01
Threads that creep or strip
A stem clamp bolt tightened to 6 Nm pulls threads if the pilot hole runs oversized or the chamfer cuts into the first thread. Riders strip it at the trailhead, and the part comes back.
Bicycle Components
CNC Machined Aluminum Bicycle Components
GreatLight machines aluminum bicycle parts to ±0.005 mm: stems, dropouts, chainrings, seat clamps. Five-axis work, anodized finishes, and DFM feedback inside 12 hours.
±0.005 mm6061-T6 & 7075No MOQAnodizing in-houseNDA on request
±0.005 mmMachining tolerance
16Simultaneous 5-axis centers
3–5 daysTypical part shipping
99.99%Qualification rate
Common Problems
Where Aluminum Bicycle Parts Go Wrong
Most failures we see trace back to the same four issues.
02
Wall thickness that varies
A chainring spider that measures 4.2 mm on one arm and 3.6 mm on another flexes under load. Shifting gets vague, and fatigue life drops at the thin arm.
03
Anodize color that does not match
Parts from two lots come back a shade apart. Clear anodize on 6061 reads warmer than on 7075, and dye uptake changes with surface finish. Mixed lots on one bike look wrong.
04
Round parts machined on square setups
A hub shell held in a three-jaw chuck for every operation drifts between setups. Bearing bores end up 0.03 mm off center, and the wheel never runs true.
How We Machine It
One Setup, One Datum, One Inspection Sheet
The process is built around keeping the datum consistent from blank to finished part.
Setup Strategy
Five-Axis Work for Parts With Angles
Stems, seat clamps, and linkage plates rarely sit square to a vise. On our 16 simultaneous 5-axis centers, we machine the bearing bore, the clamp slot, and the bolt face in one setup. That removes the stack-up you get when a part moves between three fixtures.
For a 7075 stem, we rough at 12,000 rpm, leave 0.3 mm on the bore, then finish after a stress-relief pause. The bore stays round because the material is not moving under the cutter anymore.
- 1Ø400 mm rotary tableHandles hub shells and large chainrings in one rotation.
- 24,000 mm travel on the large frameCovers tandem and cargo-bike frame sections.
- 3±0.005 mm positional toleranceHolds bolt circles and bearing seats across the run.
Material & Finish
Picking 6061-T6, 7075, or 6082
6061-T6 is the default for stems, dropouts, and seat posts. It welds, anodizes evenly, and costs less than 7075. Yield sits around 276 MPa, which is enough for most clamped joints.
7075 machines cleaner and runs about 503 MPa yield, so it suits chainring spiders and suspension links where stiffness per gram matters. It does not weld well and anodizes darker, so keep it away from clear-anodized 6061 on the same bike.
6082 and 6063 cover extruded or welded assemblies. 2024 is for high-load plates, but it needs a protective finish because it corrodes faster than the 6000 series.
- 16061-T6General structural parts, good anodize response.
- 27075-T6High-stress links and spiders, tighter grain.
- 36082 / 6063Welded or extruded frame furniture.
Alloy Selection
Which Aluminum for Which Bicycle Part
Match the alloy to the load case, not to the drawing default.
| Part | Alloy | Why |
|---|---|---|
| Stem body | 6061-T6 | Weldable, even anodize, 276 MPa yield |
| Chainring spider | 7075-T6 | 503 MPa yield, holds stiffness at low mass |
| Suspension link | 7075-T6 | Fatigue resistance under reversing load |
| Hub shell | 6061-T6 | Machines well, takes bearing press fits |
| Seat post | 6082-T6 | Good strength after welding |
| Cargo frame bracket | 6061-T6 | Thick sections, easy to anodize |
Capabilities
What We Run for Bicycle Work
Six processes that cover most aluminum bicycle programs.
01
5-Axis CNC Machining
Stems, links, and dropouts machined in one setup on 16 simultaneous 5-axis centers. Angular faces and bores hold position without refixturing.
02
CNC Milling & Turning
Mill-turn centers cut hub shells and bottom bracket cups from bar stock. OD turning and cross-drilling happen in one cycle.
03
Rapid Prototyping
One-off stems and brackets for fit checks before tooling. Same alloy as production so the ride feel transfers.
04
Surface Finishing
Anodizing in clear, color, hardcoat, and conductive grades. Bead blasting and brushing set the texture before dye.
05
Laser Marking
Torque specs, logos, and serial numbers engraved at 1.5 mm minimum character height. Readable after anodize.
06
Inspection & Reports
Raw material check, in-process monitoring, and final inspection on every lot. Dimensional reports on request.
Scope
Tolerance, Size, and Volume Ranges
Numbers to check before you send a drawing.
| Item | Range | Note |
|---|---|---|
| General tolerance | ±0.005 mm | Tighter on request where geometry allows |
| As-machined finish | Ra 1.6–3.2 μm | Standard off the cutter |
| Fine finish | Ra 0.2–0.8 μm | Adds a finishing pass |
| Maximum part size | 4,000 mm | On the large-travel frame |
| Order quantity | 1 to 10,000+ | No minimum order quantity |
| Quote turnaround | 12 hours | Includes free DFM analysis |
Why GreatLight
What You Get With the Parts
Six things that decide whether a bicycle program runs smoothly.
15Y
Machining since 2011
Fifteen years of aluminum work across three wholly-owned plants and 7,600 m² of floor space, with 150 technicians on staff.
±0.005
Tolerance held in millimeters
Bearing bores, bolt circles, and press fits come off the machine inside ±0.005 mm. That is the number we inspect against.
12H
Quote and DFM in 12 hours
Send a STEP file and we return pricing plus a DFM note flagging thin walls, tight corners, and datum conflicts before cutting metal.
24H
Production starts in 24 hours
Once drawings and material are confirmed, the first setup goes on the machine the next working day.
99.99%
Qualification rate
100% inspection before shipment, with raw material check and in-process monitoring behind it. Reports on request.
NDA
Confidential by default
Uploads stay secure, and we sign a non-disclosure agreement before reviewing your frame or linkage geometry.
127High-precision CNC machines
7,600 m²Manufacturing space
150Technicians on staff
<2%Historical late-delivery rate
Industry Fit
Where These Parts Get Used
Low-volume frame runs
Small-batch aluminum frame furniture machined to the same datum as the prototype.
- 1 to 10,000+ parts
- No MOQ
- 3–5 day shipping
E-bike drive brackets
Motor mounts and torque plates that need flat mating faces and tight bore alignment.
- ±0.005 mm
- 6061-T6
- Hardcoat anodize
Cargo and utility bikes
Long brackets and rack plates cut on the 4,000 mm travel frame.
- 4,000 mm max
- 6082-T6
- Bead blasted
Prototype linkage sets
One-off suspension links for ride testing before committing to a batch.
- 7075-T6
- Ra 0.8–1.6 μm
- 12-hour quote
FAQs
Questions Engineers Ask Before Ordering
Which aluminum alloy should a stem be made from?
6061-T6 covers most stems. It welds if you build the stem from sections, anodizes evenly in clear or color, and holds a 276 MPa yield.
Go to 7075-T6 only if you need the extra stiffness at lower mass and you are not welding. 7075 anodizes darker, so do not mix it with clear-anodized 6061 on the same bike.
How tight can you hold a bearing bore?
±0.005 mm on diameter is our standard machining tolerance, and bearing seats are inspected against it.
If the bore is a press fit for a cartridge bearing, tell us the bearing part number. We machine to the bearing's published tolerance rather than a generic number.
Do you anodize in-house or send it out?
Finishing runs through our surface finishing service, including clear, color, hardcoat, and conductive anodizing, plus plating, powder coating, and black oxide.
Because the finish sits in the same production chain, we can sequence bead blasting and dye so parts from one lot match in color.
What file format do you need for a quote?
Send a STEP or IGES file plus a 2D drawing with tolerances and critical dimensions marked. A PDF drawing alone works if it carries the GD&T.
We return pricing and a DFM note within 12 hours. The note flags thin walls, sharp internal corners, and datum conflicts before anything is cut.
Can you make just one prototype?
Yes. There is no minimum order quantity, so a single stem or linkage plate is fine.
Prototypes run on the same machines as production parts and in the same alloy, so the fit and stiffness you test carry over to the batch.
How do you handle thin walls on a lightweight part?
We check wall thickness against the alloy and the part's load path during DFM. 6061-T6 below about 0.8 mm starts to deflect under finishing and clamping pressure.
Where a design needs a very thin section, we adjust the fixturing and take lighter finishing passes instead of leaving the wall unsupported.
What inspection comes with an order?
Every lot gets a raw material check, in-process monitoring, and a final inspection before shipment. That is 100% inspection, not sampling.
Dimensional reports and material certificates are available on request, and we can add first-article inspection for a new part number.
Do you sign an NDA for frame geometry?
Yes. Uploads are handled as confidential, and we sign a non-disclosure agreement before reviewing drawings if you prefer to have it in writing.
Frame geometry and linkage layouts are the kind of thing that should not circulate, so we keep project files limited to the people machining the part.
Send Your Aluminum Bicycle Part for a Quote
Upload a STEP file and drawing. We return pricing and DFM feedback within 12 hours, and there is no minimum order quantity.
12-hour quote100% inspectionNo MOQNDA on request
