Property Class 8.8 Steel Bicycle General Threaded Fasteners are supplied to ISO 898-1 property class 8.8. Corrosion behaviour is requires plating (zinc) for corrosion 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 workhorse medium-carbon alloy class for structural joints.
- Grade
- ISO 898-1 property class 8.8
- Corrosion resistance
- Requires plating (zinc) for corrosion 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.
Property Class 8.8 Steel (ISO 898-1 property class 8.8) is the workhorse medium-carbon alloy class for structural joints. Specified on bicycle general threaded fasteners it determines the corrosion behaviour (requires plating (zinc) for corrosion protection) and the service temperature range (commonly limited to approx. +300 °C; confirm against the coating and the load); the dimensions are ours rather than a standard's, and are listed in full below.
Why Choose Property Class 8.8 Steel for Bicycle General Threaded Fasteners
The workhorse medium-carbon alloy class for structural joints. For bicycle general threaded fasteners, this matters when requires plating (zinc) for corrosion protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 898-1 property class 8.8 |
|---|
| Magnetic response | Magnetic |
|---|
| Service temperature | commonly limited to approx. +300 °C; confirm against the coating and the load |
|---|
| Corrosion characteristic | Requires plating (zinc) for corrosion 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.
Galvanic & Galling Considerations
For bicycle general threaded fasteners in steel, the dominant compatibility issue is hydrogen embrittlement at high property classes (10.9 and above) when electroplated. Plating must be followed by an appropriate baking treatment, or a non-electroplated finish (mechanical zinc, zinc flake) should be substituted.
Sizes of Bicycle General Threaded Fasteners Available in Property Class 8.8 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 8.8 Steel.
Custom manufacturing · Made to drawing
Need this screw in a grade that is not listed?
Grade 8 8 Steel is one of the grades the catalog describes. Where the standard stops, the drawing takes over: fine pitches, left-hand threads, partial threading, and property classes above the catalogued grade where material and heat treatment allow. 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
