Good Tube keeps going flat

[jsph.han]

Hi!
I recently bought a road bike, and on my first ride, the tube on my rear wheel unfortunately got punctured. I used a cement patch kit and the tube seems to inflate well, but whenever i put it back in the wheel and start riding, the tire goes flat again. I'll take the tube out of the wheel again, but the tube seems to work perfectly. Also, when I do inflate the tire and spin the wheel, it is a bit uneven, not side to side, but up and down. My rim and tire seem perfectly fine though. Any suggestions on how to fix the problem, or what's wrong?
Thanks!

[GeorgeET]

How can you say a tube is fine if it is loosing air. It is not fine. Fill it up and test it in a tub of water. Also test the valve. As per uneven tire , it is not mounted properly in the rim. Inspect the tire edges before inflating and make sure it is evenly mounted into the rim, roll it around a few times than inflate.

[RBurrelli]

(07-25-2014, 09:51 PM)jsph.han Wrote:  Hi!
I recently bought a road bike, and on my first ride, the tube on my rear wheel unfortunately got punctured. I used a cement patch kit and the tube seems to inflate well, but whenever i put it back in the wheel and start riding, the tire goes flat again. I'll take the tube out of the wheel again, but the tube seems to work perfectly. Also, when I do inflate the tire and spin the wheel, it is a bit uneven, not side to side, but up and down. My rim and tire seem perfectly fine though. Any suggestions on how to fix the problem, or what's wrong?
Thanks!

OK. According to you there is a perfectly good tube, tire and rim... But things keep going wrong. Does not really make a lot of sense. Inflate the tube and leave it out of the tire for a day . See if it deflates. The recommendation to inflate and immerse is the standard method. Even little air bubbles are a problem. Once you are past the tube issue, then move on to figuring what is wrong with the wheel.

[cny-man]

Only a small amount of pressure is possible on a tube when it's out of the tire, so it can seem fine even though there's a small leak. The tire will be essentially flat long before all the air is out, so again you can have a small leak and still have it go flat. The submerse method is the way to go.