Once you have a flat, it's important you know what you are looking for to be sure you don't have another one. Generally, if you have several flats in a short period of time, you didn't fix the first one.
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You’re riding along on a nice country road. The birds are singing, the sun is shining, and you have a nice quartering tailwind when all of a sudden…POW! You have a flat! Of all the mechanical problems you may have on the road, flat tires will be the most common. It is an irritant, but it doesn’t need to be a recurring problem. How many of you have known someone who had several flats in one day? On our cross country last year we had a guy who had 8 in one day…needless to say, he spent more time fixing flats than he did riding. And if he’d been more diligent when he fixed the first one, the other 7 wouldn’t have happened. This month I’ll discuss several types of flats and how to identify them (which is the first step in the repair process) and next month I’ll discuss how to avoid them in the first place…or at least lower the probability of having one. Also for the sake of discussion, I’ll assume that you know the basic procedure of repairing a flat tire—getting the tire off, repairing/replacing the tube, and replacing the tire on the rim. If you don’t know how to change a flat, you need to carry a cell phone or money to call a cab…then enroll in the effective cycling class the next time it’s offered.
A good indicator of what type of flat you have is how it sounds when it goes flat…did it go psssssssssss and just go flat, or did it go POW! Silly question you might say, but HOW your tire goes flat may give you hints on what to look for when you’re repairing your tires. There are basically three types of flats: punctures (to include pinch flats), blowouts, and deterioration.
Punctures usually go psssssss as it goes flat or it will just sneak up on you as it goes flat slowly. One type of puncture is caused when foreign material (a piece of glass, a nail, or a piece of wire, etc.) penetrates the tube. If this happens look carefully for whatever caused the flat and remove it from the tire or it will obviously cause another flat after you fix the first one. If you had the tire label aligned with the valve stem of the tube, it will help you locate problems. Always mount your tires that way for a frame of reference just for this purpose. Partially inflate the damaged tube to find the leak. Then simply look for the problem in the corresponding location on the tire. Or if you see something sticking out of the tire it may help you find the hole in the tube…which is sometimes so slight, it’s tough to find. My friend on the cross-country last year couldn’t find anything in the tire but kept having flats anyway. He kept flagging down the mechanics van and replacing the tube…had he noticed the damage was always in the same place on each tube and the damage was on the underside of the tube, he would have discovered a damaged rim tape was the culprit. If the tape that covers the holes in the rim becomes misaligned, it will cause a hole to be pinched in the tube. You should realign the tape or use a piece of the electrical tape from your handlebars or a folded Power Bar wrapper to repair the rim tape by covering the spoke hole. Another type of puncture is the dreaded pinch flat or "snake bite." Like the rim tape problem, you’ll not find any foreign material to remove…you’ll just find holes in the tube. A snake bite will always be on the underside of the tube and will generally be two, side by side puncture holes…like snake fang holes. This is caused by hitting a pothole or possibly a rock. This pinches the tube against the rim and even though there is foreign material involved (usually something you ran over), you won’t find it stuck in the tire…you just hit it. You’ll usually know when you have done something to cause this type of flat…by the THUNK! As a side light, pinch flats are better avoided if you keep proper tire inflation as you ride.
If your tire goes POW, you’ve had a blowout. When this happens, you generally should find a big hole in the tire someplace, usually in the sidewall, that will need to be booted to allow you to get home. After you get home you should replace the tire as soon as possible. Boots are temporary fixes to get home, but I must admit, I’ve ridden over 3000 miles on a booted tire (not a front tire). What, you don’t carry something to boot a tire with you on every ride? A folded dollar bill makes a good boot…or a twenty dollar bill will work too. It just depends how much you’re willing to spend to get home…you’ll get it back when you change out the tire when you get home. Also, I’ve found that a folded Power Bar wrapper makes an excellent tire boot. So next time you think about throwing away that used wrapper, fold it and put it in your tool kit instead. Just fold it into about 4-6 layers and it will hold forever! There are cases where you will have a blowout and not find a tear in the tire. Sometimes the tube gets between the tire and the rim (due to improper mounting) and doesn’t blow right away…it will wait till the time is right…when you are 30 miles from home perhaps. But if you don’t find a tear, inflate the tire slowly and visually check the sidewalls as you go. If you had a tear that you missed, you’ll see the tube start to poke out…in this case, deflate immediately and boot the tire.
Deterioration flats can go psssss or POW. Age plays havoc with your rubber and it will simply wear out and won’t hold air over time. When checking for deterioration, you should inspect for cracks in the casing, cuts, cord showing through, or bulges in the sidewall. Minor cuts in the tread usually aren’t serious if it doesn’t include the casing. But leaving them unattended can cause problems too. Small items may become lodged in the hole and eventually wear into the tube. Repair small cuts with a rubber compound like "Shoe Goo."
If you haven’t ridden in a couple of years and you dust off the old bike and pump up the tires you may be in for a surprise. You should check your tires regularly at home for wear, weather rot, or foreign material. It’s much easier to find the problem at home where you can fix it in the comfort of your air conditioned den then to fix a problem when the heat index is over 100 on the road around here. Replace any badly worn or rotted tires or tubes to prevent these problems.
By knowing what caused your flat tire, you are able to better determine if you should find something in the tire or whether you should find a tear in the tire. By identifying the cause of your flat you may prevent recurring problems down the road. I hope this info will help you the next time you have a flat…and you will have them. Oh yeah, always get completely off the road to fix your flats…or you may be flat yourself! Keep cycling and keep the rubber down! Mike
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