HED on ceramic bearings

On Feb 6, 6:09 am, Dan Connelly <d_j_c_o_n_n_e_l@y_a_h_o_o_._c_o_m>

Quoted message said:

I've always liked HED wheels.... from what I've seen and read, they
aren't as good as Zipp in marketing, but their stuff stands up better,
and technically is at least a match. I'm especially impressed when
someone tries to talk me out of buying something.... in this case I need
to replace bearings in (what I believe) is a Hed hub on a custom built
wheel I got from Competitive Cyclist a long time ago. Essentially they
claim an advantage in durability, but not really in loaded drag.

http://www.hedcycling.com/wheels/ceramicbearings.php

We have spent significant time investigating hub rolling resistance.
(details of our test rig are below) With our test rig we compared steel
vs. ceramic bearings, and bearing bore variations. The biggest
measurable difference was in bearing bore accuracy. Bores that were not
concentric or that were undersized (in the hub shell) or oversized (on
the axle) made the most difference. The wrong size bore, even as small
as .001" undersized, deforms the bearing race and increases drag.
Likewise, non-concentric bores bind the bearings slightly and increase
bearing drag. These differences were evident in both an unloaded wheel
and one loaded with 100lbs.

There was a measurable drag difference between ceramic bearings and
steel bearings when we tested unloaded wheels, but the difference was
small enough that we could not measure it on a loaded wheel.

The upshot of our testing is this - We continue to focus on high quality
hubs with exact machining tolerances. Ceramic bearings do give a small
but measurable reduction in drag. They also offer greatly increased
durability and longevity. Based on this they are now an option on our
wheels.

Which is it? A small but unmeasurable difference in drag or a small
but measurable reduction in drag? And how much are these???

Qui si parla Campagnolo said:

Which is it? A small but unmeasurable difference in drag or a small
but measurable reduction in drag? And how much are these???

"Measurable" on an unloaded wheel, unmeasurable on a loaded wheel, so
overall measurable, but small.

Hmmm, I can either pay $40 for generic ball-bearing hubs, or I can pay
$240 for a set of boutique sealed-bearing hubs, built with sealed
bearings because it's cheaper for the manufacturer that way, plus $100
for a set of ceramic bearings, and the ceramic bearing-hubs will
ALMOST have a rolling resistance as low as the simple ball-bearing
cup-and-cone hubs, at only 7x the cost ...

fool me once, shame on you ... fool me twice, shame on me ...

- Don Gillies
San Diego, CA

Dan Connelly said:

Quoted message said:

Which is it? A small but unmeasurable difference in drag or a
small but measurable reduction in drag? And how much are these?

Quoted message said:

"Measurable" on an unloaded wheel, unmeasurable on a loaded wheel,
so overall measurable, but small.

Those are interesting units of measure. They don't seem to be any
conventional ones seen in engineering. Can you convert into power or
drag force for the technically inclined?

Jobst Brandt

Quoted message said:

Dan Connelly said:

Quoted message said:

Which is it? A small but unmeasurable difference in drag or a
small but measurable reduction in drag? And how much are these?

Quoted message said:

"Measurable" on an unloaded wheel, unmeasurable on a loaded wheel,
so overall measurable, but small.

Those are interesting units of measure. They don't seem to be any
conventional ones seen in engineering. Can you convert into power or
drag force for the technically inclined?

Jobst Brandt

Well, they spin the wheel, allowing it to creep ahead on the axle, as
rim rotation is coupled into axis rotation via friction, and axle
rotation drives the wheel due to traction with the mystery surface.
Obviously, this sort of measurement would need to be calibrated....

You should send HED an email and ask them for more quantitative info.
Perhaps they did some sort of calibration on this measurement....

Dan

Quoted message said:

Those are interesting units of measure. They don't seem to be any
conventional ones seen in engineering. Can you convert into power or
drag force for the technically inclined?

Nonsense, I'm sure they're using dimes balanced on spokes like just
about every other self-respecting scientist or engineer.

- Don *grin* Gillies
San Diego, CA

On Feb 6, 5:09 am, Dan Connelly <d_j_c_o_n_n_e_l@y_a_h_o_o_._c_o_m>

Quoted message said:

I've always liked HED wheels.... from what I've seen and read, they
aren't as good as Zipp in marketing, but their stuff stands up better,
and technically is at least a match. I'm especially impressed when
someone tries to talk me out of buying something.... in this case I need
to replace bearings in (what I believe) is a Hed hub on a custom built
wheel I got from Competitive Cyclist a long time ago. Essentially they
claim an advantage in durability, but not really in loaded drag.

http://www.hedcycling.com/wheels/ceramicbearings.php

We have spent significant time investigating hub rolling resistance.
(details of our test rig are below) With our test rig we compared steel
vs. ceramic bearings, and bearing bore variations. The biggest
measurable difference was in bearing bore accuracy. Bores that were not
concentric or that were undersized (in the hub shell) or oversized (on
the axle) made the most difference. The wrong size bore, even as small
as .001" undersized, deforms the bearing race and increases drag.
Likewise, non-concentric bores bind the bearings slightly and increase
bearing drag. These differences were evident in both an unloaded wheel
and one loaded with 100lbs.

There was a measurable drag difference between ceramic bearings and
steel bearings when we tested unloaded wheels, but the difference was
small enough that we could not measure it on a loaded wheel.

The upshot of our testing is this - We continue to focus on high quality
hubs with exact machining tolerances. Ceramic bearings do give a small
but measurable reduction in drag. They also offer greatly increased
durability and longevity. Based on this they are now an option on our
wheels.

OHHHH, I get it, the paragraphs after the HED web site reference was
theirs...so in other words, marketing gobbidygook. Nobody in their
right mind would believe anything any of these guys would put on their
web site...you need to add quotation marks or something, I thought is
was Dan talking..but I guess ya believe it. Loaded wheel, like one
being ridden??

(Donald Gillies) said:

Hmmm, I can either pay $40 for generic ball-bearing hubs, or I can pay
$240 for a set of boutique sealed-bearing hubs, built with sealed
bearings because it's cheaper for the manufacturer that way, plus $100
for a set of ceramic bearings, and the ceramic bearing-hubs will
ALMOST have a rolling resistance as low as the simple ball-bearing
cup-and-cone hubs, at only 7x the cost ...

fool me once, shame on you ... fool me twice, shame on me ...

- Don Gillies
San Diego, CA

Reality, what a concept. 21st century version of biopace.

Qui si parla Campagnolo said:

On Feb 6, 5:09 am, Dan Connelly <d_j_c_o_n_n_e_l@y_a_h_o_o_._c_o_m>
wrote:

[snip]

Quoted message said:

OHHHH, I get it, the paragraphs after the HED web site reference was
theirs...so in other words, marketing gobbidygook. Nobody in their
right mind would believe anything any of these guys would put on their
web site...you need to add quotation marks or something, I thought is
was Dan talking..but I guess ya believe it. Loaded wheel, like one
being ridden??

It took me a while to figure that one out too. And Dan, you left out
the second half of their gobblygook, btw. Here's a good way to quote
something like that, to avoid confusing people:

<citation>

Quoted message said:

Quoted message said:

Quoted message said:

>>>>>begin excerpt

marketingspeak gobblygook marketingspeak gobblygook marketingspeak
gobblygook marketingspeak gobblygook marketingspeak gobblygook
marketingspeak gobblygook marketingspeak gobblygook marketingspeak
gobblygook marketingspeak gobblygook marketingspeak gobblygook
marketingspeak gobblyg

Quoted message said:

Quoted message said:

Quoted message said:

>>>>>end excerpt

Bill Westphal

Bill Westphal said:

Qui si parla Campagnolo said:

On Feb 6, 5:09 am, Dan Connelly <d_j_c_o_n_n_e_l@y_a_h_o_o_._c_o_m>
wrote:

[snip]

Quoted message said:

OHHHH, I get it, the paragraphs after the HED web site reference was
theirs...so in other words, marketing gobbidygook. Nobody in their
right mind would believe anything any of these guys would put on their
web site...you need to add quotation marks or something, I thought is
was Dan talking..but I guess ya believe it. Loaded wheel, like one
being ridden??

It took me a while to figure that one out too. And Dan, you left out
the second half of their gobblygook, btw. Here's a good way to quote
something like that, to avoid confusing people:

<citation>

Quoted message said:

Quoted message said:

>>>>>>begin excerpt

marketingspeak gobblygook marketingspeak gobblygook marketingspeak
gobblygook marketingspeak gobblygook marketingspeak gobblygook
marketingspeak gobblygook marketingspeak gobblygook marketingspeak
gobblygook marketingspeak gobblygook marketingspeak gobblygook
marketingspeak gobblyg

Quoted message said:

Quoted message said:

>>>>>>end excerpt

You forgot: "techno-babble" and "psuedo science". ;-)

On Tue, 06 Feb 2007 13:09:10 GMT, Dan Connelly

d_j_c_o_n_n_e_l@y_a_h_o_o_._c_o_m said:

I've always liked HED wheels.... from what I've seen and read, they
aren't as good as Zipp in marketing, but their stuff stands up better,
and technically is at least a match. I'm especially impressed when
someone tries to talk me out of buying something.... in this case I need
to replace bearings in (what I believe) is a Hed hub on a custom built
wheel I got from Competitive Cyclist a long time ago. Essentially they
claim an advantage in durability, but not really in loaded drag.

http://www.hedcycling.com/wheels/ceramicbearings.php

We have spent significant time investigating hub rolling resistance.
(details of our test rig are below) With our test rig we compared steel
vs. ceramic bearings, and bearing bore variations. The biggest
measurable difference was in bearing bore accuracy. Bores that were not
concentric or that were undersized (in the hub shell) or oversized (on
the axle) made the most difference. The wrong size bore, even as small
as .001" undersized, deforms the bearing race and increases drag.
Likewise, non-concentric bores bind the bearings slightly and increase
bearing drag. These differences were evident in both an unloaded wheel
and one loaded with 100lbs.

There was a measurable drag difference between ceramic bearings and
steel bearings when we tested unloaded wheels, but the difference was
small enough that we could not measure it on a loaded wheel.

The upshot of our testing is this - We continue to focus on high quality
hubs with exact machining tolerances. Ceramic bearings do give a small
but measurable reduction in drag. They also offer greatly increased
durability and longevity. Based on this they are now an option on our
wheels.

That kind of soft/nuanced sell persuades me. That said, it doesn't
persuage me for something as costly as ceramic bearings. But it works
as general marketing -- it makes me trust the company more.

--
JT
****************************
Remove "remove" to reply
Visit http://www.jt10000.com
****************************

You guys are way too cynical. Other companies are selling this
produce, and HED said, in effect "The benefits are tiny and are not
for speed but a tiny benefit in durablity. Buy them if you want" and
you think they're being all bullshitty.
--
JT
****************************
Remove "remove" to reply
Visit http://www.jt10000.com
****************************

"John Forrest Tomlinson" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

You guys are way too cynical. Other companies are selling this
produce, and HED said, in effect "The benefits are tiny and are not
for speed but a tiny benefit in durablity. Buy them if you want" and
you think they're being all bullshitty.
--
JT
****************************
Remove "remove" to reply
Visit http://www.jt10000.com
****************************

One of my friends runs an industrial bearing supply company. He is astounded
how many cyclists are calling him lately. He asked me why the volume of
calls, like never before. I showed him some of the banter about ceramic
bearings on this NG and others. Shocked at what he read does not cover it.

I had him look at a disassembled DA hub. He made the comment that the cone
and race structure is probably the best design for a bike hub. Industrial
sealed bearings have a really bad time with shock and side loading or
stress. I am no engineer, so please forgive my technical weakness here. The
other thing he said is that ceramic bearings are generally used for very
high RPM applications. Bike wheels are not that.

I showed him the bearing price list from one of the cycling supply
companies. What costs a few dollars there would be 10 times the price from
an industrial supply. The stuff sold into the bike business is pretty cheap
by comparison. On the other hand some guy did buy a complete set of Koyo
bearings for his carbon time trial wheels. I hope he can install them
correctly. It would be a real shame if they were damaged...

Bruce

In article
<[email hidden]>,
Dan Connelly <d_j_c_o_n_n_e_l@y_a_h_o_o_._c_o_m>

Quoted message said:

I've always liked HED wheels.... from what I've seen and read, they
aren't as good as Zipp in marketing, but their stuff stands up better,
and technically is at least a match. I'm especially impressed when
someone tries to talk me out of buying something.... in this case I need
to replace bearings in (what I believe) is a Hed hub on a custom built
wheel I got from Competitive Cyclist a long time ago. Essentially they
claim an advantage in durability, but not really in loaded drag.

http://www.hedcycling.com/wheels/ceramicbearings.php

We have spent significant time investigating hub rolling resistance.
(details of our test rig are below) With our test rig we compared steel
vs. ceramic bearings, and bearing bore variations. The biggest
measurable difference was in bearing bore accuracy. Bores that were not
concentric or that were undersized (in the hub shell) or oversized (on
the axle) made the most difference. The wrong size bore, even as small
as .001" undersized, deforms the bearing race and increases drag.
Likewise, non-concentric bores bind the bearings slightly and increase
bearing drag. These differences were evident in both an unloaded wheel
and one loaded with 100lbs.

There was a measurable drag difference between ceramic bearings and
steel bearings when we tested unloaded wheels, but the difference was
small enough that we could not measure it on a loaded wheel.

The upshot of our testing is this - We continue to focus on high quality
hubs with exact machining tolerances. Ceramic bearings do give a small
but measurable reduction in drag. They also offer greatly increased
durability and longevity. Based on this they are now an option on our
wheels.

I sure could use some help. Will these bearings get me
up South Park Drive without seeing spots?

--
Michael Press

Are we there yet?

Donald Gillies said:

Hmmm, I can either pay $40 for generic ball-bearing hubs, or I can pay
$240 for a set of boutique sealed-bearing hubs, built with sealed
bearings because it's cheaper for the manufacturer that way, plus $100
for a set of ceramic bearings, and the ceramic bearing-hubs will
ALMOST have a rolling resistance as low as the simple ball-bearing
cup-and-cone hubs, at only 7x the cost ...

But, I *know* it will make me faster. I figure without all those extra
d$ll$r bills weighing me down, just think how fast I'll fly up those
hills!

--
Dane Buson - [email hidden]
Confess your sins to the Lord and you will be forgiven;
confess them to man and you will be laughed at.
-- Josh Billings

On Feb 6, 4:44 pm, John Forrest Tomlinson <[email hidden]>

Quoted message said:

You guys are way too cynical. Other companies are selling this
produce, and HED said, in effect "The benefits are tiny and are not
for speed but a tiny benefit in durablity. Buy them if you want" and
you think they're being all bullshitty.

I agree with you. HED knows they are BS, but they will be seen as
behind the times if they don't offer a ceramic bearing option. There
are many (maybe most?) cyclists who believe ceramic bearings offer
huge gains. Bicycling mag claims that they are good for 1 higher gear!
(and I assume they mean at the same cadence). Look at the claims that
FSA and others are making if you want a really good laugh. The
consumers have been convinced to spend their money... it would be
silly of HED to force them to spend it elsewhere.

Ron Ruff said:

On Feb 6, 4:44 pm, John Forrest Tomlinson <[email hidden]>

Quoted message said:

You guys are way too cynical. Other companies are selling this
produce, and HED said, in effect "The benefits are tiny and are not
for speed but a tiny benefit in durablity. Buy them if you want" and
you think they're being all bullshitty.

I agree with you. HED knows they are BS, but they will be seen as
behind the times if they don't offer a ceramic bearing option. There
are many (maybe most?) cyclists who believe ceramic bearings offer
huge gains. Bicycling mag claims that they are good for 1 higher gear!
(and I assume they mean at the same cadence). Look at the claims that
FSA and others are making if you want a really good laugh. The
consumers have been convinced to spend their money... it would be
silly of HED to force them to spend it elsewhere.

If you believe 0.8 watts versus high-quality steel bearings (Zipp's claim), then
out of a baseline of 250 watts, assuming typically 7% per gear, it should be
"worth 4.5 centigears".

Dan

Dan Connelly d_j_c_o_n_n_e_l@y_a_h_o_o_._c_o_m said:

At Tour of California in San Jose (stage 3), the Zipp rep told me their ceramic
hubs make a difference of 2 watts.

Also, if they're selling such [censored] hubs that they have 2 watts of drag
with steel bearings, they should be dragged out and shot. My *dynamo*
front hub has 2 watts of drag when off. There just isn't enough drag in
normal hubs to make it worthwhile to spend dosh reducing it.

--
Dane Buson - [email hidden]
Remember that as a teenager you are in the last stage of your life when
you will be happy to hear that the phone is for you.
-- Fran Lebowitz, "Social Studies"

On Feb 26, 7:09 pm, Dan Connelly <d_j_c_o_n_n_e_l@y_a_h_o_o_._c_o_m>

Quoted message said:

Ron Ruff said:

On Feb 6, 4:44 pm, John Forrest Tomlinson <[email hidden]>

Quoted message said:

You guys are way too cynical. Other companies are selling this
produce, and HED said, in effect "The benefits are tiny and are not
for speed but a tiny benefit in durablity. Buy them if you want" and
you think they're being all bullshitty.

Quoted message said:

I agree with you. HED knows they are BS, but they will be seen as
behind the times if they don't offer a ceramic bearing option. There
are many (maybe most?) cyclists who believe ceramic bearings offer
huge gains. Bicycling mag claims that they are good for 1 higher gear!
(and I assume they mean at the same cadence). Look at the claims that
FSA and others are making if you want a really good laugh. The
consumers have been convinced to spend their money... it would be
silly of HED to force them to spend it elsewhere.

If you believe 0.8 watts versus high-quality steel bearings (Zipp's claim), then
out of a baseline of 250 watts, assuming typically 7% per gear, it should be
"worth 4.5 centigears".

Dan

That's not believable.

Power dissipated in standard steel hub bearings should
be of order 0.5 watts. Ceramic bearings could maybe
shave off a few percent of that (if ceramic bearings have
0.95 the friction of steel bearings, they save ~ 0.02 watt).
Calculations here:

http://groups.google.com/group/rec.bicycles.tech/msg/9306a25dadee264e
http://groups.google.com/group/rec.bicycles.tech/msg/5d65113944c8b9b3

When I sent the original calculation to Zinn and he
quoted it in his column, people wrote him back and
moaned about all the technical mumbo-jumbo. These are
the same people who are buying ceramic bearing upgrades
to their wheels, I expect.

Ben