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Mechanic's Tips and Secrets(5 posts)

Mechanic's Tips and SecretsKillerQuads
Aug 5, 2002 9:08 PM
Here are a few wrenching tips I learned as a bike mechanic and by tinkering with my stable of bikes.

Cables:
1. If you buy one dedicated bicycle tool, buy a cable cutter. It gives a clean round cut without fraying.
2. Instead of using aluminum crimps on the ends, use 1/2 drop of Super Glue on the freshly cut end. Once it dries, the end will never fray and you can thread it in and out of housing without snagging.
3. To take slack out of a front derailleur cable (that does not have an adjuster), you can use a short piece of inner tube inside of pliers to pull the cable end without crimping the cable. Or you can screw in the low set screw, pull and secure the cable end, and then unscrew the set screw the same number of turns.
4. The best cables I have found are mandrel drawn (Avenir). They are rounder in cross section with lower friction and can fix a balky index shift system.
5. When lubing cables, don't forget to grease the area under the bottom bracket where the cables run. Wipe off any excees to avoid dirt accumulation.

Wheel trueing and rims care:
1. Get wheel trueing stand. Turning the bike upside down and using the brake pads is not accurate enough. Dual pivot brakes don't let you move the pads to one side.
2. Get a dishing tool. Self centering trueing stands are not accurate enough to check for dish. The center contact on the dishing tool must touch the outer nut surface, not the axle end. Theoretically, you should also remove the tire. If a wheel has skinny tires, I sometimes cheat and leave the tire on (I have checked this by measuring at different sites on a wheel and confirming with the tire off).
3. For lateral trueing, I loosen the spoke on the convex side first. If I feel a lot of resistance, the spot is probably out of true because of a too tight spoke, and I may not tighen the spoke on the opposite side. Other wise I tighten the opposite spoke the same amount.
4. Only slight out of roundness can be corrected. Dents are best avoided.
5. After trueing, stress the wheel by applying your body weight at several sites on the rim to settle the spokes and nipples. It may then need more fine tuning.
6. For shallow rims, deflate the tire before trueing to avoid spoke nipple flats.
7. Some rims may have a seam 180 degrees from the valve hole were the rim is joined. If you hear a thunk, thunk while braking, you may need to remove the raised edge with sand paper.
8. Extra material is used inside the rim at this seam, so the heaviest part of the wheel is not the valve stem end, but the opposite end. So attach wheel magnets to spokes near the valve stem.
9. Burrs along the inside of the valve hole can cut the inner tube at the stem and create an unpatchable flat. Bevel the inside of the valve hole with a Dremel tool.
10. Squeaking rims may be due to grease on the rim (degrease with rubbing alcohol), or toe in (it is better to shim the pads rather than bend the caliper arms).

Nice tools to own:
1. Cable cutter (see above)
2. Sears "T" handled allen wrenches (for spinning off bolts)
3. 10 mm Gear Wrench (for old-style 10 mm seat post bolts under the seat)
4. Tool box (with drawers) dedicated to bike tools
5. Work stand (I like the Ultimate Pro)

Setup tips:
1. Once your seat height is determined, mark the seat post with a magic marker at the top of the seat tube. This makes it easier to return to the same height or make 2 mm adjustments. It can be removed with rubbing alcohol and is better than putting a nick in the post. Measure the seat height by measuring the distance from the center of the crank bolt to the top of the seat. This is more repeatable than measuring down to the pedal and can be transferred from one bike to another (assuming the same crank arm length).
2. With handlebar height, it is hard to measure the drop from the seat to the handlebars. Instead, measure from the top of the front wheel to the bottom of the bars where they m
re: Mechanic's Tips and SecretsKillerQuads
Aug 5, 2002 9:17 PM
Sorry, I got cut off by writing too much.

2. With handlebar height, it is hard to measure the drop from the seat to the handlebars. Instead, measure from the top of the front wheel to the bottom of the bars where they meet the stem. My commuter bike is set to 8 1/4", my "race" bike is set to 7 3/4" for aerodynamics. Again this measurement is easy to duplicate and transfer.

More to follow

Got any other tips?
re: Mechanic's Tips and SecretsPing_Pong
Aug 6, 2002 4:16 AM
Good tip on the super gluing cable ends - I am always swapping stuff on and off my bike , this tip will save me many yards of cable.
re: Thanks. I saved these for future reference. (nm)JL
Aug 6, 2002 4:37 AM
solder on cable ends works nice too (nm)IAmtnbikr
Aug 6, 2002 5:07 PM
NM