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Wheel Hub Differences

Discussion in 'Flat Fender Tech' started by garage gnome, Feb 24, 2021.

  1. Feb 24, 2021
    garage gnome

    garage gnome ECJ5 welder

    Western MA
    Joined:
    Jun 19, 2009
    Messages:
    3,083
    Are there any differences between a drum brake D30 hub, a D27 and a D25 hub? I have a set of D25 hubs that are machined for a disc to be mounted to the backside. From what I can see, everything looks the same including the bearings. I am upgrading the NT D30 to disc with GM calipers on my 3A.
     
  2. Feb 24, 2021
    73 cj5

    73 cj5 Not ready for the junkyard yet

    Clinton, Mississippi
    Joined:
    Jan 10, 2014
    Messages:
    2,137
    I used d25 hubs on a d30 drum axle.
     
    garage gnome likes this.
  3. Feb 24, 2021
    45es

    45es Active Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Naches, WA
    Joined:
    Mar 31, 2007
    Messages:
    1,103
    The bearings are the same but you may find as I did that the hub mounts a little far out onto the end of the spindle. I discovered there are 3 different bearing races of different widths that can be used. I had to find the correct one so the spindle nut threaded on correctly for proper thread engagement. I noted this in Focker's "Front Disc Brake Tutorial" page 2 of the thread.

    Front Disc Brake Tutorial | Page 2 | ECJ5 (earlycj5.com)
     
    47v6 likes this.
  4. Feb 24, 2021
    jpflat2a

    jpflat2a what's that noise?

    Hermosa, SD
    Joined:
    Jul 30, 2003
    Messages:
    8,513
    Be cautious here.
    There are diameter differences on the wheel bearings.
    Generally speaking, the D25 bearings are smaller in outside diameter, as is the wheel seal for a D25 hub.
    Some of the D27 wheel bearings will be the same as the D30 for drum brakes, larger in diameter.
    There was a change by serial number in the production change of the hub/bearing diameters.
    Spindle diameter (where the wheel bearings ride) will be the same for drum brakes.
    Of course there are obvious differences in spindles as far as spindle bushings vs bearings are concerned.
     
    47v6 likes this.
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