The Spoke Curriculum - Session 1: Difference between revisions

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The Spoke Curriculum - Session 1 (view source)

Revision as of 05:07, 16 February 2012

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=== Description ===
=== Description ===
Discuss ways to best diagnose: on the bike, off the bike


=== Details ===
=== Details ===
On the bike tells many things that you can't tell off-the-bike: a sound every pedal stroke, or problems only when torqueing, etc. Off-the-bike lets you actually see and feel things.


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=== Content ===
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Diagnosing mechanical problems is a skill that becomes easier as you gain experience with the different repairs that a bicycle might need. Asking experienced mechanics is often very helpful, but even they may not always be able to correctly identify a problem immediately.
Some problems are only apparent while riding a bicycle. For example, if an unusual noise is repetitive, occurring with every pedal revolution,  the problem could be in the crankset area (pedal, bottom bracket, or chainring). A noise every second or third revolution might be in the chain, such as a stiff link. Ask yourself if the noise occurs when pedaling only or when coasting, and note if the noise occurs under load, such as on a hill or if you hit a bump.
The first step to examining a bike is to ask the owner if they've noticed any issues while riding. Does the chain fall off? When (e.g. only when they're shifting and climbing a hill?), and in what gear? Do the tires hold air? How does it shift? Brake? Do the brakes squeal? Are there any other noises?
If the bike is safe to ride, and the tires have adequate air pressure, you can take the bike for a test ride yourself. Often this is not possible or necessary until after some repairs have been made first.
With the bike in a repair stand, you can also visually inspect the bike for problems, test shifting, and feel for loose or overtight adjustments. This is where you can often pinpoint the source of problems that you felt or heard while riding.
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== Tools ==
=== Description ===
Show tools, explain importance of using the right tool to not damage tool or bike
=== Details ===
Tools can be expensive, some are speciality, some are general. Metric vs. imperial? Use the right size: smallest wrench possible, biggest screwdriver possible.
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Bicycles use both common tools such as screwdrivers, wrenches, and hex wrenches (allen keys), as well as specialty bike tools. Tools can be very expensive (hundreds of dollars for a single tool), and improper use can wreck a bike, wreck a tool, or cause injury, so it's very important to use the right tool.
Almost all bicycles (with the exception of some very old, usually English bikes) use metric nuts and bolts. You should avoid imperial-sized (inches) tools, as even if they seem to fit, trying to use them will usually cause the damage to nuts and bolts, rounding them off and making them impossible to remove. You should also avoid using an adjustable wrench wherever possible, for the same reason.
When using wrenches, use the smallest size that will fit over the bolt head/nut. Make sure it is on fully before turning. This will prevent it from slipping. Hold the wrench for good mechanical advantage, and watch where you place your hands, so that if the tool moves suddenly while you're applying force (torque), you won't injure yourself.
When using screwdrivers and hex wrenches, use the largest one that will fit properly. Using smaller screwdrivers or hex wrenches can strip the bolts.
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== Repair stand ==
=== Description ===
How to use the repair stand
=== Details ===
Don't overclamp, clamp on the seatpost if possible. Ask what happens if you clamp a cable. Driveside out.
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! scope="col" | Instructor Notes
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Repair stands are the basic piece of equipment for a bike shop. They allow bikes to be raised or lowered and rotated, and make repairs much easier. Some adjustments (brakes and shifting) can only properly be done in a bike stand, and not with the bike upside-down.
Clamp the bike using the seatpost, if possible. You may have to raise the seat to do this. Ensure that the seatpost is clamped tightly in the bike frame, so it doesn't slip out while you're working on the bike!
If you can't clamp the seatpost, clamp on an area of the frame that won't interfere with your repairs. The pedals should turn freely (without hitting the stand), and the clamp shouldn't compress any cables or cable housing. Most repair stand clamps have a groove for cables to pass through without being compressed by the clamp, but it's still best to avoid clamping over cables, since this can get in the way of replacement or create problems if the cable doesn't move freely.
Don't overtighten the clamp. You should be able to close it with two fingers! Overtightening the clamp can crush a bicycle frame, permanently ruining it.
When you put a bike in a stand, have the driveside (the chain side) facing out, since you'll need to see and access this side to work on it.
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== ==
== Picking a bike ==


=== Description ===
=== Description ===
Students select a bike. Size, style.


=== Details ===
=== Details ===
Proper bike fit is important, especially for larger bikes. If you don't like the bike to start with, you won't want to ride it.


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The most important thing about selecting a bike is that you should want to ride it. If you don't want to ride a particular bike when you see it, you should pick a different bike.
Once you find a bike you like, you need to make sure it fits you. If the bike is too large, it will be unstable when you ride it, and can cause knee and back injury. You can also injure yourself if you slide off the saddle and land on the top tube. A bike that's too small can also cause knee pain, as well as being inefficient to ride (i.e. you have to work harder to go places, and you can't go as fast).
When your saddle height is set correctly, you should have a 5-10 degree bend in your knee at the lowest point of your pedal stroke. Check this while sitting in the saddle with both feet on the pedals: use a workbench to help balance. If you place your heels on the pedals at the lowest point (instead of the ball of the foot), your leg should be nearly fully extended. You shouldn't be able to place your feet flat on the ground while you're seated.
After adjusting the saddle height, see how the bike feels with your hands on the handlebars. Have someone help stabilize the bike for you. Make sure you don't feel like you're overreaching or crouched too much, nor that you're cramped from a bike that's too small. You will be able to make some adjustments to the handlebar height, but generally not more than a couple centimetres.
Now that the you've found a bike that fits, visually inspect the frame for damage. Rust is okay, but any cracks in the frame (especially near the joints) make the bike unsafe. Dents in aluminum frames are also unsafe. Dents in steel frames require a judgement call. You can tell steel frames from aluminum with a magnet: magnets will only stick to steel parts on a bike.
Look at the fork to see if one side is misaligned with the other, or if the entire fork has been bent backwards from a crash. Look straight down the bike to see if  the frame is obviously out of alignment.
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Traditionally, a bike frame is measured along the seat tube of the bike frame, from the centre of the bottom bracket spindle (where the cranks attached) to the middle of the top tube. This is only appropriate for bikes that have horizontal top tubes (level with the ground). On such a bike, the rider should generally have about 1-inch of clearance between the top-tube when standing with both feet flat on the ground.
Many modern bikes, as well as smaller bikes, have top tubes that slope down toward the seat tube, so bicycle manufacturers give frame sizes that don't necessarily correspond to any direct measurement of a bike. These measurements can vary between manufacturers, further making comparisons difficult.
Forward reach, standover clearance, and comfort are the main factors to observe when sizing a bike for an individual. With the saddle is properly adjusted, the person should be able to steer without risk of hitting their knees on the handlebars, nor should the elbows be fully extended.
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== ==
== Diagnosis ==


=== Description ===
=== Description ===
Retrieved from "https://apps.bikeedmonton.ca/w/Special:MobileDiff/949"

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