Question on Brake Installation

Barbara L said:

I'm switching out some 105 brakes that came with a new bike for some
Ultegras I already have. I noticed that the center bolts that the recessed
nut goes into had what looked to be the plumbers Teflon tape wrapped on
them. I just assumed I would use some lithium grease on the bolts before
installing the Ultegras but wondered if using the tape is better or done in
lieu of grease.

Thanks,

Barbara L

That stuff is the color of Teflon tape, but I think it's actually
thread locker. Shimano's brake instructions say you should use either
thread locker or, for non-recessed frames, a nylock nut.

You'll be fine either way - thread locker or grease - as long as you
get the nuts tight. Shimano recommends thread locker because they
don't want to get sued if somebody's brake caliper falls off, but
you'll notice your caliper is loose long before that happens.

-Vee

Barbara L said:

I'm switching out some 105 brakes that came with a new bike for some
Ultegras I already have. I noticed that the center bolts that the recessed
nut goes into had what looked to be the plumbers Teflon tape wrapped on
them. I just assumed I would use some lithium grease on the bolts before
installing the Ultegras but wondered if using the tape is better or done in
lieu of grease.

Thanks,

Barbara L

It's a form of loctite but use grease on all threaded anything on a
bici.

Qui si parla Campagnolo said:

Barbara L said:

I'm switching out some 105 brakes that came with a new bike for some
Ultegras I already have. I noticed that the center bolts that the recessed
nut goes into had what looked to be the plumbers Teflon tape wrapped on
them. I just assumed I would use some lithium grease on the bolts before
installing the Ultegras but wondered if using the tape is better or done in
lieu of grease.

It's a form of loctite but use grease on all threaded anything on a
bici.

I've always been curious about the thread locker that's applied to
brake bolts (road and MTB). I've theorized that it's a liability
blocker (but yer honor, we put thread locker on that bolt so it
wouldn't come off... musta been installation error).

Obviously 90+% of the bolts that are ever removed and reinstalled
aren't slathered with thread locker, yet they don't seem to come
loose.

Has anyone out there ever had a canti brake bolt or caliper mount ever
actually come loose?

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

Mark Hickey said:

Qui si parla Campagnolo said:

Barbara L said:

I'm switching out some 105 brakes that came with a new bike for some
Ultegras I already have. I noticed that the center bolts that the recessed
nut goes into had what looked to be the plumbers Teflon tape wrapped on
them. I just assumed I would use some lithium grease on the bolts before
installing the Ultegras but wondered if using the tape is better or done in
lieu of grease.

It's a form of loctite but use grease on all threaded anything on a
bici.

I've always been curious about the thread locker that's applied to
brake bolts (road and MTB). I've theorized that it's a liability
blocker (but yer honor, we put thread locker on that bolt so it
wouldn't come off... musta been installation error).

Obviously 90+% of the bolts that are ever removed and reinstalled
aren't slathered with thread locker, yet they don't seem to come
loose.

Has anyone out there ever had a canti brake bolt or caliper mount ever
actually come loose?

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

Sure, on bikes I have worked on, they came in with the bolts loose. . I
even had a woman where the bolt on cable stop for STI came off. One
gent broke a spoke on the front and the back and forth of the wheel
against the brake actually loosened the caliper until it fell off.

Mark Hickey said:

Has anyone out there ever had a canti brake bolt or caliper mount ever
actually come loose?

Actually, after a couple winters around here, the road salt makes it
nearly impossible to get the darn nut off.

--

David L. Johnson

__o | "It doesn't get any easier, you just go faster." --Greg LeMond
_`\(,_ |
(_)/ (_) |

"Mark Hickey" wrote: (clip) Obviously 90+% of the bolts that are ever
removed and reinstalled aren't slathered with thread locker, yet they don't
seem to come loose. (clip)
^^^^^^^^^^^^^
90%+ of the bolts are tightened so that the torque produces tension in the
bolt. This produces locking friction in the threads which usually is enough
to prevent loosening. In cases like the brake caliper nut, (correct me if
I'm wrong) the nut is tightened enough to take out excess play, while still
allowing the arms to move without binding. So there is no tension on the
threads to produce the locking friction. Hence, the need for a Nylock type
nut, or Loc-tite or tape.

The other way to deal with this would be to use a shoulder bolt, but that
would be more expensive, would not allow fine tuning the clearance or
compensation for wear.

Mark Hickey said:

Qui si parla Campagnolo said:

Barbara L said:

I'm switching out some 105 brakes that came with a new bike for some
Ultegras I already have. I noticed that the center bolts that the recessed
nut goes into had what looked to be the plumbers Teflon tape wrapped on
them. I just assumed I would use some lithium grease on the bolts before
installing the Ultegras but wondered if using the tape is better or done in
lieu of grease.

It's a form of loctite but use grease on all threaded anything on a
bici.

I've always been curious about the thread locker that's applied to
brake bolts (road and MTB). I've theorized that it's a liability
blocker (but yer honor, we put thread locker on that bolt so it
wouldn't come off... musta been installation error).

Obviously 90+% of the bolts that are ever removed and reinstalled
aren't slathered with thread locker, yet they don't seem to come
loose.

Has anyone out there ever had a canti brake bolt or caliper mount ever
actually come loose?

Not here.

Greg

--
"All my time I spent in heaven
Revelries of dance and wine
Waking to the sound of laughter
Up I'd rise and kiss the sky" - The Mekons

Leo Lichtman said:

"Mark Hickey" wrote: (clip) Obviously 90+% of the bolts that are ever
removed and reinstalled aren't slathered with thread locker, yet they don't
seem to come loose. (clip)
^^^^^^^^^^^^^
90%+ of the bolts are tightened so that the torque produces tension in the
bolt. This produces locking friction in the threads which usually is enough
to prevent loosening. In cases like the brake caliper nut, (correct me if
I'm wrong) the nut is tightened enough to take out excess play, while still
allowing the arms to move without binding. So there is no tension on the
threads to produce the locking friction. Hence, the need for a Nylock type
nut, or Loc-tite or tape.

Many use a capnut.

Quoted message said:

The other way to deal with this would be to use a shoulder bolt,

Or a sleeve, or two nuts locked together if there's no shoulder or
sleeve.

Quoted message said:

but that [shoulder bolt]
would be more expensive, would not allow fine tuning the clearance or
compensation for wear.

Why would that be a problem? I ask because it appears that this is a
common design.

A quick look at the cheap calipers in the junkbox and the in-use
stable reveals that most of the ones here have a shoulder for the
caliper arms. The only exception is a scrapped-out early-70s
department store bike whose brakes are little more than scrap metal in
my opinion. Some older cheap side-pull calipers that I can recall
(like the ones I just cited) were essentially impossible to keep
centered reliably; on those, double-nutted caliper mounting
studs/bolts were often employed (and left loose enough that the whole
assembly could "float" to allow the pads to not make heavy contact),
but this was far from an optimal solution.

--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Mark Hickey said:

Has anyone out there ever had a canti brake bolt or caliper mount ever
actually come loose?

Yes, last June, on a fixed-gear bike with only a front brake :-O

I rode out 15 miles to the start of a 10 mile time trial, did the TT and
rode home again. I noticed a rattling on the way home but only realised
the cause when I arrived.

The bike had had a new fork fitted a few days before and the LBS that
did it hadn't tightened the brake properly. Needless to say, I used
threadlock when fixing it.

If the brake had actually come adrift, the consequences would have been
particularly unpleasant. It would probably have tilted, grabbed the
tyre and caused a lockup, but with 20mm tyres it may also have popped
right off the wheel. Leg braking is not something that works well in an
emergency.

Barbara L said:

I'm switching out some 105 brakes that came with a new bike for some
Ultegras I already have.

What are you doing with the 105 brakes?

I might be interested in taking them off of your hands.

--
Paul M. Hobson
Georgia Institute of Technology
..:change the f to ph to reply:.

Paul Hobson said:

Barbara L said:

I'm switching out some 105 brakes that came with a new bike for some
Ultegras I already have.

What are you doing with the 105 brakes?

I might be interested in taking them off of your hands.

note: I've corrected my reply-to address, but the sig still applies

--
Paul M. Hobson
Georgia Institute of Technology
..:change the f to ph to reply:.