Monday, February 3, 2014

Flat tires!

Flat tires are a constant struggle for most cyclists or all stripes. When you get a flat tire, you need to figure out WHY you have a flat before replacing the tube. If you get a flat and don't remedy the reason you got a flat in the first place, it will just happen again. Sometimes your new tube will go flat ten seconds after you pump it up, so figure out the WHY of a flat before you proceed. Here are some examples:

*Two small "snake bite" punctures near each other- This is the most common flat you will get on a BMX bike and it is caused by an under-inflated tire, or you hit something REALLY hard. I would never recommend riding a bike with tire pressure lower than 65 psi. Most riders use around 90 and some go to 110-120. If your tire pressure is too low, your rim will bottom out on a landing and pinch the tube, leaving the telltale "snake bite" marks on your tube. Installing very large-volume tires on your bike will reduce the chance of pinch flats.


*Small hole, puncture- something sharp pushed it's way through your tube and popped it. You have a sharp object such as a thorn, wire, or bit of glass stuck in your tire, or if you have a single-wall rim, your rim strip is not covering your spoke nipples or you don't have one at all. Find the offending object and pry it out before it assassinates your next tube. If the end of your spoke is poking your tube, you will need to cover the spoke ends with some thick rim take. your local bike shop will sell you a roll of this for a few bucks, but several layers of electrical tape or that fancy Gorilla tape will work in a pinch. You can patch the tube or replace it, depending on your skills with a patch kit and how big the hole is. These are usually small holes.


*Explosion, long split in tube- Your tire bead slipped off the edge of the rim and the tube popped out and exploded. There was likely a loud, terrifying bang associated with this. This could be due to you not centering the bead of the tire on the rim, the bead of the tire is damaged, or the outer edge of the rim is damaged. Find out what it is and proceed. If the tire bead is badly damaged, you are probably going to have to replace the tire. if you are far from home and need to pedal somewhere, you might be able to pump up a new tube to a low pressure and hobble home.


*Star-shaped hole- If you have a double-walled rim, this can happen if you don't have a sturdy rim strip in your rim, or you don't have one at all. Or you have a sizeable hole in the tread or side of your tire.The tube bulged through the hole or the outer wall of the rim and exploded. Get a good rim strip (not some cello tape) on your rim before putting a new tube in there. Rubber rim strips do NOT hold up under pressure, so get a decent stiff plastic strip or a fabric strip like Velox or various BMX companies make. If there is a large hole in the tire, you can put a "boot," or sturdy patch inside the tire, but you will probably need to replace the whole tire soon.


*Rip near valve- You have a faulty or old, decayed tube, or you ripped it by pulling too hard on the valve to disconnect your pump. Not much you can do here but replace the tube.


Patch kits are a great way to save a lot of time and money on tubes. The vulcanizing compound that comes in a little tube from a decent patch kit makes a permanent bond if you do it right. The key is the clean the area where the hole is, spread a THIN layer of rubber cement on the area, then let it dry for 5-10 minutes. Then smash the patch on the area, squeeze out any possible bubbles under the patch, and hold it there for a few seconds. Ta-da! just like new.


I highly recommend that every rider carry the following in a backpack or something to deal with flats so you don't have to end your session early or walk home while carrying your bike:

1. spare tube and patch kit. These cost a few bucks and are small. No excuse.
2. tools to remove either or both of your wheels. If you have pegs, you will probably need a socket and extension to loosen the nuts inside the pegs. This makes for a heavy, clumsy toolkit, but it's better than carrying your whole dead bike around. DK and Animal bikes make BMX multi-tools that make it easier to carry all the tools you need in a convenient package. If you are shopping for new hubs, consider a hub that has broached bolts instead of traditional axle nuts, so you can use an allen wrench to loosen your wheels.
3. Mini-pump, or at least some change to run a gas station pump. You can get a min-pump at any bike shop for under $20. It slips in your backpack, but it takes a long time to pump up. Most gas stations have coin-operated air compressors, but if you ask nicely, sometimes the clerk in the station will turn it on for you. (Don't leave your bike outside while you go in to ask, your bike will get stolen!)
4. Some cash and a cell phone. You can probably go into any department store or bike shop and buy a tube and pump up your tire there. (Again, don't leave your bike unattended outside, it will get stolen within 30 seconds!) Maybe the bike shop will let you borrow a tool to do it, but don't be surprised if they tell you they can't. You can use cash for a bus ticket home if you're stranded, to buy a new tube, or a get a snack when you're hungry. When all else fails, call a friend for a ride home.