This past Wednesday, I attended a general bike maintenance class at REI.  This is a free class and I would recommend it to any beginning rider.

To kick off the class, we covered changing a tire.  The instructor, Cat, demonstrated on a road bike tire, but assured us that the principles she was going to show us applied to several different types of tires including mountain bike and hybrid tires.  Though stressing that a better practice is to bring a spare, she proceeded to show us how to patch a hole in a tube.  This exercise was thorough and complete.  Here are some of the tips she shared with us:

• Identify where the hole in the damaged tube is, even if you are going to replace it, so that you locate the area on the tire for inspection.
• Ensure that the tube has a little air in it before trying to install it.  This will keep the tube from twisting and make it easier to manage.  A tube that is installed with a twist, once inflated, can rupture or have other problems.
• If possible, refit the bike tire using only your hands, as using tire levers to perform this task risks damage to the tube.
• Before fully inflating the tire, inspect the entire tire to insure that the tube will not get pinched between the tire and the rim.  This could either cause the tire to lose its bead, or the tube to get a pinch flat.
• Fill tire to proper pressure.  When on a trail, there are two basic ways of inflating your tire.  A hand pump or a CO2 cartridge.  It is tempting to put “just enough” pressure with a hand pump.  Be sure not to under inflate the tire.  Most tires have minimum and maximum tire pressures listed on the side wall.  Make sure you achieve a tire pressure that falls within that range.  A lot of tires max out at 120psi and CO2 cartridges dump about that pressure into the tire when fully engaged.  Be cognizant of this and check your pressure before you ride. 

Next we covered derailleurs.  A quick definition of derailleurs.  Most bicycles have multiple “gears” and the mechanism that changes these gears is the derailleur system.  The derailleur system consists of a front and rear derailleur.  Both consisting of a chain and several sprockets.  The front derailleur has a guide called a cage that is used to move the chain between sprockets derailing it.  The rear derailleur has what’s called a jockey pulley to control the derailing of the chain between the rear sprockets.  Both the front and rear derailleurs have adjustment screws that control the high and low gear limit stops.  The limit stop is the distance that the cage or jockey pulley allow the chain to go horizontally along the sprocket grouping.  A maladjusted limit stop can either allow to chain to go too far, causing it to fall off of the sprocket group, or not far enough, causing it to not shift into the highest (or lowest) gear.  When adjusting derailleurs, you should also consider the amount of tension the cables have.  Too loose or taught cables can also affect the shifting of gears.

I am by no means an expert in this area, so I will not attempt to explain how to adjust derailleurs.  In fact, some REI store locations offer a Derailleur Adjustment class.  In Atlanta, the Perimeter location is the only one that offers it ($30 for members/$50 for non-members).

Finally we covered basic maintenance.  How to care for your chain and other components.  Here are some of the talking points:

• All Allen Bolts on bicycles are metric.  It is very easy to mistakenly use a standard Allen Wrench on them, thus stripping them.  Only use metric Allen Wrenches.
• Keeping the components that have moving parts properly cleaned will extend the life of the component.
• Use a degreaser to clean the chain.  She recommended  Finish Line Speed Degreaser.  Ensure that you do not ride the bike after degreasing without first lubing the chain.
• Allow the degreaser to completely dry before applying lube to the chain.  She recommended Tri-Flow Superior Lubricant.
• When lubricating the bicycle, find all parts where metal touches metal and add lubricant to that area.  A single drop of lubricant is usually enough.
• Do not forget to add lubricant to the cables where they meet the housing.  These cables are called Bowden Cables and the plastic sheathed housing is lined with metal where it contacts the cable.  Be sure to place the cable on the smallest sprocket when applying the lubricant as the smallest sprocket causes the least amount of resistance on the cable, thus putting it in the most exposed position.  Then change the gears to the largest sprocket (progressing to the easiest gear for the rear derailleur and the hardest gear for the front derailleur).  This will increase the tension of the cable causing it to get pulled through the housing dragging the newly applied lubricant with it.

One quick note that was covered in the class was to be cognizant of chain wear.  The chain is the quickest thing to wear out on a bike and is often overlooked until it breaks.   She recommended the Park CC-2 Chain Checker though REI doesn’t carry it.

And there you have it.

Joe.

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