Why does oiling the axles of a bicycle make the bicycle move more easily?

Answer 1

Sometimes oil is used in competitions, because the density of oil is less than the grease and provides less friction to the bearings, but it's recommended only during the race, after that you must clean the bearings and apply a proper grease! (Remember use it only in cases of hi performance!)

Answer 2

Same reason a wet floor is more slippery than a dry floor. The liquid gets between the moving parts and create a thin slippery layer. With that said, oiling bicycle wheel axles isn't such a hot idea. Oil doesn't stay in place very well, and will soon move away from where it's needed. Bicycle wheel bearings are better off greased than oiled. Grease is almost as slippery, but a lot better at staying where you put it.

Answer 3

Oil is good for a short period, then it's not so good. Oil does two things that make it not appropriate for wheel bearings, it tends to run right out after being applied, and it attracts dirt. Dirt causes wear.

For wheels, waterproof grease would be the product of choice. Personally, I find Phil Wood grease to be the best.

Answer 4

If your brakes are making the bike difficult to move without the rider activating the brakes(through back-pedalling or through pulling on the levers), there's something wrong with them and they should be repaired.

It's possible that your brake is sticking in the on-position, and that a little oil helps it disengage. The general consequence of pouring oil on something is to reduce friction and make stuff move easier.

Oiling the brakes is only OK if you know what you're doing. In rim, disc, and drum brakes, there are some parts that has to remain dry and clean. Any oil there can damage the brake badly.