On bearing cleaning

Last night at Scooters was, for me, a disaster. I don't know if its the fear of the tight formations, fatigue, or a lack of endurance, (I have good sprinting abilities but cannot sustain speed for more than ten or twenty laps) but I just could not stay in formation. After practice Scott Pauly (to my knowledge no blog or website) suggested that I should try to keep my feet closer together around the corners. Something to think about for me.

Anyway I'd like to spend today's post discussing something that ought to be important to cyclists and skaters. How to look after your metal parts.

To start with there seems to be some ambiguity as to what causes rust. Steel, which bearings, bike chains and many other moving parts are almost always made from is almost entirely Iron. In fact according to the Wikipedia article steel is roughly 1-3% carbon and the rest is almost purely Iron. Now recall from high school chemistry what happens when Iron with a low electonegativity is exposed to Oxygen in the air, which is second only to Fluorine in a list of elements with high electonegativity. The Oxygen combines with the Iron and moisture and creates Iron Oxide, or rust. Why doesn't steel rust when simply left in the open air? Not enough water, rust is actually Iron, Oxygen and Hydrogen, you get the Hydrogen from water in the form of a Hydroxide. Remove water or oxygen and you get no rust. If you did underwater inline skating you would not need to worry about rust, just like skating in dry weather.

So how to take care of bearings? Hose 'em down with WD-40 and forget about them? Absolutely NOT! Although WD-40 is composed of Napthas and other solvents WD-40 is very adhesive and as such is the dictionary definition of a bad lubricant. (Might as well just squirt some loctite in and wait for the bearings to seize right up.) The WD-40 will displace the water, that's what it stands for, Water Displacement 40'th try, but it is sticky. Dirt will get in the bearings and instead of being displaced by the lubricant will instead just sit between the balls and the races gradually wearing the balls down, and since the balls and races are being roughed up there will be more room for the sticky nature of WD-40 to really manifest itself.

Bearings should be cleaned by something that is not water based, I like Napthas in the form of paint thinners, but these are toxic, other options include Isopropyl Alcohol in a 99% solution. In a crunch citrus cleaners are an option, but too many manufacturers dilute their product with too much water. Yet another option is combinations, paint thinner that is reused with each cleaning can get rid of the dirt and old lubricant, then a bath in clean Isopropyl Alcohol to displace the paint thinner and remove any remaining dirt works very effectively.

Once the dirt has been displaced a lubricant is required, very light oil works, or white lithium grease. Grease needs to be broken in over a period of about 100km for skaters but will require about a tenth the maintenance of oil. In theory oil will give a better skate than greased bearings, although I have never seen a statically valid study to justify that belief. Cyclists should go to a good bike shop to find out the scoop, but I believe gears are generally packed with lithium grease, chains get oil. Use of WD-40 is, obviously, not recommended. In fact if you use WD-40 you probably shouldn't tell anyone, hide the fact and your face in shame!

In the event of a rainy race WD-40 can make sense, spray the outside of the bearings prior to the race, this will displace the water while racing. Once the race is over get the bearings in to a sealed plastic bottle topped with some fluid, water is fine. The main thing is keep the bearings away from Oxygen until you can get them into a bath of Naptha or Alcohol. The solvents will displace the water, then after removing the steel from the solvents the oxygen will have no water to react with.

Another important thing for racing in the rain, make sure you have good rain wheels, but wheels are a discussion for another day.