Stripped Bottom Bracket Shell

Kevin Zhu said:

I was wondering if anyone could help me with a problem. I felt play
in the bottom bracket of my bike and I took it apart to see what was
wrong. It turns out the bottom bracket shell or the threads in the
frame on the drive side is stripped. They are half the height they
should be. The other side is perfect. Now I can't tighten the
fixed cup enough and it comes loose after about 10 minutes. The
bike is still ridable, but there's play. Anybody have any ideas? I
thought maybe tapping it and putting in an insert. I've also been
recommended to use Loctite to secure it. Help would be greatly
appreciated.

Loctite is much weaker than steel and won't work. You see what
happened to steel. The left hand thread on that cup is there because
it is always moving. I don't know where you are located and how much
you want to spend, but I had my BB fixed by a local shop that can do
such repairs.

The old thread was bored out and a new threaded sleeve made to fit the
recess and silver soldered in place. This is a thin shell just thick
enough to support threads. Other than that I have no suggestions.

Jobst Brandt

Loctite is the easy answer. It comes in many strengths. Start with a
mid level. If that doesn't hold, go stronger. Use a shimano cartridge
bearing bb so it will last plenty long without having to regrease
periodically.

Another option is a rare type of cartridge bottom bracket where the
lock ring threads to the cartridge instead of the inside of the shell.
We used to install them in Lambert and early Viscounts that had pressed
in bearings when the axles broke. Not sure what is on the market these
days along that design.

Option 3. Brass melted in, reamed, threaded. Would likely trash the
paint. Use the same brass used for torch brazing the frames together
in the first place. Many bikeshops have bb taps that could cut the new
threads. Doh, guess that depends on the frame material/construction.

Replacing the bb shell in a tradional lugged steel frame would be quite
a bit of work. Probably not worth the effort or cost.

The problem with a threaded insert is you would have to remove lots of
material from the shell, weakening it beyond all hope. Many new
aluminum or carbon frames have such steel inserts.

R

dazookeeper said:

I was wondering if anyone could help me with a problem. I felt play in
the bottom bracket of my bike and i took it apart to see what was
wrong. It turns out the bottom bracket shell or the threads in the
frame on the drive side is stripped. They are half the height they
should be. The other side is perfect. Now i can't tighten the fixed cup
enough and it comes loose after about 10 minutes. The bike is still
rideable, but there's play. Anybody have any ideas? I thought maybe
tapping it and putting in an insert. I've also been recommended to use
loctite to secure it. Help would be greatly appreciated. Thanks.

Mavic BB or Stronglight BB is what you need. Look on e-bay- there was a
Mavic BB there last week, and I have sold a few myself through the years.
Need a chamfering tool to bevel ends of bb shell, and they are not that
uncommon in good bikeshops that have been around.
Maybe do a google search if this NG.

Gary Jacobson
Rosendale, NY

"dazookeeper" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

I was wondering if anyone could help me with a problem. I felt play in
the bottom bracket of my bike and i took it apart to see what was
wrong. It turns out the bottom bracket shell or the threads in the
frame on the drive side is stripped. They are half the height they
should be. The other side is perfect. Now i can't tighten the fixed cup
enough and it comes loose after about 10 minutes. The bike is still
rideable, but there's play. Anybody have any ideas? I thought maybe
tapping it and putting in an insert. I've also been recommended to use
loctite to secure it. Help would be greatly appreciated. Thanks.

Well seeing from your email address, i live in palo alto just like you.
Your suggestion sounds pretty good. What bikeshop is it? Also, how much
do you estimate the job to cost?

Quoted message said:

Kevin Zhu said:

I was wondering if anyone could help me with a problem. I felt play
in the bottom bracket of my bike and I took it apart to see what was
wrong. It turns out the bottom bracket shell or the threads in the
frame on the drive side is stripped. They are half the height they
should be. The other side is perfect. Now I can't tighten the
fixed cup enough and it comes loose after about 10 minutes. The
bike is still ridable, but there's play. Anybody have any ideas? I
thought maybe tapping it and putting in an insert. I've also been
recommended to use Loctite to secure it. Help would be greatly
appreciated.

Loctite is much weaker than steel and won't work. You see what
happened to steel. The left hand thread on that cup is there because
it is always moving. I don't know where you are located and how much
you want to spend, but I had my BB fixed by a local shop that can do
such repairs.

The old thread was bored out and a new threaded sleeve made to fit the
recess and silver soldered in place. This is a thin shell just thick
enough to support threads. Other than that I have no suggestions.

Jobst Brandt

dazookeeper wrote:

-snip-

Quoted message said:

It turns out the bottom bracket shell or the threads in the
frame on the drive side is stripped.

-snip-

Dear zoo keep

The best way to fix this, IMO, is to ream the BB out to an Italian ID &
then rethread it w/ an Italian threads & replace your old cartage with
an Italian BB. The downside to this is that one of the cups tends to be
backed out due to the rotation of the spindles bearings. There are ways
to overcome this, although except for Loctite, I can't remember any.

If the frame isn't extremely valuable, I would try the strongest
Loctite suitable for this type application directly to the buggered
threads. (Check their web site or phone tech rep.) The down side of
this is that it might not hold or U might not be able to remove the cup
@ a later date.

Good luck, John

dazookeeper wrote:

-snip-

Quoted message said:

It turns out the bottom bracket shell or the threads in the
frame on the drive side is stripped.

-snip-

Dear zoo keep

The best way to fix this, IMO, is to ream the BB out to an Italian ID &
then rethread it w/ an Italian threads & replace your old cartage with
an Italian BB. The downside to this is that one of the cups tends to be
backed out due to the rotation of the spindles bearings. There are ways
to overcome this, although except for Loctite, I can't remember any.

If the frame isn't extremely valuable, I would try the strongest
Loctite suitable for this type application directly to the buggered
threads. (Check their web site or phone tech rep.) The down side of
this is that it might not hold or U might not be able to remove the cup
@ a later date.

Good luck, John

Quoted message said:

Kevin Zhu said:

I was wondering if anyone could help me with a problem. I felt play
in the bottom bracket of my bike and I took it apart to see what was
wrong. It turns out the bottom bracket shell or the threads in the
frame on the drive side is stripped. They are half the height they
should be. The other side is perfect. Now I can't tighten the
fixed cup enough and it comes loose after about 10 minutes. The
bike is still ridable, but there's play. Anybody have any ideas? I
thought maybe tapping it and putting in an insert. I've also been
recommended to use Loctite to secure it. Help would be greatly
appreciated.

Loctite is much weaker than steel and won't work. You see what
happened to steel. The left hand thread on that cup is there because
it is always moving. I don't know where you are located and how much
you want to spend, but I had my BB fixed by a local shop that can do
such repairs.

What about a step up from Loctite, say an epoxy like JB Weld?

Greg

I was wondering what would happen if I used a thick coating of JB weld
and let it fully dry. Then use a tool to recut the threads the same
size. Would that possibly work?

G.T. said:

Quoted message said:

Kevin Zhu said:

I was wondering if anyone could help me with a problem. I felt play
in the bottom bracket of my bike and I took it apart to see what was
wrong. It turns out the bottom bracket shell or the threads in the
frame on the drive side is stripped. They are half the height they
should be. The other side is perfect. Now I can't tighten the
fixed cup enough and it comes loose after about 10 minutes. The
bike is still ridable, but there's play. Anybody have any ideas? I
thought maybe tapping it and putting in an insert. I've also been
recommended to use Loctite to secure it. Help would be greatly
appreciated.

Loctite is much weaker than steel and won't work. You see what
happened to steel. The left hand thread on that cup is there because
it is always moving. I don't know where you are located and how much
you want to spend, but I had my BB fixed by a local shop that can do
such repairs.

What about a step up from Loctite, say an epoxy like JB Weld?

Greg

dazookeeper said:

I was wondering what would happen if I used a thick coating of JB weld
and let it fully dry. Then use a tool to recut the threads the same
size. Would that possibly work?

Don't know but I don't think the epoxy will cut very cleanly. If it
were mine I'd just JB Weld the cup in place and see how it goes.

Greg

Quoted message said:

G.T. said:

Quoted message said:

Kevin Zhu writes:

> I was wondering if anyone could help me with a problem. I felt play
> in the bottom bracket of my bike and I took it apart to see what was
> wrong. It turns out the bottom bracket shell or the threads in the
> frame on the drive side is stripped. They are half the height they
> should be. The other side is perfect. Now I can't tighten the
> fixed cup enough and it comes loose after about 10 minutes. The
> bike is still ridable, but there's play. Anybody have any ideas? I
> thought maybe tapping it and putting in an insert. I've also been
> recommended to use Loctite to secure it. Help would be greatly
> appreciated.
Loctite is much weaker than steel and won't work. You see what
happened to steel. The left hand thread on that cup is there because
it is always moving. I don't know where you are located and how much
you want to spend, but I had my BB fixed by a local shop that can do
such repairs.

What about a step up from Loctite, say an epoxy like JB Weld?

Greg

Kevin Zhu said:

I was wondering what would happen if I used a thick coating of JB
weld and let it fully dry. Then use a tool to re-cut the threads the
same size. Would that possibly work?

The thread cutting die trying to cut through the matrix exerts more
torque than the adhesion to the BB shell and would either make it come
out as a whole or chunks. Besides, none of these epoxy/Loctite things
are as strong as steel... or even aluminum.

Jobst Brandt

In article <[email hidden]>, rick-
[email hidden] says...

Quoted message said:

Option 3. Brass melted in, reamed, threaded. Would likely trash the
paint. Use the same brass used for torch brazing the frames together
in the first place.

There are brazing fillers specifically designed for resurfacing worn
parts, with better wear characteristics than ordinary brass filler.
Don't have my brazing manuals handy (I'm at the office) but I recall
nickel silver alloys used for threads and splines, they build a thicker
layer in a single pass, cut cleanly, wear better, etc.

--
[email hidden] is Joshua Putnam
<http://www.phred.org/~josh/>
Braze your own bicycle frames. See
<http://www.phred.org/~josh/build/build.html>

G.T. said:

[email hidden] wrote:

Quoted message said:

Quoted message said:

Kevin Zhu said:

I was wondering if anyone could help me with a problem. I felt play
in the bottom bracket of my bike and I took it apart to see what was
wrong. It turns out the bottom bracket shell or the threads in the
frame on the drive side is stripped. They are half the height they
should be. The other side is perfect. Now I can't tighten the fixed
cup enough and it comes loose after about 10 minutes. The bike is
still ridable, but there's play. Anybody have any ideas? I thought
maybe tapping it and putting in an insert. I've also been recommended
to use Loctite to secure it. Help would be greatly appreciated.

Loctite is much weaker than steel and won't work. You see what
happened to steel. The left hand thread on that cup is there because
it is always moving. I don't know where you are located and how much
you want to spend, but I had my BB fixed by a local shop that can do
such repairs.

What about a step up from Loctite, say an epoxy like JB Weld?

I've done that. I can't say I put thousands of miles on it, but it held
up for years on a couple of old beach cruiser bikes.

After cleaning the metal with a wire brush and acid, I smeared a layer of
JB Weld over the threads, let it cure, then bored it from the other side
with a BB thread cutter.

I don't think I'd rely on this for a real road bike though.

Jobst's method is best, because silver brazing won't overheat the steel in
the existing BB shell and adjacent tubes, a possibility with regular brass
brazing. Other than that, brass brazing might be fine, depending on the
alloy of your frame tubes and the skill of the brazer.

Unless your frame is special, a new one (new to you anyway) might be a
better value.

Matt O.

jobst.brandt said:

Kevin Zhu said:

I was wondering what would happen if I used a thick coating of JB
weld and let it fully dry. Then use a tool to re-cut the threads the
same size. Would that possibly work?

The thread cutting die trying to cut through the matrix exerts more
torque than the adhesion to the BB shell and would either make it come
out as a whole or chunks. Besides, none of these epoxy/Loctite things
are as strong as steel... or even aluminum.

Nonetheless it worked for me.

Matt O.

In article
<[email hidden]>,

Matt O'Toole said:

jobst.brandt said:

Kevin Zhu said:

I was wondering what would happen if I used a thick coating of JB
weld and let it fully dry. Then use a tool to re-cut the threads the
same size. Would that possibly work?

The thread cutting die trying to cut through the matrix exerts more
torque than the adhesion to the BB shell and would either make it come
out as a whole or chunks. Besides, none of these epoxy/Loctite things
are as strong as steel... or even aluminum.

Nonetheless it worked for me.

JB Weld machines fine at about four to six hours after
mixing. When it is fully cured, I do not know how well it
machines.

--
Michael Press

john said:

dazookeeper wrote:

-snip-

Quoted message said:

It turns out the bottom bracket shell or the threads in the
frame on the drive side is stripped.

-snip-

Dear zoo keep

The best way to fix this, IMO, is to ream the BB out to an Italian ID &
then rethread it w/ an Italian threads & replace your old cartage with
an Italian BB. The downside to this is that one of the cups tends to be
backed out due to the rotation of the spindles bearings. There are ways
to overcome this, although except for Loctite, I can't remember any.

If the frame isn't extremely valuable, I would try the strongest
Loctite suitable for this type application directly to the buggered
threads. (Check their web site or phone tech rep.) The down side of
this is that it might not hold or U might not be able to remove the cup
@ a later date.

Good luck, John

Red Loctite does not work. I tried it on an aluminum Nashbar frame. I
damaged the threads on the non drive side and the cup would not stay
tight. So I Red Loctited it. Did not hold. And now I can't get the
cup out to try to JB Weld it in place. Red Loctite holds well enough
to not get the cup out but not well enough to keep the bottom bracket
from moving. For me the cheapest solution was to buy another Nashbar
frame for $77 delivered. It will take time to transfer the parts over.

dazookeeper said:

I was wondering if anyone could help me with a problem. I felt play in
the bottom bracket of my bike and i took it apart to see what was
wrong. It turns out the bottom bracket shell or the threads in the
frame on the drive side is stripped. They are half the height they
should be. The other side is perfect. Now i can't tighten the fixed cup
enough and it comes loose after about 10 minutes. The bike is still
rideable, but there's play. Anybody have any ideas? I thought maybe
tapping it and putting in an insert. I've also been recommended to use
loctite to secure it. Help would be greatly appreciated. Thanks.

Both Stronglight and YST make cartridge BBs to deal with this problem.

Here's a source for the Stronglight (you want the JP 1000):

http://tinyurl.com/gfmhf

And for the YST:

http://tinyurl.com/m6qkl

(note that different length YSTs are listed as separete entries on that
site, so click around to find the proper length)

With either the Stronlight or the YST, the BB shell will need to be
champhered, as another poster mentioned.

The problem with the those bottom brackets is that they are square
tapered which means I cannot get a really good crank set. Also, most of
them are meant for racing bikes, not mountain bikes. But thanks anyway.

Quoted message said:

dazookeeper said:

I was wondering if anyone could help me with a problem. I felt play in
the bottom bracket of my bike and i took it apart to see what was
wrong. It turns out the bottom bracket shell or the threads in the
frame on the drive side is stripped. They are half the height they
should be. The other side is perfect. Now i can't tighten the fixed cup
enough and it comes loose after about 10 minutes. The bike is still
rideable, but there's play. Anybody have any ideas? I thought maybe
tapping it and putting in an insert. I've also been recommended to use
loctite to secure it. Help would be greatly appreciated. Thanks.

Both Stronglight and YST make cartridge BBs to deal with this problem.

Here's a source for the Stronglight (you want the JP 1000):

http://tinyurl.com/gfmhf

And for the YST:

http://tinyurl.com/m6qkl

(note that different length YSTs are listed as separete entries on that
site, so click around to find the proper length)

With either the Stronlight or the YST, the BB shell will need to be
champhered, as another poster mentioned.

dazookeeper said:

The problem with the those bottom brackets is that they are square
tapered which means I cannot get a really good crank set. Also, most of
them are meant for racing bikes, not mountain bikes. But thanks anyway.

Sugino, for one, makes good quality square taper cranks. Also, it now
appears that both Octalink and ISIS are doomed standards, so investing
in those designs is questionable.

The YSTs come in a wide range of spindle lengths, you should be able to
find what you need.

Quoted message said:

Quoted message said:

dazookeeper said:

I was wondering if anyone could help me with a problem. I felt play in
the bottom bracket of my bike and i took it apart to see what was
wrong. It turns out the bottom bracket shell or the threads in the
frame on the drive side is stripped. They are half the height they
should be. The other side is perfect. Now i can't tighten the fixed cup
enough and it comes loose after about 10 minutes. The bike is still
rideable, but there's play. Anybody have any ideas? I thought maybe
tapping it and putting in an insert. I've also been recommended to use
loctite to secure it. Help would be greatly appreciated. Thanks.

Both Stronglight and YST make cartridge BBs to deal with this problem.

Here's a source for the Stronglight (you want the JP 1000):

http://tinyurl.com/gfmhf

And for the YST:

http://tinyurl.com/m6qkl

(note that different length YSTs are listed as separete entries on that
site, so click around to find the proper length)

With either the Stronlight or the YST, the BB shell will need to be
champhered, as another poster mentioned.

dazookeeper said:

Well seeing from your email address, i live in palo alto just like you.
Your suggestion sounds pretty good. What bikeshop is it? Also, how much
do you estimate the job to cost?

Quoted message said:

Kevin Zhu said:

I was wondering if anyone could help me with a problem. I felt play
in the bottom bracket of my bike and I took it apart to see what was
wrong. It turns out the bottom bracket shell or the threads in the
frame on the drive side is stripped. They are half the height they
should be. The other side is perfect. Now I can't tighten the
fixed cup enough and it comes loose after about 10 minutes. The
bike is still ridable, but there's play. Anybody have any ideas? I
thought maybe tapping it and putting in an insert. I've also been
recommended to use Loctite to secure it. Help would be greatly
appreciated.

Loctite is much weaker than steel and won't work. You see what
happened to steel. The left hand thread on that cup is there because
it is always moving. I don't know where you are located and how much
you want to spend, but I had my BB fixed by a local shop that can do
such repairs.

The old thread was bored out and a new threaded sleeve made to fit the
recess and silver soldered in place. This is a thin shell just thick
enough to support threads. Other than that I have no suggestions.

Jobst Brandt

In another recent thread, Jobst mentioned that this repair was
"expensive". That descriptor can cover a lot of ground, but think about
what is involved. Precision boring of the BB shell, precision turning
of the new sleeve with threads at both ends. Silver brazing of the
sleeve in place. Not a job for the faint of heart, or those without
costly equipment and the skills to use them.

--
Ted Bennett