Why does my tire keep going flat?

Quoted post said:

Originally posted by wolfgang
I ride every other day and before each ride I need to pump up my rear tire. It stays full of air for the entire ride, but it goes flat again by the second day. I guess this is what they call a slow leak. I'm afraid that it may eventually go flat more quickly when I'm in the middle of a ride. Should I just replace the tube now? What causes a slow leak anyway? Is it just a really tiny puncture? Air escaping from the stem? I ride a road bike with Presta valves btw. Thanks.

Just get a New tube, Problem solved, less hassle.

I think that's what I'll end up doing. I'm just wondering what's causing this. Seems to me that a tube should either stay pumped up or stay flat. I don't see how air can escape slowly. I wonder if it has to do with being heavy. I'm 6'4" and I weigh about 250 lbs. right now. However, as I mentioned, my tire stays pumped for my entire three hour ride.

Take your tube out, inflate it, and see for yourself where the leak is. There's no way we can tell you. You can either patch it for about 2bucks for a kit, or you can replace it for like the whole 5 that a tube cost. If punctures persist, invest in some spinskins.

acutally there is a way to tell where the hole is

Take your tube out, soke it in water, get the dish soap you use, ie:dial or whatever else thats soapy...rub it on the tire then inflate the tire and watch bubbles magically appear where the hole is...doesnt matter how small the hole is, it will show large amounts of bubbles in the area of the hole.

Quoted post said:

Originally posted by Sidmyre
acutally there is a way to tell where the hole is
Take your tube out, soke it in water, get the dish soap you use, ie:dial or whatever else thats soapy...rub it on the tire then inflate the tire and watch bubbles magically appear where the hole is...doesnt matter how small the hole is, it will show large amounts of bubbles in the area of the hole.

You don't need the soap. Just submerge the inflated tyre and slowly work around it, looking caefully for any bubbles. When
you find a bubble, rub it away and see if another one appears.
If it does, you have found a leak.

the dishwashing liquid etc costs more than a new tube......
a new tube is a new tube.

Sometimes valves can go dodgey which means they slowly leak.

Quoted post said:

Originally posted by Marx SS
the dishwashing liquid etc costs more than a new tube......
a new tube is a new tube.
Sometimes valves can go dodgey which means they slowly leak.

Which will also be revealed with the ancient 'submersion' technique revealed above.. 🙂

Thanks, everybody. I already know all these techniques. I was just wondering how a tube could go flat slowly over a couple of days.

Anyways, I just changed the tube. I must admit I'm a newbie to road biking and this was my first tube change. I was surprised how much easier it is to change a road tube than a MTB tube!

Quoted post said:

Originally posted by wolfgang
Thanks, everybody. I already know all these techniques. I was just wondering how a tube could go flat slowly over a couple of days.

Anyways, I just changed the tube. I must admit I'm a newbie to road biking and this was my first tube change. I was surprised how much easier it is to change a road tube than a MTB tube!

You must have lucked it with your tyre/rim combo.. my road tyres
are a *^(*% to remove!

have fun!
hippy

Quoted post said:

Originally posted by Marx SS
the dishwashing liquid etc costs more than a new tube......
a new tube is a new tube.

Sometimes valves can go dodgey which means they slowly leak.

uhh...any type of soap will work, doesnt HAVE to be dish soap...COMMON SENSE...jeez, it doesnt mean you have to go out and buy a container of dish soap...........

and the reason why I said use soap is that some times it's hard to tell where the hole is and much easier in the long run...

but whatever....doesnt matter now.

Sorry I just get ticked when people would rather whine and comlpain instead of using common sense

Soap is a classic, and a $2 patch kit will do about eight tubes. That works out to .25 a patch. Now if you want to get technical there is the cost to get to the bike store to buy the patch or the tube. There is also the fact that each tube you throw out takes about 200 years to beak down in the land fill. Yes I am cheap and I care about things like that. Plus I actually learned the art of tube patching some 30 years ago. So I figure if I save $30 a year times 30 years and still counting. Hey its your money.

Let's see:

.Dog is secretly sitting on the valve when you're not looking.

a small hole -- if the hole is small, the air will leak out more slowly.

I had one of them a few weeks ago. Tire would soften overnight; pump it up and ride it in, pump it up before heading to the picnic, pump it up three hourse later to get home. I couldn't find the leak even submerging the puppy.

A friend called attention to the tire adn it's nicks and bald spots -- has it really been 4700 miles? POssibly a contributor -- how are your tires?

Quoted post said:

Originally posted by wolfgang
I ride every other day and before each ride I need to pump up my rear tire. It stays full of air for the entire ride, but it goes flat again by the second day. I guess this is what they call a slow leak. I'm afraid that it may eventually go flat more quickly when I'm in the middle of a ride. Should I just replace the tube now? What causes a slow leak anyway? Is it just a really tiny puncture? Air escaping from the stem? I ride a road bike with Presta valves btw. Thanks.

No valve seals perfectly, and rubber/latax is a very tiny bit porous, so some pressure leakage is inevitable over time. Of course if you've got a hole in your tube it's going to leak faster. Make sure you check your tyre for cuts and/or embedded debris - after all this and the effort of changing/repairing tubes you don't want a residual tyre owie to undo all your good work.