Biopace versions

On Sun, 24 Sep 2006 11:58:37 -0700, "* * Chas" <[email hidden]>

Quoted message said:

I recently picked up a used MTB with Shimano Biopace HP triple
chainrings. I really like the way I can climb with them vs. standard
round chainrings.

I've seen 4 different versions of Biopace chainrings: Original Biopace,
Biopace II, Biopace SG and Biopace HP.

The Biopace SG labels say they are for thin chains whatever that means.

Biopace HP is supposed to have changed the features on the original
design that riders complained about.

What's Biopace II?

What other differences are there between the styles?

I read on a Biopace package that Shimano recommended 44-50 tooth and
38-48tooth chainring combinations for best shifting.

Thanks is advance for the warnings about knee problems with Biopace
chainrings.

I've lived with intermittent knee problems for 28 years that has limited
my cycling and cross country/telemark skiing from time to time. I guess
that I'll just have to find out for myself.

Chas.

Dear Chas,

Biopace II was "rounder":

"By the way, Biopace two was a 'rounder' version released after the
racers complained that the normal Biopace felt like having a worn
crank taper.....It didn't help."

http://archive.mtbr.com/00/0EFB7012.php

Sheldon has a page about biopace that may say more, but--horrors!--his
site is down again:

http://www.sheldonbrown.com/biopace.html

Cheers,

Carl Fogel

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

Quoted message said:

On Sun, 24 Sep 2006 11:58:37 -0700, "* * Chas" <[email hidden]>

Quoted message said:

I recently picked up a used MTB with Shimano Biopace HP triple
chainrings. I really like the way I can climb with them vs. standard
round chainrings.

I've seen 4 different versions of Biopace chainrings: Original

Biopace,

Quoted message said:

Quoted message said:

Biopace II, Biopace SG and Biopace HP.

The Biopace SG labels say they are for thin chains whatever that

means.

Quoted message said:

Quoted message said:

Biopace HP is supposed to have changed the features on the original
design that riders complained about.

What's Biopace II?

What other differences are there between the styles?

I read on a Biopace package that Shimano recommended 44-50 tooth and
38-48tooth chainring combinations for best shifting.

Thanks is advance for the warnings about knee problems with Biopace
chainrings.

I've lived with intermittent knee problems for 28 years that has

limited

Quoted message said:

Quoted message said:

my cycling and cross country/telemark skiing from time to time. I

guess

Quoted message said:

Quoted message said:

that I'll just have to find out for myself.

Chas.

Dear Chas,

Biopace II was "rounder":

"By the way, Biopace two was a 'rounder' version released after the
racers complained that the normal Biopace felt like having a worn
crank taper.....It didn't help."

http://archive.mtbr.com/00/0EFB7012.php

Sheldon has a page about biopace that may say more, but--horrors!--his
site is down again:

http://www.sheldonbrown.com/biopace.html

Cheers,

Carl Fogel

Thanks for the response. I should have mentioned that I did an extensive
web search before posting. I missed the MTB site though.

So, is there a difference between Biopace II and Biopace HP? What about
Biopace SG chainrings, are they 'rounder' too?

Chas.

On Sun, 24 Sep 2006 12:40:42 -0700, "* * Chas" <[email hidden]>

Quoted message said:

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

Quoted message said:

On Sun, 24 Sep 2006 11:58:37 -0700, "* * Chas" <[email hidden]>

Quoted message said:

I recently picked up a used MTB with Shimano Biopace HP triple
chainrings. I really like the way I can climb with them vs. standard
round chainrings.

I've seen 4 different versions of Biopace chainrings: Original

Biopace,

Quoted message said:

Quoted message said:

Biopace II, Biopace SG and Biopace HP.

The Biopace SG labels say they are for thin chains whatever that

means.

Quoted message said:

Quoted message said:

Biopace HP is supposed to have changed the features on the original
design that riders complained about.

What's Biopace II?

What other differences are there between the styles?

I read on a Biopace package that Shimano recommended 44-50 tooth and
38-48tooth chainring combinations for best shifting.

Thanks is advance for the warnings about knee problems with Biopace
chainrings.

I've lived with intermittent knee problems for 28 years that has

limited

Quoted message said:

Quoted message said:

my cycling and cross country/telemark skiing from time to time. I

guess

Quoted message said:

Quoted message said:

that I'll just have to find out for myself.

Chas.

Dear Chas,

Biopace II was "rounder":

"By the way, Biopace two was a 'rounder' version released after the
racers complained that the normal Biopace felt like having a worn
crank taper.....It didn't help."

http://archive.mtbr.com/00/0EFB7012.php

Sheldon has a page about biopace that may say more, but--horrors!--his
site is down again:

http://www.sheldonbrown.com/biopace.html

Cheers,

Carl Fogel

Thanks for the response. I should have mentioned that I did an extensive
web search before posting. I missed the MTB site though.

So, is there a difference between Biopace II and Biopace HP? What about
Biopace SG chainrings, are they 'rounder' too?

Chas.

Dear Chas.,

I dont know, but it's likely that later versions of BioPace are also
"rounder" BioPace II because the reduced oval of BioPace II addressed
complaints.

Sheldon's site is back up, but his BioPace page doesn't mention the
variants:

http://www.sheldonbrown.com/biopace.html

Cheers,

Carl Fogel

On Sun, 24 Sep 2006 11:58:37 -0700, "* * Chas" <[email hidden]>

Quoted message said:

I recently picked up a used MTB with Shimano Biopace HP triple
chainrings. I really like the way I can climb with them vs. standard
round chainrings.

I've seen 4 different versions of Biopace chainrings: Original Biopace,
Biopace II, Biopace SG and Biopace HP.

The Biopace SG labels say they are for thin chains whatever that means.

Biopace HP is supposed to have changed the features on the original
design that riders complained about.

What's Biopace II?

What other differences are there between the styles?

I read on a Biopace package that Shimano recommended 44-50 tooth and
38-48tooth chainring combinations for best shifting.

Thanks is advance for the warnings about knee problems with Biopace
chainrings.

I've lived with intermittent knee problems for 28 years that has limited
my cycling and cross country/telemark skiing from time to time. I guess
that I'll just have to find out for myself.

Chas.

Rotor has some new fangled ones. They'll be at Interbike:

http://www.interbike.com/ib/showcase/product/display_product_list.jsp

Group: rec.bicycles.tech
Date: Sun, Sep 24, 2006, 11:58am (EDT-3)
From: [email hidden] (* * Chas)

I recently picked up a used MTB with Shimano BioPace HP triple
chainrings. I really like the way I can climb with them vs. standard
round chainrings.

I've seen 4 different versions of Biopace chainrings: Original Biopace,
Biopace II, Biopace SG and Biopace HP.

The Biopace SG labels say they are for thin chains whatever that means.

- - - - - - - - - - -

"Thin" chains are the narrower ones developed for 8 cog, 9 cog, and so
on.

- - - - - - - - - - -

Biopace HP is supposed to have changed the features on the original
design that riders complained about.

- - - - - - - - - - -

Right. Biopace HP (High Performance) was designed to be used with a
faster, smoother spin. Basically this was an attempt to placate the
people who liked to spin and didn't like it when Shimano discontinued
the production of round rings, a stupid idea on Shimano's part, if you
ask me.

- - - - - - - - - - - -

What's Biopace II?

What other differences are there between the styles?

- - - - - - - - - - - -

I'm not sure, but I think BioPace II was a slight "mellowing out" of the
original design, based on further research (Sheldon would know better
about this). Personally, I've used both original and "BP-II's" and
noticed little if any difference.

- - - - - - - - - - - - -

I read on a Biopace package that Shimano recommended 44-50 tooth and
38-48tooth chainring combinations for best shifting.

Thanks is advance for the warnings about knee problems with Biopace
chainrings.
I've lived with intermittent knee problems for 28 years that has limited
my cycling and cross country/telemark skiing from time to time. I guess
that I'll just have to find out for myself.

Chas.

- - - - - - - - - - -

The shape of BioPace get's more eccentric as the rings get smaller, This
is because smaller rings are usually used when the going gets tougher
(hills, for example) and therefore the irregularity of leg motion
increases, so the irregularity of the ring does so also to compensate.

This does, however raise another problem when gearing combinations are
used that require shifting back and forth between different rings
throughout the range. for example half step and alpine.

With half-step the two chainrings are very close in size (usually around
4-6 teeth different) and shape, so alternating between the two would not
cause any problems. So this would be one of the configurations I would
recommend.

The other system is crossover, with 10 or more teeth difference between
chainrings, depending n the range of the cogset. Although this would
give two very differently shaped rings, the smaller, more exagerated
ring would be used primarily with the lower gears, which it was designed
for, and the larger, rounder ring mainly with the higher gears, which
_it_ was designed for.

Alpine, which would require alternating between two vary different
shaped rings throughout the range, I would NOT recommend.

AFAIK, there wasn't any reliable research done on knee strain or
benefits during BioPace's ten year life span. I'm sure there were biased
studies from both sides, but these obviously cannot be considered
reliable by any definition.

For a good read on BioPace see Sheldon's site
http://www.sheldonbrown.com/biopace.html

Hope this helps.

- -
Comments and opinions compliments of,
"Your Friendly Neighborhood Wheelman"

My web Site:
http://geocities.com/czcorner

Messages sent to the above "E" addy will be lost forever
to E-mail me:
ChrisZCorner "at" webtv "dot" net

Chris thanks for the info, the rest is bottom posted.

Chas.

"Chris Y.F.N.W." <[email hidden]> wrote in message
news:[email hidden]...
Group: rec.bicycles.tech
Date: Sun, Sep 24, 2006, 11:58am (EDT-3)
From: [email hidden] (* * Chas)

Quoted message said:

Quoted message said:

I recently picked up a used MTB with Shimano BioPace HP triple
chainrings. I really like the way I can climb with them vs. standard
round chainrings.

Quoted message said:

Quoted message said:

I've seen 4 different versions of Biopace chainrings: Original

Biopace,

Quoted message said:

Quoted message said:

Biopace II, Biopace SG and Biopace HP.

Quoted message said:

Quoted message said:

The Biopace SG labels say they are for thin chains whatever that

means.

Quoted message said:

- - - - - - - - - - -
"Thin" chains are the narrower ones developed for 8 cog, 9 cog, and so
on.
- - - - - - - - - - -

Is there any difference in the shape of the chainrings?

<snip>

Quoted message said:

Quoted message said:

What's Biopace II?

Quoted message said:

Quoted message said:

What other differences are there between the styles?

Quoted message said:

- - - - - - - - - - - -
I'm not sure, but I think BioPace II was a slight "mellowing out" of

the

Quoted message said:

original design, based on further research (Sheldon would know better
about this). Personally, I've used both original and "BP-II's" and
noticed little if any difference.
- - - - - - - - - - - - -

<snip>

Quoted message said:

- - - - - - - - - - -

Quoted message said:

The shape of BioPace get's more eccentric as the rings get smaller,

This

Quoted message said:

is because smaller rings are usually used when the going gets tougher
(hills, for example) and therefore the irregularity of leg motion
increases, so the irregularity of the ring does so also to compensate.

Quoted message said:

This does, however raise another problem when gearing combinations are
used that require shifting back and forth between different rings
throughout the range. for example half step and alpine.

Quoted message said:

With half-step the two chainrings are very close in size (usually

around

Quoted message said:

4-6 teeth different) and shape, so alternating between the two would

not

Quoted message said:

cause any problems. So this would be one of the configurations I would
recommend.

Quoted message said:

The other system is crossover, with 10 or more teeth difference between
chainrings, depending on the range of the cogset. Although this would
give two very differently shaped rings, the smaller, more exagerated
ring would be used primarily with the lower gears, which it was

designed

Quoted message said:

for, and the larger, rounder ring mainly with the higher gears, which
_it_ was designed for.

Quoted message said:

Alpine, which would require alternating between two vary different
shaped rings throughout the range, I would NOT recommend.

Quoted message said:

AFAIK, there wasn't any reliable research done on knee strain or
benefits during BioPace's ten year life span. I'm sure there were

biased

Quoted message said:

studies from both sides, but these obviously cannot be considered
reliable by any definition.

Quoted message said:

For a good read on BioPace see Sheldon's site
http://www.sheldonbrown.com/biopace.html

Quoted message said:

Hope this helps.

As I mentioned, I liked the feel of the Biopace chainrings on the used
MTB that I bought so I picked up 2 new Shimano Deore XT vintage
cranksets with 28-38-48 Biopace HP chainrings on eBay.

I replaced the TA Cyclotourist cranks on my retro-grouch lugged DB 531
vintage MTB with one set and I want to try the other one on a road bike
using half step gearing.

I've been using half step gearing on my road bikes for over 30 years.
I've found that I don't need close gearing in the highest and lowest
ranges but I like about 5" jumps in the 50" to 80" range which worked
great with 5 and 6 cog freewheels. Over 80" I'm usually going down hill
so big jumps are not a problem and I can easily handle fewer gears under
50".

I have a set of freewheels from a 13-18 corn cob for time trials to a
14-34 that I used for touring in the Rockies. These combined with 45-49
chainrings on my regular road bike and a 30-45-49 triple setup on my
touring bike gave me all the choice that I needed.

I'm just now trying 7 & 8 speed cassette hubs on my road bikes (retro
grouch). I made up a bunch of gear charts to check out the different
possibilities. There's a lot of overlap with so many rear sprockets and
I'm trying to keep half step gearing for the mid range.

I've seen 110 BCD Biopace chainrings in 44-46-48-50 teeth and I'm trying
to find out the differences between the different types. That's why all
of the questions.

Chas.

Chas:

The difference between chanring shapes is not that apparent between
close sizes. Compare, say a 48 and a 32 and you'll see the difference.
Actually, the shape doesn't really _change_ it stays the same but gets
more extreme as the ring gets smaller..

- -
Comments and opinions compliments of,
"Your Friendly Neighborhood Wheelman"

Messages sent to the above "E" addy will be lost forever!

to E-mail me:
ChrisZCorner "at" webtv "dot" net

My website:
http://geocities.com/czcorner