Headset probs...

[CTK]

Just checked again and top cover will not slide over step at bottom of steerer yet bottom race is loose at bottom of steerer!!!

 

[one-eyed_jim]

The thing is that we're not really talking fractions of mm- Its at least 1mm- on different steerers too. The top cover (the bit that sits just below the stem or spacers) is actually a better, tighter fit than the bottom race!!!

The difference between a JIS and an ISO crown race feels like a lot when the race is rattling on the steerer, but it's only 0.6mm. That's more than enough. It's the only real possibility, and quite a common mistake. The steerer is the same in each case, so the "top cover" should be a better fit than the crown race.

If you've got a Vernier caliper it's a five second job to check, but I'd bet beer that you've got a JIS and need ISO.

Just out of interest, what brand is the headset?

 

[one-eyed_jim]

Just checked again and top cover will not slide over step at bottom of steerer

It shouldn't. It should be a snug fit on the steerer, and the crown race seat is significantly wider.

yet bottom race is loose at bottom of steerer!!!

JIS. Trust me. I've been there.

 

[CTK]

Dia compe aheadset, no calipers to hand unfortunately...


0.6mm is a possibility I suppose what brand headset should I buy then?

 

[one-eyed_jim]

Dia compe aheadset

If you'd said Stronglight or Campag that would have ruled out JIS, but Dia Compe make both standards. I'm still betting JIS.

what brand headset should I buy then?

It doesn't matter - just make sure you get ISO this time. European and American brands will almost always be ISO - I can't think of an exception to that rule. With Japanese and Taiwanese brands you just have to make sure you get the right (ISO) variant.

 

[CTK]

OK, I am gonna use this as an oppurtunity to upgrade...

silver lining etc

Scants Chris King... looks nice

 

[dbmtb]

The "problem" is the fork manufacturer.....

Headset manufacturers produced headsets in a variety of size crown race until quite recently.

I think there are actually 3 versions..... Asian/US, Italian and French/Dutch/Belgian.

To argue a point Stronglight used to be the best at supplying the different sizes as spares.

 

[one-eyed_jim]

The "problem" is the fork manufacturer.....

Three different forks? What makes you think so?

Headset manufacturers produced headsets in a variety of size
crown race until quite recently.

Not in threadless. ISO is by far the most common on quality bikes, and JIS exists, but was always rare outside of Japanese and Taiwanese OEM.

I think there are actually 3 versions..... Asian/US, Italian and French/Dutch/Belgian.

Again, not in threadless.

In threaded, Italian and BSC headsets differ only in thread profile. French have metric threads, of course, and 1" American (Schwinn) is a very different animal from JIS.

To argue a point Stronglight used to be the best at supplying the different sizes as spares.

But not, I think, JIS races for 1" Aheadsets.

 

[Carsten]

i'm sure jim is right. did you try to mount the head set cups in the frame? they should go in very easily as they are 0.2mm smaller than the ISO cups.

Carsten

 

[GrumbleJay]

Oh dear, think I might be going to have the same problem.
Have just purchased a 1" Dia compe aheadset and hoping to fit to an old Orange Clockwork fork :?