Check spokes often to avoid a dangerous wheel failure on the road.
Much of the appeal of Harley-Davidson’s motorcycles lies in their classic appearances. Although the general trend is moving away from wire-spoked wheels in favor of solid, one-piece wheels, many Harley owners prefer the look of spokes. However, spoked wheels have a tendency to vibrate loose over time, requiring regular inspection and adjustment to maintain the motorcycle’s stability.
Regular Spoke Maintenance
According to Harley-Davidson’s maintenance schedule, all motorcycles fitted with wire-spoked wheels must have the spokes checked and tightened after the motorcycle’s first 1,000 and 5,000 miles, then every 20,000 miles thereafter. While most Harley-Davidson motorcycles may be able to follow this schedule without a problem, the amount the motorcycle is ridden and the conditions it is ridden through may mandate a spoke inspection much sooner than the recommended service interval. Bumpy road conditions as well as long-distance riding works to loosen the spokes beyond a safe limit — meaning the wheels should be inspected often.
Effects of Loose Wheel Spokes
A typical Harley-Davidson wheel is made up of four distinct parts: the inner hub, the outer rim, wheel spokes and the spoke nipples. The L-shaped portion of the wheel spokes are hooked into holes machined into the inner hub, with the outer, threaded portion of the spoke running toward the outer rim. Spoke nipples are pushed through the outer rim and screwed onto the threaded end of the spokes until the rim is held firmly in place. Each individual spoke is tightened in a specific order until the outer rim spins evenly with the inner hub without a side-to-side wobble or up-and-down hopping motion. The interlaced wire spokes form a strong structure that can support the weight of the motorcycle and its riders. When a spoke, or set of spokes, loosens, the outer rim can begin to move away from the loosened spoke and create instability. If the condition is left to worsen, the wheel can completely fail since it can no longer support the weight of the motorcycle.
Methods and Tools
Many motorcycle mechanics rely on the sound a spoke makes when struck with a spoke wrench to determine how tight it is. However, being able to properly identify the right sound takes several years to master and often leads to less-than-desirable results. The best method, and one that can be performed by most Harley-Davidson owners with little training, is performed by using a wheel spoke-specific torque wrench. Being able to tighten the spokes to a specific torque wrench eliminates any doubt as to how tight, or loose, a single spoke is at any given point along the wheel. Aside from a torque wrench, a service stand is needed to allow the wheels to spin freely.
Spoke Inspection and Tightening Procedure
Mount the motorcycle on a service stand to lift one wheel off the ground at a time. Label one spoke with a piece of tape to serve as a visual reminder of your starting point, then loosen the labeled spoke one-quarter of a turn using a spoke wrench. Immediately tighten the spoke to 55 inch-pounds using a spoke-specific torque wrench. Skip past the next two spokes so you are tightening the fourth spoke. Loosen the spoke one-quarter of a turn, then tighten it to 55 inch-pounds. Continue to tighten every fourth spoke until you have returned to the first spoke, then move to the second spoke. Repeat again until you return to the second spoke from the starting point. Continue in this manner until all of the spokes have been tightened. Spin the wheel and watch the outer rim for a side-to-side or up-and-down motion, indicating a condition called runout. If the wheel exhibits any signs of runout, the wheel must be re-trued by your local Harley-Davidson repair center.