Bottom Bracket Drag

Lou Holtman said:

Jim Higson said:

HarryB said:

How much drag is considered normal for a cartridge bearing BB?

Don't know about normal, but if I give my cranks a good push with no
chain connected they continue to spin for several minutes.

Veloce cartridge BB (2006 model I think)

Several minutes??? That's not normal.

I must admit, I hadn't timed it. Now it has caused all this (unexpected!)
response I will do.

--
Jim

Quoted message said:

Lou Holtman said:

* * Chas said:

"Lou Holtman" <[email hidden]> wrote in message
news:[email hidden]...

>Jim Higson wrote:
>
>>HarryB wrote:
>>
>>
>>
>>>How much drag is considered normal for a cartridge bearing BB?
>>
>>
>>Don't know about normal, but if I give my cranks a good push with no

chain

>>connected they continue to spin for several minutes.
>>
>>Veloce cartridge BB (2006 model I think)
>>
>
>
>Several minutes??? That's not normal.
>
>Lou
>--

Well, it depends on how heavy your chainrings are, just like the
flywheel on a car. If you used nice heavy steel chainrings not the
flimsy alloy [censored] you see today, then yes they could possibly keep
spinning for quite some time.

Oh please, alloy chainrings are fine. For several minutes spin time
those clunky chainrings must be very heavy and large in diameter.

Lou

Dear Lou,

Actually, heavy pedals would probably be more helpful, since they're
further out and provide more angular momentum.

Ah, yes, that is with quite heavy steel SPD pedals.

--
Jim

On 4 Dec 2006 19:58:15 -0800, "Jay Beattie" <[email hidden]>

Quoted message said:

HarryB wrote:

[snip]

Quoted message said:

Quoted message said:

I am also concerned about the proper torque. The BB tool that I have,
a Park BBT8, is an eight sided socket that needs a crow's foot to work
with a torque wrench - and although I have a couple of torque
wrenches, I don't have a crow's foot. I have intentionally tightened
the BB to what I think is a low torque and will see how it goes. If
it's too loose I can always tighten it some more.

I've decided to live with this amount of drag for the time being. For
one thing, the "LBS" where I had the work done is about an
hour-and-a-half's drive from my house. So, to return it there would
consume a complete morning. And the other reason is that this tandem
(a recumbent) is an experiment to see if we like it better than our
present upright one. If we decide to keep it, I'll probably upgrade
the BB in the future and deal with this issue at that time.

Thanks for your help.

Those BBs also have o-rings and spacers between the flange and the BB
shell. Are any of those missing/needed? If one is needed and missing,
that might account for some end loading. Also, some BBs can get binding
at low torque when the bearings don't seat in to the left cup/ring.
Make sure that area is greased. BTW, I hate that notched retaining
ring BBT8, which I am going to have to buy to work on my POS Truvativ
BB - which is creaking, groaning and snapping all of the time, although
it still spins O.K. -- Jay Beattie.

Jay,

The Park Tool's BB tool is the one my LBS sold me. When I looked at it
I did notice that there were flats on one side, but hadn't noticed
that there were eight of them rather than six. I had just assumed that
I could have used a regular socket between the tool and my torque
wrench. If I were to do it over again I would probably purchase
TruVativ's BB-02-SPL tool since it has a 1/2" drive that would have
allowed me to use one of my torque wrenches.

Cheers,
Harry

[email hidden] wrote in news:co89n21uek77h73tspgvq1afvtnaomlirv@
4ax.com:

Quoted message said:

performed exhaustive
experiments for several minutes.

LOL (really).

But I question your results. After all, you knew which crank you were
testing so it wasn't a blind test. Also, did you kick up any dust or check
the trees before performing your tests? <grin>

Cheers,
David

[email hidden] (Donald Gillies) wrote in news:el2d35$dlj$1
@cascade.cs.ubc.ca:

Quoted message said:

As we all know, cartridge bearings can be used to make a cheaper
bottom bracket but not a better bottom bracket.

Well I certainly don't know that!

First, how can cartridge bearings be cheaper than equivalent quality
loose bearings? I can't imagine anything cheaper than the steel cup
bearings on an old Huffy.

Second, I don't see a value in the ability to spin a bottom bracket when
there's no load. Once you add the lateral force of pressing on the
pedals, any difference in friction due to the cartridge seals becomes
completely meaningless. Therefore, the maintenance free attribute of high
quality sealed bearings earn a ranking of "better" in my book.

Cheers,
David

Quoted message said:

[email hidden] (Donald Gillies) wrote in news:el2d35$dlj$1
@cascade.cs.ubc.ca:

Quoted message said:

Quoted message said:

As we all know, cartridge bearings can be used to make a cheaper
bottom bracket but not a better bottom bracket.

- cheaper to use a commercial sealed bearing whose manufacturing
quantity is in the zillions, than to mess around with bearing
retainers and grinding and hardening your own cups.

- cheaper to install because it takes less time to get it perfect and
the bottom bracket doesn't have to be faced - as well - for it to
work - acceptable.

cheaper? yes.
better? never.

- Don Gillies
San Diego, CA

[email hidden] (Donald Gillies) wrote in news:el7r5b$9r6$1
@cascade.cs.ubc.ca:

Quoted message said:

Quoted message said:

[email hidden] (Donald Gillies) wrote in news:el2d35$dlj$1
@cascade.cs.ubc.ca:

Quoted message said:

Quoted message said:

As we all know, cartridge bearings can be used to make a cheaper
bottom bracket but not a better bottom bracket.

- cheaper to use a commercial sealed bearing whose manufacturing
quantity is in the zillions, than to mess around with bearing
retainers and grinding and hardening your own cups.

What you define as cheaper, I see as a better value: You get much higher
quality cartridge bearings that are manufactured in high quantities as
compared to equally priced custom made open cup versions.

Quoted message said:

- cheaper to install because it takes less time to get it perfect and
the bottom bracket doesn't have to be faced - as well - for it to
work - acceptable.

cheaper? yes.
better? never.

- Don Gillies
San Diego, CA

You place zero value in the concept of lower maintenance for sealed
bearings?

Also, in what way are conventional open cup bottom brackets superior? Do
you value their slight advantage in unloaded free spinning? This would
have a minuscule (if any) advantage once the lateral forces of pedaling
is added. Or is there something else I'm missing?

Cheers,
David

Jim Higson said:

Quoted message said:

How much drag is considered normal for a cartridge bearing BB?

Don't know about normal, but if I give my cranks a good push with no chain
connected they continue to spin for several minutes.

Veloce cartridge BB (2006 model I think)

One thing to keep in mind is that a bearing can behave very differently
under load than when unloaded. That fact that your cranks spin for
several minutes when unloaded has very little relevence to how they will
perform under load.

--

John ([email hidden])

John Thompson said:

Quoted message said:

Quoted message said:

How much drag is considered normal for a cartridge bearing BB?

Quoted message said:

Quoted message said:

Don't know about normal, but if I give my cranks a good push with
no chain connected they continue to spin for several minutes.

Quoted message said:

Quoted message said:

Veloce cartridge BB (2006 model I think)

Quoted message said:

One thing to keep in mind is that a bearing can behave very
differently under load than when unloaded. That fact that your
cranks spin for several minutes when unloaded has very little
relevence to how they will perform under load.

Let's not go off fear mongering. Explain where you believe there are
hidden aspects of bearing drag that would not be apparent in the
no-load test. Assuming the bearing isn't loose and nothing is broken,
where do you see relevant differences under load?

Jobst Brandt

[email hidden] wrote in news:4578a202$0$34575
[email hidden]:

Quoted message said:

Let's not go off fear mongering. Explain where you believe there are
hidden aspects of bearing drag that would not be apparent in the
no-load test. Assuming the bearing isn't loose and nothing is broken,
where do you see relevant differences under load?

I think the point was the opposite. Some in this thread are claiming that
open cup bearings are superior to sealed cartridge based on the
comparison of no-load spinning. The point about that not being relevant
to loaded conditions is that this difference, while substantial without a
load, is insignificant under loaded conditions. Under a load, you will
not notice any difference in drag caused by the bearing seals.

At least that's the point that I've been trying to make here. <grin>

Cheers,
David

Solvang Cyclist said:

[email hidden] wrote in news:4578a202$0$34575
[email hidden]:

Quoted message said:

Let's not go off fear mongering. Explain where you believe there are
hidden aspects of bearing drag that would not be apparent in the
no-load test. Assuming the bearing isn't loose and nothing is broken,
where do you see relevant differences under load?

I think the point was the opposite. Some in this thread are claiming that
open cup bearings are superior to sealed cartridge based on the
comparison of no-load spinning. The point about that not being relevant
to loaded conditions is that this difference, while substantial without a
load, is insignificant under loaded conditions. Under a load, you will
not notice any difference in drag caused by the bearing seals.

At least that's the point that I've been trying to make here. <grin>

Cheers,
David

I'm kinda new here and I must confess I lurk and try not to get into
controversial threads except maybe to inject a little humor here and
there. Laughter really is the best medicine.
I've seen many references to the weight of the bicycle versus the weight
of the rider when attempting to gain or lose just a smidgen more or less
of this or that. A 20 lb bike under a 200 lb rider with say 300 watts
power input. 220 lbs ... 300 watts. A 19.5 lb bike under a 200 lb
rider with 300 watts. 219.5 lbs ... 300 watts.
I haven't the means (or the want to) of measuring the drag of seals on a
BB. I think we can agree it's a small amount. What effect does that
drag have on a rotating mass of ? (how much does the BB, cranks, etc.
weigh? A couple/three or four lbs?) with 0 watts input versus 300 watts
input?
Besides, we need that drag to help stop the pedals when we want to rest.
(yeah, pretty lame)

--

Ted P.
Don't forget to take out the trash

I have an Ultera 6500 Octalink bottom bracket - unmounted - in my
garage. When I spin (twist is a more apt word) the bottom bracket,
not only is it smooth and quiet, but when I stop twisting it with my
fingers, the spindle goes for 0 mm before halting. There is even some
amount of stiction to get it going.

With a similar cup & cone bearing sitting properly aligned on the
washing machine, i can get some actual coasting out of the raw
bearing.

- Don Gillies
San Diego, CA

[email hidden] (Donald Gillies) wrote in news:elcedq$e08$1
@cascade.cs.ubc.ca:

Quoted message said:

I have an Ultera 6500 Octalink bottom bracket - unmounted - in my
garage. When I spin (twist is a more apt word) the bottom bracket,
not only is it smooth and quiet, but when I stop twisting it with my
fingers, the spindle goes for 0 mm before halting. There is even some
amount of stiction to get it going.

With a similar cup & cone bearing sitting properly aligned on the
washing machine, i can get some actual coasting out of the raw
bearing.

- Don Gillies
San Diego, CA

I don't see the point here. You have a single, currently bad, cartridge
bearing (or perhaps misaligned BB, who knows?) and you are comparing that
to a single open cup bearing under no load conditions. Is that your basis
for your statement that cartridge bearings are always worse than open cup
bearings?

First, not having any idea as to why the Ultegra BB doesn't spin freely,
we don't know it's due to the fact that the bearings have seals. Second,
regardless of the reason, a single sample can't be extrapolated to the
general statement that sealed bearings are inferior to open cup bearings.

Finally (and most importantly) I still fail to understand how these
"tests" (while perhaps entertaining when the weather is cold outside) are
at all useful in determining which design is "better".

You have made the claim that cartridge bearings are never better than
sealed bearings, but you still have not explained why. Is it because,
when the chain is off, you can spin the crank arms for a longer time?
That just isn't the way my bikes get used. I tend to ride them.

When riding, I defy you to tell the difference between a clean, greased
and properly adjusted open cup bearing and a "decent quality" cartridge
bearing. If that's the case, then for their use on a bike, both designs
are equal in quality.

On the other hand, keeping an open cup bearing "clean, greased and
properly adjusted" requires regular maintenance, while a "decent
quality" cartridge bearing requires none. Therefore, unless I'm missing
some qualities of open cup bearings, it would seem to me that all things
considered, sealed bearings are the superior design for bicycle
applications.

Please help me to understand why this is not so.

Cheers,
David

Solvang Cyclist said:

[email hidden] (Donald Gillies) wrote in news:elcedq$e08$1
@cascade.cs.ubc.ca:

Quoted message said:

I have an Ultera 6500 Octalink bottom bracket - unmounted - in my
garage. When I spin (twist is a more apt word) the bottom bracket,
not only is it smooth and quiet, but when I stop twisting it with my
fingers, the spindle goes for 0 mm before halting. There is even some
amount of stiction to get it going.

With a similar cup & cone bearing sitting properly aligned on the
washing machine, i can get some actual coasting out of the raw
bearing.

- Don Gillies
San Diego, CA

I don't see the point here. You have a single, currently bad, cartridge
bearing (or perhaps misaligned BB, who knows?) and you are comparing that
to a single open cup bearing under no load conditions. Is that your basis
for your statement that cartridge bearings are always worse than open cup
bearings?

First, not having any idea as to why the Ultegra BB doesn't spin freely,
we don't know it's due to the fact that the bearings have seals. Second,
regardless of the reason, a single sample can't be extrapolated to the
general statement that sealed bearings are inferior to open cup bearings.

Finally (and most importantly) I still fail to understand how these
"tests" (while perhaps entertaining when the weather is cold outside) are
at all useful in determining which design is "better".

You have made the claim that cartridge bearings are never better than
sealed bearings, but you still have not explained why. Is it because,
when the chain is off, you can spin the crank arms for a longer time?
That just isn't the way my bikes get used. I tend to ride them.

When riding, I defy you to tell the difference between a clean, greased
and properly adjusted open cup bearing and a "decent quality" cartridge
bearing. If that's the case, then for their use on a bike, both designs
are equal in quality.

On the other hand, keeping an open cup bearing "clean, greased and
properly adjusted" requires regular maintenance, while a "decent
quality" cartridge bearing requires none. Therefore, unless I'm missing
some qualities of open cup bearings, it would seem to me that all things
considered, sealed bearings are the superior design for bicycle
applications.

Please help me to understand why this is not so.

Cartridge BB are a blessing especially on a ATB. Who wants to take
apart, clean, grease and adjust his BB after every couple of wet and
dirty rides. Not me.

Lou
--
Posted by news://news.nb.nu

You guys really don't have a clue why Cartridge bottom brackets are
promoted and sold by the manufacturers. do you ??

- Don Gillies
San Diego, CA

Donald Gillies said:

You guys really don't have a clue why Cartridge bottom brackets are
promoted and sold by the manufacturers. do you ??

- Don Gillies
San Diego, CA

Enlighten us, the ignorant, please. Let me guess. It's a marketing
scheme to let us buy more of their stuff?

Lou
--
Posted by news://news.nb.nu

Donald Gillies said:

You guys really don't have a clue why Cartridge bottom brackets are
promoted and sold by the manufacturers. do you ??

The installation of a cartridge bottom bracket (BB) takes less time and
skill than a cup and cone BB. A manufacturer specifying cup and cone
BB's will be at a competitive disadvantage.

I suspect that the above is the reason Shimano has been moving away
from square taper BB's, as installation is more dependent on user skill
than their more recent designs.

--
Tom Sherman - Post Free or Die!

[email hidden] (Donald Gillies) wrote in news:eldoqu$8o4$1
@cascade.cs.ubc.ca:

Quoted message said:

You guys really don't have a clue why Cartridge bottom brackets are
promoted and sold by the manufacturers. do you ??

- Don Gillies
San Diego, CA

I'm certain it's to make more money, since that's why (successful)
companies promote and sell anything. But why they are sold is not
relevant to this discussion.

You continue to claim that cartridge bearings are inferior to open cup
and cone bearings, yet you don't explain the reason. I have given an
explanation for why I disagree. That is: Sealed bearings offer lower
maintenance and *no* appreciable difference in feel "under normal usage
conditions."

Can you please explain the advantages of open cup and cone bearings to
me? If it's only that you can spin them longer when the chain is off, as
I've stated, that's not how I use my bike so it's of no advantage to me
given the extra maintenance required. If there are other advantages, you
have yet to state them.

Cheers,
David

Johnny Sunset said:

Donald Gillies said:

You guys really don't have a clue why Cartridge bottom brackets are
promoted and sold by the manufacturers. do you ??

The installation of a cartridge bottom bracket (BB) takes less time and
skill than a cup and cone BB. A manufacturer specifying cup and cone
BB's will be at a competitive disadvantage.

I suspect that the above is the reason Shimano has been moving away
from square taper BB's, as installation is more dependent on user skill
than their more recent designs.

I supect that the reasons Shimano has been moving away from square
taper are:

1) Marketing (New! Different!! Better!!!)

2) Proprietary designs mean they have a captive market when the crappy
originals wear out, assuming the buyer is unwilling to replace the
crank as well as the BB.