Bicycle Mechanics - Phantom evening flats

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View Full Version : Phantom evening flats


L Dude 7
03-15-06, 12:50 PM
A few months back, I had a 'turbo-flat' as a 2-inch nail found its way to the rear tire. I feared there may be damage to the tire, but after checking it out (and having the bike mechanic take a look, there did not appear to be any problem.) After that, the bike seemed to run fine for the next few months.

Three times in the past month I've gone to the garage to get on my bike in the morning, and found the rear tire (700x38) flat. In each case, I had ridden the previous night without any problems. and after each time, I checked the tire and wheel for noticable puncture points, and didn't find any. The second time, I just pumped up the tire road a mile, three hours later pumped it up again, and road a mile back home. Then I replaced the tube, and found there was a small leak roughly opposite the valve. So, it appears that the pressure may have been a little low, thus causing the valve to puncture the other side of the tube - though the puncture was small enough to allow riding on it for the short time.

After that, I put a 'slime filled' tube in place. In theory that would help 'patch' the quick leak if it happened again. However, this morning, the tire was again flat. I pumped it up, and spun it around a bit, and then rode in to work. It seems to be at about the same pressure three hours later. So that leaves a mystery. If the tire seemed to run fine last night, and spinning it around seemed to allow it to maintain the air, how did it end up flat this morning?


Al1943
03-15-06, 04:21 PM
Start by finding exactly where the hole is in the tube. If it's not obvious put some air in it and hold it under water.

rmfnla
03-16-06, 07:41 AM
Most likely you have a small piece of glass (or whatever) embedded in the tire that keeps puncturing the tube. Locate the hole in the tube and check the corresponding spot on your tire (the reason you should line the tire label up with the valve stem). You might have to squeeze the tire between your thumb and forefinger to expose the offending object, but odds are very good it's there.

The nail probably has nothing to do with it but is distracting you from finding the problem.


Retro Grouch
03-16-06, 07:48 AM
I agree with rmfnla. I've had a couple of cases in which I never was able to find the glass or thorn or whatever was causing my flats. Replacing the tire was worth the cost for restoreing my serenity.

Illah
03-16-06, 03:43 PM
With those slime tubes the slime will pool up at the lowest point, so if you just install it and let it sit there the slime will all be at the bottom of your tire. When you pumped it and spun it around, the slime was distributed all over the place, likely sealing up the offending hole.

As pointed out above, probably glass in the tire caused the hole to begin with. Slime may have sealed up the tube, but the glass is still there to cause future headaches.

--Illah