There are probably thousands of great tips for changing tires and fixing flats, just as there are thousands of horror stories for flats. I once spent over an hour at a rest stop near Columbia, TN, going through five tubes changing a flat. David Bauer's flats fiasco at Paris-Brest-Paris in 2007 are almost the stuff of legend. I invite everyone to post their "favorite" flat tip or horror story below, primarily because misery loves company.
An Ounce of Prevention
First, be prepared. Before you go for a ride, make sure that your tires are inflated properly.
How much is "proper," you ask? That depends. You want enough pressure that hitting a pothole will not deform the tire and tube to a degree that the rim will hit, because this is how you get a pinch flat. However, you don't want so much pressure that you blow the tire off the rim, or that you even make your ride horribly uncomfortable and immediately sell your bike on eBay ... although, this would keep you from having any more flats.
Play with your tire pressure until you find the right balance. Then, be willing to adjust it when the weather changes and you are wearing and/or carrying more/less, or when you go on a tour and pack 45 pounds in your panniers, or after a huge Christmas dinner at Aunt Myrtle's. That 95 psi sweet spot may need to go over 100 when you're fully loaded.
Second, use the right tires. I love Continental Ultra Gatorskins -- particularly 700x25Cs. They are wonderfully puncture-resistant, have a great tread, the sidewall is very strong, and they don't weigh so much that you feel like you're riding through sand. I can only fit up to 25Cs on my Lynskey, or I would be tempted to run something wider.
Max Watzz does not use Gatorskins. Why? Because he's never so far from home that a serious cut in his tire will give him trouble. He has RandoGirl on speed-dial, and since he's cuter than I am, she will even go fetch him.
Third, bring the right stuff. For a 200K or less, bring at least one spare tube, a patch kit, a C02 inflator, two cartridges, and a tire lever or two. Put these in half of a tube sock, and stuff it all in the under-the-seat bag. The half-sock will keep things tidy and organized, gives you something to wipe your hands on afterwards, and can help you diagnose the issue.
What about a boot, you ask? If you're just doing a 200K, you can usually make your own boot from stuff along the side of the road, a dollar bill, or a gel wrapper, so you may not need to bother.
For longer rides, bring more stuff. If I'm going over 200K, I put my Arkel Tail Rider on the rear rack. In there, I keep two more spare tubes (in their own socks, thank you very much), rubber gloves, a "real" patch kit (with glue and everything -- as opposed to the instant patches in the under-the-seat bag), and a boot. I also carry the frame pump on longer rides, since this keeps me from worrying about running out of C02 cartridges.
After last weekend, I'm adding a spare folding Gatorskin and rim tape. Better to have it and not need it than to need it and not have it.
A Pound of Cure
So now you're prepared. This doesn't mean that you won't get the flat, of course. Even Gatorskins are only puncture-resistant ... not puncture-proof.
When you flat, here's how you fix the tire in such a way that (hopefully) it will stay fixed.
- If the flat is on the rear wheel, shift into your highest gear.
- Hang the bike by it's saddle on something, lay it on it's side (drive side up), or let a friend hold it. Do not turn your bike upside down. It can scrape up your brake hoods, get dirt in your shifters, and does not look "pro."
- Open the brakes, flip open the quick-release, and remove the wheel.
- Let the rest of the air out of the tire.
- Hook the "scoopy" side (not the hook side on Park or the slotted side on Pedro's) of the tire lever under the bead, grab the tire right next to this with your free hand, and then push the tire tool away from you so that it continues to run under the bead. On Mavic Open Pro rims and Gatorskins, this will unseat the bead from the rim as you go along. On other tires and rims, it may not. Sorry about that.
- Leave the other bead of the tire on the rim for now, and pull the tube out. I like to start at the tube stem, but it's up to you.
- Find the hole in the tube. If this is a huge gaping hole, thank your lucky stars that you didn't crash (if you did crash ... well, again, sorry). If it's not a big hole, you may have to pump some air into the tube and listen for the "hssssss." Sometimes you can work the tube around and feel the air on your cheek, and sometimes just the act of working the tube around in your hand will put a finger over the "hsssss" and turn it into a whistle.
- Is it one hole or two? If there are two holes next to one another -- so that it looks as if a snake bit your tire -- it was probably a pinch flat. These are caused by not having enough air in the tire for the road surface, or just hitting a pothole or rock or something really hard. Of course, it could have actually been a snake that bit your tire. A friend of mine in Florida had one try this -- the snake missed and did not fare well in the spokes.
- If it's one hole, figure out where the hole in the tube corresponds to the tire (if you're wondering how to know, I will give you a tip below). There should be a piece of glass, wire, rock, abalone shell, or something in the tire there. If not, it may have fallen out already. This happens, but will leave you feeling uneasy for at least 15 miles.
- If the hole seems like it would be more on the rim side than the tire side, pull the tire the rest of the way off the rim and check the rim.
- If you haven't found the problem in the tire and/or rim, you will have to feel for it instead. This is another time when that half tube sock comes in handy. Running that around in the inside of the tire and rim can keep you from getting cut by the wire, glass, etc. Even better, it will also often snag on the offending puncture-producer when you can't feel it, putting a thread "flag" on your problem.
- If you can remove the sharp thing, do so. If you can't, put something over it to protect the tube. This may be a boot, a cut-up old inner tube, a gel wrapper, a piece of a plastic bottle ... whatever will protect the tube without creating another hole.
- If you pulled the tire off the rim, put one bead back on. While doing this, ensure that the label of the tire (where it says Continental Ultra-Gatorskin 700x25C, for example) is centered above the hole in the rim where your inner tube inflation stem goes. Why? Because doing this lets you know how the tire was aligned with the tube the next time you have to find the piece of glass that flatted you. Also, it just looks more "pro."
- Put some air in the new tube (enough to give it a semblance of shape).
- Hold the wheel horizontal, with the "free" (e.g., loose) bead of the tire up.
- Put the tube stem in the rim hole, and slowly work the tube around so that it is now lying in the tire. Isn't that much easier when you hold the wheel horizontally?
- Starting anywhere (I like to begin close to the stem), use your thumbs to push the free bead of the tire in to be captured by the rim. Either work both hands outward from a single location, or keep a captured portion in place with one hand while you work around with the other. It's like tucking in a fitted sheet on a bed -- once you get half of it in, the rest will come.
- The last bit of the tire is usually more difficult. Use both thumbs if you can, or grab the wheel with your whole hand and use the bottom of your palms to push the last of the bead, rolling it over with your wrist as if you were kneading dough. As a last resort, you can use the tire lever, but I've had this ruin all my work by puncturing the tube and/or pinching it under the tire bead.
- Inflate the tire halfway, and then check to ensure that you got the bead seated under the rim all the way around the tire, on both sides. If not, you'll see a bulge. If you inflate it fully like this, the bulge can blow the tube. If it doesn't, it still makes for an uncomfortable ride. If there's a bulge, deflate the tube a bit and get the bead under the rim.
- With the tire properly seated, finish inflating the tube to the proper pressure, put the tire back on, close the brakes, close the quick release, make sure everything is spinning right, put all of your tools and stuff back where it's supposed to be, and ride on.
Patched tubes are the best things to carry on long rides, because as part of the patching process you will check to make sure that it holds air. We've all pulled tubes out of the box only to find that there was something wrong with them. Once a tube is patched, it is actually better than new.
Some other good references: