A4 Stainless Steel Bicycle Bottle-Cage, Rack and Fender Bolts combine the dimensional form of Trade series (bicycle mounting bolts) with the material properties of grade ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80: superior, including marine and chloride environments, largely non-magnetic, service range approx. -200 °C to +400 °C, subject to the property class and the joint. This page summarizes the grade data, its corrosion behavior in service, the comparable grades, and the sizes supplied.
Why Choose A4 Stainless Steel for Bicycle Bottle-Cage, Rack and Fender Bolts
Specified for marine, coastal and chemical applications. For bicycle bottle-cage, rack and fender bolts, this matters when superior, including marine and chloride environments is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80 |
|---|---|
| Magnetic response | Largely non-magnetic |
| Service temperature | approx. -200 °C to +400 °C, subject to the property class and the joint |
| Corrosion characteristic | Superior, including marine and chloride environments |
Galvanic & Galling Considerations
Two important notes for stainless bicycle bottle-cage, rack and fender bolts: (1) stainless can gall on stainless threads under load — use a thread lubricant or anti-galling compound, especially for M6 and below; (2) when joined to aluminum or galvanized steel, stainless can drive galvanic corrosion of the less-noble metal in wet service — isolate with a coating or sleeve where appropriate.
Comparable Grades
For Bicycle Bottle-Cage, Rack and Fender Bolts, the alternative stainless grade is A2 (304). The practical dividing line is chlorides: A2 (304) is fine until salt is involved, and A4 (316) exists for the cases where it is — coastal, marine and road-salt service. Neither reaches the strength of a plated class 8.8 or 10.9 fastener.
Using Stainless Fasteners in Aluminum
Stainless steel is more noble than aluminum, so with an electrolyte present — rain, condensation, salt spray — the aluminum becomes the anode and corrodes at the joint. Area ratio decides how bad it gets: a small stainless fastener in a large aluminum section is normally acceptable, a large stainless fastener in thin aluminum is not. Where the joint gets wet, isolate the metals with a coated or nylon washer and a sealant, or specify an aluminum or coated fastener instead.
Sizes of Bicycle Bottle-Cage, Rack and Fender Bolts Available in A4 Stainless Steel
| Thread size | Length options (mm) | Drive examples | Head diameter (mm) | Head height (mm) | Typical location |
|---|---|---|---|---|---|
| M5u00d70.8 | 10 / 12 / 15 | 2.5 mm hex or T25 | 9~9.3 | 1.6~3.2 | bottle cage, fender and rack bosses |
| M5u00d70.8 | 20 or stack-selected | 2.5 mm hex or T25 | cargo, fork and rack mounts with spacers | ||
| M6u00d71.0 | application-selected | varies | frame and bracket mounting points |
