Inside: Wheels Manufacturing

See how nearly half a million headset spacers are made each year

Despite the name, Wheels Manufacturing doesn't actually make wheels. What they do make, however, are lots of everyday items you may not have thought much about, like headset spacers, rear derailleur hangers, bottom brackets and bottom bracket adapters. The company makes an awful lot of that stuff, too, with more than 440,000 spacers made each year. Take a walk inside with us to see how it's done.

Save for some shop supply items like ball bearings and cable donuts, Wheels Manufacturing produces all of its wares inside a modest facility in Louisville, Colorado. Every item is produced via CNC machining and the company deals exclusively in aluminum, carbon fiber, and Delrin.

Raw stock is delivered through the back of the building where it's sorted and stacked. Despite the enormous volumes Wheels Manufacturing produces, there isn't actually much raw material kept on hand at any given moment. As it's purchased by weight, it makes sense to only buy as much as is needed.

From there, much of that material gets chopped up into smaller and more manageable pieces before they're fed into one of Wheels Manufacturing's army of CNC mills and lathes. Making headset spacers and seatpost shims is a fairly straightforward process (especially for carbon spacers that already have the correct internal and external diameters and only need to be cut to size). Machining nearly 200 different types of rear derailleur hangers with the exact dimensions needed for a perfect fit, however, is a little trickier.

These aluminum plates are first roughly cut on a band saw. they'll eventually be machined into rear derailleur hangers:

Wheels Manufacturing first starts with a stock OEM hanger and measures every surface with a precision coordinate measuring machine to ensure a perfect match. From there, those dimensions are translated into CNC code that the machines can understand.

Wheels manufacturing uses this to coordinate measuring machine to collect precise dimensions on new hanger models. the information gathered here guarantees that wheels' aftermarket hangers will fit properly:

Hangers are machined out of short pieces of aluminum plate, with each segment yielding about six parts depending on the model. The mill doesn't simply cut away all the excess material around each hanger and spit out finished parts, though. In the first step, the machine only mills away material on the front face and sides of each hanger.

Derailleur hangers are milled almost completely around in the first step of production.:

Afterward, each plate is removed from the mill, flipped over, and then dropped into an aluminum template that's milled away with the exact negative image. That assembly is then reinserted into the machine where the backside of each hanger is finally cut away.

Afterward, the entire plate is then flipped over and inserted into this negative pattern so that the remaining material can be milled away while still holding each derailleur hanger precisely positioned:

In this way, each hanger remains individually fixtured throughout the process to maintain the required dimensional tolerances. This method also allows Wheels Manufacturing to produce more hangers than if they were machined one by one.

Many stock rear derailleur hangers are cheaply made from cast aluminum, making them prone to failure. wheels manufacturing has earned a solid following for its aftermarket hangers thanks to more durable 6061 alloys and precision machining:

Every machined aluminum part still requires finishing work after it's done on the mill or lathe as otherwise the edges would remain razor-sharp. Freshly machined parts are tumbled in giant tanks filled with small ceramic bits and cutting fluid. After an extended stay, they emerge with smooth edges and an impressive polish.

Seatpost shims underdoing some final finishing work:

Final steps include anodizing – which is done off-site – and packaging, after which the parts are ready to ship.

Sounds simple, right?

James Huang

Technical Editor, US
James started as a roadie in 1990 with his high school team but switched to dirt in 1994 and has enjoyed both ever since. Anything that comes through his hands is bound to be taken apart, and those hands still sometimes smell like fork oil even though he retired from shop life in 2007. He prefers manual over automatic, fizzy over still, and the right way over the easy way.
  • Discipline: Mountain, road, cyclocross
  • Preferred Terrain: Up in the Colorado high-country where the singletrack is still single, the dirt is still brown, and the aspens are in full bloom. Also, those perfect stretches of pavement where the road snakes across the mountainside like an artist's paintbrush.
  • Beer of Choice: Mexican Coke
  • Location: Boulder, Colorado, USA

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