Classic & Vintage - Thread question: Super Record Headset?

Will a 1'x24Tpi-BSC Headset work on my 1983 Bianchi Specialissima?

I Know BSC stands for British Standard Cycle, so will I mess up my threads trying to install this unit?

Do I need an Italian Specific Headset, or will this work? What about the whole thing about Italian threads being cut at 55 degrees?

Little help?

Nope, wont fit. Italian, BSC, and ISO headsets share the 55 degree thread pitch, BUT the BSC headset has 26 threads per inch and Italian thread is 24 threads per inch.

Edit: The lower cup, top race, and crown race will fit into the headtube and fork crown, but the the adjustable cup and locknut that screw onto the fork wont. Just thought I'd clarify.

Per sheldon brown:


Italian threading is a curious mixture of metric and British. Diameters are specified in millimeters, but threads are in threads-per-inch! In addition, the thread angle is 55 degrees, like the obsolete British Whitworth system, rather than 60 degrees as with U.S. and metric threads.

long story short, you can force it on ad make it work, but you're going to change and weaken the threads on the headset. something you want to do once at best and preferably not at all.

won't fit well, but it'll work. I confess, I have done it. It is a real grade B fit and the chances of going back to Italian are lessened. Just send the headset to me to remove the temptation to use it...I'll find a place to put it.

Will a 1'x24Tpi-BSC Headset work on my 1983 Bianchi Specialissima?

Short answer: Yes, but it's 1", not 1'...didn't you ever see Spinal Tap? ;-)




I Know BSC stands for British Standard Cycle, so will I mess up my threads trying to install this unit?

Do I need an Italian Specific Headset, or will this work? What about the whole thing about Italian threads being cut at 55 degrees?

They are 55 vs 60 degrees, but that's the only difference in Italian vs Standard headset threading. It's a non issue unless you would later want to install an Italian thread headset again. Since Italian thread headsets are basically extinct, don't worry about it.



Nope, wont fit. Italian, BSC, and ISO headsets share the 55 degree thread pitch, BUT the BSC headset has 26 threads per inch and Italian thread is 24 threads per inch.

Sorry, every part of that is incorrect except the bit about Italian thread being 24 tpi. The only 26 tpi headsets are the extinct Raleigh proprietary size.

ISO headsets are 60 degrees, but that's not an important difference.

See: http://sheldonbrown.com/gloss_i-k.html#italian

and: http://sheldonbrown.com/cribsheet-headsets.html

Sheldon "Imaginary Problem" Brown


+-----------------------------------------------------------+
| Faith is believing what you know ain't so. --Mark Twain |
+-----------------------------------------------------------+

I still think you should just send this headset along to me and save yourself from the potential imaginary problems, though...