By Tom Kunich
For an Explanation with Pictures, see also Bicycling Life
What you will need:
1) A small seat pack
2) A triple tire lever set.
3) TWO spare innertubes
4) two Park instant patch kits.
5) Zefal HPx frame pump if it can possibly fit on your bike
Never put a new innertube into the tire until you have assured yourself what caused the original flat.
I don't know how strong you are and the technique needs to be modified somewhat if you are small or have weak hands. Here's the form:
(Prelude: Whenever you put a tire on a bike you always align the label of the tire with the filler tube. If you didn't install the tire and the label isn't aligned then use a pen or pencil to mark the filler location)
1) If it is a back tire flat, shift the bike into high gear (the smallest cog on the back). Release the brake with whatever mechanism is on your bike. (If you don't know how yours work have a shop show them to you.) Remove the wheel.
2) Remove any tire filler cap and lock nut and let out any remaining air. Some tires are fairly loose on the rims and if you have strong hands you can lift the whole tire/tube assembly up and off of the rim. Other's are so tight that you think that you might break the levers (indeed, I have.) The best way to work on the tire is to remove it all the way from the rim unless it is one of those that are so tight that you think you may not be able to put it back on.
3) Closely inspect the tire all the way around. You MUST find what caused the flat. If you can't find the location of the puncture inflate the tube and find the hole there. Be aware that sometimes when you have a fairly small puncture that the tire will get so soft that you will hit a pothole that you will get a 'snakebite' (pinch) flat and you might think that it was simply a pinch flat that caused the flat. When these occur carefully sand the area with the sandpaper from the Park Instant Patch kit and put a patch on the snakebite and fill the tube and try again. On a fresh patch do not try and blow the tube up like a balloon to find a small hole. Chances are that you will find an obvious hole. By laying the tube on the tire you can find the approximate location (remember that you might have flipped the innertube so if you don't find it on one side, turn the tube over and look on the other side). Make absolutely certain that there is no glass or rock or thorn left to cause a new flat. Pinching the rubber around the cut to look into the puncture location works quite well.
Very rarely you will find a Michelin wire at the puncture site. These are sometimes extremely difficult to fix. These wires come from the steel belts on Michelin (mostly truck) tires these days. You pick them up by riding over what looks like innocent pieces of tire tread along the road. Avoid tire tread as if it were glass. Sometimes the wire will break off level with the outside tread and will be almost level with the inside cord. They are nearly impossible to see. As the tire rolls the wire will work up and down and cause small round punctures. Sometimes the wire is sticking out enough that it is (relatively) easy to remove while the other times you are pressing on the external side of the tire with some sort of steel implement trying to push enough of the wire inside to grab with tweezers. Very large pain in the butt. I've had to throw away two tires that were almost new because wires were perfectly vertical and flush on both sides and would answer to no method whatsoever. On the good size, aramid belts are becoming more and more popular and some day steel wire may become a thing of the past.
Another source of mysterious flats is a break in the tire rim liner. There is really only one good rim liner and it is cloth tape. If you have a box section rim that has the spoke nipple heads showing on the rim floor a rubber liner will work. But cloth tape is always preferable. If your rim has pockets into which the spoke nipples are sunken you absolutely must have cloth tape. Even this tape can possibly cut on the edge of these wells and that slight sharp edge will cause a hole on the inner edge of the innertube. Be aware that they can happen and look for them if you can't find any other reason for a flat and the hole is on the inside edge of the tube.
4) Under normal circumstances you have found a piece of glass stuck in the tire and removed it. You have then inspected the rest of the tire to make sure that was the culprit. It is a good practice to run your hand all the way around the inside of the tire to feel for any wires or glass. And running your hand around like that will break off the point of any thorn puncture. There is a fear that you will find something sharp and cut your hand but in 12 years I haven't had that happen so I wouldn't worry about it too much. You then insert the new innertube with the filler in line with the label.
5) Boots: if your tire has been cut so badly that there is the slightest danger that an innertube might putch through the hole (in other words any cut that you can see on the inside of the tire cord) you should boot the spot. You can get some boot material from bike shops sometimes, but most shops don't carry anything practical. The best boot material is the cord of a sewup tire that has been stripped of it's rubber and cut up into pieces. But you aren't going to find much of that these days. I always carry some paper money when I'm riding and the good old American Dollar is made from some of the toughest paper known. Folding this a couple of times and it makes a perfect boot. I have also walked up and down the street a bit and recovered pieces of cardboard that have worked serviceably until I could put on a new tire. If worse comes to worse you have to experiment. I bet that you could get a piece of aluminum can to work if you were careful to make certain that there were no sharp edges.
6) The way a tire fits on the rim is planned. There is a sunken center well and a larger diameter bead area. I usually insert the filler into the rim hole and make certain that the tire is properly seated and not being held high by the innertube in that area. I then sort of push the tire onto the rim all the way around going up both sides at once. You will end up with an 8 inch or so area at the side of the rim opposite the filler that is tight. Some tires will roll on from here if you have strong hands. Others you have to back everything off a bit and push the far side of the tire on first, push everything over as far as possible so as to get the tire bead into the center well of the rim and then roll the tire on by hand.
Here let's talk about using levers. You should NEVER use levers to put a tire on. The problem with that rule is that there are plenty of people whose hands simply aren't strong enough to put on a tight tire. A friend of mine is an ex-football player who could squash most people under his thumb, but couldn't push putty through a coffee cup with his hands. His wife is a small woman but her hands can wrench the top off of the strongest bottle and can flip most tires on like a seasoned European pro racing mechanic. So you never know what you can do until you try it.
If you MUST use levers you have to develop your own method of getting the innertube completely away from the lever. But I have never been very successful at this and about 1/2 the time I get a lever puncture no matter how careful I am. But the football player seems able to put on tires with levers successfully about 95% of the time. Necessity is the father of invention.
7) I have found that there are only two or three pumps that I consider workable and the best by far is the Zefal HPx frame pumps (the x stands for numbers 1-5 and denotes the length of the pump to fit the particular size frame). The other two pumps are the Silca frame pump and the Rhode Gear double action frame pump. The Silca fills the fastest but is a tricky pump to use and it requires quite a bit of arm strength to get to over 100 lb.s. The Rhode Gear has the lightest handle pressure but the angle of the head and the rubber washer leaves quite a bit to be desired. The Zefal is has the best filler attachment and an effort about half way in between the other two.
Never put on the filler lock nut before you fill the tire. A locked filler and a rocking motion of the pump can break the filler off of a tube. Without the nut the whole tube rocks inside.
I've found that with a Zefal I have to put in at least 80 strokes before the tire is hard enough to ride. Arghhhhh. I REALLY hate pumping tires up but CO2 cartridges don't get a road tire hard enough for my weight and if you make the mistake of using a larger capacity (offroad volume) cartridge you end up with an exploded tube and possibly tire with a broken bead.
After about 20 strokes on the pump look carefully around the bead section to make sure that you didn't catch the innertube under the bead of the tire and it isn't beginning to show signs of lifting. If it is immediately release all the air.
You get the innertube out from under the tire bead by pushing down on the tire, pinching as if to grab the tube and sort of pulling and rotating in such a manner to pull the tube into the tire inside diameter. This is sometimes a long and frustrating exercise but keep at it. You should be able to push the tire away from the bead all the way around the rim on both sides and not see the innertube anywhere.
Fill the tire to riding pressure.
8) When you are installing the tire back into the bike follow the proper procedure. On the back wheel insert the chain onto the smallest cog (remember that you previously shifted the bike into this gear), align the tire between the brake shoes, avoid any speedometer pickup, reach down and pull the rear derailleur back while rotating the lower section backwards. If all goes well the wheel will flop into the dropouts. You then need to make sure that the tire is aligned between the chain stays and tighten the quick release. Quick releases should be tight enough so that you have to push them on, but not so tight that after they've been on for 5 minutes you can't release them by hand. Better a little loose than too tight.
All that remains is to make sure that the speedometer pickup hasn't been knocked too far out. Spin the wheel to make sure that it is correctly aligned and then set the brake release to its operating position. ALWAYS test the brake before you try to use the bike.
All of this sounds very difficult, but in most cases its a ten minute job at worst and you can practice it to the point where you can go from flat to riding again in less than 5 minutes.
A friend standing along side could even repair the old tube while you are fixing the flat and you could insert the repaired tube back into the seat pack rather than carrying a tube needing repair in your back pocket.
Happy riding and avoid all that road debris.
"Tom Kunich" <tkunich@diabloresearch.com> 12/14/99
To Summer of 2000 Newsletter
