I am planning on making the above replacement.

The original fork is the composite fork with alloy steerer, however the replacement (from Giant) has a carbon steerer. Can I still use the same original headset?

  • 1
    Can't see why not. You'll need to be more particular about torque clamping pressure, so absolutely use a torque wrench. If your existing parts don't clamp at that torque they'll need replacing, not overtightening. (NAA cos never done it myself.) Probably the right time to fit new bearings though, not reuse old ones in the headset.
    – Criggie
    Apr 10, 2019 at 19:50
  • If the steerers have the same dimensions I don't see why not. I've never heard of CFC specific headset bearings. Apr 10, 2019 at 20:08
  • The only possible issue is if Giant sent a fork with the overdrive2 steerer (1 and 1/4) which will use different bearings. Compare the steerer widths when you get the replacement.
    – Rider_X
    Apr 10, 2019 at 20:22
  • @Rider_X I can confirm that they are OD1 - just measured to double check. Apr 10, 2019 at 20:56

2 Answers 2


As other have stated you should be able to use the old headset providing it is in good condition. If you are swapping forks due to an accident then replace the headset even if it feels smooth. Your alloy steerer likely used a "star fangled nut " to apply the headset preload. With a carbon steerer you need a expandable plug that is made for use with carbon steerers.

  • I've decided to use expandable plugs instead of star-fangled nuts even for alloy steerers. Star-fangled nuts are a pain to deal with, and can't easily be removed. Apr 11, 2019 at 11:05
  • @mikes thanks for the advice - the change is indeed due to a crash so I will look into getting a new headset. The fork came with the expandable plug, so that's taken care of. I am wondering about what kind of anti-seize to use on the on the bearings - is this decision affected by the use of carbon components? Apr 11, 2019 at 19:20

Giant make forks with two different steerer tube diameters. Overdrive is a standard 28.6 mm (1 1/8"), while Overdrive2 is an oversized 31.8 mm (1 1/4") steerer. Provided that the new fork has the same steerer tube diameter, you should be fine.

Giant's bike archive doesn't include the specs for the 2013 defy 4, but it has the 2013 defy 3 and defy 5 listed as both having the Overdrive steerer (28.6 mm), so it's safe to assume that yours will too. This means that if the fork is Overdrive, with a 28.6mm steerer, then it'll work fine.

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