Part of the wheel anatomy, spokes are wires usually secured by spoke nipples radiating from the hub to the rim. Nonetheless they are usually very stiff and provide almost all structural support for the wheel to function properly via tension between the hub and rim. During the wheel building process, spokes are installed according to certain tried and true lacing patterns to provide the strongest lightweight design.
Adjusting the tension on spokes can move alignment of the entire rim, making wobbling of a wheel either better or worse. They are a small, but sensitive component that is extremely important.
Nipples, grease and other accessories (lights, beads, etc) can be bought on Amazon.com for really cheap.
Spokes can also be purchased individually for pennies, or in sets. Sometimes spoke sets can be quite pricey, but it would be worth it. Spokes are one of the most important components to the wheelset. Overall however, aluminum spokes are aluminum spokes. There are other materials out there, and many riders love to customize their rides (gold, silver, and any color scheme imaginable).
Most performance spoke sets fall between $50-$100, while some can be over $200 for a set of 100.
Assembly of a wheel starts with the big three: hub, spokes, and the rim. You will need a spoke wrench, truing stand, a flathead screwdriver, and a lot of patience. Wheelbuilding is an art.
On average, wheels have 32 spokes. There's variation, but keep in mind that with fewer spokes requires a bulkier rim and hub to handle the tension spread out farther. Nickel-plated brass spoke nipples are commonly purchased with the set of spokes.
Let's get started: It's a great idea to lubricate spoke threads, holes and nipples during assembly. Having grease on these spots allow the nipples to reach high tensions (super important). After that preparation, it's time to start lacing the spokes.
NOTE: This is just one of many ways to lace spokes.
Spokes are laced in groups. The first place to start is aptly named the key spoke. If a mistake is made on the first spoke, the others will all be assembled in correctly. It goes next to the valve hole on the rim and through the hub flange, inside to outside. Spokes are set trailing the freewheel around the circle. Along the rim, spoke holes are drilled offset to each other every other hole. They are a little forward from the corresponding hub flange to accommodate the trailing style that spokes are laced. Looking at the wheel from the drive side, the spokes should go clockwise.
Loosely attach spoke nipples to hold the spokes in place. Don't tighten until al the spokes are in the rim and ready to rock. On a 32-spoke wheel, the spokes are installed in groups of 9. They should be evenly spaced, and wired to the same side on the rim as the corresponding hub flange. When the first group is in place there should be a spoke, 3 empty holes, another spoke.
Next comes the 2nd group. It should follow the holes behind the 9 first spokes in the same flow. The first spoke of the second group goes into the first hole opposite the key spoke. After this group there will be 18 spokes in the wheel, all up to this point have been trailing spokes.
The third and final group is a leading group. The spokes will insert the opposite direction and cross 3 of the trailing spokes before finding their home. Remember to keep the spokes in holes on the same side of both the rim and the hub. Install the remaining spokes this way to complete what is called a normal cross 3 pattern. Now the spokes will need to be tensioned properly.
If you are still unsure, check out the great bike tube tutorial on how to build a wheel. It really breaks it down and there's a lot of humor to keep you awake.
Cutting spokes to the appropriate length is a science not for the faint of heart. Being the distance between hub flanges and the lip of the rim, spoke length needs to be perfect. Too long and it could puncture an inner tube (or not fasten tight enough), and too short of a spoke could lead to pulling the nipple through the spoke hole. According to a few sources, to calculate proper spoke length:
d = distance from the center of the hub to the flange
r1 = spoke hole radius of the hub
r2 = half of the effective rim diameter (ERD)
r3 = radius of spoke holes in the flange
m = number of spokes to be used for just one side of the wheel
k = number of crossings per spoke
a = 360o x k/m
NOTE: When doing it yourself, spokes can be cut using pliers, bolt cutters, etc. Anything that can cut to an exact measurement.
Aside from just handling the weight of the bike frame and the rider, torque is applied to the wheel when cornering, accelerating, and braking. Spokes are required to perform accordingly to give the strongest and lightest design possible. Tangential lacing allows for the transfer of torque, something that is necessary with rear (drive) wheels and any disc brake systems.
The number of spokes in a given wheel varies. Once upon a time, manufacturers were cutting back on the number of spokes and marketing them as improved and lighter weight. In reality they were just weaker. On average, most wheelsets will have a spoke count of 32.
The thickness of spokes has been standardized by the ISO (millimeters in thickness):
|US/British spoke gauge number||ISO spoke diameter (mm)|