The bicycle industry has a long
history of using many different thread standards. Both factional and
metric sizes are in use. Some threads are also used almost exclusively
in the bicycle industry. Below is a table of some of the threads and
their uses. This table is not intended to be complete and exhaustive.
Always measure diameter and pitch when possible to determine threading.
Nominal Thread Size
Example of Bicycle Uses
2.2mm x 56 tpi
Common 2mm spoke threading
3mm x 0.5mm
Dropout adjustment screws, some derailleur hardware, accessory hardware
4mm x 0.7mm
Some derailleur limit screws (DIN standard)
4mm x 0.75mm
Common derailleur limit screw (JIS standard)
5mm x 0.8mm
Many
uses on bicycles, including derailleur wire pinch bolts/nuts, disc
rotor mounting bolts, fender and racks mounts, water bottle cage bolts,
and others
6mm x 1mm
Many uses on bicycles,
including brake caliper mounting bolts, brake pad bolts/nuts, some
fender racks, some brake adjusting barrels
7mm x 1mm
Some handlebar binder bolts
5/16 inch x 24 tpi
Front hubs, solid axle, less expensive bikes
8mm x 1mm
Square-type crank bolts, front solid axle hubs, suspension system hardware
8mm x 1.25mm
Stem hardware, stud type crank nuts, suspension hardware
8mm x 0.75mm
Chainring bolt
9mm x 1mm
Front hubs, quick release, Asian manufacturer
9mm x 26 tpi
Front hubs, Campagnolo®
3/8 inch x 24 tpi
Some solid axle bike, including coaster brake
3/8 inch x 26 tpi
Solid rear axle
10mm x 1mm
Most quick release rear axles, derailleur mounting bolts, brake lever adjusting barrels
10mm x 26 tpi
Rear axle, quick release, Campganolo®
12mm x 1mm
Some spline crankset bolts
1/2 inch x 20 tpi
Pedal threads, one-piece cranks
9/16 inch x 20 tpi
Pedal threads- common three piece cranks
14mm x 1mm
Oversized frestyle axles
15mm x 1mm tpi
Crank bolt, Octalink® and ISIS Drive®
1-inch x 24 tpi
Threaded headsets, one-inch standard
1-1/8 inch x 26 tpi
Thread headset, 1-1/8 inch standard
1-1/4 inch x 26 tpi
Thread headset, 1-1/4 inch standard
1.37 inch x 24 tpi
Bottom brackets, ISO/English/BSC, and threaded freewheel hubs
