Record BB binding after reinstall

I'm building up a used Seven Axiom Ti frame and when I reinstall the BB
that was originally on the bike, I can't get anywhere near the spec'd
torque without a noticable increase in friction on the spindle. If this
is the original BB that was on the bike, why would it be binding?

James

On 4 Feb 2006 10:19:19 -0800, wrote:

Seven Axiom Ti frame

Are you using a Campy cartridge?

It is possible one of the press fit bearings is not pressed all the
way onto the spindle.

The adjusting cup usually only puts pressure on the outer race of the
bearing.

Check the cartridge and make sure there is no gap between the outside
race of the bearing and the tube body of the cartridge.

wrote:
I'm building up a used Seven Axiom Ti frame and when I reinstall the
BB that was originally on the bike, I can't get anywhere near the
spec'd torque without a noticable increase in friction on the
spindle. If this is the original BB that was on the bike, why would
it be binding?

Maybe it wasn't done up tight or you just didn't notice the friction
originally?

I've found with two different bikes that Record and new-style Centaur BBs
are highly susceptible to binding (presuably shells were not perfect),
more so than the cheaper Campag types (Veloce, AC-H, etc).

Solution that worked for mine (English): leave the left side "loose" but
saturate with Loctite blue Threadlocker -- leave 48 hours to cure before
riding. Campag also advise using threadlock for these cases except they
specify 30 Nm (instead of the usual 70 Nm without threadlock) -- see
instructions in booklet or on www.campagnolo.com

~PB

anonymous wrote:
On 4 Feb 2006 10:19:19 -0800, wrote:

Seven Axiom Ti frame

Are you using a Campy cartridge?

It is possible one of the press fit bearings is not pressed all the
way onto the spindle.

The adjusting cup usually only puts pressure on the outer race of the
bearing.

Side effects can put the whole thing under pressure, as I have found with
brand new cartridge BBs.

"If you should notice an increase in axle pin rotation friction, the
bottom bracket cage may be deformed or the supports are no longer axial"
- Campagnolo.

~PB

wrote:
I'm building up a used Seven Axiom Ti frame and when I reinstall the BB
that was originally on the bike, I can't get anywhere near the spec'd
torque without a noticable increase in friction on the spindle. If this
is the original BB that was on the bike, why would it be binding?

James

Only two reasons, neither good. The BB 'faces' are not parallel or the
threads in the BB are not...either can make the BB bind.

Peter wrote:

Only two reasons, neither good. The BB 'faces' are not parallel or the
threads in the BB are not...either can make the BB bind.

And very few shops want to dull their end mills or taps on titanium.
No?

John

Thanks for the replies everyone. I bought this frame and parts used so
I never rode it initially and can't say how the BB was originally
installed. But if it was binding when originally installed, I would
expect the BB bearings to be trashed by now since the owner rode it for
two years. And I can't imagine that the shell faces or threads would
have somehow gone bad.

I wrapped the left cup with teflon tape and tightened it just enough so
that it doesn't bind. I guess we'll see if it loosens or not. I did see
where Campy instructs to use Locktite in this case but after reading
the warnings against doing so on this list, I decided against it.

James

wrote:
Thanks for the replies everyone. I bought this frame and parts used so
I never rode it initially and can't say how the BB was originally
installed. But if it was binding when originally installed, I would
expect the BB bearings to be trashed by now since the owner rode it
for two years. And I can't imagine that the shell faces or threads
would have somehow gone bad.

Maybe the bearings can stand some binding afterall? (I don't know with
Record. An over-tightened AC-H I used did get dry & rough-feeling but was
still usuable a few thousand miles later). Or it was never very tight?

I wrapped the left cup with teflon tape and tightened it just enough
so that it doesn't bind. I guess we'll see if it loosens or not.

It will *tighten* if it moves at all (assuming 'English' BB).

I did see where Campy instructs to use Locktite in this case but after
reading the warnings against doing so on this list, I decided against
it.

PTFE tape was a dismal failure on mine (I think it's only useful if you
can have the cup fairly tight). To be fair, Loctite wasn't perfect
either and the left cup did move a little on the first ride, but was OK
after that. Loctite should provide some protection against corrosion and
"welding" and you will be able to remove the cup when needed since it
won't be extremely tight.

~PB

Peter wrote:
Only two reasons, neither good. The BB 'faces' are not parallel or the
threads in the BB are not...either can make the BB bind.

john wrote:
And very few shops want to dull their end mills or taps on titanium.
No?

Titanium is quite soft, cuts much more easily than CrMo when
trimming handlebars for example. It tends to be "sticky"
like brass when tapping or cutting bores, so proper cutting
fluid is important. The occasional bit of chrome on a frame
is _much_ worse for our tools than titanium.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

john wrote:
Peter wrote:

Only two reasons, neither good. The BB 'faces' are not parallel or the
threads in the BB are not...either can make the BB bind.

And very few shops want to dull their end mills or taps on titanium.
No?

John

Lots of decent cutting flid and it would be fine with a normal facing
tool. I would have the guy have the BB shell chased, thread-wise then
faced and then with a new BB-see. If the threads are askew, then the
guides will be tough to screw in-a sign that the threads are gooned up.