BB thread

[3narf]

I have an old Falcon frame and was wondering which BB thread it has.

It's probably c. late '70s / early '80s unless someone knows more precisely (it's a Team Equipe, see Photo Gallery thread '£10 Falcon' for pics).

I have a thread guage and can measure the cups that came out, if anyone knows the TPIs of the respective threads...

Many thanks!

 

[tyred]

I'd expect it to be 1 3/8" x 24 tpi

 

[guitarpete247]

Sheldon's BB size chart might give you some Idea of possiblities. British I.S.O. or Raleigh. Did it have anything on the cups or are they missing?

 

[PpPete]

I'd expect it to be 1 3/8" x 24 tpi

I'd be surprised if it was anything different !

 

[3narf]

Sheldon's BB size chart might give you some Idea of possiblities. British I.S.O. or Raleigh. Did it have anything on the cups or are they missing?

No, they're in my workshop so I'll have a look tomorrow.

Thanks.

 

[3narf]

Well, 'tis as you say; 24 tpi and 1 3/8"!

Is that good news or bad? Do I have to wait 'til the 24th Dec when Santa's elves make the next batch of special BBs?

Or is this size actually widely available?

 

[tyred]

This size is the standard BSA size and is very easily available. Virtually any cups you buy will fit.

 

[3narf]

I'm hoping to use a cartridge BB... Is it the same thread as a standard Shimano (or compatible) BB?

 

[PpPete]

Yes any cartridge BB that is marked "English Thread" will fit.

Make sure the threads on the frame are thoroughly clean... you don't want to exert too much force winding in that plastic ring that Shimano insist on... and it's threaded length is longer than an old-school cup, so you could be into unused and still rough old thread. With steel cups you could just lean on them to overcome any thread imperfections. Plastic won't accept that abuse and it's all too easy to start breaking those splines.

 

[3narf]

That's great, thanks.

Will be careful with that cup...