Headset thread question

KJB said:

I have an Eddy Merckx TSX steel frameset from the early 90's on its way to
me.
Also picking up a NOS Colnago Master Piu frame/fork.

Can you guys please tell me what thread headset I would need for these?
English/British or Italian?

ISO/British and Italian headsets (and hubs/freewheels) are
interchangeable with a "class b fit."

They're the same pitch and diameter, but the ISO threads are slightly
sharper (60 degree angle vs 55 for Italian.)

It is advised not to _repeatedly_ go back and forth between them, but
since Italian headsets (and freewheels) are essentially extinct, this is
a non-issue in practice.

Quoted message said:

And same question for the BB shell too!!

Those will be Italian size, not interchangeable with anything else.

The Italian BB size is larger than any other size, so if you tried to
install a different type of BB in an Italian shell, it would just fall
through.

Quickest way to check is to measure the width of the shell. Virtually
all Italian BB shells are 70 mm wide, vs 68 mm for most others.

Sheldon "Whitworthio" Brown
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kbesner-<< I have an Eddy Merckx TSX steel frameset from the early 90's on its
way to
me.
Also picking up a NOS Colnago Master Piu frame/fork.

Can you guys please tell me what thread headset I would need for these?
English/British or Italian?

And same question for the BB shell too!!

I answer-the BB are Italian for both. The fork threads are Italian as well but
a run thru with a standard BSC for die, a Campagnolo one, and you can use an
English HS. If you wish to not chase the threads, use an ITL threaded HS.

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"