Dura Ace freehub ID 7400 7402 7403 101
blast from the past •
This is brought up fairly frequently so I thought I'd throw something together. Shimano offered 3 different version of the 740X series freehubs, 7400, 7402 and 7403. There is NO 7401 hub. First lets clarify some terminolgy in 'Jim Speak' which is valid for the purposes of this thread only.
Freehub: Ratcheting mechanism is built into hub.
Cassette: Group of sprockets that slide onto freehub
Uni-glide cassette: group of sprockets with 1 threaded sprocket that holds it all on
Hyperglide cassette: group of sprockets that uses an inner lockring to hold it all on. All Hyperglide hubs have
FULL LENGTH splines. Important!!!
Locknut: nut that holds axle parts tightly together
126mm: flat lock nut
130mm: mushroom locknut
6-speed: flat locknut
7-speed: flat locknut
8-speed: mushroom locknut
FH-7400: Uniglide only. 126mm spacing only. Available in both 6 or 7 speed versions.
The freehub itself is identicle with the only difference being a difference in cassette spacing and number of cogs. Shimano labled these as FH-7400-6/7. From what I've been able to tell you could order a FH-7400-6 hubset that came with a 6-speed cassette or a FH-7400-7 that came with a 7-speed cassette.
FH-7402: Uniglide only. 130mm spacing. A very similar hub to the FH-7400, its just a little wider to fit 8-speeds
FH-7403: Both Uniglide and Hyperglide. 130mm spacing. Although this hub is Uni-Glide I dont believe its 1st and 2nd cog interchange with the 7400 or 7402 hubs due to difference in threaded area diameters.
So...here we go. First up is the FH-7400. Visual cues are the flat locknut which means 6/7 speed and the external threading which is a Uni-Glide feature. Notice that the splines are NOT full length. This NOT a Hyperglide hub!!!
Next up we have the FH-7402. Visual cues are the mushroom locknut which means 8-speed and the external threading which in a Uni-Glide feature. Notice that the splines are NOT full length. This is NOT a HyperGlide hub!!!
Last in the lineup is the versatle FH-7403. Visual cues are the mushroom locknut which means 8-speed and the full length splines which is a HyperGlide feature. External threading is a UniGlide feature. The FH-7403 is both a UniGlide and HyperGlide hub.