Dura-Ace hub problem

2alexcoo Posts: 251
edited March 2010 in Workshop
I'm a bit miffed to discover that the axle in my 7800 rear hub is bent!

I imagine my not inconsiderable heft is a contributory factor, but to my mind the hub has a bit of a design flaw. The drive side bearings are inboard of the freehub:

Dura-Ace exploded diagram

Whereas on an Ultegra hub they are outboard, supporting the axle over its whole length:

Ultegra exploded diagram

Sheldon Brown states that moving the bearings outboard was one of the big improvements of cassette hubs over screw-on freewheels. It seems daft to me that Shimano would change this design for their top of the range hub, unless there's something I'm missing.

Anyone else broke one of these, or am I just unlucky?


  • keef66
    keef66 Posts: 13,123
    You're right, it does seem a bit daft. I can only assume that in some way this helped in reducing weight, which at this end of the price spectrum is more important than durability

    My only experience of axle failure was on my son's mtb which does indeed have the old screw-on freewheel.
  • rake
    rake Posts: 3,204
    theyve gone back to the normal freehub i think on dura ace. its like many 4 cartridge bearing hubs, there is a nasty stress on the axle where the hub meets the body. why they try and use oversized axles probably.