Help me commit the mortal sin of using large-large

Reid Priedhorsky said:

Hi folks,

(This was posted over in r.b.tech a few days ago, admittedly with a less
provocative title, and didn't garner many useful responses.

Maybe that's because nobody wants to be seen helping you commit a
cardinal sin ;-)

Austin

Reid Priedhorsky said:

Hi folks,

(This was posted over in r.b.tech a few days ago, admittedly with a less
provocative title, and didn't garner many useful responses. My apologies
to those who've seen it already.)

I shift my 3-ring chainwheels with a Tiagra brifter and a Sora derailleur.
This works great, except that it is very difficult (i.e., pretty much
impossible) to adjust the shifting so that I can use both the middle
chainwheel with the smallest cog and the largest chainwheel with the
largest cog (or even the largest two). I have 9 speeds in the back.

For those of you who are already composing an eloquently worded "you are a
lunatic/bozo/turnip twaddler/etc." response, please read this whole post
first. 🙂

I would like to get a brifter which will let me do both of these
things. I can think of a couple of potential options, but I don't know if
they will work.

1. Non-indexed shifting.
2. Brifters with a greater number of fine-tune clicks (e.g. my Tiagra has
two clicks in the middle chainwheel but only one on the large and small).
3. Upgrade the derailleur.

I like the form factor of the Shimano brifters, so I'm hesitant to switch
to something else.

Now, I'm aware that using the large-large combination is held to the same
level of regard as plumber's crack in public. I do have plenty of
duplication between the middle- and large-chainring ranges. The reason I
like having big-big available is that starting out in that combination
makes it easier to access the smaller cogs which are useful in fast level
cruising. If I don't anticipate using these soon, I do shift down to the
middle ring.

To elaborate, here's my setup. Numbers in the table are gear inches.

52 42 30
---- ---- ----
34 41.3 33.4 23.8
30 46.8 37.8 27.0
27 52.0 42.0 30.0
24 58.5 47.3 33.8
21 66.9 54.0 38.6
19 73.9 59.7 42.6
17 82.6 66.7 47.6
15 93.6 75.6 54.0
14 100.3 81.0 57.9

Now, if I'm going to be moving quickly, I usually end up on the large
chainring in the neighborhood of 19-15 teeth in the back, perhaps 14. The
smallest cog with a duplicate on the middle chainring is (roughly) 17.

Shifting the rear cogs is considerably faster and can be done under much
greater load than shifting the chainrings.

For example, if as I speed up I want to end up in 52x15, I can either
start on the middle chainring (on, say, the 27) and do 7 fast shifts and 1
slow one (to 24, 21, 19, 17, 15, 14, large, 15) -- not to mention that
during my stopping, I would have had to to throw down several rear gears
_and_ shift the front -- or I can start on the large chainring and do 7
fast shifts.

From a usability standpoint, the latter is clearly better.

That's why I want my "deranged" shifting pattern. My ideal (which I don't
do fully because the front derailer grinds on the chain) is to use the
large chainring when I'm in places where I go fast, medium in medium to
slow places, and small in very slow places.

Any suggestions would be most welcome. Please let me know what additional
information I can provide. Thanks!

Reid

Hi there.

Using the big big combo on a 9 speed cluster puts a lot of stress on
the components. I think that is why you are having trouble shifting
it.

Most every one will tell you that it is a very bad idea, due to the
stress on the components, to ride a big big combo. You can snap a
chain in that combo. That is probably why you are not getting many
replies.

If yoy persist in riding the big big you might just have to accept
that the shifting will suffer. Expect rapid wear of your components
too.

Peter

Reid Priedhorsky said:

I shift my 3-ring chainwheels with a Tiagra brifter and a Sora derailleur.
This works great, except that it is very difficult (i.e., pretty much
impossible) to adjust the shifting so that I can use both the middle
chainwheel with the smallest cog and the largest chainwheel with the
largest cog (or even the largest two). I have 9 speeds in the back.

That's because it is not designed to do that (but you already knew that).

Quoted message said:

For those of you who are already composing an eloquently worded "you are a
lunatic/bozo/turnip twaddler/etc." response, please read this whole post
first. 🙂

Can't I do both? ;-)

Quoted message said:

I would like to get a brifter which will let me do both of these
things. I can think of a couple of potential options, but I don't know if
they will work.

1. Non-indexed shifting.

Use a DT or bar-end shifter on the left. You'll save weight too!

Quoted message said:

2. Brifters with a greater number of fine-tune clicks (e.g. my Tiagra has
two clicks in the middle chainwheel but only one on the large and small).

Go Campy.

Quoted message said:

3. Upgrade the derailleur.

Won't help a damn.

Quoted message said:

I like the form factor of the Shimano brifters, so I'm hesitant to switch
to something else.

You're screwed.

Quoted message said:

Now, I'm aware that using the large-large combination is held to the same
level of regard as plumber's crack in public. I do have plenty of
duplication between the middle- and large-chainring ranges. The reason I
like having big-big available is that starting out in that combination
makes it easier to access the smaller cogs which are useful in fast level
cruising. If I don't anticipate using these soon, I do shift down to the
middle ring.

My only other advice is to go compact double or use a Rohloff. You're
try to use your triple drivetrain in a way it is *not* meant to be used.

Quoted message said:

To elaborate, here's my setup. Numbers in the table are gear inches.

52 42 30
---- ---- ----
34 41.3 33.4 23.8
30 46.8 37.8 27.0
27 52.0 42.0 30.0
24 58.5 47.3 33.8
21 66.9 54.0 38.6
19 73.9 59.7 42.6
17 82.6 66.7 47.6
15 93.6 75.6 54.0
14 100.3 81.0 57.9

33 48
---- ----
12 72.5 105.5
14 62.2 90.4
16 54.4 79.1
18 48.4 70.3
20 43.5 63.3
23 37.8 55.1
26 33.5 48.7
30 29.0 42.2
34 25.6 37.2

Quoted message said:

Now, if I'm going to be moving quickly, I usually end up on the large
chainring in the neighborhood of 19-15 teeth in the back, perhaps 14. The
smallest cog with a duplicate on the middle chainring is (roughly) 17.

Shifting the rear cogs is considerably faster and can be done under much
greater load than shifting the chainrings.

Pffft. Quickly schmickly. Bar-ends shift across a large range faster
than brifters.

Quoted message said:

For example, if as I speed up I want to end up in 52x15, I can either
start on the middle chainring (on, say, the 27) and do 7 fast shifts and 1
slow one (to 24, 21, 19, 17, 15, 14, large, 15) -- not to mention that
during my stopping, I would have had to to throw down several rear gears
_and_ shift the front -- or I can start on the large chainring and do 7
fast shifts.

From a usability standpoint, the latter is clearly better.

I'd quibble with clearly, but you are not me. I'll translate that to
"might possibly be better for that particular cyclist".

Quoted message said:

That's why I want my "deranged" shifting pattern. My ideal (which I don't
do fully because the front derailer grinds on the chain) is to use the
large chainring when I'm in places where I go fast, medium in medium to
slow places, and small in very slow places.

Any suggestions would be most welcome. Please let me know what additional
information I can provide. Thanks!

Budget? I really think you're a prime candidate for a Rohloff. What
you want is an internal gear hub, what you have is a triple /
derailleur.

--
Dane Buson - [email hidden]
"sic transit gloria:Gloria threw up on the bus."

Quoted message said:

Now, I'm aware that using the large-large combination is held to the same
level of regard as plumber's crack in public. I do have plenty of
duplication between the middle- and large-chainring ranges. The reason I
like having big-big available is that starting out in that combination
makes it easier to access the smaller cogs which are useful in fast level
cruising. If I don't anticipate using these soon, I do shift down to the
middle ring.

You want the worst of all-possible worlds. It's one thing to want to use
large-large with a less-extreme set of gears. But 52/34? What you want is
simply unrealistic. It's not about being "sinful"- not just bad technique or
whatever- it's just plain bad and likely to cause mechanical issues. The
chain is going to want to tear itself off both the chainring up front and
the large cog in the back. Neither one of those is a happy situation.

I'd love to have a drivetrain with infinitely-variable all-usable gears! But
that's not the situation with modern bikes. What you're asking for might be
similar to expecting to be able to alter the automatic transmission in a car
so that it will run in an abnormally high or low rpm range under certain
circumstances, so that you can get it to perform in some way differently
than it was designed for.

In general, you can make a case that chain combinations that are noisy and
hesitant to get into are likely to cause excessive wear on components, as
well as try to drop out of gear.

It may sound harsh, but ultimately you can *wish* all you want that
something work a certain way, but at some point have to get it. "It" being
the fact that there are good sound reasons why what you want isn't
practical. Of course, this is the Internet, so once you've defined your
answer, you'll find someone who agrees with it.

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA

Mike Jacoubowsky said:

Reid Priedhorsky said:

Now, I'm aware that using the large-large combination is held to the same
level of regard as plumber's crack in public. I do have plenty of
duplication between the middle- and large-chainring ranges. The reason I
like having big-big available is that starting out in that combination
makes it easier to access the smaller cogs which are useful in fast level
cruising. If I don't anticipate using these soon, I do shift down to the
middle ring.

All,

Thanks for your help on this.

Dane's suggestion of dropping to a compact double is very appealing,
especially given that I have a nearly new 11-32 cassette in the basement.
Following up on this:

1. Budget is a good question. Answer: not sure exactly, but low... Where
are good places to get cheap parts online? I poked around a little on eBay
but there doesn't seem to be much going on.

2. The smallest compact doubles I found in brief poking around the
Internet (Nashbar, Harris Cyclery) were 50x36 or 50x34. I assume Dane's
suggestion of 48x33 implied that such a combination could be had. Where?
How about even lower, like 48x30?

Quoted message said:

You want the worst of all-possible worlds. It's one thing to want to use
large-large with a less-extreme set of gears. But 52/34?

How is 52-34 different than, say, 52-23? The chainline would be the same.
On the other hand, given equal torque around the rear axle, there is less
chain tension in 52-34 than 52-23.

Quoted message said:

In general, you can make a case that chain combinations that are noisy and
hesitant to get into are likely to cause excessive wear on components, as
well as try to drop out of gear.

To clarify, it shifts just fine. It is indeed noisy. I haven't noticed any
tendency to drop out of gear, but I haven't studied this.

Excessive wear is fine with me, since I'm not planning to use it for
miles on end.

I'd love to see numbers on how much additional stress the large-large
creates, vs. say large-3rd largest, especially if the first is sitting and
the second is standing. Are there any out there?

Quoted message said:

It may sound harsh, but ultimately you can *wish* all you want that
something work a certain way, but at some point have to get it. "It" being
the fact that there are good sound reasons why what you want isn't
practical.

Well, I do indeed wish for the answer to be what I hope, but that's not
why I'm asking. I'm asking because I don't fully believe the conventional
wisdom and I'm interested in understanding the reasoning behind it.

Take care,

Reid

Reid Priedhorsky said:

On Wed, 09 May 2007 21:28:46 +0000, Mike Jacoubowsky wrote:

1. Budget is a good question. Answer: not sure exactly, but low... Where
are good places to get cheap parts online? I poked around a little on eBay
but there doesn't seem to be much going on.

Nashbar.com, aebike.com, airbomb.com, various others. eBay is not
really a good place to get cheap parts, too many people bidding things
up above market price. It can be, I scored 4 26" tandem rims for $40
shipped total, but I consider that an anomaly.

Quoted message said:

2. The smallest compact doubles I found in brief poking around the
Internet (Nashbar, Harris Cyclery) were 50x36 or 50x34. I assume Dane's
suggestion of 48x33 implied that such a combination could be had. Where?

I'd suggest buying the Sugino XD300 ($45) and swapping some rings (~$50).

http://aebike.com/page.cfm?PageID=30&action=details&sku=CR1032

It's a 110/74 triple that comes with 46/36/26 gearing. Simply remove
the smallest ring, you'll probably want a 110 BB to use that as a
double.

Alternately the XD500 ($85) comes as a compact double with 50/36 gearing.

Quoted message said:

How about even lower, like 48x30?

33 is the smallest chainring you can put on a 110 BCD crank. It looks
like you could theoretically do it using the outer ring from a mountain
triple (94/58 BCD).

http://sheldonbrown.com/harris/chainrings/94.html

Also the shifting from 48->30 would most likely suck (no pun intended).
18 teeth is a big drop. 15 is sort of marginal, but will most likely
work.

Quoted message said:

Quoted message said:

It may sound harsh, but ultimately you can *wish* all you want that
something work a certain way, but at some point have to get it. "It" being
the fact that there are good sound reasons why what you want isn't
practical.

Well, I do indeed wish for the answer to be what I hope, but that's not
why I'm asking. I'm asking because I don't fully believe the conventional
wisdom and I'm interested in understanding the reasoning behind it.

Well, knock yourself out (hopefully not literally).

I still think you would be happier with an internal gear hub. A Rohloff
14 speed would run you $1200 or so, or $3-400 for a SRAM 7 speed hub.

--
Dane Buson - [email hidden]
There is no delight the equal of dread. As long as it is somebody else's.
--Clive Barker

In article <[email hidden]>,

Dane Buson said:

Reid Priedhorsky said:

On Wed, 09 May 2007 21:28:46 +0000, Mike Jacoubowsky wrote:

1. Budget is a good question. Answer: not sure exactly, but low... Where
are good places to get cheap parts online? I poked around a little on eBay
but there doesn't seem to be much going on.

Quoted message said:

Quoted message said:

Quoted message said:

It may sound harsh, but ultimately you can *wish* all you want that
something work a certain way, but at some point have to get it. "It" being
the fact that there are good sound reasons why what you want isn't
practical.

Quoted message said:

Well, knock yourself out (hopefully not literally).

I still think you would be happier with an internal gear hub. A Rohloff
14 speed would run you $1200 or so, or $3-400 for a SRAM 7 speed hub.

Harris will sell you a Shimano Red Band Nexus-8 for $230, shifter is
another $25. They sell complete wheels with that hub starting at $300.

But the new Sturmey-Archer X-RF8 sells for a ludicrously cheap $170
including shifter!

Note that the X-RF8's direct-drive gear is the lowest gear, which is a
bit weird for some applications, though Sheldon built one into a Raleigh
Twenty because that quirk suits small-wheel bikes.

For my part, this slides very close to the justifiable-purchase zone. I
have some theories about the applicability of hub gears to CX that I'd
like to check out.

http://sheldonbrown.com/harris/sturmey-archer-hubs.html

--
Ryan Cousineau [email hidden] http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos

Ryan Cousineau said:

Dane Buson said:

I still think you would be happier with an internal gear hub. A Rohloff
14 speed would run you $1200 or so, or $3-400 for a SRAM 7 speed hub.

Harris will sell you a Shimano Red Band Nexus-8 for $230, shifter is
another $25. They sell complete wheels with that hub starting at $300.

But the new Sturmey-Archer X-RF8 sells for a ludicrously cheap $170
including shifter!

Zarquon! I like that there is a disc brake option also. Too bad I've
already bought and installed into a wheel a SRAM 7 speed (with drum
brake). Still, definitely something to keep in mind.

Quoted message said:

Note that the X-RF8's direct-drive gear is the lowest gear, which is a
bit weird for some applications, though Sheldon built one into a Raleigh
Twenty because that quirk suits small-wheel bikes.

This was the bit I really liked:

Quoted message said:

Over Locknut Dimension (rear spacing) anywhere from 115 to 135 mm,
depending on what nuts/washers you use.

That would have saved me some time with a 2x4.

Quoted message said:

For my part, this slides very close to the justifiable-purchase zone. I
have some theories about the applicability of hub gears to CX that I'd
like to check out.

Well, at least you wouldn't have to worry about your drive train getting
mucked up.

--
Dane Buson - [email hidden]
A diplomat is man who always remembers a woman's birthday but never her age.
-- Robert Frost

In article <[email hidden]>,

Dane Buson said:

Ryan Cousineau said:

Dane Buson said:

I still think you would be happier with an internal gear hub. A Rohloff
14 speed would run you $1200 or so, or $3-400 for a SRAM 7 speed hub.

Quoted message said:

Quoted message said:

But the new Sturmey-Archer X-RF8 sells for a ludicrously cheap $170
including shifter!

Quoted message said:

Quoted message said:

For my part, this slides very close to the justifiable-purchase zone. I
have some theories about the applicability of hub gears to CX that I'd
like to check out.

Well, at least you wouldn't have to worry about your drive train getting
mucked up.

That's the theory!

For a duffer like me, the question really has to be whether it makes the
race simpler and more fun, but I want to know if the efficiency and
weight issues prevent the bike from being any fun at all.

But boy, wouldn't this be fun? I see using an 8-speed hub, discs front
and rear, and never caring about the mud's effect on my bike ever again.

Hm. Anyone know of a singlespeed frame designed with a rear disc mount
and fat tire clearances?

--
Ryan Cousineau [email hidden] http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos

Ryan Cousineau said:

Hm. Anyone know of a singlespeed frame designed with a rear disc mount
and fat tire clearances?

If you don't find a $600 price tag (frame only) and a steeply sloping
top tube off-putting, the Fisher Rig fits the bill. So would the
Ferrous, but I think it's only available as a complete geared bike.

In article <[email hidden]>,

Steve Gravrock said:

Ryan Cousineau said:

Hm. Anyone know of a singlespeed frame designed with a rear disc mount
and fat tire clearances?

If you don't find a $600 price tag (frame only) and a steeply sloping
top tube off-putting, the Fisher Rig fits the bill. So would the
Ferrous, but I think it's only available as a complete geared bike.

Well, about half the Surly frames would work for less. I shouldn't ask
questions I know the answer to.

Karate Monkey and Crosscheck would be fine.

Hmm... Steamroller will take a 700x38 tire. I'd have to use a CX fork
and a hub rear brake, but...

--
Ryan Cousineau [email hidden] http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos