No matter what bike you're riding, the drivetrain is going to need lube. That means using a bike-specific lubricant that is made for bike chains, but can also function to lube other moving or connecting parts on your bike, such as cable contact points, cables themselves, and even nuts and bolts. All that said, the main thing you need bike lubricants for is the bike chain. There are many different lubricant formulations, and perhaps the easiest way to break them out is as either dry lube or wet lube. Dry lubes set up better in riding environments where there is less sand, dirt, and other debris in the air. Wet lubes, on the other hand, do good in damp environments and are thought to protect better against rust. The other split-out for bike lubes is the core ingredient - usually, it's either teflon or wax-based. But there are certainly a host of other bike lubricant ingredients spanning the spectrum of hi-tech polymers and the latest science on friction. How to apply lubricant? Ideally, you should drop and clean your bike chain using a degreaser or solvent, most notably some of the earth-friendly citrus-based natural degreasing products which are great at cutting through chain grime, sludge and dirt. Then, you re-install your chain, and apply lubricant lovingly to each and every chain link. More typically, though, you will use a shop rag to wipe down your bike chain good, or perhaps use a chain cleaner contraption. These are usually box-shaped, that holds liquid degreaser (of your choice) and fits on your chain while still installed on your bike, allowing you to de-grit your chain more easily. Then, back to applying the lube - you should apply the chain lubricant to each chain link and on each chain pin.