sealed bottom bracket installation: chainring clearance

[[email protected]]

I had to replace the old Campy 68-mm wide, 115-mm long adjustable-cup
bottom bracket spindle on my Schwinn Paramount, and couldn't find the
old replacement parts, so I need to convert to a sealed bottom bracket.
I had plenty of chainring clearance with the old BB. I ordered a Campy
Chorus sealed unit with a 115-mm spindle, but the inner chainring
barely clears the chainstay and it hits when you flex the crank arms a
little bit. Is there something I'm missing, or doing wrong? Is there
any way to increase the chainring clearance? Thanks for your help.

 

[philcycles]

" had to replace the old Campy 68-mm wide, 115-mm long adjustable-cup
bottom bracket spindle on my Schwinn Paramount, and couldn't find the
old replacement parts, "

Parts for your no doubt Campy bottom bracket are widely avaulable.
Start with bicycleclassics.com or americancyclery.com and work upward.
Phil Brown

 

[Werehatrack]

On 5 May 2006 09:04:17 -0700, [email protected] wrote:

>I had to replace the old Campy 68-mm wide, 115-mm long adjustable-cup
>bottom bracket spindle on my Schwinn Paramount, and couldn't find the
>old replacement parts, so I need to convert to a sealed bottom bracket.
>I had plenty of chainring clearance with the old BB. I ordered a Campy
>Chorus sealed unit with a 115-mm spindle, but the inner chainring
>barely clears the chainstay and it hits when you flex the crank arms a
>little bit. Is there something I'm missing, or doing wrong? Is there
>any way to increase the chainring clearance? Thanks for your help.

I've noticed that some older BB assemblies were asymmetric; merely
measuring the shaft length doesn't always get you to the right
replacement unit. I suspect that this is what's happening here.
There may be a potential solution; if the need for added clearance at
the sprocket is small, and there's lots of clearance for the left
crank where it passes the chainstay, you can add a thin spacer (from
an old freewheel) between the BB shoulder and the frame. If the
clearance on the left is tight as well, you're hosed. In that case,
about all you can do is get a 120mm BB and install that instead.

Note that there's a limit to how much of a spacer you can use on the
BB; as the assembly is moved to the right, you run into the hazard of
the left threaded cup bottoming out on the threads before it gets
tight against the cartridge. In some cases, that's going to happen on
the first try, but usually it's possible to add about 2mm safely.

The spacer trick generally does not work with any assembly that uses a
lockring to keep the left cup in position.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

 

[Booker C. Bense]

-----BEGIN PGP SIGNED MESSAGE-----

In article <[email protected]>,
<[email protected]> wrote:
>I had to replace the old Campy 68-mm wide, 115-mm long adjustable-cup
>bottom bracket spindle on my Schwinn Paramount, and couldn't find the
>old replacement parts, so I need to convert to a sealed bottom bracket.
>I had plenty of chainring clearance with the old BB. I ordered a Campy
>Chorus sealed unit with a 115-mm spindle, but the inner chainring
>barely clears the chainstay and it hits when you flex the crank arms a
>little bit. Is there something I'm missing, or doing wrong? Is there
>any way to increase the chainring clearance? Thanks for your help.
>

_ The older BB's were asymmetrical. Your best bet would be to
either get the replacement parts, ( pretty easy online) or get
a Phil Wood BB with the appropriate asymmetrical setup.

_ Booker C. Bense

-----BEGIN PGP SIGNATURE-----
Version: 2.6.2

iQCVAwUBRFuhp2TWTAjn5N/lAQH+ugP/T3k2HaNti3lJ68YJcy8O7EwXjuwrTLju
LjcW+9Sh7eff14VP2zAV8/dQR7+RrPEZyoQcthvIcWLmO3XVCvE86iUspwLpUT6F
1npibdUh8vQeTehlB38nosrAoWOuBJKWB4P0mpK0LmTzYBIqcIWSRcxBM+Xnfn4U
sCA6Mod4nl4=
=nyRZ
-----END PGP SIGNATURE-----

 

[Qui si parla Campagnolo]

[email protected] wrote:
> I had to replace the old Campy 68-mm wide, 115-mm long adjustable-cup
> bottom bracket spindle on my Schwinn Paramount, and couldn't find the
> old replacement parts, so I need to convert to a sealed bottom bracket.
> I had plenty of chainring clearance with the old BB. I ordered a Campy
> Chorus sealed unit with a 115-mm spindle, but the inner chainring
> barely clears the chainstay and it hits when you flex the crank arms a
> little bit. Is there something I'm missing, or doing wrong? Is there
> any way to increase the chainring clearance? Thanks for your help.

These BBs are not really compatible with the older 114mm, asymmetrical
BBs, I'm assuming you have a Super/Nuovo/Gran sport crank, sounds like
a double crank, not a triple,

Phil makes a really nice compatible BB for these cranks. If it is an
early triple, like Racing T, then a AC-H or Centaur in 115mm will work,
not the Chorus or Record....in 111mm...No such animal as a 115mm Chorus
BB made today.