Alloys and Finishes for Bike Components
Material data for the alloys that actually get machined into bike parts, with the two columns most data sheets leave out: how the alloy machines and how it takes a finish.
Last checked September 27, 2026. Values are typical for the stated temper and are not a specification.
Mechanical properties
Read the stiffness column as carefully as the strength column. A part whose size is set by how much it is allowed to flex gains nothing from a stronger alloy.
| Material | Tensile | Yield | Density | Stiffness |
|---|---|---|---|---|
| Aluminum 6061-T6 | 310 MPa | 276 MPa | 2.70 g/cm3 | 68.9 GPa |
| Aluminum 7075-T6 | 572 MPa | 503 MPa | 2.81 g/cm3 | 71.7 GPa |
| Aluminum 6082-T6 | 310 MPa | 260 MPa | 2.70 g/cm3 | 70 GPa |
| Aluminum 7005-T6 | 350 MPa | 290 MPa | 2.78 g/cm3 | 72 GPa |
| Aluminum 2024-T3 | 483 MPa | 345 MPa | 2.78 g/cm3 | 73.1 GPa |
| Titanium Grade 5 (Ti-6Al-4V) | 950 MPa | 880 MPa | 4.43 g/cm3 | 113.8 GPa |
| Titanium Grade 2 | 344 MPa | 275 MPa | 4.51 g/cm3 | 105 GPa |
| Stainless 303 | 620 MPa | 240 MPa | 8.00 g/cm3 | 193 GPa |
| Stainless 17-4 PH (H900) | 1310 MPa | 1170 MPa | 7.80 g/cm3 | 197 GPa |
| Magnesium AZ31B | 260 MPa | 200 MPa | 1.77 g/cm3 | 45 GPa |
| Delrin (POM) | 70 MPa | 70 MPa | 1.41 g/cm3 | 3.1 GPa |
How each one behaves in a shop
The practical columns. Machinability decides the cycle time, anodizing behavior decides whether your product range can match colors.
| Material | Machining | Anodizing | Where it is used |
|---|---|---|---|
| Aluminum 6061-T6 | Good, fast feeds | Excellent, even color | Stems, brackets, collars, spacers, cages. The default bike part alloy |
| Aluminum 7075-T6 | Good, higher tool wear | Fair, darker and harder to match | Cranks, chainrings, direct mount rings, thin section parts |
| Aluminum 6082-T6 | Good | Good | European equivalent role to 6061, common in EU supply chains |
| Aluminum 7005-T6 | Good | Fair | Weldable high strength alloy, mostly frames rather than machined parts |
| Aluminum 2024-T3 | Good | Poor corrosion resistance, needs coating | Rare on bikes. Poor corrosion resistance is disqualifying outdoors |
| Titanium Grade 5 (Ti-6Al-4V) | Slow, high tool wear | Voltage colored, no dye, fixed palette | Axles, bolts, pivot pins, boutique hardware |
| Titanium Grade 2 | Moderate | Voltage colored | Commercially pure. Cages, non-critical hardware |
| Stainless 303 | Free machining grade | Not applicable, passivate instead | Axles, pivot pins, hardware that must not gall |
| Stainless 17-4 PH (H900) | Harder, machine before ageing | Not applicable, passivate instead | High load pins and shafts, heat treated after machining |
| Magnesium AZ31B | Fast, chip handling rules apply | Conversion coating, not standard anodize | Weight critical parts. Few shops take it, so expect longer quotes |
| Delrin (POM) | Fast, moves with heat | Not applicable | Pulley bodies, bushings, chain guides |
Finish thickness and what it does to a dimension
The column engineers forget. A coating grows about half its thickness outward from the original surface, so a diameter moves by roughly the full coating thickness and a bore loses it.
| Finish | Typical thickness | What it means for your drawing |
|---|---|---|
| Type II, decorative | 5 to 25 microns | Full dye range. Diameter moves by roughly the full coating thickness |
| Type III, hard anodize | 25 to 50 microns | Dark greys and blacks only. Larger fatigue penalty and larger dimensional change |
| Chemical conversion | Under 1 micron | Conductive, corrosion resistant, no meaningful dimensional change |
| Powder coat | 60 to 100 microns | Every bore, thread and mating face has to be masked |
| Cerakote and similar | About 25 microns | Thin, tough, wide color range, more expensive than anodize |
On a bearing seat that is the difference between a press fit and a crushed bearing. Mask the feature, machine an allowance or state on the drawing whether dimensions are before or after finishing. The anodize growth calculator gives the pre-coating size for a specific bore or shaft. Detail in the anodizing guide.
Three things this table cannot tell you
Material data is necessary and not sufficient. These are the gaps.
- Aluminum has no fatigue limitThere is no stress below which it runs forever. A bike part in aluminum has a life in cycles, so tensile strength alone does not tell you whether the part survives.
- Anodizing reduces fatigue lifeAnd the penalty grows with coating thickness. Test structural parts in the finish you will ship, not bare.
- Grain direction mattersMachined billet has grain running one way through the whole block. A forged blank has grain that follows the shape, which is why cranks were forged long before CNC existed.
Choosing between them
Deeper comparisons, written for a specific decision rather than a table.
- 6061 or 7075Strength against color matching, and why most parts should stay in 6061.
- Titanium or aluminumWhen titanium earns ten times the material cost, which is rarer than it looks.
- Machined or forgedWhere the two cost curves cross for a bike component.