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EXTRAS

Bike maintenance

"Ask the Mechanic"  - Fall Maintenance.

   For most of us in this part of the country the bicycling season has quickly become a memory, although it is sad to see the season end, this is an excellent time to take care of some of the larger maintenance issues that you may not want to take the time for during the riding season. If you’re an avid cyclist riding over a thousand miles annually you should consider overhauling your bike at least once a year, this is a great time to do it.

   In most bike shops an overhaul differs from a tune up in that a tune up generally consists of adjusting the various systems, adjustments to the brakes, the shifting, as well as the headset, wheel cones and bottom bracket should all be preformed as well as truing the wheels and inspecting the tires and brake pads and so on. An overhaul should include all these services as well as the cleaning and repacking (re-greasing) of all the serviceable bearings, and the inspection and replacement (if necessary) of any sealed bearings. Even if you don’t do the service yourself you should be aware of the type bearings the various components on your bicycle are equipped with.

   The components that contain bearings are the hubs, the bottom bracket (the component that sits inside the frame that the crank spins on) and the headset (the bearings that connect the fork to the frame), the type of bearings a component has will dictate the type of service it will require and the cost of that service. Bearings will typically come in two forms, loose ball (including caged) or precision in some old headsets you may encounter needle or pin bearings but those are rather rare these days.

    Components with loose ball or caged bearings are usually a serviceable component consisting an axel (or spindle in the case of the bottom bracket, in headsets the fork acts as the axel) a race, the bearings and the cones, the bearings are adjusted by tightening the cone (until there is no lateral play in the axel and the component still rotates smoothly) which is threaded onto the axel, spindle, or fork) and then locked in place by a locking nut. When the bearings are out of the component for service they and all the surfaces they ride on (the cones and races) should be inspected for signs of pitting, even the most minute pits on a bearings riding surface will be noticeable and causing bumps or grinding in the rotation, or the rotation to stop prematurely (this is especially evident in headsets when the handlebars stop turning at the same position every time, you can actually feel the bearing come to rest in the pit in the riding surface), this is when the component will need to be replaced. Precision or cartridge bearings also called sealed (the term sealed may also be applied to components using loose ball bearings that have a rubber or plastic seal to protect them from water and debris, it is important this is understood and a positive identification is made) are bearings that are self contained, they are incased in a steel cartridge that is pressed into a shell, the axel runs through the center and is held in place by some type of retainer or collar, there are many standard sizes of these bearings that are used in the bicycle industry it is important that when replacing these bearings that the exact replacement is used. Sealed bearings, although not serviceable are advantageous because they are cheap to replace (usually under $10.00 for a bearing) and don’t require any adjustment once installed. When overhauling a bicycle any components with cartridge bearings, should be inspected, if no damage is to be found no further adjustment is needed, unlike a loose ball component which needs to be cleaned repacked and adjusted, this could have an affect on how much labor is charged and you should discuss these matters with your mechanic before the work begins.

  Bearings are not the only components to receive wear and require service or possible replacement, One commonly overlooked component is the chain, most of us lube our chains but do we replace them as often as necessary? Usually a chain will last about two thousand miles or so depending on factors such as rider weight and strength as well as riding style. Tandems and mountain bikes wear chains faster than single road bikes. Chain wear will be most evident in the form of stretch; one can measure the stretch buy using a commercially available chain checker or if you don’t own a chain checker a real easy way to illustrate the stretch in your chain is to shift the chain onto the large chain ring in front and the small cog in the rear, now grab the chain at three o’clock on the chain ring and pull forward, if you can see three quarters or more of the sprockets tooth your chain should be replaced. Keep in mind that a stretched chain will accelerate the wear on the chain rings as well as the cassette so by replacing the chain more frequently you will be saving wear and tear on the more expensive drive train components. If the chain is not excessively stretched you may or may not want to clean the chain, I don’t believe in cleaning the chain in solvent if not necessary, many times a good wipe down and reapplication of lubricant is all you need, if the chain is that grimy you will need to clean it but make sure you a relatively thick chain lube afterwards.

  A few remaining details that that are often overlooked when a bicycle is being serviced is the brake pads, cables and tires, brake pads should be inspected for wear and damage, cables housing should be inspected for breaks or cracks, and the inner wire should be checked for frayed ends and broken strands at the binder bolt. Tires should be inspected for tread wear, dry rot and cuts and punctures. If you plan to use your bike on a wind trainer during the off season make sure you install a cheap pair of tires or save a worn out pair, wind trainers wear tires many times faster then the road, and don’t forget to protect your frame from sweat, human sweat is very corrosive and can do a lot of damage to the paint and welds of the frame.

  If you follow these guidelines you will have peace of mind Knowing that your bike has been thoroughly serviced and will be ready as soon as the weather is, thus beating the spring rush at the bike shop when it is easy to wait a week or more for service.  

Happy pedaling,
Kevin Sawicki

Kevin would love to hear about any questions you might have about bikes and/or their repair. You can email him at abikefixer@hotmail.com.