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Kapitelüberschriften und Struktur
(Kapitelstruktur logischer aufgebaut) |
(Kapitelüberschriften und Struktur) |
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Make sure to check the brakes after you have re-installed the wheel, especially if you disconnected it or used a quick release to help remove the wheel. | Make sure to check the brakes after you have re-installed the wheel, especially if you disconnected it or used a quick release to help remove the wheel. | ||
== | ==Prävention== | ||
Many flat tires are avoidable, but some are not. Some people seem particularly prone to them. This is often caused by poor road position: people who get an unusual number of flats often do so because they are riding in the gutter instead of the traffic lane. | Many flat tires are avoidable, but some are not. Some people seem particularly prone to them. This is often caused by poor road position: people who get an unusual number of flats often do so because they are riding in the gutter instead of the traffic lane. | ||
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Riding too close to the curb also, paradoxically, increases your risk of being hit by a car! By cowering in the gutter, you reduce your visibility. You also encourage motorists to pass you even when there is insufficient room to do so safely. You also reduce your maneuvering room, and may have nowhere to go if evasive action is required. | Riding too close to the curb also, paradoxically, increases your risk of being hit by a car! By cowering in the gutter, you reduce your visibility. You also encourage motorists to pass you even when there is insufficient room to do so safely. You also reduce your maneuvering room, and may have nowhere to go if evasive action is required. | ||
=== | ===Reifendruck=== | ||
Tire pressure is the hardness to which a tire is inflated. This is commonly measured in PSI (pounds per square inch), BAR, or kPa (kiloPascals.) | Tire pressure is the hardness to which a tire is inflated. This is commonly measured in PSI (pounds per square inch), BAR, or kPa (kiloPascals.) | ||
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For details on optimal tire pressure, see the "Pressure" section of my Tires Article. | For details on optimal tire pressure, see the "Pressure" section of my Tires Article. | ||
=== | ===Luftlose Reifen=== | ||
Of all the inventions that came out of the bicycle industry, probably none is as important and useful as Dr. Dunlop's pneumatic tire. | Of all the inventions that came out of the bicycle industry, probably none is as important and useful as Dr. Dunlop's pneumatic tire. | ||
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Airless tire schemes have also been used by con artists to gull unsuspecting investors. | Airless tire schemes have also been used by con artists to gull unsuspecting investors. | ||
=== | ===Pannenschutz-Einlagen=== | ||
Aftermarket tire liners, such as the well-known Mr. Tuffy, are not necessary for most cyclists. They make your wheels heavy and sluggish, and, if incorrectly installed, they can actually cause flats! | Aftermarket tire liners, such as the well-known Mr. Tuffy, are not necessary for most cyclists. They make your wheels heavy and sluggish, and, if incorrectly installed, they can actually cause flats! | ||
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* Kevlar-belted tires have a layer of kevlar under the tread surface, with the purpose of making the tire more resistant to punctures caused by small sharp objects, such as thorns and glass slivers. Kevlar-belted tires have slightly higher rolling resistance, price and weight than corresponding tires without the belt. | * Kevlar-belted tires have a layer of kevlar under the tread surface, with the purpose of making the tire more resistant to punctures caused by small sharp objects, such as thorns and glass slivers. Kevlar-belted tires have slightly higher rolling resistance, price and weight than corresponding tires without the belt. | ||
=== | ===Pannensichere Schläuche=== | ||
In some regions, notably the Southwestern U.S., cactus thorns are so common that special "thornproof" inner tubes are needed. These tubes are very thick on their outer circumference, so that a short thorn (or a small glass sliver) may be embedded in the tube without being able to reach in far enough to let the air out. | In some regions, notably the Southwestern U.S., cactus thorns are so common that special "thornproof" inner tubes are needed. These tubes are very thick on their outer circumference, so that a short thorn (or a small glass sliver) may be embedded in the tube without being able to reach in far enough to let the air out. | ||
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Thornproof tubes are heavy, and add to rolling resistance, so they are a poor choice for cyclists who don't ride in conditions that require them. See also tire liners. | Thornproof tubes are heavy, and add to rolling resistance, so they are a poor choice for cyclists who don't ride in conditions that require them. See also tire liners. | ||
=== | ===Reifenschützer=== | ||
Some punctures are caused by glass slivers or thorns gradually working their way through the tire tread. What can happen is that a small sharp object may be picked up by the tire, then gradually work its way in over the course of several tire revolutions. The pointy thing is driven in like a nail into wood by repeated blows against the pavement. A formerly popular device called a "tire saver" or "flint snatcher" used a loosely spring piece of wire (generally made from a bicycle spoke) to constantly brush the tire tread in hope of dislodging glass slivers and the like before they could penetrate all the way to the inner tube. | Some punctures are caused by glass slivers or thorns gradually working their way through the tire tread. What can happen is that a small sharp object may be picked up by the tire, then gradually work its way in over the course of several tire revolutions. The pointy thing is driven in like a nail into wood by repeated blows against the pavement. A formerly popular device called a "tire saver" or "flint snatcher" used a loosely spring piece of wire (generally made from a bicycle spoke) to constantly brush the tire tread in hope of dislodging glass slivers and the like before they could penetrate all the way to the inner tube. | ||
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These are of dubious value in practice, but may be of help in backward areas where throwaway beverage bottles are still legal, and glass slivers are a major problem. | These are of dubious value in practice, but may be of help in backward areas where throwaway beverage bottles are still legal, and glass slivers are a major problem. | ||
==Werkzeuge== | |||
===Druckmesser=== | |||
Pressure gauges come in 3 types: | |||
* "Pencil" gauges are the simplest and cheapest. They look like a pencil, with a fitting at one end that you can press against the valve. When you do so, a rod slides out of the other end. This rod is calibrated like a thermometer, and slides out farther the more pressure is in the tire. This type is most commonly used for Schrader valves (though Presta versions are also available.) Note that "pencil" gauges come in automotive and bicycle types. The difference is the pressure range they measure. Automotive pencil gauges commonly only read up to 50 PSI, while those intended for bicycle use run up to 120 PSI. | |||
* "Dial" gauges are a bit more expensive, but are easier to read and may be a bit more accurate. Some dial gauges have double fittings, allowing the same gauge to work with both Schrader and Presta valves. Less expensive dial gauges must be read while they are on the valve, but better ones have a "memory" feature, and will hold their readings after being removed from the valve, until the "reset" button is pressed. | |||
* "Digital" gauges have a liquid-crystal readout, and an electronic sensor. They are probably the most accurate, though real-world accuracy of any type of gauge is limited by the fact that a small amount of air is lost as the gauge is removed from the valve. | |||
===Ventiladapter=== | |||
If you have Presta valves, it is a good idea to carry a Schrader/Presta adpator | |||
===Pumps=== | |||
You have 7 possible choices of tools to inflate your tires: | |||
====CO2 Patronen==== | |||
CO2 cartridges are small cylinders of carbon dioxide, originally made for seltzer siphons. With a suitable adaptor, they can be used for inflation of bicycle tires. When everything goes well, this is the fastest way to inflate a tire. They're also the lightest and most portable inflation device available, so they're fairly popular among competitive cyclists. | |||
The down sides of CO2 cartridges are that they are expensive and wasteful, and that each cartridge is normally only good for inflating one tire one time. While a few of the cartridge systems do permit controlled release of CO2, most of them are "all or nothing" designs, so you can't use them for topping off a slightly soft tire. If you carry only one cartridge and get two flats on the same ride, you may be in for a long walk. I advise against relying on CO2 cartridges except in competition. | |||
====Kompressoren==== | |||
Compressors are a popular alternative, when available. Most gas stations will have a compressor available, either for free or coin operated. While these are convenient, they can also be dangerous. If you use a gas-station compressor, be sure to use a separate, hand-held pressure gauge, because if you rely on the gauge built into the compressor outlet, you risk blowing the tire off the rim. | |||
The typical gas-station compressor has a head with a crank on it. You turn the crank to set the display to the desired pressure value in PSI. As air flows into the tire a bell rings. Each time the bell rings, the gauge checks to see if the pressure in the tire is more or less than the desired pressure. If it is more, the flow is stopped. | |||
The problem with using these gauges for bicycle tires is that the volume of a bicycle tire is so much smaller than that of a car tire that the difference from one "ding" to the next can be 20 psi or so. If you set the dial to 100, the air will go "ding...ding...ding..." then there's, say, 99 psi in the tire. This is under 100, so it'll give it another blast and check again, and your tire could well be close to 120 psi. This assumes that the gauge is accurately calibrated for pressures in this range, which is a big assumption. The bottom line is that you really can't trust these gauges for bicycle tires. Instead, you should use a separate, hand-held gauge. | |||
====Standpumpen==== | |||
The most effective human-powered inflation tool is the "floor" or "track" pump. This has a long vertical cylinder, with a "T"-shaped handle that you raise and lower with both hands. This type of pump has some sort of footrest to keep the bottom held in place, and a hose that connects to the valve. Floor pumps get most of their action from the user's back, and with an assist from gravity, as the actuall pumping occurs on the down stroke. | |||
The better floor pumps have built-in gauges and holding tanks, so you can see just how much pressure you've got, while you're pumping. This makes them very fast and convenient to use. | |||
====Fußpumpen==== | |||
An less-common type of pump, similar to a floor pump, also sits on the ground, but is operated by pressing with the foot. These are fast, but mechanically complex due to the extra linkages required. They also tend to be designed more for delivering volume than for pressure, so they don't generally pump up to high enough pressure for narrow road-type tires. | |||
====Handpumpen oder Rahmenpumpen==== | |||
"Frame" pumps are portable pumps designed to be carried on the bicycle's frame. They are typically about as long as one of the frame tubes, and have a spring-loaded handle that holds the pump in place along one of the frame tubes. Older bikes often had two brazed-on "pump pegs" to secure the ends of a frame pump. Many newer bikes have a single peg just below the top tube on the back of the head tube, for a pump running below the top tube. | |||
Frame pumps are the best thing to carry on the bike for emergency, on-the-road use. They take a fair amount of work to get up to full pressure, but it beats walking! They pump fairly easily at first, but they can require a fair amount of strength as the pressure gets high. | |||
=====Handpumpentechnik===== | |||
As you pump your tire up closer and closer to full inflation, the pump gets harder and harder to push. This is particularly an issue with narrow tires that need to be pumped up to high pressures. | |||
Your arms may not be strong enough by themselves to get such a tire up to adequate pressure. Assuming you're right handed, it can help to brace your left hand or the pump head. If there's a convenient tree, I'll often lean the pump head against the tree, so my left arm doesn't actually need to do any work. If there's no suitable tree or other solid object handy, or if I'm topping off a tire without removing the wheel from the bike, I'll kneel on my right knee and brace my left wrist against the indside of my left knee. | |||
As I approach full inflation, and the pump gets harder to push full stroke, I will start each stroke with my right arm free, then brace my right wrist against my chest for the final, hard part of the stroke, and use my back to complete the stroke. | |||
With any type of pump, it is very important that the pump be pushed all the way to the end of its travel on each stroke, otherwise you're wasting most of your effort. | |||
=====Eine ist nicht genug===== | |||
A frame pump is not a substitute for a good floor pump; the well-equipped cyclist will own both. The floor pump is for routine pressure topping off at home, and the frame pump is for fixing flats that occur while you're out riding...they're too hard to use for non-emergencies. | |||
====Minipumpen==== | |||
The most popular type of pump these days is the "mini" pump, a pocket-sized version of a frame pump. People like them because they're small and easy to carry, but they take much longer to use than full-sized frame pumps. I generally advise against buying a mini pump unless you have particular issues with theft, because they are so inefficient. Their main advantage is that they are small enough to be carried in a bike bag that you can remove when parking in high-risk locations. | |||
===Reifenheber=== | |||
Traditional tire levers, a.k.a. "tire irons" came in sets of 3, with a rounded business end, and a bent, hooked end for hooking onto a spoke. Newer ones are fibreglass or similar materials. I have an assortment of them for different tires. For very tight fitting tires, you need tire levers with thin ends, able to get underneath tight beads. | |||
For less difficult tires, a single tire lever with a rounded, grooved end can be faster. I particularly like the "Quick Stick." | |||
A similar unit, the Crank Brothers "Speed Lever" incorporates a telescoping extension that snaps onto the axle. This works very much like the power tools used in garages for mounting/dismounting automobile tires. This doesn't work too well on very tight tires, but on average tires, it is quite fast and easy to use. | |||
The Kool Stop "bead jack" is an articulated tool for installing really tight tires. It has a comfortable handle and two ends, one of which is on a hinge. The rigid end uses the edge of the rim as a fulcrum, while the hinged end lifts the bead up and over the opposite edge of the rim. This is a very nice tool for dealing with really difficult tires. | |||
'''''Bilder von verschiedenen Reifenhebern''''' | |||
===Flicksets=== | |||
Patch kits are available in any bike shop. A patch kit is usually a small plastic box containing a few patches, a tube of rubber cememnt, and a bit of sandpaper or a metal scraper for preparing the tube surface. The best patch kit is the Rema "Tip Top" from Germany. | |||
Make sure to follow the instructions. | |||
====Glueless Patches==== | |||
Glueless (peel & stick) patches are avaialble, and they are slightly more convenient than conventional patches. Unfortunately, they don't have a very good reliability record, and I can't recommend them--you're much better off with a standard patch kit. | |||
===Schraubenschlüssel=== | |||
Unless your wheels have quick release hubs, you'll need a wrench or two to remove the wheels. (The term "wrench" is not common in British usage, where the term "spanner" or "key" is generally preferred.) | |||
Wrenches are divided into two families: | |||
====Feste Schraubenschlüssel==== | |||
Fixed Wrenches are made of a single piece of metal, and only fit specific sizes of fasteners. Types of fixed wrenches include: | |||
* Box wrenches have a complete loop that surrounds the fastener. They are substantially stronger than open-end wrenches, and are the best use for high torque applications, both because the wrench is stronger, and because it can contact more than two corners of the fastener. | |||
* Open-end wrenches have ends shaped like a two-tined fork. They normally have two parallel surfaces which bear against two of the sides of a fastener. Open-end wrenches are faster to put on to fasteners, and are the only kind that can be used where there is not clearance to slip a box wrench over the end of the fastener. Open-end wrenches don't get as good a grip as a box wrench, since they only engage two of the 6 corners of the nut. If you over-stress an open-end wrench, the jaws can spread, ruining the wrench. | |||
* Combination wrenches are double-ended wrenches with an open end and a box end, usually for the same size on each end. This is the most useful and most common general-purpose wrench style. | |||
====Verstellbare Schraubenschlüssel==== | |||
Adjustable Wrenches can be adjusted to fit different sized fasteners, usually by the use of a thumb screw. They don't fit as well as the correct size fixed wrench, so good, well equipped mechanics only use them as a last resort. See my Tool Tips article on Adjustable Wrenches. | |||
Wrenches are sometimes confused with pliers, and naive users sometimes try to use pliers for jobs that really require a wrench. This usually results in damage to the nut or bolt so abused. It can also cause failure due to undertightening the part involved. | |||
== Quellen == | == Quellen == | ||