Manufacture of spokes
Spokes are cold formed from drawn (stretched and tensioned) mild steel or stainless steel wire.
The drawing increases the strength of the spoke. In the case of mild steel spokes they are then plated with zinc or chromium or UCP* finishes while Stainless steel spokes are usually polished.
All processes associated with spokes making (drawing, bending, rolling) are done as cold processes rather than by heat.
The process of threading the spokes to accept a nipple is called rolling the thread. Rather than cutting a thread into the spoke and losing material (and introducing stresspoints) in the process, rolling reshapes the existing metal to create a thread. Some of the metal is squeezed in and a corresponding amount pushed out. This is achieved by passing the spoke between two circular or flat die plates
Spokes are made in varying thickness, referred to as gauges. In general terms the most common gauges are 8, 9 and 10 which vary in thickness from approximately 3.2mm to 4.0mm. The larger the number of the wire gauge, the thinner the spoke. Swage spokes are a combination of these gauges e.g. 8/10g
Single- and double-butted spokes are referred as swaged spokes. When they are produced the wire is drawn through a reducing die resulting in two defined diameters in the spokes. The purpose of this is the reduction increases the elasticity of the spoke. This process is usually employed on elbowed spokes rather than straight pull.
The swaging and the work hardening through this process move the stress points from the bend and the thread to the mid section of the spoke. With the introduction of stainless steel as a spoke material this process has become less critical.
It is not uncommon for pre- and post-war motorcycle wheels to have swaged spokes on the drive side of the wheel only. Modern hydraulic forks with improved damping and travel have also reduced the strain on spokes in wire wheels.
Fastline Spokes stocks a comprehensive range of single-butted spokes. Double-butted spokes are generally proprietary and apply to a specific brand or model of motorcycle. For that reason they may be difficult to obtain.
Diagram of swaged spoke styles to follow
When ordering spokes, the easiest and safest way is to send a sample of each spoke type and the number required. Inlude a nipple for reference.
Diagrams to follow
At Fastline we have a large reference library of samples for Japanese, British and European bikes. In some instances the old spokes may be rusted to the point of seizure and cutting them out from the wheel is the only option. Use wire cutters or a thin bladed grinder to cut the spoke in the approximate middle.
As shown in the diagram the two pieces can be taped together and posted to Fastline for reproduction
Diagrams to follow
Universal Chrome Plating, a process for chrome-plating cheap, steel spokes