Mysterious flat...

So I haven't ridden in about a week. Yesterday was absolutely beautiful so I decide I'm going to ride to work. I get dressed, go to the kitchen to retrieve my bike, and notice my front tire is completely flat. No air whatsoever. Bummer.

Today I take out the tube and grab my patch kit, pump a little air in the tube and listen for a telltale hiss... nothing. Not a single little pinprick. I run my fingers along the inside of the tire, nothing suspicious. Very peculiar.

Have any of you experienced this before? Now I can understand needing a little boost, I usually have to add 40-60 psi before each ride, but completely flat? It boggles the mind. I'd really like to know what caused it so I'm not caught after class with a flat. (I know I need to invest in a frame pump, just don't have the funds at the moment.)

Over inflate your tube. Small pinch flats can be difficult to find at times. Also with the tube inflated, put it in water - you'll see the hole by following the air bubbles.

if you can find no holes, it could be a broken/leaky valve

You undoubtedly have at least what you call a "Slow Leak". Sometimes, they are slow enough that they don't bother you while you are riding but left over night or a a couple of days and the tire will be flat.

There is something causing this, so you should probably try putting it in water to find the telltale bubbles where it is leaking. Fill the tube with air, put it in a bucket and squeeze on the tube to find the bubbles if they are not apparent right away.

My hubby has been known to ride for miles on Slow Leak tires (he airs them up before he leaves each time). Me, I just find the leak and patch it or change to a new tube.

spoke

I had the same thing happen this weekend. Turns out there was a slow leak where the valve connects to the rubber tube. It didn't leak unless I tilted the valve slightly. It showed up in the underwater treatment. Had to throw the tube out. :mad: Probably happened while tilting the valve out to fix a puncture in the tube.

Thanks to everyone for the suggestions! I tried the underwater treatment, and found that there was a not so small rip where the valve stem connects to the tube. It didn't leak unless I moved the stem, but when I did it was flat within seconds. Ran to the LBS to catch them before close and got a new tube.

Thanks for the help!

Yep, that's exactly how mine was! Didn't leak unless I moved the valve stem a bit.

Hey, you might want to have more than just one spare tube on hand....things happen. :)

Ditto the extra tubes. My LBS will throw the 5th free.

the area where the stem connects to the tube is one of the most fragile areas of the tube. here are some hints that will help you prevent future flats in that area:

1) don't use the little washer to "pull" the stem out of the rim.

2) if you have to use the little washer because of a combination of deep dish rim and short stem, don't tighten it too much.

3) when removing the tube from the tire, always start at the section opposite the stem. when you reach the stem, you'll be able to just pull it away from the rim without putting excess pressure on the stem area.

4) always handle your stem gingerly when pumping your tire. make sure it's perpendicular to the rim. don't pull or tug. treat it like the fragile flower it is!

hope this helps!

I've been meaning to get spare tubes and a couple of other things for ages, just haven't gotten around to it. Payday's tomorrow, so I'll probably jump on that.

velo - I'm not sure I know what little washer you're talking about. Unless you're referencing presta valves, which I'm not all that familiar with. Thanks for the tips about removing the tube and airing it up though. The LBS owner and I pretty much decided that I was being a little too hard on it when airing up. Got to work on that.

Velo- thanks for the tips! DH and I discussed some of these very points right after my tube got tossed. I suspect now that perhaps I tightened the nut on the valve a bit too much with my fingers - thus pulling the tube too tightly into the sharp hole edge. Why don't they make the edges of those rim holes smoother?? :confused:

I've had the identical problem of slowish leak near the valve... not tightening the nut down never occurred to me... You said "if you have to use it".. does that mean that if the stem is totally easy to get to because either it's long or the rims are shallow, I shouldn't be using the little nut?

thanks!

I had a leak that only showed as a small bubble under water, that would re-form if I brushed it away. Can be darned hard to find sometimes, if the tube had been facing the other way underwater I wouldn't have seen it. Just the tiniest pinprick, but it went flat overnight.

Oh - and IF you use tubes with Presta valves in rims with a hole big enough for the other valves (Schraeder? summat like that) you need a little plastic liner thingy in the hole first or the tube will squeeze in there and get a pinch flat first chance it gets. BTDT.

Correct, only use the nut/washer/thingy if you can't seal a pump on the stem because it's too short (can you tell from my use of proper terminology that I teach bike maintenance classes?).

Regarding presta valves in a schrader rim, I did it without the little rubber washers that LPH refers to, but I used the stem nut instead. Worked just fine and I didn't flat.

Quote:

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Originally Posted by Beane

You said "if you have to use it".. does that mean that if the stem is totally easy to get to because either it's long or the rims are shallow, I shouldn't be using the little nut?

thanks!

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good to know. thanks!

Since we're talking flats here, I had the fortune of 2 flats on 2 different bikes this week. One on the front tire (: and the other on the rear. Turns out the leaks on BOTH tires were on the edge or seam where the tire is joined. I hadn't changed either of these tires in a couple of years, so no surprise that the tubes finally gave out.

I recommend that you keep track of when you put your new tubes in your tires (or mended ones) so you don't have to go through fixing flats on the road like I did. I have 2 more tubes to change out as they too are old. The tires on both bikes are fine so it wasn't about a bad tire in either case.

Also, someone has probably mentioned this before- I'll say it again. If your tire shape begins to look flat on the top, you might consider changing it out for a new tire (tires start out round and flatten as they get miles on them). I say this because you do lose some of your handling ability especially when going around corners at a good clip. I really noticed a difference in the handling of my bike after I put a new tire on the rear.