Fitting a new threaded headset

Discussion in 'Bicycle Mechanics and Repairs' started by Alan O, 13 Jul 2017.

  1. Alan O

    Alan O Über Member

    Location:
    Liverpool
    I've serviced headsets before, and got them apart and back together again just fine. Now I'm trying to fit a brand new one for the very first time, a 1" steel Tange one - and I didn't expect to be so hard.

    Firstly, the race that goes on the fork crown doesn't fit. I thought positioning an adjustable wrench across the top and whacking that with a hammer would seat it - but this one simply won't fit.

    Aha, "If necessary, mill the fork crown to fit inside the diameter of the crown race", it says in the instructions. I wasn't expecting to have to do that, and I wonder how long it will take with my hand files.

    Then the cup and cone that fit the bottom and top of the head tube respectively won't fit either. And again, "The head tube may have to be reamed using a head tube reamer". Oh dear, I don't have one of those, it would probably take about six months to do it by hand with a file, and the Dremel I had years ago got lost in a move somewhere - I might have to get a new one.

    Finally, the lock washer that goes under the lock nut at the very top has a little protuberance that's presumably intended to fit a notch at the top of the steerer - but the steerer doesn't have a notch, just continuous threading all the way round.

    It's turning out to be by far the hardest part of building a bike, but I guess we live and learn.

    Anyone else had similar problems? All suggestions welcome.
     
  2. ianrauk

    ianrauk Tattooed Beat Messiah

    Take it to a bike shop to get done :okay:
     
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  3. OP
    OP
    Alan O

    Alan O Über Member

    Location:
    Liverpool
    I knew someone would suggest that ^_^
     
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  4. Drago

    Drago Flouncing Nobber

    Location:
    Valhalla
    Put the necessary components in a freezer and then use a headset press to install the races in the steerer tube while they're cold.

    A ring spanner just bigger than the fork steerer can be used to hammer on the bottom race, but great care must be taken. You can also put the forks in the freezer and try heating the race - every little helps.
     
    Last edited: 13 Jul 2017
    Alan O likes this.
  5. OP
    OP
    Alan O

    Alan O Über Member

    Location:
    Liverpool
    Interesting, thanks, I hadn't thought about using heat/cold. Unfortunately we only have a small freezer and I can't fit the forks in, but I can try freezing the cup and cone to see if they'll fit in the head tube that way, and I can try heating the crown race.

    The ring spanner idea is pretty much what I meant about using an adjustable wrench.

    Cheers,
    Alan
     
    Drago likes this.
  6. Smokin Joe

    Smokin Joe Legendary Member

    If the fit is too tight the crown race can split, as I once found out.
     
    Alan O likes this.
  7. OP
    OP
    Alan O

    Alan O Über Member

    Location:
    Liverpool
    Ah, thanks - I'll keep filing. And I should be able to track down a Dremel I can use.
     
  8. Milkfloat

    Milkfloat Veteran

    Location:
    Midlands
    If it is a cartridge bearing a split may not be too much of a problem. I use a bit of plastic waste pipe to fit crown races and a big hammer.
     
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  9. Smokin Joe

    Smokin Joe Legendary Member

    If it is a cartridge bearing headset them splitting the crown race - which is only a locating ring on such sets - is no problem at all. I saw a slot in mine to make them easier to fit. The Op is fitting a threaded headset, however.
     
    Alan O likes this.
  10. OP
    OP
    Alan O

    Alan O Über Member

    Location:
    Liverpool
    What I don't really understand is why the parts need to be so tight fastening on the fork crown and in both ends of the head tube - I'd have thought screwing everything down would hold it all together well enough.
     
  11. raleighnut

    raleighnut Guru

    Location:
    On 3 Wheels
    Whenever I've come across a bottom race that was too tight I've popped down to see John at Bob Warners, he's got a box full of slightly different sized ones and I've found one to fit without problems.
     
  12. ChrisEyles

    ChrisEyles Veteran

    Location:
    Devon
    Sounds like a toughie!

    I use a wooden mallet when installing headset cups and fork races, and I must have been lucky so far from the sounds of it, they've all tapped in OK. I have had to saw slots in the bottom fork crown race a couple of times for cartridge headsets, but you don't want to do that on a threaded one. I'm afraid I haven't had any luck with hot/cold treatments for fitting these (or on cotter pins or seatposts either for that matter).

    The notch in the washer you can file off to fit the threaded steerer if you need to without any issues. The other issues I would admit defeat on and take it to a bike shop I'm afraid.

    Good luck wth the filing, let us know if you succeed!
     
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  13. midlife

    midlife Guru

    Hard plastic pipe from a DIY store should be enough to smack home a fork race, if not you need to check sizes, have you got a calliper you can measure the fork with?

    IMG_1058.jpg
     
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  14. OP
    OP
    Alan O

    Alan O Über Member

    Location:
    Liverpool
    Nope, a plastic pipe certainly won't do it.

    To the nearest 0.1mm...
    Steerer tube dia = 25.7mm
    Steerer dia at the threads = 25.4mm
    Crown race internal dia = 26.2mm
    Fork crown thing = 26.5mm

    It seems the thing on the fork crown that the race is supposed to fit on is 0.3mm wider than the race internal diameter.

    (updated after checking again)
     
    Last edited: 14 Jul 2017
  15. midlife

    midlife Guru

    Is it an Italian bike? I'll have to go look at Sheldon Brown site on headsets to check sizes but some fork races were larger depending on origin.
     
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