Property Class 12.9 Steel Bicycle General Threaded Fasteners are supplied to ISO 898-1 property class 12.9. Corrosion behaviour is requires plating or black-oxide protection, the material is magnetic, and the usable service range is commonly limited to approx. +300 °C; confirm against the coating and the load. In practice this grade is the highest common strength class, for high-load machine assembly.
- Grade
- ISO 898-1 property class 12.9
- Corrosion resistance
- Requires plating or black-oxide protection
- Magnetic response
- Magnetic
- Service temperature
- commonly limited to approx. +300 °C; confirm against the coating and the load
Property values are typical for the grade. Certified mechanical test data is available on request for production orders.
Material page for bicycle general threaded fasteners in Property Class 12.9 Steel (ISO 898-1 property class 12.9). The sizes below are the ones we supply; there is no published dimensional standard for this article, so the table rather than a standard number is what to quote. Corrosion behaviour is requires plating or black-oxide protection and the service range is commonly limited to approx. +300 °C; confirm against the coating and the load.
Why Choose Property Class 12.9 Steel for Bicycle General Threaded Fasteners
The highest common strength class, for high-load machine assembly. For bicycle general threaded fasteners, this matters when requires plating or black-oxide protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 898-1 property class 12.9 |
|---|
| Magnetic response | Magnetic |
|---|
| Service temperature | commonly limited to approx. +300 °C; confirm against the coating and the load |
|---|
| Corrosion characteristic | Requires plating or black-oxide protection |
|---|
Corrosion Behavior in Service
Carbon and alloy steel bicycle general threaded fasteners require a coating for corrosion protection. Zinc plating (with or without passivation) is the most common; hot-dip galvanizing is used for outdoor structural service; black-oxide is mainly a tarnish-prevention finish for tool-room use.
Comparable Grades
For Bicycle General Threaded Fasteners, class 8.8 is the comparable strength step. Move up when the joint preload approaches the proof load of the current class; move down when the joint is over-specified. For corrosion-critical service, switch to stainless A2 or A4.
Sizes of Bicycle General Threaded Fasteners Available in Property Class 12.9 Steel
| Thread designation | Pitch | Typical bicycle location |
|---|
| M3 | 0.5 | dropout adjustment and small accessory hardware |
| M4 | 0.7 | some derailleur limit screws |
| M4 | 0.75 | common JIS derailleur limit screws |
| M5 | 0.8 | pinch bolts, rotor, fender, rack and bottle-cage mounts |
| M6 | 1.0 | brake caliper, brake pad and rack/fender hardware |
| M7 | 1.0 | some handlebar binder bolts |
| M8 | 0.75 | chainring bolts |
| M8 | 1.25 | stem, crank and suspension hardware |
| 2.2 mm spoke | 56 TPI | common 2 mm spoke threading |
Dimensions are independent of the material: every size above is available in Property Class 12.9 Steel.
Custom manufacturing · Made to drawing
Need this screw in a grade that is not listed?
Grade 12 9 Steel is one of the grades the catalog describes. Thread size and pitch, length, property class, drive form, head geometry and head marking are all specifiable — the standard part is where it starts, not where it stops. Made by cold heading or warm forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
Custom screw manufacturingSend a drawing
Applications & Industries
Bicycle General Threaded Fasteners are bought for a small number of well-defined jobs. These are the ones we ship them for. Stocked from M3 to 2.2 mm spoke.
Industries that specify Bicycle General Threaded Fasteners
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Wheel building
The spoke thread is a separate selection from the machine fasteners.
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Bicycle assembly
Metric thread families cover adjustment, brake, rack and accessory hardware.
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Bike service shops
The pitch distinction prevents a similar-size replacement from cross-threading.
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Performance bicycles
M5 and M6 hardware secures common frame and brake points.
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Food, pharma & cleanroom
Stainless assemblies that are washed down, where the finish matters as much as the strength.
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Machine building & OEM
The default fastener on production equipment: covers, brackets, motor mounts and sub-assemblies tightened to a specified torque.
Typical applications
- keeping spoke threading separate from metric bolt threading
- identifying the exact bicycle thread and pitch
- matching M4 0.7 to M4 0.75 where required
- selecting M5 or M6 hardware by frame location
- joints where the property class is stated on the drawing
- clamping two machined faces to a calculated preload
Service conditions to specify against
- Marine and coastal
- Available in A4 (316) stainless for chloride exposure — coastal structures, pool halls, water treatment and deck hardware, where A2 will eventually pit.
- High load
- Supplied in ISO 898-1 property classes, so the joint can be designed to a stated proof load and tightened to a calculated torque rather than by feel.
- Torque and preload
- The joint is designed around bolt tension, so lubrication, coating and the friction coefficient all change the torque figure — state them together.
Where to use something else
- Do not infer bicycle compatibility from diameter alone; pitch, head style and frame boss depth all matter.
- Do not use a machine thread into unthreaded sheet or timber; use a tapping screw, rivet nut or insert made for that parent material.
Full application guide: where Bicycle General Threaded Fasteners are used, how to specify them, and the cases they are wrong for
