Bottom brackets bearing spacing

Not only have you made an astute observation but you have done it in
extremely good English.

I hope you'll continue posting here.

Lewis.

*****

Pierluigi Zezza said:

Hi all,

I'm not aware if this group has the habit of a presentation before first
posting, so here it goes: I am an amateur bike mechanic from Italy.
Actually I should ride more and tinker less, but I've got quite a family
and it easier to find shop time in the night than ride time in the day.
English is not my mother language so I'm not sure I can always express
myself clearly or use the right terms. If something is unclear please
ask me to explain myself better.

I researched the archive of the group before posting but was unable to
find a discussion about this matter.

Recently I had to change some bottom bearings from different bicycles of
different ages: a Shimano Cartridge bearing (BBUN51), a new Campagnolo
low end (those with the flange that has 6 dimples on the circumference)
cartridge bearing and an old Campagnolo with cup and balls.
All where for an Italian BB (36x24f - 70mm).
I had the opportunity to compare them and noted something that awaken my
curiosity: the distance between the bearings is different.
I couldn't take a very precise measure due to the geometry of the thing,
but I valuated the distance between the middle plane of the left race
and that of the right one, to eliminate differences in ball size.
Shimano cartridge: 50mm
Campa (mirage?) cartridge: 56mm
Campa loose bearings: 62mm

I'm aware here the limiting factor is the flection of the BB shell and
frame, but It looks like the old "integral" bearing is better as far as
opposing to 'capsizing momentum' (unsure of the term: i'm translating
literally) is concerned.
And it's funny that recently the bike industry has gone to external cups
for the BB bearings, to space them apart more.
Something that appears the very old brackets already did.

What is the industry notion about that?
What's your opinion?

--
Ciao,

Pierluigi Zezza

Writing from Italy.

Outboard BBs are not a solution to BB bearings that were too close
together but a solution to small bearings because splined BBs(Both
octastink and ISIS) were such large BB spindles, outside diameter. Poor
reliability resulted and hence the outboard bearings. None of the
outboard stuff was a solution to square taper BBs.

9 May 2006 06:07:01 -0700, Qui si parla Campagnolo scriveva:

Quoted message said:

Outboard BBs are not a solution to BB bearings that were too close
together but a solution to small bearings because splined BBs(Both
octastink and ISIS) were such large BB spindles, outside diameter. Poor

I hadn't thought about that.
It makes sense that a big spindle needs larger diameter bearings but, at
least here in Italy, outboard BBs are touted, along with "integrated"
cranks as being stiffer. The new frame-Viagra.
I failed to notice they are for ISIS or Octalink only.

Quoted message said:

reliability resulted and hence the outboard bearings. None of the
outboard stuff was a solution to square taper BBs.

Never thought it was: there's nothing wrong with square taper, IMVHO.

What about the rest of the post:
What do you think of non-cartridge BB bearings in respect to spacing of
the planes of the two ball-races?

--
Ciao,

Pierluigi Zezza

Writing from Italy.

9 May 2006 05:27:23 -0700, [email hidden] scriveva:

Quoted message said:

Not only have you made an astute observation but you have done it in
extremely good English.

Sure this is a warm welcome, Thank you Lewis.

Quoted message said:

I hope you'll continue posting here.

Thanks again, but I don't know if I can put up with such an high
traffic.
Maybe If I can rig some sort of filter to fend off the helmet-posts and
keep just what I'm interested in.

--
Ciao,

Pierluigi Zezza

Writing from Italy.

Pierluigi Zezza said:

9 May 2006 06:07:01 -0700, Qui si parla Campagnolo scriveva:

Quoted message said:

Outboard BBs are not a solution to BB bearings that were too close
together but a solution to small bearings because splined BBs(Both
octastink and ISIS) were such large BB spindles, outside diameter. Poor

I hadn't thought about that.
It makes sense that a big spindle needs larger diameter bearings but, at
least here in Italy, outboard BBs are touted, along with "integrated"
cranks as being stiffer. The new frame-Viagra.
I failed to notice they are for ISIS or Octalink only.

Quoted message said:

reliability resulted and hence the outboard bearings. None of the
outboard stuff was a solution to square taper BBs.

Never thought it was: there's nothing wrong with square taper, IMVHO.

What about the rest of the post:
What do you think of non-cartridge BB bearings in respect to spacing of
the planes of the two ball-races?

--
Ciao,

Pierluigi Zezza

Writing from Italy.

Well, when cranks went to a low profile center, recessed cups and cart
bearings were the only way to acheive this. I look at cup and ball BBs
as the ultimate in reliability, serviceability and smoothness...not
about stiffness. As for outbaord bearing BBs and 2 piece cranks, they
'may' be stiffer, altho a Aussie mag named Ride said all the FSA ones
were LESS stiff than Campag cranks. But saying it's 'stiff' implys that
other designs are soft, flexy, prone to failure and that of course, is
not true.

On Fri, 12 May 2006 09:19:52 +0200, Pierluigi Zezza <[email hidden]>

Quoted message said:

Thanks again, but I don't know if I can put up with such an high
traffic.
Maybe If I can rig some sort of filter to fend off the helmet-posts and
keep just what I'm interested in.

As you're using forte agent, just hit 'i' when on a helmet thread and it
will henceforth Ignore said thread. It may not be quite as efficient as a
real filter but it takes much less setup time.

Jasper

12 May 2006 05:32:40 -0700, Qui si parla Campagnolo scriveva:

Quoted message said:

Well, when cranks went to a low profile center, recessed cups and cart
bearings were the only way to acheive this.

I'm sorry, I can't understand.
Do you mind explaining me why?
Can't I put a new, low-profile crank on a cup and ball BB ?

Quoted message said:

I look at cup and ball BBs
as the ultimate in reliability, serviceability and smoothness...not
about stiffness.

I didn't want to imply that.
My observation was that probably what is regarded as old technology has
more (un-needed) stiffness than the new cartridge and has something in
common with the newest fad.
I would not use a cup and cone BB for the sake of stiffness.
Smoothness? in my limited experience: Yes!
For sure it is much smoother of the low-end cartridges I employ.
But I don't know anything about the high end ones.

Quoted message said:

As for outbaord bearing BBs and 2 piece cranks, they
'may' be stiffer, altho a Aussie mag named Ride said all the FSA ones
were LESS stiff than Campag cranks. But saying it's 'stiff' implys that
other designs are soft, flexy, prone to failure and that of course, is
not true.

In my very humble opinion all this tests have a defect: they say the
truth but don't say how that applies to relity.
Bigger diameter spindles are stiffer than the smaller ones?
Bigger and more spaced apart races are stiffer?
A cilindrcal splined coupling is better than a conical one to resist
high lateral loads?

Sure: it is common mechanical knowledge, that the tests can only confirm
(if the quality of the manufacturing is the same) but has this any
influence with loads and speeds commonly associated with cycling?
For all sorts of people or just for the 800W sprinter pro cyclist?
I never saw that in the mags.

--
Ciao,

Pierluigi Zezza

Writing from Italy.