of the actual problem might help.

You may have left debris stuck in the tire. poking thru.

sounds like the slime plugged the hole at low pressure, but may be less effective,
Fully inflated..

Check your rim strip too, make sure there aren't any spokes or nipples poking through. Does the hole happen in the same place?

Also, if you don't do it already, now is a great time to start lining up your valve stem to a specific spot on the tire. Some do it to the center of the label, some, the PSI suggestion. Either way, by doing this, you only have to inspect two areas of the tire once you've found the hole (2 & 10 o'clock for example).

Ok....

Homebrew01: The ACTUAL problem is that the inner tube loses air pressure to the point that I'm riding on the rim. The first tube took about an hour to deflate. This new tire took about 20 minutes. Thanks anyway.

fietsbob: As I mentioned, I checked the tire and the wheel rim, and there is nothing sticking through either the tire or the rim strip that can be seen or felt on either one.

IthaDan: Same as above. Thanks for the tip about lining up the tube and tire though, that is a good idea!


If it had been any of these simple things, I know to look for them. Everyone does. That's why I'm so perplexed as to what keeps happening. It just doesn't make much sense...

I think the original tube that came with the bike must've lasted 4 years, and the one I replaced it with another 2+... Are Slime tubes really crappy or something? I thought I had used them before with good results...

Anyone have any other suggestions?

What type of valve is it? Make sure it's not leaking at the valve, but you probably already checked that too.

If it leaks down there has to be a hole in it somewhere. Try putting a little more air in it while out of the tire and see if that shows where the hole is. Doesn't do much good to know where the tube is in relation to the tire if you can't find a hole in the tube first.

Pretty much all the questions I can come up with:

Where was the hole? Have you been locating the hole or just swapping the tube? Are you using the same pump each time? Sometimes the gauge can be off, or you could be loosening your valve for somehow. Presta or schraeder? Do you buy either the proper width or slightly smaller width tubes? Are you adding a little bit of air to give the tube shape before you install it? Are you taking the tire all the off the rim to change the tubes, or just slipping off one bead? I ask because you can pinch the tube in the bead of the tire, which will put a hole in the tube as air is added.

It is simply not possible to determine the cause of your flats from your riding habits, type of bike, tires, tube or what you did not find. The ONLY way to determine the cause of a flat is to find the puncture, look at where it is and what it looks like.

First remove the tube, but mark it so that you know the relative position of the tire, tube, and rim in relation to each other. For example, I always mount my tires so that the pressure info is next to the valve stem and on the right side of the bicycle. When I remove the tube I put an X on the same spot on the right side of the tube next to the valve with permanent magic marker. That way when you find a leak in the tube you can match it to a specific spot on the tire or rim.

Next find the leak - tub of water, soapy solution, feeling for it next to your cheek, whatever is necessary or works for you. Also check the valve by putting some soapy solution on it. Once you find the leak the type of puncture will tell you in many cases what caused it. I'll try to upload a drawing of the different types of punctures later, but the big thing is location. Match the location to the same spot on the tire (or rim if the puncture is away from the road/sidewall surface. Look for a cause....more later.

Actually, the first tube that popped was a presta, and the one that popped today is a schrader. But after re-inflating both, still no bubbles or leaks that I can see! I'm mystified... Obviously the air is getting out somehow.....

Check your spokes arent getting through the rim tape, that can cause it as well.

There's really no point in telling us you can't find the leak. Inflate as much as possible and push sections into a tub of water. It helps if you do it in a quiet area as well. If you still can't find the leak then you will need to carefully inspect every inch of the inside of your tire and rim and hope to find the cause. Also, I would think a slime tube that leaks would leave some residue at the point of the leak. I actually would recommend putting in a non-slime tube (and carrying a spare of course) to see if you get another flat and if it is then easier to spot the leak.

Also, using the term "popped" implies a quick release of air (blowout). It's more common and clearer to say the tube leaked or went flat when it is a slow loss of air.

What does "popped" mean?

When you determine that you have a problem, how much pressure is left in your tire? I'm not even convinced you're getting a flat.

Pump up just the tube (no tire) until its about as big around as your calf. If there's a hole, you'll certainly be able to find it.

The fact that your tube went flat but no air is escaping it seems to be contradictory. Look harder, air IS escaping somewhere. In times like this, I find it helps to way overinflate the tube, so it's 2 almost meters diameter. Sometimes this will rip open the little pinhole so you can see it. My guess is going to be a piece of truck tire wire embedded just below the surface of the tire, so you can't feel it with your finger, but it works through and punctures the tube when you ride.

So when you flat, do you find that the tire holds air for another hour if you pump it up again?