Forum home Road cycling forum Workshop

Giant OD2 headset top bearing

kingofthetailwindkingofthetailwind Posts: 571
edited December 2016 in Workshop
So I replaced the headset bearings on my 2014 TCR Composite 1 today.

The bottom bearing was fine, but the top bearing seems to be a different height. The old bearing was 8mm tall but the new one is 6mm. Googling seems to suggest that 6mm is the correct height.

It's fitted now and seems 100%. Could it be that the one originally fitted was the wrong size? There was a lot of crud accumulated on top of the lower bearing, would this indicate that the original bearing was too tall and the headset wasn't properly sealed?


  • dj58dj58 Posts: 2,184
    The spec for your bike shows it as having the standard OverDrive (1 1/8" - 1 1/4") headset not the OverDrive2 (1 1/4" - 1.1/2").

    Top Bearing should be one of these ... backstep=1
  • The new and old bearings were identical in size, apart from the height of the top bearing.

    So it's got to be OverDrive2? Smaller OverDrive bearings wouldn't have fitted onto the steerer?
  • dj58dj58 Posts: 2,184
    Non of the 2014 TCR Composite models had OD2 headsets from what I can see on The Giant website archive, so if you are convinced that your bike is OD2 it must be an TCR Advanced 1 model, which did have OD2 along with the Advanced SL models.

    If it is an FSA type like this, it shows the top bearing to be 6mm deep. ... -ACB-1.pdf
Sign In or Register to comment.