Compact Crank Ring Differential

David L. Johnson said:

If that pulls your chain, fine, but frankly "need" and huge gears don't
make much sense to me, unless you need to win that downhill sprint to
become a stage winner on the Tour.

So if a gear like 52x12 would help someone win a low level bike race,
that's not "need" since their livelihood or something doesn't depend
on it?

I've been in in two local/regional cycling events this year where not
having a 12 would be a significant disadvantage.

But we don't need it? How do you define need if not by failing at the
task at hand w/o something?

Quoted message said:

No one, and that means no one, can "spin" a 52/12 on the flats. Build
up to a good rpm in a sprint,

I'm not sure what you mean by spin, but in the early 1990s I did a
three or four mile time trial with a ripping tail wind and was
turning a 12 cog with 50 or 51 uncomfortably fast the whole time and
finished in the back quarter of the field. Tyler Hamilton and Kirk
Willett were first and second and I'm pretty sure they would have been
spinning 52x12. Willet at least had a much bigger gear that he used
the whole time apart from the first few seconds of the event. The even
was flat.

And I've been in races with very shallow grades like a percent or two
where we were spinning 12 frantically downhill. Not flat I guess.

--
JT
****************************
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Visit http://www.jt10000.com
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Quoted message said:

No one, and that means no one, can "spin" a 52/12 on the flats. Build up to
a good rpm in a sprint, maybe, if you are very strong, but spin along the
road? No.

For what it's worth, a 52/12 with a cadence of 90 rpm is about 30.5 mph. A
cadence of 100 would be about 34 mph.

Barry said:

Quoted message said:

No one, and that means no one, can "spin" a 52/12 on the flats. Build up to
a good rpm in a sprint, maybe, if you are very strong, but spin along the
road? No.

For what it's worth, a 52/12 with a cadence of 90 rpm is about 30.5 mph. A
cadence of 100 would be about 34 mph.

Another for what it's worth is going downhill at 50 MPH on a mountain
bike with a 46/11 and trying to pedal, which just does not work. I
couldn't spin fast enough to even get the freewheel to engage. Maybe if
I put on my 58 front ring it would work but then the chain hangs up half
the time, so the 58 ring is just a decoration now.
Sometimes it makes sense to coast and enjoy the free speed.
Bill Baka

Wayne said:

Drew Saunders said:

On Jun 4, 10:38 am, VeloJon <[email hidden]> wrote:

Quoted message said:

Quoted message said:

> According to Cyclingnews, several Giro riders were running 52/34 chain
> rings for the big climbs. I thought the conventional wisdom was that
> a 16-tooth differential between the 2 rings was the max for shifting
> smoothness on the front der. Before I go and try a 52/34 combo,
> opinions please?

Quoted message said:

I know many folks don't like the "T" word, but you're entering the realm
where a triple makes a whole lot more sense. I don't know what rear
cassette you want to use, but most of the folks on this thread have been
discussing a 12-25 or 12-27. With a 26-38-48 and and 11-21, you get
about the same top gear as a 52/12, a lower bottom gear than a 34/27,
and really really small jumps in the cassette, with easier shifting up
front too. A 28-38-48 with an 11-23 gives even easier shifting up front
and an even lower bottom gear (close to the 34-29 that some of the folks
reportedly used in the Giro). Both setups are easily done with any
74/110 crank, and even possible with a 74/130 "Racing Triple" crank.

Quoted message said:

Sorry, I'm suggesting practical gearing, I should know better...

Quoted message said:

Drew

Quoted message said:

--
Drew W. Saunders

Quoted message said:

dru (at) stanford (dot) eee dee you

Amen - or 30/40/50 with 12-25 or so rear

Or even a 30/39/53 (Shimano Dura Ace 7703 Triple Crank)
What could be more simple than having your standard 53/39 and a 30T
bailout ring up front?

Yes, a cloaking device to make it appear to be a double would be nice
but pricey.

-bdbafh

Quoted message said:

Quoted message said:

Quoted message said:

How is it that you have the strength to spin out a
52x12 but don't have the power to climb in anything harder than a
34x25 or 34x27?

Quoted message said:

Steve Gravrock said:

On the contrary, folks who need a low bottom gear very often have more
use for a high top gear as well. The 52x12 is for going down the hills
that you need the 34x25 for. Or in my case, the hills that I need the
30x30 for. I suppose you could always coast down the steeper hills, but
pedaling down them is sometimes useful and often fun.

David L. Johnson said:

If that pulls your chain, fine, but frankly "need" and huge gears don't
make much sense to me, unless you need to win that downhill sprint to
become a stage winner on the Tour.

No one, and that means no one, can "spin" a 52/12 on the flats. Build
up to a good rpm in a sprint, maybe, if you are very strong, but spin
along the road? No. On downhills, I can usually beat most anyone I
ride with, and my top gear is a 46/12. I do that by knowing better how
to corner, and by having a better mass/frontal area ratio.

Maybe change Steve's 'need' to 'prefer' or 'desire'?

No rider is wrong about his opinion. Despite my own opinion, which seems
similar to yours on gearing, others can and do differ. Greatly. Note
Carl happily rides at a cadence which may seem odd to us but he happily
rides every day. 'YMMV' has never been more apt.

Ask any bike mechanic and you'll find the greater bulk of bicycles with
multiple gearing are ridden in high gear until the small cog wears out.
For every new bike changed to lower gearing we are asked a dozen times
for higher ratios. I doubt we are unique in that and it is not at all a
recent trend.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

bdbafh said:

Wayne said:

On Jun 5, 11:32 am, Drew Saunders <[email hidden]> wrote:

Quoted message said:

Quoted message said:

On Jun 4, 10:38 am, VeloJon <[email hidden]> wrote:

Quoted message said:

Quoted message said:

> > According to Cyclingnews, several Giro riders were running 52/34 chain
> > rings for the big climbs. I thought the conventional wisdom was that
> > a 16-tooth differential between the 2 rings was the max for shifting
> > smoothness on the front der. Before I go and try a 52/34 combo,
> > opinions please?

Quoted message said:

Quoted message said:

I know many folks don't like the "T" word, but you're entering the realm
where a triple makes a whole lot more sense. I don't know what rear
cassette you want to use, but most of the folks on this thread have been
discussing a 12-25 or 12-27. With a 26-38-48 and and 11-21, you get
about the same top gear as a 52/12, a lower bottom gear than a 34/27,
and really really small jumps in the cassette, with easier shifting up
front too. A 28-38-48 with an 11-23 gives even easier shifting up front
and an even lower bottom gear (close to the 34-29 that some of the folks
reportedly used in the Giro). Both setups are easily done with any
74/110 crank, and even possible with a 74/130 "Racing Triple" crank.

Quoted message said:

Quoted message said:

Sorry, I'm suggesting practical gearing, I should know better...

Quoted message said:

Quoted message said:

Drew

Quoted message said:

Quoted message said:

--
Drew W. Saunders

Quoted message said:

Quoted message said:

dru (at) stanford (dot) eee dee you

Quoted message said:

Amen - or 30/40/50 with 12-25 or so rear

Or even a 30/39/53 (Shimano Dura Ace 7703 Triple Crank)
What could be more simple than having your standard 53/39 and a 30T
bailout ring up front?

Yes, a cloaking device to make it appear to be a double would be nice
but pricey.

I suspect there is a market for a "clear plastic" inner ring. However
short it's service life, some people would line up to buy 'em.

"Image is everything."

Ozark Bicycle said:

bdbafh said:

On Jun 5, 3:10 pm, Wayne <[email hidden]> wrote:

Snipped somebody.

Quoted message said:

Quoted message said:

Or even a 30/39/53 (Shimano Dura Ace 7703 Triple Crank)
What could be more simple than having your standard 53/39 and a 30T
bailout ring up front?

Yes, a cloaking device to make it appear to be a double would be nice
but pricey.

What's the problem with a third ring? Sometimes (well, most times) I get
lazy and just want to spin a granny gear up a hill. Why not?

Quoted message said:

Quoted message said:

I suspect there is a market for a "clear plastic" inner ring. However
short it's service life, some people would line up to buy 'em.

"Image is everything."

Another Lance imitator?
Bill Baka

In article
<[email hidden]>
,

VeloJon said:

According to Cyclingnews, several Giro riders were running 52/34 chain
rings for the big climbs. I thought the conventional wisdom was that
a 16-tooth differential between the 2 rings was the max for shifting
smoothness on the front der. Before I go and try a 52/34 combo,
opinions please?

Put on a triple.
26/19 ~= 34/25
26/21 ~= 34/27
Then you can go 39-53 with a 13 tooth jump to the
granny gear, and run an 11-21 cassette with impunity.
Heck, use a 26-38-48 and the shifts between the middle
and big ring are like buttah; you will not hesitate to
shift between the middle and large rings. There is room
at the bottom for even lower gears with no penalty in
shifting or jumps in the cassette.

If you cannot turn a 39/23, get a third chain wheel.
39/23 is plenty low except for very steep extended
pitches. It is not worth the effort trying to squeeze
the last bit of utility out of a double chain ring. You
end up with a marginal system that only barely, if at
all, meets the goals.

I am kind to my knees and not strong yet run 38/21 up
long 6% grades.

--
Michael Press

In article
<[email hidden]>,

Drew Saunders said:

VeloJon said:

Quoted message said:

According to Cyclingnews, several Giro riders were running 52/34 chain
rings for the big climbs. I thought the conventional wisdom was that
a 16-tooth differential between the 2 rings was the max for shifting
smoothness on the front der. Before I go and try a 52/34 combo,
opinions please?

I know many folks don't like the "T" word, but you're entering the realm
where a triple makes a whole lot more sense. I don't know what rear
cassette you want to use, but most of the folks on this thread have been
discussing a 12-25 or 12-27. With a 26-38-48 and and 11-21, you get
about the same top gear as a 52/12, a lower bottom gear than a 34/27,
and really really small jumps in the cassette, with easier shifting up
front too. A 28-38-48 with an 11-23 gives even easier shifting up front
and an even lower bottom gear (close to the 34-29 that some of the folks
reportedly used in the Giro). Both setups are easily done with any
74/110 crank, and even possible with a 74/130 "Racing Triple" crank.

Sorry, I'm suggesting practical gearing, I should know better...

I recently composed an article with the same notions,
and I should know better too. The saving grace is that
when I post nonsense, I can depend on a response.

--
Michael Press

David L. Johnson said:

Steve Gravrock said:

Quoted message said:

How is it that you have the strength to spin out a
52x12 but don't have the power to climb in anything harder than a
34x25 or 34x27?

On the contrary, folks who need a low bottom gear very often have more
use for a high top gear as well. The 52x12 is for going down the hills
that you need the 34x25 for. Or in my case, the hills that I need the
30x30 for. I suppose you could always coast down the steeper hills, but
pedaling down them is sometimes useful and often fun.

If that pulls your chain, fine, but frankly "need" and huge gears don't
make much sense to me, unless you need to win that downhill sprint to
become a stage winner on the Tour.

In the situation I described, which you snipped, I'd need to spin at
close to 120 RPM with your top gear in order to keep up with traffic. I
can do that, but not comfortably and not for very long. While not being
able to keep up with traffic isn't the end of the world, it sometimes
means missing a lane change and thus the left turn. That's not a huge
deal -- I can always go around the block or turn into a pedestrian at
the intersection -- but it's nice to be able to avoid it. That happened
often enough when my top gear was a 44/12 that having a 52 tooth ring
was a refreshing change.

Necessary? No. I got by without it in the past and could do so again.
Makes sense for me? Absolutely. The fact that it doesn't make sense for
you in the sort of riding you do doesn't change that.

Steve Gravrock said:

That happened
often enough when my top gear was a 44/12 that having a 52 tooth ring
was a refreshing change.

By 44/12 I mean 44/14, for what difference it makes.

On Tue, 05 Jun 2007 21:53:58 -0500, A Muzi <[email hidden]>

Quoted message said:

Ask any bike mechanic and you'll find the greater bulk of bicycles with
multiple gearing are ridden in high gear until the small cog wears out.
For every new bike changed to lower gearing we are asked a dozen times
for higher ratios. I doubt we are unique in that and it is not at all a
recent trend.

What is a recent trend, however, is the popularity and marketing of
110mm BCD compact cranks, and wide cassettes starting with an 11 and
ending with between 25 - 28 teeth.

When manufacturers such as FSA and IRD started heavily marketing
"neo-compact" a few years back, virtually all cassettes sold which
started an 11 ended with a 21 or 23. If a compact crank user wanted
their cake and eat it - to regain their high gear ( lost when
swapping a 50 tooth ring for the 53, but keeping a cassette which
started with 12) and at the same time having a low gear with a cog of
25-28 (which is WHY they switched to compact in the first place) -
they had the choice of buying individual cogs and cobbing together
their own cassette (which Harris Cyclery does with their Shimano 9
speed cassette called "High and Wide"😉 or, as I actually did, buying
both an Ultegra 11-23 AND a 12-27 on e-bay, and swapping cogs.

IRD started was early on the bandwagon, selling 11-25 and 11-28
"compact friendly" cassettes for 9 and 10 speed 3 years ago (not to
mention being the first to come out with a compact specific front
derailleur). SRAM came out with an 11-26 10 speed last year with
their new groupo, and this year Campy sells an 11-25 10 speed. But
you STILL can't find a wide Shimano cassette 9 or 10 speed (except the
Harris Cyclery "High and Wide"😉.

When will Shimano jump on this marketing bandwagon?

Here is how I see it: millions of aging baby boomers, way too image
(and weight weenie) conscious to switch to triples, frothing at the
mouth and ready to blow mega cash on compact (that would be me, for
example). Not to mention female and junior racers who really can't
push the same gears as their male counterparts. Or male pros racing
up huge inclines.

Doug Taylor said:

What is a recent trend, however, is the popularity and marketing of
110mm BCD compact cranks, and wide cassettes starting with an 11 and
ending with between 25 - 28 teeth.

Maybe I'm missing your point, but... I've had difficulty finding a wide
range cassette that *doesn't* start at 11 (i.e. 12-28, 12-32, etc). IRD
recently (2006?) released 12-28 cassettes in 9-speed, but I don't know
where you can get a 12-30, 12-32, or 12-34 cassette. Sheldon sells a
custom 13-30 cassette, but it's really expensive.

On the other hand, MTB cassettes in 7/8/9 speed have been available in
11-28, 11-30, 11-32, 11-34 combinations for quite some time. I have an
11-34 cassette that I sometimes run with a 34-48 crank for a really wide
range of gears at the expense of narrow gaps between gears. If a 12-32
or 12-34 had been available, I would have chosen narrower gaps at the
expense of a really high gear.

--
Dave
dvt at psu dot edu

Everyone confesses that exertion which brings out all the powers of body
and mind is the best thing for us; but most people do all they can to
get rid of it, and as a general rule nobody does much more than
circumstances drive them to do. -Harriet Beecher Stowe, abolitionist and
novelist (1811-1896)

Doug Taylor said:

derailleur). SRAM came out with an 11-26 10 speed last year with
their new groupo, and this year Campy sells an 11-25 10 speed. But
you STILL can't find a wide Shimano cassette 9 or 10 speed (except the
Harris Cyclery "High and Wide"😉.

When will Shimano jump on this marketing bandwagon?

You *can* buy an 11-25 from Shimano in the new 105 10 speed group, at
least. I know because I have one (which came in the clearly labled
Shimano box). That isn't to say that here in Pittsburgh I might not
like an 11-27 from time to time, but 25 is certainly better than 23.
Having the 11 is nice with the 50-34 compact.

Quoted message said:

You *can* buy an 11-25 from Shimano in the new 105 10 speed group, at
least. I know because I have one (which came in the clearly labled
Shimano box).

Good for Shimano: they jumped on as well.

A year ago they didn't exist:
http://www.velonews.com/tech/report/articles/9882.0.html

Now we'll see if they upgrade to Ultegra and Dura Ace

dvt said:

Maybe I'm missing your point,

You did. Re-read the post.

Doug Taylor said:

dvt said:

Maybe I'm missing your point,

You did. Re-read the post.

Sorry, I still don't get it. I've used 11-28 Shimano and aftermarket
cassettes in 8 and 9-speed configurations for several years. It's the
12-28 that was missing from the lineup, IMO.

Maybe you were talking about 7-speed? 8-speed bits have been available
for around 15 years, and I know that 8 spd 11-28 cassettes were
available for the past several years.

I've never seen an 11-25, so I'm with you on that one.

--
Dave
dvt at psu dot edu

Everyone confesses that exertion which brings out all the powers of body
and mind is the best thing for us; but most people do all they can to
get rid of it, and as a general rule nobody does much more than
circumstances drive them to do. -Harriet Beecher Stowe, abolitionist and
novelist (1811-1896)

In article <[email hidden]>,

dvt said:

Doug Taylor said:

What is a recent trend, however, is the popularity and marketing of
110mm BCD compact cranks, and wide cassettes starting with an 11 and
ending with between 25 - 28 teeth.

Maybe I'm missing your point, but... I've had difficulty finding a wide
range cassette that *doesn't* start at 11 (i.e. 12-28, 12-32, etc). IRD
recently (2006?) released 12-28 cassettes in 9-speed, but I don't know
where you can get a 12-30, 12-32, or 12-34 cassette. Sheldon sells a
custom 13-30 cassette, but it's really expensive.

On the other hand, MTB cassettes in 7/8/9 speed have been available in
11-28, 11-30, 11-32, 11-34 combinations for quite some time. I have an
11-34 cassette that I sometimes run with a 34-48 crank for a really wide
range of gears at the expense of narrow gaps between gears. If a 12-32
or 12-34 had been available, I would have chosen narrower gaps at the
expense of a really high gear.

Shimano still makes a 14-32 seven speed. I run it with
a half-step gearing double chain-ring on a utility
bicycle. Not a lot of range, but it has close steps.
Fourteen different gears.
..

--
Michael Press

dvt said:

Doug Taylor said:

dvt said:

Maybe I'm missing your point,

You did. Re-read the post.

Sorry, I still don't get it.

Then either I can't write or you can't read.

Someone said:

According to Cyclingnews, several Giro riders were running 52/34 chain
rings for the big climbs. I thought the conventional wisdom was that
a 16-tooth differential between the 2 rings was the max for shifting
smoothness on the front der. Before I go and try a 52/34 combo,
opinions please?

I've been very happy withthe 50-28 double on my Hetchins. Running
with a 12-28 9-speed cassette in back.

Shifting the front takes a bit more care and skill than a stock setup,
but it's not that difficult to master.

The idea of this setup is that 99% of riding is done on the 50 tooth
ring, which is lined up so that it works with all 9 sprockets in
back. Makes for a super-simple shifting pattern.

The 28 chainring is reserved for the worst hills, I generally only
used it with the 2 or 3 biggest rear sprockets. When the hill would
get steep enough that I needed the little chainring, I didn't mind the
gap in the gearing.

Sheldon "Wide Range Double" Brown
+----------------------------------------------+
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