Guides / Finishing
Finish Options for a Machined Bike Part
September 9, 2026
Anodizing is the default on machined aluminum, but it is not the only option and it is not always the right one. Here is the rest of the menu, what each finish does to the part and where it lets you down.
Mechanical finishes, applied before anything else
As machined. Tool marks visible, cutter paths readable across the surface. Honest, cheap and fine for prototypes, internal parts and anything hidden. Bare aluminum oxidizes dull and picks up fingerprints, so it is not a shipping finish for a visible component.
Bead blast. Glass or ceramic media fired at the surface. Gives an even matte texture, hides machining marks and tool changes, and is the standard preparation under anodizing. Grit size changes the look, so put it on the drawing: 120 grit and 220 grit do not look the same.
Tumble or vibratory finish. Parts run in media in a bowl. Deburrs edges and softens the whole surface at once, which is efficient on small parts in quantity. Loses sharp edges, so it is wrong for anything with a defined chamfer, and it will round a knife edge you wanted kept.
Polish. Hand or wheel work to a bright surface. Looks expensive because it is. Cost scales with the number of faces and the tightness of the corners, and any polished aluminum part needs a clear anodize or lacquer over it to stay bright.
Brushed or wire drawn. Directional grain, applied with abrasive belt or pad. Popular on flat faceplates and top caps. The grain direction has to be specified or you will get three different directions on three faces.
Conversion and coating finishes
Type II and Type III anodizing. Covered in detail in the Type II versus Type III guide. The default for aluminum bike parts and the one to start from.
Chemical conversion coating (Alodine, chromate). Very thin, conductive, corrosion resistant, and it does not change dimensions in any way you will notice. Used where a part needs electrical continuity, which on an e-bike can matter. Not decorative and not hard.
Powder coat. Electrostatic powder baked on. Thick, tough, good color range, cheap at volume. The thickness is the catch: typically 60 to 100 microns, which is several times an anodize layer. Every bore, thread and mating face has to be masked. Best on bash plates, racks, frames and large brackets.
Electroplating (nickel, chrome). Hard, bright, wear resistant. Common on steel hardware, less so on aluminum bike parts because it needs an intermediate layer and it adds real weight. Hydrogen embrittlement is a genuine concern on high strength steel fasteners and needs a bake after plating.
Cerakote and similar ceramic polymer coatings. Thin, tough, wide color range, good chemical resistance. Around 25 microns so it sits between anodize and powder coat. More expensive than either and worth it mostly when you want a specific color on a part that also has to survive.
PVD. Excellent wear resistance and a distinctive look. Needs high temperature, which can affect aluminum temper, so it is mostly a steel and titanium option on bike parts.
Marking
Laser mark. Logos, sizes, serials, torque values. On anodized aluminum the laser removes dye and leaves a pale mark. Permanent, fast, and it needs no tooling, so changing the artwork between batches is free.
Engraving. Cut into the metal with a cutter. Deeper and more tactile than a laser mark, slower, and it creates a stress raiser, so keep it off highly stressed surfaces.
Pad print or screen. Cheap, full color, and it wears off. Fine for a size marking on a part the rider never touches.
Putting it on the drawing
Name the finish, the color, the thickness or grit, the direction if there is one, what is masked and what is marked. A drawing that says “anodized black with logo” leaves five decisions to whoever is holding the part, and they will not make them the way you would.
Say all of it on the RFQ and the quotes come back comparable. Leave it out and every quote you get is for a different part.
Frequently asked questions
What is the cheapest acceptable finish?
Bead blast plus clear or black Type II anodize. It hides tool marks, resists corrosion and is on every anodizer's standard schedule. As machined and bare is cheaper still but aluminum in a wet drivetrain will not stay clean.
Does the finish go on before or after laser marking?
After, in most cases. A laser mark on an anodized surface ablates the dye and leaves a light mark on a dark part, which is crisp and permanent. Marking bare metal then anodizing over it usually leaves a mark that is hard to read.
Is powder coat a good idea on bike parts?
On large low-precision parts such as bash plates and racks, yes. On anything with a bore or a thread, the coating is thick enough to matter and has to be masked, which erodes the cost advantage.
Need a quote for this part?
Send the drawing. We match you with up to 3 shops that machine bike parts and reply within 24 business hours.
Get matched with a bike parts shop