A replacement thru-axle needs more than “12×142”
“12×142” describes diameter and rear hub spacing. It does not fully describe the axle screwed into your frame. A replacement can look right and still have the wrong thread or seating shape.
Use the original specification
Get the axle drawing or part code from the frame maker. Robert Axle Project’s fit guide illustrates identifying length and thread pitch from an existing axle. Its length scale starts under the head; print at actual size and verify the scale with a ruler before using it. Follow the supplier’s measurement convention rather than substituting total length including the head. Do not test an uncertain pitch by forcing the axle into the frame.
Record the parts that disappear in the shorthand
For a GRARO replacement, confirm the exact frame/fork revision and whether the rear hanger interface imposes additional requirements. Front and rear need separate records. Include head/seat shape and any specified washer as well as the dimensions.
ICAN’s GRARO specification lists “100*12mm/142*12mm”. These hub-fit labels still leave replacement axle length, pitch and threaded length unspecified. A reply that only repeats “142×12” therefore leaves the order incomplete: ask for the axle drawing or part number rather than entering 142mm as its length.
| Detail | Record |
|---|---|
| Location | Front/rear, exact frame or fork |
| Dimensions | Diameter and length by supplier convention |
| Thread | Pitch and threaded length |
| Head | Seat shape and specified washer |
| Use | Normal wheel fastening or approved trainer/accessory |
Confirm before fastening
Have the replacement confirmed against the drawing and fitted using the frame/axle instructions and torque. A trainer or cargo accessory needs its own approval; a matching thread alone does not approve the load or use. Keep the original axle labelled for the bike. A nearly fitting bolt is not a useful spare.
If the rear axle meets a hanger interface, use the spare-hanger order checklist to confirm the related fastening parts as a separate item.
Sources
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