1.5″ Steerer, Internal Headset?

It can be done. Take your Internal headset bike and make sure it has a 44mm I.D…

44mm ID headtube

Then get a 44mm headset whcih takes 1.5″ steerers, there’s a few available, but Nukeproof is easy to get. You need to reduce the throat length of the headset to suit the inset depth on your frame though, as no one in the entire universe has a reaming tool to fit these frames!

Spin 'em down

Bosh it all together and voila – fat forks in a skinny bike. Easy!

Pace with 1.5

13 Responses to “1.5″ Steerer, Internal Headset?”

  1. Andy says:

    This is exactly what I’d like to do! – it would be neat if someone compiled a list of compatible frames though…. Nuke Proof now do that headset in deep cup and non-deep cup versions, so maybe no cutting down of the throat is necessary with the non-deep cup on some frames.

  2. Sideways Tim says:

    That was the non-deep version. Sadly it’s not non-deep enough, as most internal headset frames are only reamed down about 10mm.

    Happy to sort one out for you though.

  3. Jonathan says:

    Park Tool have a 15mm one, they’re in the Universe… kinda.

  4. Sideways Tim says:

    If it’s anything like the 1.5″ reamer, then it’s only £370.


  5. Jonathan says:

    Yours for $100-ish US. You’ll feel like you’re robbin’ ’em. Provided you already have the HTR1, yours for one million dollars!

  6. PJ says:

    What did you use to cut down the headset? The ones you did looks really good! =)
    I’m looking to do the same, but need to get the cup depth down to a headtube that will only take 6.5mm insertion.
    Do you think it will be possible?

  7. Andy says:

    I’d like to ask the same question! Would only 6.5mm depth be safe?

  8. Sideways Tim says:

    Lathe. I can’t see why 6mm isn’t possible. By altering the cups you invalidated the warranty anyway, but how many broken headset cups have you ever had?
    Go for it!

    Please note I am not an engineer, all opinions are mine and based on being drunk or hungover. Your investment can go down as well as up and your home is at risk from alien invasion.

  9. PJ says:


    Yes, it shouldn’t be any more of a problem then using a standard ZS headset that are <6.5mm in my opinion..

    So how did you go about cutting them?
    The edges look to good to be done by a simple hacksaw..

  10. Sideways Tim says:

    They’re done in a lathe. I wish I could hacksaw that neatly 🙂

  11. Andy says:

    Cool, ok, final question! Could you do this with a Tranny?

  12. Andy says:

    In case you are wondering, I have 110-140mm U-turn Revs with 1.5″ straight steerer. If I put them on a Tranny I’d probably run them only at 110mm!

  13. Sideways Tim says:

    No reason why not that I can see. The top cup in the Tranny I just built was a horrid thing, not sure if it was standard fit though. Do they come with a headset included?