Fitting a new threaded headset

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.
 

ianrauk

Tattooed Beat Messiah
Take it to a bike shop to get done :okay:
 

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.
 
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OP
Alan O

Alan O

Über Member
Location
Liverpool
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.
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
 

Smokin Joe

Legendary Member
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.
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.
 
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.
 

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.
 

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!
 
OP
Alan O

Alan O

Über Member
Location
Liverpool
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?

View attachment 361977
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)
 
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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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