Respondents, I'm grateful for all your input/suggestions. Once again, I've
learned through your experiences.
John, read your suggestion about possibility of screw retaining BB cable guide
being too long and interfering with BB and immediately grabbed my screw driver
to check it. Unfortunately (or fortunately), that's not source of increased BB
spindle rotation resistance I described in my original post. Given the location
of screw in BB shell and shape of BB itself in same location, the screw does
not touch the BB when fully seated. Great suggestion, though!
Mr. Ray, I think this model BB came onto the market beginning in the mid 90's,
so it is likely as old as you note. If the grease viscosity changed over time,
I think spindle spin resistance would feel same with BB uninstalled vs
installed. However, I do buy into your suggestions "just attach cranks and
ride" and "the spindle should spin smoothly after breaking in." Thanks for the
reassuring "don't worry" advice.
Garth, my issue isn't bits coming loose. I'm going to stick with factory torque
specs; and if something comes loose, I'll throw (or at least consider) the
kitchen sink at it.
George, thanks for the tips about how to address loose bits.
Nick, a quick search on Google machine for pros/cons to chase and face of new
frames reveals entrenched camps both for and against. Both camps make sound
arguments, depending on the BB type and other factors. I'm going to avoid the
DEEP rabbit hole my comments/thoughts for or against would take us. I welcome
yours, though. For now, since my BB is a cartridge-type and threading-in DS and
NDS by hand felt way smooth, I'm going to forgo chase and face steps.
Andy, I appreciate you sharing the personal metrics you've acquired having
installed many BBs. It's that knowledge base I wanted to tap into. I'm inclined
to agree with your comment "the [BB] bearings (of units that become legend like
yours) are ... superior enough in precision that you can feel some resistance
prior to what break in will produce. They ought to be fine." Regarding your
sentence "No grinding or destructive feeling load felt, I built enough box
bikes to know how a cruddy BB feels by the intermittence of resistance or that
grinding feeling in the 360° of rotation," that's insightful. While I do feel
an increased resistance to spinning the spindle by hand after the BB is
installed, there is no "grinding or destructive feel" to the 360 spindle
rotation, and it is perfectly smooth, just increased resistance.
While my wrenching skills are deft (IMHO), I lack the metrics one gains through
voluminous installations of various bits. BUT, I'm not scared to ask those that
do have experiences, so thanks, all!
Hope everyone's 2023 is off to a good start...
Scott
On Tuesday, January 17, 2023 at 05:39:16 AM MST, ascpgh
wrote:
Your NOS BBs have really nice high quality bearings. I would imagine that the
tolerances related to a mild load on those bearings that accumulate from the
bearings themselves in the cylinder, the cartridge installation cups'
receptacle ends, their threading and the frame's BB threading when all torqued
to spec add up enough to produce some perceived interference to silk smooth
finger rotation.
BBs take a pretty big load in use and the bearings (of units that become legend
like yours) are not particularly delicate but superior enough in precision that
you can feel some resistance prior to what break in will produce. They ought
to be fine.
When I replaced the Phil Wood BB in my Rambouillet with an SKF for a shorter
spindle when going from triple to wide double I was stunned by the drag the
SKF's seal system put on finger rotation and installed crank free rotation
after spinning them. Not because of a single outer rubber grommet but the
labyrinths of each end and lubricant inside. No grinding or destructive feeling
load felt, I built enough box bikes to know how a cruddy BB feels by the
intermittence of resistance or that grinding feeling in the 360° of rotation.
By free tune up time after the sale some of the most mundane no-brand BBs were
running smoothly and kept doing their job for a reasonable if not notable
duration given how primitive and cheap they appeared to be.
Hubs act the same way to finger rotation or wheel free spinning after
installation. I came to dislike Shimano Parallax architecture hubs because of
their rubber cone seals, connected to axle nut, engaged and rotated in a large
diameter but thin groove on the end of he hub body. Lots of drag on top of the
tactile sense that they were easily overcome by dust, water or mud.
Andy CheathamPittsbugrh
On Sunday, January 15, 2023 at 1:36:11 PM UTC-5 Scott wrote:
Hey, Bunch:
Pinging the group's knowledge for input/feedback on an issue I'm having with an
install of a new cartridge style BB in a new frame.
I'm building a new Atlantis and Gus. I installed a new BB (Shimano XTR UN91) in
Atlantis and torqued to
