Stripped BB shell threads - options?

search!!
an exhaustive and enlightening column on the subject 2-3 weeks ago.

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search!!
an exhaustive and enlightening column on the subject 2-3 weeks ago.

Whadyaknow? Thanks.

http://tinyurl.com/4q4c3

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>

An old lugged steel frame of mine has a problem, the left BB threads
are
sort of stripped. A Shimano BB plastic lockring will thread in, but
slips when I begin to torque it down.

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>>

I don't think you really need to 'torque' the plastic ring down. The
BB screws in from the right with a steel thread, which holds the unit
in place. The plastic part serves more to stop the left side from
moving up and down, not in and out.

Lewis.

*******

Quoted message said:

Quoted message said:

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>

An old lugged steel frame of mine has a problem, the left BB threads
are
sort of stripped. A Shimano BB plastic lockring will thread in, but
slips when I begin to torque it down.

Quoted message said:

Quoted message said:

Quoted message said:

>>

I don't think you really need to 'torque' the plastic ring down. The
BB screws in from the right with a steel thread, which holds the unit
in place. The plastic part serves more to stop the left side from
moving up and down, not in and out.

Lewis.

*******

Kyle.B.H. said:

An old lugged steel frame of mine has a problem, the left BB threads are
sort of stripped. A Shimano BB plastic lockring will thread in, but
slips when I begin to torque it down. I had a mechanic look at it, tried
to chase it out, and he agrees they're shot. Suggestions?
1) Replace BB shell.
Expensive, destroys paint.
2) Some other method of restoring the threads?
Some sort of insert?
Braze in a lockring?
3) Re-tap to Italian, which is supposedly slightly larger.
Probably least expensive option, if it works.
Would need a 68mm Italian BB.
4) Use as-is with a Mavic BB...
Just a rumor, would have to find one.
I'm going to have a frame builder or two look at it, but figured I'd get
some ideas first.

Yes, consult a framebuilder.

(BB shells don't get replaced, they get repaired.)

Your decision may well hinge on the labor rates and
available parts in your area. And the condition of the
paint. Filling the threads and cutting new BSC threads will
burn 2-3 inches of paint. Sort of the inverse of this:
http://www.yellowjersey.org/FORKTHRD.JPG

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

Kyle.B.H. said:

An old lugged steel frame of mine has a problem, the left BB threads

are

Quoted message said:

sort of stripped. A Shimano BB plastic lockring will thread in, but
slips when I begin to torque it down. I had a mechanic look at it,

tried

Quoted message said:

to chase it out, and he agrees they're shot. Suggestions?

google "YST Threadless". the lockring threads on to the cartridge
body.

begin quoting A Muzi <[email hidden]>:

Quoted message said:

Kyle.B.H. said:

An old lugged steel frame of mine has a problem, the left BB threads are
sort of stripped.

So does mine.

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Quoted message said:

1) Replace BB shell.
Expensive, destroys paint.

Yes, consult a framebuilder.
(BB shells don't get replaced, they get repaired.)

They do? Bob Jackson recommended replacement for mine.

YST also make a BB that does not demand shell threads - or refacing of the
shell - but has a relatively short life IME.
--
David Damerell <[email hidden]> Distortion Field!

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

Quoted message said:

4) Use as-is with a Mavic BB...
Just a rumor, would have to find one.

This will work, but you will have to find the right size BB. You should also
get the BB shell chamfered using the Mavic tool. I'm pretty sure there is
another company, maybe YST, that made a similar BB that did not require the
thread in the BB to work. With old age, my memory is fading. 🙁
--------------
Alex

" - but has a relatively short life IME."
Hi David
Can you explain further? The bearings ware out quickly or ?????
Thanks, John

" - but has a relatively short life IME."
Hi David
Can you explain further? The bearings ware out quickly or ?????
Thanks, John

Quoted message said:

YST also make a BB that does not demand shell threads - or refacing

of the

Quoted message said:

shell - but has a relatively short life IME.

I just ordered one. Figured I see what it looks like before undergoing
more expensive options. According to the listing, they use 1/4"
bearings on the right, and 3/16" on the left, as opposed to 5/32" on
both like many manufacturers. That seems good. I suppose the seals and
bearing quality could be lousy - who knows.

My main concern is how securely it mounts to the BB shell. The version
from Stronglight (http://tinyurl.com/53tmm) requires chamfering of the
BB shell like the old Mavics, so perhaps it's more secure (and at $65
perhaps better quality). For $17, I'm trying the YST. I'll report back
upon installation.

Kyle

A Muzi said:

Yes, consult a framebuilder.

(BB shells don't get replaced, they get repaired.)

Beg to differ -- I've replaced BB shells on frames; in fact my daily
commuter bike is just such a beast. The BB shell cracked and separated at
the seat tube insertion, so I sweated it off and brazed on a new one. That
was 20 years ago, and its still going strong. :-)

--

John ([email hidden])

begin quoting <[email hidden]>:
[of the YST bottom bracket]

Quoted message said:

" - but has a relatively short life IME."
Hi David
Can you explain further?

Can you change your vile quoting style?

I mean that after a relatively short number of miles the spindle has
noticeably increased play, so that the chainrings flop from side to side
and foul the front derailleur. I expect more drastic things would happen
if one continues to ride it.

I don't have my notes readily accessible, but at a rough guess I would say
it was good for only 3,000 miles or so, and that even whichever of the
UN-51 and the UN-71 is the lowest-end Shimano unit was good for at least
twice that.
--
David Damerell <[email hidden]> Kill the tomato!

begin quoting Kyle.B.H. <[email hidden]>:
[I'm writing about the YST BB]

Quoted message said:

My main concern is how securely it mounts to the BB shell. The version
from Stronglight (http://tinyurl.com/53tmm) requires chamfering of the
BB shell like the old Mavics, so perhaps it's more secure (and at $65
perhaps better quality). For $17, I'm trying the YST. I'll report back
upon installation.

It didn't come loose for me when I did it up jolly tight. I know that's
not a technical term, but I don't have a torque wrench; I had the two BB
tools (obviously, you need two) held in 9" adjustable spanners, and pulled
pretty hard - but not [censored]-tight like installing crank bolts.
--
David Damerell <[email hidden]> Kill the tomato!

David Damerell said:

It didn't come loose for me when I did it up jolly tight. I know that's
not a technical term, but I don't have a torque wrench; I had the two BB
tools (obviously, you need two) held in 9" adjustable spanners, and pulled
pretty hard - but not [censored]-tight like installing crank bolts.

I think at least Campagnolo recommends a higher torque for the BB cups
than crank bolts. The recommendation for crank bolts of 32-38 Nm, which
is pretty tight using my 12-inch torque wrench. The number on the
Campagnolo BB cups is 70 Nm. If you have the Tacx tool which attaches
to the spindle, 70 Nm should be easily done, as the Tacx tool is turned
with a 32-mm cone wrench which are usually long.

-as

begin quoting Antti Salonen <[email hidden]>:

Quoted message said:

David Damerell said:

It didn't come loose for me when I did it up jolly tight. I know that's
not a technical term, but I don't have a torque wrench; I had the two BB
tools (obviously, you need two) held in 9" adjustable spanners, and pulled
pretty hard - but not [censored]-tight like installing crank bolts.

I think at least Campagnolo recommends a higher torque for the BB cups
than crank bolts. The recommendation for crank bolts of 32-38 Nm, which
is pretty tight using my 12-inch torque wrench. The number on the
Campagnolo BB cups is 70 Nm.

Ah... that's not Italian thread, is it? That seems like quite a lot.
Barnett's wants up to 40Nm on BB cups (they still use Imperial, but that's
another issue) and even that would strip the thread on the plastic side of
a cheap Shimano BB - Google suggests this is quite a common problem with
people trying 30-40Nm.

Bear in mind also, when doing up the YST BB, because it screws into
itself, the torque is twice that being applied on each side.
--
David Damerell <[email hidden]> Kill the tomato!

begin quoting Antti Salonen <[email hidden]>:

Quoted message said:

David Damerell said:

It didn't come loose for me when I did it up jolly tight. I know that's
not a technical term, but I don't have a torque wrench; I had the two BB
tools (obviously, you need two) held in 9" adjustable spanners, and pulled
pretty hard - but not [censored]-tight like installing crank bolts.

I think at least Campagnolo recommends a higher torque for the BB cups
than crank bolts. The recommendation for crank bolts of 32-38 Nm, which
is pretty tight using my 12-inch torque wrench. The number on the
Campagnolo BB cups is 70 Nm.

Ah... that's not Italian thread, is it? That seems like quite a lot.
Barnett's wants up to 40Nm on BB cups (they still use Imperial, but that's
another issue) and even that would strip the thread on the plastic side of
a cheap Shimano BB - Google suggests this is quite a common problem with
people trying 30-40Nm.

Bear in mind also, when doing up the YST BB, because it screws into
itself, the torque is twice that being applied on each side.
--
David Damerell <[email hidden]> Kill the tomato!

David Damerell said:

Ah... that's not Italian thread, is it? That seems like quite a lot.

It is a bottom bracket with BSA thread, and it says 70 Nm on both cups.
I agree that it's probably a bit excessive.

-as

David Damerell said:

begin quoting <[email hidden]>:
[of the YST bottom bracket]

Quoted message said:

" - but has a relatively short life IME."
Hi David
Can you explain further?

Can you change your vile quoting style?

I mean that after a relatively short number of miles the spindle has
noticeably increased play, so that the chainrings flop from side to side
and foul the front derailleur. I expect more drastic things would happen
if one continues to ride it.

I don't have my notes readily accessible, but at a rough guess I would say
it was good for only 3,000 miles or so, and that even whichever of the
UN-51 and the UN-71 is the lowest-end Shimano unit was good for at least
twice that.

Question for ya... The threads on one side of my shell are still good -
will installing the YST BB ruin the existing threads?

Also, how heavy are you and how hard do you ride? I'm 175 and I pedal
low gears, so maybe I'll get better life out of it.