ABOUT THIS CHAPTER
This chapter is about repairing wheels. It covers truing the wheels (adjusting spokes so that the rim is more round, centered, and wobbles less), replacing broken spokes and damaged nipples, and fixing minor rim damage. The chapter WHEEL BUILDING AND RIM REPLACEMENT is about replacing rims and building new wheels. That chapter does notinclude anything about truing wheels, but refers back to this chapter for that process. Eyelet: A separate metal reinforcement that goes in the spoke nipple hole in the rim. Cross pattern: The pattern created by two sets of spokes in a hub flange that radiate in opposite directions on their way to the rim. If one clockwise radiating spoke crosses three counterclockwise radiating spokes from the same hubflange, then the wheel is said to be a three-cross pattern. Interlace: If a spoke switches from crossing over spokes to crossing under the last spoke it crosses on way to the rim, the switch from crossing over to crossing under is called an interlace. Dish: The centering of the rim to the hub locknuts. Because the flanges of a rear hub may not be equidistant from the locknuts, a rim centered tothe locknuts is not necessarily centered to the hub flanges. Viewed from the wheels edge, this makes the wheel appear like a dish viewed from its edge. Radial error: This is a deviation in the round of the rim. Radial errors are sometimes called round errors. Radial bump: This is a radial error that deviates further from the center of the wheel than the rest of the rim. Radial dip: This is aradial error that deviates closer to the center of the wheel than the rest of the rim. Kgf: Stands for kilograms of force. This is a unit used to measure the tension of a spoke. Reading unit: A number that is read from a spoketension meter. The reading unit must be looked up on a chart specific to the spoke-tension tool being used to convert to kgf.
Rim: Themetal hoop at the outer end of the spokes that the rubber tire attaches to. The word rim is sometimes misused to apply to the wheel, including the spokes and hub. Rim sidewall: The face of the rim that contacts the brake pads. Rim beads: The two edges of the rim at the rims outer perimeter. Hub: The mechanism at the center of the wheel that an axle rotates inside of, and the spokes attach to theoutside of. Hub flange: The disc on either end of the hub to which the spokes attach. Spokes: The wires that go between the hub and the rim. Spoke elbow: The end of the spoke that makes a 90° bend where the spoke goes through the hole in the hub flange. Spoke head: The flattened disc at the end of the spoke elbow that keeps the spoke from pulling through the holes in the hub flange. Nipple: Theelongated nut that threads onto the threaded end of the spoke and attaches the spoke to the rim. Spoke hole: The hole in the rim where the nipple comes out, although it would be better called the nipple hole. With regard to the hub, the hole in the hub flange that the spoke goes through is also called the spoke hole.
W e lr m v la di s a l t o he eoa n ntlain
Before repairing awheel, the wheel must be removed from the bike. See the WHEEL REMOVAL, REPLACEMENT, AND RE-INSTALLATION chapter (page 18-6) if unsure about wheel removal and installation.
T r r m v la di s a l t o ie eoa n ntlain
Before repairing a wheel, the tire usually must be removed from the wheel. See the TIRES AND TUBES chapter (page 19-3) if unsure about tire removal and installation.
17 – 1
REP17 – WHEEL TRUING AND REPAIR
F e w e lr m v la di s a l t o rehe eoa n ntlain
To replace a broken spoke, it is necessary to remove the freewheel or freehub cogs. See the FREEHUB MECHANISMS AND THREAD-ON FREEWHEELS chapter for freewheel removal (page 25-9) and freehub cog removal (page 25-16).
Smtm idctn ne o wel ypos niaig ed f he r p a e e to r b i d n elcmn r eulig
Either during the...