T.R | Title | User | Personal Name | Date | Lines |
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2582.1 | Spindle Bolt Tightening ? | ODIXIE::RRODRIGUEZ | Shake that grits tree! | Tue Jun 01 1993 10:57 | 12 |
| JUST A THOUGHT...
I've heard of creaking noises from a loose crank. The crank
would have to have been pulled from the spindle to replace
the bottom bracket, so maybe it just wasn't tightened enough
and the bearing situation was okay all along(?)
If the shop had managed to "move" the drive side in by tightening
the spindle bolt, a distance of a millimeter or more would have
been sufficient to through off your shifting.
r�
|
2582.2 | Brain still on holiday... | ODIXIE::RRODRIGUEZ | Shake that grits tree! | Tue Jun 01 1993 10:59 | 3 |
| re: .1
I meant "throw-off", not _through off_!
|
2582.3 | | NOVA::FISHER | DEC Rdb/Dinosaur | Tue Jun 01 1993 11:49 | 13 |
| There is a chance that the sealed bb just puts the crank and
chainwheels into a slightly plane from the previous bb. That is
certainly possible with Phil Wood's bb's I haven't measured
the Shimano's, but I did get a similar difference in my front
shifting when I did this to my Serotta -- changed an Ultegra
bb to an Ultegra sealed bb.
I have gotten creaking out of loose cups, never from a loose
crank. If the crank was loose, I'd just ruin it and have to replace
the danged thing, usually only happens when the crankset is over $100.
:-(
ed
|
2582.4 | Grease threads? | NQOPS::THIBODEAU | | Tue Jun 01 1993 12:00 | 8 |
| As far as the creak goes, it sounded like they were telling me that
they had to take it out and regrease the threads. I just hope it's not
an on going thing because I tend to ride through a lot of water and
mud, which is why I decided to get the new BB.
Thanks
Alan
|
2582.5 | QUACKS LIKE BB | WMOIS::GIROUARD_C | | Tue Jun 01 1993 13:08 | 4 |
| From experience... It usually sounds like a BB creak, but rarely
is the BB
Chip
|
2582.6 | The nature of the creak? | ESKIMO::ASMITH | | Tue Jun 01 1993 13:58 | 8 |
| re .0
One question, did you get the creaking consistently at one point
in your pedal stroke? If so, then your sealed BB probaly was not
installed right at the initial installation ( this happens a lot at even
the best shops, all you need is a person who is rushing the job ).
AS
|
2582.7 | | NQOPS::THIBODEAU | | Tue Jun 01 1993 14:21 | 6 |
| I'm not real sure but it was a rythmic, creak, creak, creak. Probably
twice per revolution. The shop was pretty busy at the time so maybe
they did rush the job. They didn't complain at all about fixing it and
even tightened my headset for me because they noticed it was loose.
Alan
|
2582.8 | This does make sense, honest | JURA::PELAZ::MACFADYEN | | Wed Jun 02 1993 05:00 | 9 |
| Your sealed BB itself was almost certainly OK but if the lockrings securing
it inside the BB shell were not tight enough, then the BB unit could have
been able to move slightly and cause a creak. I had this on my bike last
year, a creak solved by getting the shop to reinstall the BB and chamfer
the BB shell so that the lockrings located the BB more accurately and
firmly.
Rod
|
2582.9 | Chamfer? | ODIXIE::RRODRIGUEZ | Shake that grits tree! | Wed Jun 02 1993 09:31 | 7 |
| Rod,
I've run accross the word "chamfer" in Notes a few times. None
describes what chamfering is; neither does the dictionary. Can
you describe what kind of modification it is?
r�
|
2582.10 | chamfer, per Websters... | ATIS::BODGE | Andy Bodge | Wed Jun 02 1993 10:17 | 9 |
| I had to haul out the heavy artillery (Webster's Unabridged) to find:
chamfer, v.t.: 1. in carpentry, to cut a groove in; to flute; to channel.
2. to cut or grind in a sloping manner, as the edge of anything square,
so as to form a chamfer or bevel.
How this applies to bottom brackets, I will leave to others...
Andy
|
2582.11 | Chamfering alters the bike frame | JURA::PELAZ::MACFADYEN | dieting | Wed Jun 02 1993 11:13 | 33 |
| This is the one that applies...
> 2. to cut or grind in a sloping manner, as the edge of anything square,
> so as to form a chamfer or bevel.
Definitions...
BB shell: the part of the bike frame between the cranks, where the bb lives.
BB unit: a sealed bottom bracket unit.
lockring: threaded ring on the outside of a bb unit, used to lock the unit
into the frame.
Think of the bb shell of a frame. It's essentially cylindrical. The ends of
the cyclinder are normally flat. When you insert a sealed bb unit into the
shell and screw up the lockrings tight against the ends of the cyclindrical
shell, the lockrings secure the bb unit perfectly against any transverse
movement, but not against any up-and-down movement (since the flat lockrings
can slide against the flat ends of the bb shell). Thus any slight play between
the bb unit and the bb shell can lead to a creaking noise as you turn the
cranks.
So to solve this, the shop cuts a chamfer into the ends of the frame bb shell
(yes, metal is ground off the frame!). This means that the ends of the shell
are no longer flat, but slope inwards as if they were part of a large cone.
BB unit lockrings are generally similarly conical on one side. So when the bb
unit is installed in the frame, the sloping (conical) side of the lockrings
is tightened up against the similarly conical ends of the bb shell and hey
presto, the bb unit is now firmly located against any type of movement at all.
No creaking.
Rod
|
2582.12 | | NOVA::FISHER | DEC Rdb/Dinosaur | Wed Jun 02 1993 11:54 | 4 |
| ya know, I always thought I was making the faces of the bb perfectly
parallel instead of slightly beveled. hmmm, I'll hafta check this out.
ed
|