Star nut v expansion bolt

Tigger con carne
Tigger con carne Posts: 181
edited March 2014 in MTB workshop & tech
Is there any advantage to getting an expansion bolt like this or this over a regular star nut for the alloy steerer of my new Rebas? It seems straight forward to install a star nut from Park Tools and elsewhere, but I can see how it might go wrong

Comments

  • Antm81
    Antm81 Posts: 1,406
    I use a hope one, works fine but the only advantage I can see is that it was a lot easier when changing forks being easily reuseable
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  • rockmonkeysc
    rockmonkeysc Posts: 14,774
    No advantage at all.
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  • nicklouse
    nicklouse Posts: 50,675
    One is lighter than the other. One costs more than the other.

    I have a whole pile of unused expanders in my tool box.
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  • arthur_scrimshaw
    arthur_scrimshaw Posts: 2,596
    Don't expansion bolts tend to get used in forks with carbon steerer tubes?
  • nicklouse
    nicklouse Posts: 50,675
    Arthur Scrimshaw wrote:
    Don't expansion bolts tend to get used in forks with carbon steerer tubes?
    Well you don't want to be using a star flanged nut in a fork with a carbon steerer.
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  • arthur_scrimshaw
    arthur_scrimshaw Posts: 2,596
    nicklouse wrote:
    Arthur Scrimshaw wrote:
    Don't expansion bolts tend to get used in forks with carbon steerer tubes?
    Well you don't want to be using a star flanged nut in a fork with a carbon steerer.

    Quite, what I meant was they are for carbon steerer's rather than aluminium and steel.
  • Chunkers1980
    Chunkers1980 Posts: 8,035
    No, they are for use in all steerers, just happens they are most use for carbon.
  • WindyG
    WindyG Posts: 1,099
    edited March 2014
    If you correctly fit an expander they are fine and easier if your cack handed fitting a star nut but they are overpriced for what they are compared to a star nut doing the same job.
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  • supersonic
    supersonic Posts: 82,708
    SFN for steel and alu. Expander for carbon.
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  • nicklouse
    nicklouse Posts: 50,675
    Arthur Scrimshaw wrote:
    nicklouse wrote:
    Arthur Scrimshaw wrote:
    Don't expansion bolts tend to get used in forks with carbon steerer tubes?
    Well you don't want to be using a star flanged nut in a fork with a carbon steerer.

    Quite, what I meant was they are for carbon steerer's rather than aluminium and steel.
    Nope. But some expanders are not that good for carbon steerers.

    Some have even been suggested as being responsible for splitting open steel or alloy steerers.

    Most expanders marketed at carbon steerers are a lot longer than, many, and are also knurled to provide greater grip for less force.

    Also some expanders will not fit some steerers.
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  • Tigger con carne
    Tigger con carne Posts: 181
    Looks like I'll get a star nut then. I don't think I'm particularly cack-handed so it should be OK installing it. Thanks for all for the input
  • njee20
    njee20 Posts: 9,613
    supersonic wrote:
    SFN for steel and alu. Expander for carbon.

    This. Even then, a lot of the expanders for carbon steerers are so much heavier than a SFN they negate half the weight savings.
  • poah
    poah Posts: 3,369
    nicklouse wrote:
    Also some expanders will not fit some steerers.

    yip, took my hope head doctor out of my manitou's and the ID of the pike's steerer is too small. had to use a SFN but reused the hope cap.
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  • Giraffoto
    Giraffoto Posts: 2,078
    Considering how little force it has to apply the SFN is way over-specified for the job, so I'd be inclined to use an expander in all circumstances. You'd have to be extraordinarily ham-fisted to tighten one up enough to damage the steerer, whereas the SFN does tend to scratch the inside of the steerer on the way down
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  • njee20
    njee20 Posts: 9,613
    Considering how little force it has to apply the SFN is way over-specified for the job, so I'd be inclined to use an expander in all circumstances.

    But they're cheaper and lighter and they definitely won't cause your steerer to crack! I don't see why anyone would ever use an expander if they didn't have to.

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