Avoid a flat right after you put on a new bicycle tube

Avoid a flat right after you put on a new bicycle tube

"How to put on a patch" instructions are at the bottom of this  page.

If a new tube leaks soon after you put it on the bicycle,  

it was probably caused by one of these:  The tire still had a thorn or the piece of glass in it that punched a hole in the old tube, and now it has punched a hole in the new tube - or, the spokes nipples were not covered up by a liner and a nipple punched a hole in the new tube - or, a spoke was sticking up above the nipple and the spoke punched a hole in the new tube - or, the tire came off the rim causing the tube to come out at that place, causing the tube to burst - or, there is something under the valve causing it to leak - or, you pinched a hole in the tube as you were putting the tube on the rim. 

How to not get a hole in the tube while putting it on:

Even if you get the best tube that you can buy, you can have a flat two minutes after you put on a new tube before you ride the bike if you don't try to eliminate the things that could cause a flat.  

Even if you have the best new tube that you could buy, something may cause a hole in the tube while you are putting the tube on, or within a few minutes after you put the tube on, and before anyone rides the bicycle. This could cause the tire to go flat before you even put it back on the bicycle. If it is a small hole, the tire could go flat a few days later because there was something like a piece of glass, a thorn or something that was already sticking through your tire when you put the new tube on. Many flats can be prevented if you do everything that you need to do while you are putting on a new tube. Causes of flats which could have easily been prevented are:

(1) The tube gets pinched between the rim and the tire while you are putting it on;

(2) You do not push the tire far enough down into the rim in one place, and the tire comes off the rim at that place when you air the tire up tightly, bursting the tube;

(3) A spoke is sticking up above the nipple. File off all spokes like that so they will not punch a hole in the tube;

(4) One of the spoke nipples is not covered by a liner, and it will rub a hole in the new tube;

(5) When you take the old tube out of the tire, mark the tube and the tire so you can find the place on the tire where the hole in the tube was. Find the hole in the old tube even if you plan to throw the tube away. Feel all over that place on the inside of the tire to see if there is a piece of glass, a piece of wire, a thorn or something that is sticking all the way through the tire. Feel everywhere else on the inside of the tire just to be sure there is nothing that could put a hole in the new tube. Also, look at the outside of the tire at the place where the hole in the tube was to see if there is anything sticking in the tire. 

(6) Even the best tubes could leak at the valve. After you put air in the tube, put something on the top of the valve stem to see if it will make a bubble by air leaking out. If it is leaking, sometimes you can fix it by pushing the valve down all the way with the tube aired up tightly. If the valve still leaks, you may be able to stop the leak by putting in a different valve from an old tube.  This does not happen often, but it happens with the best tube you can buy just as often as with cheaper tubes. 

Inflate the bicycle tube slightly before you put it in the tire. Do not put enough air in it to stretch the tube. Leave it inflated slightly while you are putting the tire on the rim. You may have to let some air out so you can put the last few inches of the tire on the rim.

After you get the tire on the rim, put just enough air in it so that the tire will stay in place, but not so much air that you cannot push or pull the tire up or down in the rim. Look at the bead line on each side of the tire to see if it is the same distance from the rim everywhere. You may need to pull the tire up where it is too far down in the rim, and push it down into the rim where it is not far enough down in the rim. After you get the bead line on the tire the same distance from the rim everywhere (you may not be able to get it exactly the same distance everywhere), put air in the tire to the recommended pressure.

If you use an air compressor to put air in the tire, do not put the air in too quickly because it might blow the tire off the rim, or it might push the tire up too far in one place which could cause trouble later. Before you get to the recommended pressure, check the bead lines again to see if the tire has come up too far our of the the rim in one place, and if it has, let the air out enough so that you can push the tire down in the rim at that place and air up the tire again. It is more difficult to get wide tires seated evenly in the rim than narrow tires.

Before you put on a new tube,
feel all inside the tire and see if you can feel a thorn, piece of glass, wire, etc. that is sticking through the tire.  If the object is a piece of wire, you may be able to pull it out with tweezers from the inside of the tire.  You cannot pull out a thorn, piece of glass, or a tack from the inside of a tire because the end of the object that is toward the outside of the tire is larger than the end that is inside the tire.  For objects that you cannot pull out from the inside of the tire, you will have to find the object on the outside of the tire and dig it out with the sharp point of a knife or pull it out with tweezers from the outside of the tire - don't stick the knife too far in the tire and don't cut the tire.  You can probably feel those objects by feeling inside the tire with the tire off the rim while pushing on the outside of the tire with your thumbs while feeling inside of the tire with your fingers. 

After you have removed anything from the tire that could stick a hole in the new tube,  look under the rim liner (don't stretch the liner much because liners can easily break after they get old) to make sure that no spoke is sticking up above the nipple, because if it is, it will punch a hole in your new tube.  The reason that spokes are sometimes sticking up above the nipple is that someone tightened the spoke, maybe months ago, causing it to stick up above the nipple.  File off the end of the spoke that is sticking up above the nipple.  Check the rim liner to see that it covers the nipples.  Sometimes there will be a hole in the liner at a nipple and the nipple could work through that hole and then make a hole in the new tube eventually.  If the liner has some holes in it, you do not have to throw away the liner - you can cut some pieces of rubber from an old tube and put it under the holes. 

Next,  partly inflate the tube - barely round it out - and put it in the tire. 

Then, put  one side of the tire on the rim.  Next, start putting the other side of the tire on the rim while looking to see that the tube does not get pinched between the tire and the rim.  Start putting the second side of the tire on about 8 inches from the valve stem so that the last part of the tire that you put on the rim will be the part that is at the valve stem.  If some of the tube is getting between the tire and the rim as you are putting the second side of the tire on the rim, you can use a tire tool to punch the tube out of the way so it won't get pinched.  You can easily pinch a hole in the tube while you are putting it on if you are not careful.  You will probably need to let some air out of the tube in order to put the last part of the tire on the rim. 

After you have put the tire on the rim, 

check to see if the valve stem is straight.  After you get the valve stem straight, push the valve stem up into the tire, then pull it back out until you are sure it is down against the rim. 

Don't air up the tire completely because the tire may not be far enough down in the rim in one or two places, or it may be too far down in the rim in some places.  Just put enough air in it so that the tire will stay in place and so that you can pull the tire up if it is down in the rim too far in some places, and so that you can push it farther down in the rim if it is not far enough down in some place.  The tire must have enough air in it so that it will stay where you push it down or pull it up, but not so much air that you cannot push the tire down or pull it up. After you have pushed the tire down in some places and pulled it up in other places, you will need to look all around the tire on both sides to  to make sure that the tire is down in the rim evenly everywhere.  Some new tires, especially wide tires, will blow off the rim when you air them up all the way if one place on the tire was not far enough down in the rim.
As you air up a tire completely, look all around on both sides to be sure that the tire is not coming off the rim at a place where it is not far enough down in the rim. If the tire is not far enough down in the rim at a certain place, you will need to let enough air out of the tire so that you can push the tire down at that place but don't let so much air out that other places will go down in the rim too far. 

>> HOW TO PUT ON A PATCH:

First, clean all around the hole in the tube and let it dry. Then, roughen an area that is a little larger than the patch all around the hole with a metal scraper that is made for that purpose: or, you can use a clean piece of sandpaper. Blow away the dust from scraping.

If the hole is on a seam, and if the seam is raised like a ridge, you can grind down the seam until there is a flat surface around the hole. If you don't grind down the seam, air may be able to escape along the seam after you put the patch on - but sometimes air will not escape even if you don't grind down the seam. And, if you grind down the seam, the tube along the seam where you ground it down may be so thin that it will split when you air up the tire - it usually doesn't but it could and it could be dangerous if you are riding the bike when the seam tears. If the hole is on a seam and there is a groove or channel along the seam, air may be able to escape along the groove after you put the patch on - but sometimes it does not escape along the groove, so that is just a chance that you can take or not. You could grind down the tube at the groove until you have a flat area, but that may make the tube so thin at the grove that it could split when you air up the tire. And, if it splits while you are riding the bicycle, if could cause you to have a wreck.

Before you put the glue on, get something clean to spread the glue with. You can use the backing from the patch to spread the glue after you take the backing off the patch. After you take the backing off, don't touch the patch on the side that was covered and don't let it touch anything. Put some glue on the hole and spread it over an area that is a little larger than the patch. Spread the glue fairly thin. Let the glue dry thoroughly for a several minutes and don't let anything touch the glue. Next, take the backing off the patch, if you have not already taken it off, and put the patch over the hole. Mash the patch hard everywhere a few times.

Sometimes, the thorn or whatever punched one hole in the tube punched several holes in the tube as the tube moved around in the tire. These other holes may be so small that will be difficult to find. Many times, you can find several holes the first time you put the tube under water to check for holes. You can put your finger over the first hole you find and then look for other holes. After you have found all the holes you can find, mark those holes with a piece of chalk or something far enough away from the holes so that none of the chalk will be in the area that you scrape and patch. So, after you patch all of the holes that you found, air the tube up fairly tight and put it under water to find the other small holes. If you put the patch on properly, it should hold well enough so that you can put enough air in the tube to check it under water to see if it has other holes in it.

I usually air up a tube to check for other holes in it immediately after I put on a patch, but if you are not in a hurry, I would wait several minutes before airing the tube up very tight when it is not inside the tire on the wheel to give the patches more time to stick tighter to the tube. Sometimes airing a tube up when it is not on the wheel will cause a patch to peel away from the tube, even though the patch may have held the air in if it had been inside the tire on the wheel.

DISCLAIMER 

I am not responsible if anyone is injured because they followed the instructions in any of the articles I wrote, or in any video or article by others that I recommend.  Some information in the articles that I wrote and in the videos and articles by others that I recommend could be dangerous, and anyone who tries to follow the instructions in those articles and videos could be seriously injured.  Repairing or servicing bicycles can be dangerous.