Cotterpin bb conversion

Keeper of the Mighty Macaulay said:

I'm working on getting a 1960s Torpado up and running and have removed the
cranks and bottom brack spindle but can't get the fixed cup off (it's got
three notches, not opposing flat faces, and I don't have the proper diameter
lockring and hammering with a screwdriver is just damaging my screwdriver).

There's a trick to doing these with a big bolt.

See: http://www.sheldonbrown.com/tooltips/bbcups.html

Quoted message said:

I'm thinking that I could just leave the fixed cup on an get a new bottom
bracket for the other side and put on newer square-taper cranks.

That's perfectly reasonable if the cups are in decent shape.

Quoted message said:

1. If I dremel or otherwise get a good hold on the cup to put the frame in
the bench vice, which way is the fixed cup threaded?

Italian thread is right-hand on both sides, lefty loosey.

Quoted message said:

2. If I go for a new square-taper spindle, is there a formula for
determining a proper spindle length? Current spindle is 134mm end-to-end,
42mm edge-of-cone-to-end driveside, 32mm non-driveside. The bearings look
to be the same size (1/4"?) as other bottom brackets so I'm assuming I can
use the fixed cup that's well fixed in there.

That's true. You'll also want to match the distance betwixt the cone
ridges on the spindle. Italian bikes generally have 70 mm shells and
call for a 5** series spindle.

How long it needs to be is not a matter of formulae, but has to do with
the crankset you choose and the desired chainline.

See: http://sheldonbrown.com/bbsize for detailed info on that.

Sheldon "I'd Use A Shimano Cartridge Unit..." Brown
+-------------------------------------+
| Only those who attempt the absurd |
| will achieve the impossible. |
| --Albert Einstein |
+-------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Keeper of the Mighty Macaulay said:

I'm working on getting a 1960s Torpado up and running and have removed the
cranks and bottom brack spindle but can't get the fixed cup off (it's got
three notches, not opposing flat faces, and I don't have the proper diameter
lockring and hammering with a screwdriver is just damaging my screwdriver).

Which way are you trying to turn it?

Quoted message said:

I'm thinking that I could just leave the fixed cup on an get a new bottom
bracket for the other side and put on newer square-taper cranks. So I've got
few questions:

Don't do that. Those old bottom-brackets are a RPITA. Get a sealed one.
Much better.

Quoted message said:

1. If I dremel or otherwise get a good hold on the cup to put the frame
in the bench vice, which way is the fixed cup threaded?

Depends on the type of frame. Check Sheldon Brown's website for details.
One thing to check is the width of the bottom bracket shell. If it is
68mm, it is likely British, and so the right cup will be left-hand thread.
If it is 70mm, it is likely Italian, so right-hand thread. I donno what
a Torpado is, though, so .... hope it ain't French.

--

David L. Johnson

__o | There is always an easy solution to every human problem - neat,
_`\(,_ | plausible, and wrong. --H.L. Mencken
(_)/ (_) |