Bicycle Warranties
Most bicycle warranties are similar, at least for bikes sold in bicycle specialty stores. This information is general--it may not apply to your bike.
Warranties are from the manufacturer, not the bike shop. Consequential damages are not covered. In other words, you get no compensation for not being able to use your bike, and labor charges are not covered.
Frame Warranty
Most frames are warranted to be free from manufacturer's defects for the lifetime of the original owner. Labor charges are not covered.
The warranty only applies to the original owner. The manufacturer may refuse to warranty a frame unless you present the original receipt.
No one guarantees that you cannot break a frame--only that the frame is free from manufacturer's defects.
If a frame breaks at a weld, most manufacturers will warranty it. If a frame bends or breaks where there is not a weld, most manufacturers will not warranty it.
A frame is not defective if it breaks or bends because it is used for a purpose it was not intended. Examples of unintended purposes are:
using a road bike on a BMX track
off road cycling on a road bike
large jumps on any bike other than "big hit" bikes
banging any object (curbs) on a road or track bike
running into things, like trees, rocks and cars
dropping it
A frame is not defective if it bends or breaks due to improper component installation. If you build your own bike, you are responsible to install the components correctly. If your shop built it, it is responsible.
If the frame is damaged in shipping, it is not defective. The shipper is responsible.
Defective frames are rare. If your bike was built by a professional mechanic, he probably noticed any frame cracks, misshaped tubes, or crossed threads. If you are building your own bike, you should inspect the frame carefully.
A few frames break after repeated stress, but these breaks will be at welds.
If you believe your frame should be warranted, contact the vendor where you bought it. If you bought a bike in a bicycle specialty store, you can probably take a warranty claim to any store that sells the same brand.
Your bike store can tell you what to expect from the manufacturer. Some manufacturers will send a new frame at a store's request, and others require the store to send the frame back to the manufacturer for it to decide if the frame is defective. Some manufactures require the consumer to pay the freight charges. Bike stores usually charge for labor necessary to remove the original parts from the frame. The process can take a few weeks or a few months.
Manufacturers normally send a replacement frame. Sometimes it is impossible to get a new frame that exactly matches all the old components. The manufacturer may, but may not, pay for needed component changes. Bike stores usually charge for labor to rebuild the components on the new frame. Naturally, the shop that sold you the bike will be more cheerful about warranty claims.
Sometimes the manufacturer will offer the consumer a credit against the price of a new complete bike or an upgraded frame. If you are interested in an upgrade, ask your shop to try to negotiate one.
Bike Forks
Rigid steel and aluminum forks usually have the same warranty as the frame. Carbon forks are sometimes warranted for a shorter period, because they are more fragile.
Suspension forks are usually warranted against manufacturer's defects for either 1 or 2 years. Most bike manufacturers require the bike owner to refer suspension warranty issues to the fork manufacturer.
Suspension forks are warranted more than other components.
Most suspension manufacturers are good about replacing defective products. The major manufacturers will usually send a part or fork on a bike shop's request, but a few require the shop to send in the fork for the manufacturer to evaluate the problem. Freight to the manufacturer is the consumer's expense. Labor is not covered, but the shop that sold you the bike will often absorb the labor.
Components
Bike components are usually warranted for 1 year against manufacturer's defects. Valid warranty claims by consumers are very rare. A bad component is usually noticed and corrected by the bike builder, so the stuff works when the consumer gets it. If a component is installed incorrectly, it is the mechanic's responsibility.
Component manufacturers can be real horsey. Shimano, for example, requires the claimant (at his expense) to send the component to an authorized service center. If--and a very big IF at that--Shimano agrees that the part is defective, it will repair or replace it, but it will not cover any shop labor.
Component warranties do not cover misuse. The consumer is expected to operate the component within the component's tolerances. Examples of misuse are:
bent chain link (don't shift under load)
bent chain ring (don't shift under load)
crossed threads
stripped threads (don't over-tighten)
bent derailleurs
bent stems and handlebars
taco'd wheels
damage caused by loose bolts and incorrect installation
damage caused by not fixing a problem before the part was ruined--a loose hub, headset, or crank arm bolt
damage caused by dust, dirt, water, rust, or corrosion--particularly damaged hubs caused by immersion in water
Normal wear and tear is not a manufacture's defect. Examples include:
punctured tubes
worn tires
wheels out of true
chain stretch
worn gear teeth
over-stressed freehub body
exhausted springs
Contact the vendor that sold you the bike for warranty issues. Other shops will have very little interest in processing component warranty claims.
Mechanic Relations
The person who processes your warranty claim is just like everybody else--being nice gets the best service.
Don't lie. If you say, "I was just riding along and my rear derailleur jumped into my spokes ...", nobody is going to believe you. Metal does not spontaneously bend, so don't claim that it does. Be square with your shop, and don't try to finagle somebody else into paying for your screw-up.
If you are a newbie, learn how to finesse your bike. It's not the bike's fault if you shift under load and bend the chain.
So, be polite, be honest, take responsibility, and you will get the best possible service.