Compact Crank Ring Differential

Doug Taylor said:

dvt said:

Doug Taylor said:

On Wed, 06 Jun 2007 09:14:23 -0400, dvt <[email hidden]> wrote:

Quoted message said:

Quoted message said:

Sorry, I still don't get it.

Quoted message said:

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

One more try... you said:

...a few years back, virtually all cassettes sold which
started an 11 ended with a 21 or 23.

Shimano has offered 11-28 cassettes available in 7/8/9 speed for many
years. That seems to contradict what you said. Did I misread?

--
Dave
dvt at psu dot edu

dvt said:

Doug Taylor said:

dvt said:

Doug Taylor wrote:
> On Wed, 06 Jun 2007 09:14:23 -0400, dvt <[email hidden]> wrote:

Quoted message said:

Quoted message said:

Sorry, I still don't get it.

Quoted message said:

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

One more try... you said:

...a few years back, virtually all cassettes sold which
started an 11 ended with a 21 or 23.

Shimano has offered 11-28 cassettes available in 7/8/9 speed for many
years. That seems to contradict what you said. Did I misread?

2 cents worth.
I have a 7 speed 11,13,15,18,21,24,28 that works for me. It is also the
one that has the silent clutch mechanism. I don't know who made it
though unless I want to take the wheel off and look.
2 cents off.
Bill Baka

Michael Press said:

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.

Quoted message said:

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.

Quoted message said:

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- Hide quoted text -

- Show quoted text -

I use either a 14-32 or 12-28 7 speed Shimano cassette on my loaded
touring bike. 45-42-20 chainrings. Great half step gearing and super
low granny. Used to have a 34 cog I put on instead of the 32, but the
new frame's rear derailleur hanger won't allow the derailleur to clear
the 34. So I had to go back to the 32 cog. The 12-28 cassette is for
when I take the loaded touring bike on week long rides and ride
unloaded in a pack and might need a high gear of 45x12 (101"😉 instead
of 45x14 (87"😉.

Quoted message said:

A Muzi 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.

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.

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.

I believe the Shimano IG-7 (11~28, now others) has been around since
1994 or so. This is not a new concept, I can't explain or defend other
trends mentioned.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

A Muzi of Yellow Jersey said:

Quoted message said:

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?

Quoted message said:

I've used a 48-30 ring combination with a standard double front
derailleur. It shifted badly. But I did not shift it too often. A
46-30 with a compact front derailleur works OK. Again, I don't really
shift it too often. I've never figured out why people/companies seem
to love the 50-34 combination. And now you want to go with a 52-34?
Shimano makes a 12-25 and 12-27 cassette in 9 and 10 speed.
Campagnolo makes a 12-25 cassette in 10 speed. One would think you
could get a more than high enough gear with a 50x12 and a low enough
with a 34x27 or 34x25. But you need a high of 52x12 AND a low of
34x25 or 34x27? 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?

Just because.

I remember Nishiki Internationals with a then-new 34t low gear
freewheel. Our friend Peter Davis in Champaign IL...

Bought an ATB from Peter's shop some years back (but actually dealt
with Fritz for the purchase).

Quoted message said:

sold a ton of them -
on the prairie, where the Interstate overpass is the highest point.

The hilliest ride in Champaign County is south out of Philo (Center of
the Universe) on 1700E, then on to Block on 600E, since it crosses
Yankee Ridge.

Quoted message said:

No rider can be wrong about his own opinion. Doesn't have to be logical.

Champaign County may be flat, but it is windy, especially in the
spring before the corn is tall enough to provide a windbreak. On a
Saturday morning ride in April, we went from Meadowbrook to Tolono at
7-8 mph into the southerly wind, and then returned at near 30 mph. Low
gears are very helpful in these situations.

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful

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?

I used to run a 73/52 double on a bicycle with an ISO 406-mm drive
wheel. Shifting with a Shimano RSX road derailleur was slow (no ramps
and pins on the large chainring) but otherwise acceptable.

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful

Johnny Sunset said:

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?

I used to run a 73/52 double on a bicycle with an ISO 406-mm drive
wheel. Shifting with a Shimano RSX road derailleur was slow (no ramps
and pins on the large chainring) but otherwise acceptable.

If you were running a gear like that just what the hell did you have in
the rear? 73/?? seems way unlikely.
Bill Baka

Quoted message said:

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful

On Wed, 06 Jun 2007 21:44:51 -0500, A Muzi <[email hidden]>

Quoted message said:

I believe the Shimano IG-7 (11~28, now others) has been around since
1994 or so. This is not a new concept, I can't explain or defend other
trends mentioned.

One more time:

What is new is the heavy MARKETING of 110 bcd compact front cranks and
chainrings, commencing with FSA and IRD around 2002 or 2003, IIRC.

Before that, the normal usual spec. on most new bikes was 53/39.

As far as cassettes, I'm specifically addressing 9 and 10 speed, not
7, 8 or anything else.

IRD was the first manufacturer to sell 11-25 and 11-28 cassettes for 9
and 10 speed (except for Sheldon Brown's High and Wide) - which were
specifically marketed for people using compact rings.

In 2006, SRAM started selling an 11-26 cassette, marketed for compact.

Until 2007, Shimano and Campy did not sell cassettes for 9 and 10
speed which started with 11 and ended with 25, 26,27, or 28 (except
for Sheldon Brown's High and Wide), as confirmed by Lennard Zinn
http://www.velonews.com/tech/report/articles/9882.0.html

As an example of this marketing ( 2007 Campy):

"11-25 Sprocket sets. The 11-25 combination springs from a demand from
users for compact cranksets with a broader range of ratios, just as
suitable for the steepest climbs as for fast pedalable descents."

http://www.ppolnews.com/?id=82140&keys=campagnolo-differentiated-brakes

Does this make sense to anyone except me?

Guess not.

Doug Taylor said:

What is new is the heavy MARKETING of 110 bcd compact front cranks and
chainrings, commencing with FSA and IRD around 2002 or 2003, IIRC.

Before that, the normal usual spec. on most new bikes was 53/39.

As far as cassettes, I'm specifically addressing 9 and 10 speed, not
7, 8 or anything else.

[snip]

Quoted message said:

Does this make sense to anyone except me?

I got it now. Your earlier post said something different.

--
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)

A Muzi said:

Quoted message said:

A Muzi 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.

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.

Quoted message said:

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.

Quoted message said:

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"😉.

Quoted message said:

When will Shimano jump on this marketing bandwagon?

Quoted message said:

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.

I believe the Shimano IG-7 (11~28, now others) has been around since
1994 or so. This is not a new concept, I can't explain or defend other
trends mentioned.

Isn't the mid 1990s when the micro compact mountain bike crankset was
developed? 94/58 mm bcd instead of the standard compact 110/74 mm bcd
crankset. I think the 94/58 cranks came with 44-32-22 rings. 110/74
came with 48-36-24 rings. So the 11-28 cassette paired with the
44-32-22 gave the exact same highs and about the same lows as the
48-36-24 paired with a 12-28. Have to keep that high gear the same.

I guess the advantages of the smaller bcd and smaller cassette were a
couple grams weight savings and the ability to ride over bigger logs
without hitting the chainrings on the wood.

Quoted message said:

--
Andrew Muziwww.yellowjersey.org
Open every day since 1 April, 1971- Hide quoted text -

- Show quoted text -

Bill said:

Johnny Sunset said:

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?

Quoted message said:

I used to run a 73/52 double on a bicycle with an ISO 406-mm drive
wheel. Shifting with a Shimano RSX road derailleur was slow (no ramps
and pins on the large chainring) but otherwise acceptable.

If you were running a gear like that just what the hell did you have in
the rear? 73/?? seems way unlikely.
Bill Baka

406mm tires are about 16-18" or so in diameter. I forget if 406 tires
are closer to 16" or 18". 73x13 with 406 gets you about 100 gear
inches. 52x28 gets you about 33 gear inches. Equivalent of a
sensibly geared compact double crankset today. I think 406mm is used
by Moulton bikes and foldable bikes. Bike Friday uses 406 I think on
their touring models. 420 on their racy models.

Quoted message said:

Quoted message said:

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful- Hide quoted text -

- Show quoted text -

Quoted message said:

Bill said:

Johnny Sunset said:

On Jun 4, 10:38 am, VeloJon wrote:
> 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 used to run a 73/52 double on a bicycle with an ISO 406-mm drive
wheel. Shifting with a Shimano RSX road derailleur was slow (no ramps
and pins on the large chainring) but otherwise acceptable.

If you were running a gear like that just what the hell did you have in
the rear? 73/?? seems way unlikely.
Bill Baka

406mm tires are about 16-18" or so in diameter. I forget if 406 tires
are closer to 16" or 18". 73x13 with 406 gets you about 100 gear
inches. 52x28 gets you about 33 gear inches. Equivalent of a
sensibly geared compact double crankset today. I think 406mm is used
by Moulton bikes and foldable bikes. Bike Friday uses 406 I think on
their touring models. 420 on their racy models.

Got a picture? It sounds like the crank would be almost as big as the
tires and you would have a ground clearance problem. I don't recall ever
seeing something like that in either of my LBS's.
Bill Baka

Quoted message said:

Quoted message said:

Quoted message said:

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful- Hide quoted text -

- Show quoted text -

Bill said:

Quoted message said:

Bill said:

Johnny Sunset wrote:
> I used to run a 73/52 double on a bicycle with an ISO 406-mm drive
> wheel. Shifting with a Shimano RSX road derailleur was slow (no ramps
> and pins on the large chainring) but otherwise acceptable.

Quoted message said:

Quoted message said:

Quoted message said:

If you were running a gear like that just what the hell did you have in
the rear? 73/?? seems way unlikely.
Bill Baka

Quoted message said:

Quoted message said:

406mm tires are about 16-18" or so in diameter. I forget if 406 tires
are closer to 16" or 18". 73x13 with 406 gets you about 100 gear
inches. 52x28 gets you about 33 gear inches. Equivalent of a
sensibly geared compact double crankset today. I think 406mm is used
by Moulton bikes and foldable bikes. Bike Friday uses 406 I think on
their touring models. 420 on their racy models.

Quoted message said:

Got a picture? It sounds like the crank would be almost as big as the
tires and you would have a ground clearance problem. I don't recall ever
seeing something like that in either of my LBS's.

Now you've done it... Tom loves to post links to pictures of his
bikes/trikes... check the archives. I'm 99.9% sure he's talking about a
recumbent of some sort.

--
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)

dvt said:

Bill said:

[email hidden] wrote:

Quoted message said:

Quoted message said:

406mm tires are about 16-18" or so in diameter. I forget if 406 tires
are closer to 16" or 18". 73x13 with 406 gets you about 100 gear
inches. 52x28 gets you about 33 gear inches. Equivalent of a
sensibly geared compact double crankset today. I think 406mm is used
by Moulton bikes and foldable bikes. Bike Friday uses 406 I think on
their touring models. 420 on their racy models.

Quoted message said:

Got a picture? It sounds like the crank would be almost as big as the
tires and you would have a ground clearance problem. I don't recall
ever seeing something like that in either of my LBS's.

Now you've done it... Tom loves to post links to pictures of his
bikes/trikes... check the archives. I'm 99.9% sure he's talking about a
recumbent of some sort.

I think that is likely the case, but it would still make for a good
conversation starter, hopefully with a babe.
Bill Baka

Bill said:

Quoted message said:

Bill said:

Johnny Sunset wrote:
> On Jun 4, 10:38 am, VeloJon wrote:
>> 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 used to run a 73/52 double on a bicycle with an ISO 406-mm drive
> wheel. Shifting with a Shimano RSX road derailleur was slow (no ramps
> and pins on the large chainring) but otherwise acceptable.
If you were running a gear like that just what the hell did you have in
the rear? 73/?? seems way unlikely.
Bill Baka

Quoted message said:

406mm tires are about 16-18" or so in diameter. I forget if 406 tires
are closer to 16" or 18". 73x13 with 406 gets you about 100 gear
inches. 52x28 gets you about 33 gear inches. Equivalent of a
sensibly geared compact double crankset today. I think 406mm is used
by Moulton bikes and foldable bikes. Bike Friday uses 406 I think on
their touring models. 420 on their racy models.

Got a picture? It sounds like the crank would be almost as big as the
tires and you would have a ground clearance problem. I don't recall ever
seeing something like that in either of my LBS's.

Well now, if seeing something in my local bike shop was a prerequisite
for it existing, then Shimano and factory bikes would be the only non
department store bikes on earth. Maybe you have bike shops that carry
something besides Shimano and factory bikes. Around here its Shimano
and factory bikes. Shimano and factory bikes. Shimano and factory
bikes. Thankfully there is mail order.

Quoted message said:

Bill Baka

Quoted message said:

Quoted message said:

> --
> Tom Sherman - Holstein-Friesland Bovinia
> The weather is here, wish you were beautiful- Hide quoted text -
- Show quoted text -- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

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?

I have used a 53/34 for a while now (11 or 12-23 on the rear). Works
fine. However, at 34/11 the chain is verging on being slack and at
53/23 it's almost maxed out.
So I don't know how much (if any) problem there would be with a 25 or
27 on the rear, but it would require the rear deraileur to accomodate
2 or 4 more links/teeth of chain wrap.

DR

A Muzi 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.

I'm sure you're right, but speaking for myself I have been converting
all my bikes to smaller chainrings and lower high gears. The biggest
ring I now run is 50T, on my tandem, with a 14-30 freewheel in the back.

The large rings on my other bikes range from 43T to 48T.

FWIW, I don't get dropped on group rides.

--

John ([email hidden])

Quoted message said:

Bill said:

Got a picture? It sounds like the crank would be almost as big as the
tires and you would have a ground clearance problem. I don't recall ever
seeing something like that in either of my LBS's.

Well now, if seeing something in my local bike shop was a prerequisite
for it existing, then Shimano and factory bikes would be the only non
department store bikes on earth. Maybe you have bike shops that carry
something besides Shimano and factory bikes. Around here its Shimano
and factory bikes. Shimano and factory bikes. Shimano and factory
bikes. Thankfully there is mail order.

Quoted message said:

Bill Baka

Maybe my Little Bike Shops are too little. There's always Ebay.
Bill Baka

Bill Baka said:

Johnny Sunset said:

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?

Quoted message said:

I used to run a 73/52 double on a bicycle with an ISO 406-mm drive
wheel. Shifting with a Shimano RSX road derailleur was slow (no ramps
and pins on the large chainring) but otherwise acceptable.

If you were running a gear like that just what the hell did you have in
the rear? 73/?? seems way unlikely.

More likely than going downhill at 50 mph on a children's tricycle!

Note that I wrote ISO 406-mm drive wheel. With a Tioga Comp Pool tire,
the 73/52 chainring and 11-28 cassette results in a range of 36 to 129
gear inches.

This is the bike, at the time of purchase <http://www.ihpva.org/
incoming/2001/wbone2.jpg> and shortly after I sold it: <http://
www.liegeradinfo.de/wisbone2.jpg>.

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful

Bill Baka said:

Quoted message said:

Bill Baka said:

Johnny Sunset wrote:
> On Jun 4, 10:38 am, VeloJon wrote:
>> 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 used to run a 73/52 double on a bicycle with an ISO 406-mm drive
> wheel. Shifting with a Shimano RSX road derailleur was slow (no ramps
> and pins on the large chainring) but otherwise acceptable.
If you were running a gear like that just what the hell did you have in
the rear? 73/?? seems way unlikely.
Bill Baka

Quoted message said:

406mm tires are about 16-18" or so in diameter. I forget if 406 tires
are closer to 16" or 18". 73x13 with 406 gets you about 100 gear
inches. 52x28 gets you about 33 gear inches. Equivalent of a
sensibly geared compact double crankset today. I think 406mm is used
by Moulton bikes and foldable bikes. Bike Friday uses 406 I think on
their touring models. 420 on their racy models.

Got a picture? It sounds like the crank would be almost as big as the
tires and you would have a ground clearance problem. I don't recall ever
seeing something like that in either of my LBS's.

See post below for picture. The big ring started life as an aluminium
alloy plate, and was custom machined into a chainring - hence the lack
of "ramps and pins" seen on modern mid to high end commercial
chainrings.

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful