The tube inside by bicycle tire (inner-tube) got a hole and now I can't ride the bike. It isn't a big hole, so I am going to repair it myself. The only problem is that it takes an extremely long time to find the hole. I usually run my finger around the entire tube looking for it, until I eventually find it. This usually takes 20-30 minutes. There must be an better alternative. What is an easy way to quickly find a hole in a tire tube?
Take a bucket full of water (the bigger the diameter is, the better) and push your inflated inner tube into the water - section for section. As long as the hole isn't like really, really tiny, you will see some bubbles right away. With tiny holes you need some steady hands, more time and a good pair of eyes. Small bubbles are hard to spot.
For easiest bubble-spotting, use a dark bucket, because you will see the bubbles better if the background is dark.
Just make sure to dry the area around the hole thoroughly before applying any kind of fix to it.
There is also an improvement to the run-the-finger-along-tube-method you already know: Instead of moving your finger along the tube, move the tube along your lips - not really touching them, of course. The area around our lips and tip of the nose is extremely sensitive to airflows.
Use soapy water if you don't have where to submerge the tire:
- Take soap and some water and make soapy water solution (liquid soap dissolves faster)
- Start to apply soapy water on the tire with your hand
- When you put soapy water on the hole you will see soap bubbles appearing. At the same time you can feel the air flow with your hand. Wet hand becomes more sensitive to air flows.
I have seen some children using this method to find a hole on a football or basketball ball, and it will surely work for tires.
You may need to use water, as others have said, but before you do that....
Get the tube and partially inflate it
Hold the tube to your ear and slowly rotate it
When you hear the air hissing out, you have found the hole.
Not only is this quicker than water, it also works out on the road (as there never seems to be a bucket of water around when you need it).
The quickest overall method is this: Pull the tube from the tire and pump it up well above the volume it would be inside the tire. Then (in a quiet place) rotate the tube past your ear. You will almost certainly be able to find the general location of the leak by hearing the hiss, then explore more closely with your finger, keeping your ear close to the suspected area. You will probably hear a noise as your finger blocks and then unblocks the hole. Lips are also good for detecting the stream of air, as Alex pointed out.
Bonus technique: when you remount a tire, move the valve stem so that it is near the tire label. When you get your next flat, find the hole in the inner tube, and then find the corresponding location on the tire itself and explore it for thorns, nails, glass or other puncture-causing objects. If you don't do this, there may still be a sharp object imbeded in your tire and you will quickly get another flat.
In the absence of a bucket with soapy water (eg. on the go), I usually use my tongue.
If you don't mind the taste of the rubber, it works even better than using your lips. The saliva on your tongue will create a seal against the hole and gently squeezing air out of the tube will 'burp' or 'fart' against your tongue.
This is very helpful with tiny holes because it's not the size of the hole you are detecting, it is the amount of air that is trapped beneath your tongue before it escapes. You regulate this with air pressure in the tube and tongue pressure on the tube, so take your time and allow the air to build up momentarily before it escapes from beneath your tongue.
To be clear, I'm not talking about licking the tube! Lightly press the tip of your tongue against the tube and run the tube against your tongue. When you think you have found the hole then you can press a bit more firmly with the tip of your tongue to seal the hole and verify it's location.
Personally, it works so well I don't bother with soapy water. Also, if it's not an emergency, I don't patch tubes anyway.
I like to hook up something in generally. If you have found the leakage, while on the go, saliva works almost as good as leakage-search-spray which is nothing else as soap-water. You can now double check it and check it again to ensure your patch is close. It works very good for the valve also (in addition for car-tires valves also...)
At home, I use the bucket method. However, "in the field" I don't carry a bucket with me when I cycle. Finding the source of the puncture can be critical, whether one is patching the tube or using a replacement.
I first chalk the tire at the value stem, and mark the rotation direction on the tube. This allows me to "align" the punctured tube with the tire.
After removing the wheel, and separating the tire from the tube, I inflate the tube and both listen and feel for a leak. Sometimes I hear it. Other times I feel the escaping air on my face or eye. Once I know where the puncture is on the tube, I can align it to the tire, and find the place on the tire where the puncture occurred. There may still be debris in the tire that I need to remove such as metal, glass, nails, and even a wood splinter once.
I also like the method of finding the hole in the inner tube by partially filling it with air and submerging it in water. I do it a bit differently though:
For all types of holes inflate the inner tube so that it is larger than it would normally be in the tire.
For very tiny holes that empty a tire over 2-5 days, finding the hole by just submerging the inner tube can be difficult to impossible. The low inner pressure of the lone inner tube combined with the static pressure of the water can prevent any air from escaping through a tiny hole. When I had this once, I solved it by additionally stretching the submerged inner tube section while holding it underwater with both hands.
Both of these techniques stretches the rubber material, which enlarges the puncture hole, which again produces bigger and easier to detect bubbles.