Tuesday, 9 March 2010

Repair tips

Some of us like to have our bikes in perfect order, no ticking, skipping, squealing. Here are some things that I learned over the years, by experience or from the net.

  1. Tyre wear at one spot can be the result of a bent or untrue rim. When the bent part of the rim hits the brakes, the part of the tyre which is at the contact with the ground at that instant skips. As this is
    always the same point of the tyre (unless you are rotating it regularly on the rim) it will eventually wear out and blow. The thing happened to me in Kyrgyzstan, the explanation is Sheldon Brown's.
  2. Broken brake cable usualy doesn't happen unexpectedly. The individual wires in the cable break first with a warning sound that can be heard, and which usualy happens after a sudden squeeze of the brakes. Check out the cables when such warning comes.
  3. When breaking the chain the pin should not be extruded completely. If this happens however, you can hammer it back by holding it with some narrow tool. Needle plies are the best, but a piece of wood with the hole in it might do as well. The stiff link is loosed simply by bending the side plates of the adjacent links.
  4. If you feel a bump every wheel revolution and the rim is true, it's most probably a tyre bead that is unevenly engaged in the rim or is even pinching the tube. It may also be due to the damaged tyre sidewall.
  5. If the chain stucks in the deraileur seemingly unrelated to the revolution of the cranks, check out the side plates of the chain - they may be broken.
  6. Ticking in the handlebar most likely comes from a stem/stearer connection. Grease every part of this connection, including bolts, and tighten.
  7. Ticking in seatpost. Check if your seat tube has a metal shim between the tube and the seatpost. Grease all the surfaces that come into contact (shim/seatpost, shim/seat tube).
  8. Squeal in the rear derailleur during shifting. Oil the axis of pulley wheels.
  9. Ticking in the crankset area. Could be number of things. Check out the simple things first: oil the pedals; tigten cranck bolts; see if cranck is not hitting the front derailleur cable; make sure the sound is not coming from your shoes. The sound could be comming from loose saddle or seatpost.
  10. Cracking sounds unrelated with pedal or wheel revolution. When the spokes are too loose they can slip at the points where they cross each other. Happens both when seated or not, holding handlebar or not. Can't happen on radially laced wheels.
  11. Squeel when turning the handlebar. Break/shifting cables are fretting in cable stops - oil the cable stops. Cables may fret one against other - tie them with tape.
  12. Rattling when going over rough surface. It can be caused by anything that is attached to the bike (bags, lock, pump, water bottle, ...) or anything loose in the bags. If it happens on "naked" bike: check the headset for looseness; check that the shifting or braking cables are not hitting each other.
  13. Unusual sounds. Deal with them by eliminatig possible causes one at the time. Is the sound present only while turning pedals? Only while seated? Only while riding a bike (i.e. not when turning the wheel by hand)? Only when holding the handlebar? Only when peddaling forward? Only with bags attached?
    With each crank revolution? With each wheel revolution? Sounds may not necesarily come from the bicycle - check the panniers, racks, shoes, things in your pockets.
  14. Derraileur adjustment is most easily done when the bike is turned upside down. Just check visually that the pulley wheel runs in the middle of the cog.
  15. Rim wear can be drastically reduced by using quality brake pads. The sand particles will embed quickly in most of the ordinary pads. This will act as sand paper, chipping off bit of rim material, which will in turn embed into the pad rubber, resulting in even more wear. Use best pads you can get:
    Kool-Stop pads are the best.
  16. Brake squeal is reduced by proper toe-in of the brake pads and sand-papering the rim.
  17. Cleaning the chain on the road. Find a piece of rug by the side of the road. Start by cleaning the pulley wheels. Then clean the front chainrings. Then start cleaning each chain link: shift the chain to the big front ring and clean the links as they go around the front ring teeth. The chain is not flexing there so you can clean it using one hand only. (This is one operation where I would not agree with Jobst Brandt
    and prefer to do it with the bike upside-down.) Then oil the chain: dip the end of a toothpick into oil and put one drop of oil in the roller/sideplate gap of each chain link. Wipe excessive oil.
  18. Carbon forks have a bad reputation for touring. I don't know why. I cover mine with electric tape or with bubble wrap as a protection from scratches. So far, it worked rather good.
  19. Low pressure is bad. Among other things it can result in cracked tyre sidewall.
  20. Tips about reducing probability of punctures are given elsewhere.
  21. If you don't have the appropriate tool try to improvise. Imagine what the procedure would be like if you had the tool. Think about the principle of that tool. You may find a simple substitute that has the same principle.

No comments:

Post a Comment