Chain rub and usable gears

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

Quoted message said:

I have a 2005 Trek 1500 with Shimano 105 triple front derailleur and
9-speed
cassette. No matter how much I fiddle with front derailleur
adjustment, I
find that chain rub limits the usable rear gears enough that there's
less
overlap than I would like between one chainring (52-42-30) and the
next. My
LBS doesn't seem to do any better. This is my first bike with indexed
shifting, and the first I've even owned in almost 20 years, so maybe
I'm just
being too picky. But my questions are:

1) With proper adjustment, which rear sprockets should I expect to be
usable
for each chainring and trim setting?

2) Same question for a Shimano double with 10-speed cassette.

3) When adjusting the front derailleur, which factors are most
important in
getting the maximum number of usable gears? Any special tricks?

Absolutely! How good are you at determining where the rub is and
tweaking the shape of cage with a pair of pliers? It's called
customizing and I and several others have been successful.

Phil H

Barry said:

I have a 2005 Trek 1500 with Shimano 105 triple front derailleur and 9-speed
cassette. No matter how much I fiddle with front derailleur adjustment, I
find that chain rub limits the usable rear gears enough that there's less
overlap than I would like between one chainring (52-42-30) and the next. My
LBS doesn't seem to do any better. This is my first bike with indexed
shifting, and the first I've even owned in almost 20 years, so maybe I'm just
being too picky. But my questions are:

1) With proper adjustment, which rear sprockets should I expect to be usable
for each chainring and trim setting?

2) Same question for a Shimano double with 10-speed cassette.

3) When adjusting the front derailleur, which factors are most important in
getting the maximum number of usable gears? Any special tricks?

Thanks.

Barry

Isn't this effect pretty much normal, unless something's really out of
whack? If the chain angles are extreme when you hear the rub, you are
better off switching to another chainring, anyway.

Barry said:

I have a 2005 Trek 1500 with Shimano 105 triple front derailleur and 9-speed
cassette. No matter how much I fiddle with front derailleur adjustment, I
find that chain rub limits the usable rear gears enough that there's less
overlap than I would like between one chainring (52-42-30) and the next. My
LBS doesn't seem to do any better. This is my first bike with indexed
shifting, and the first I've even owned in almost 20 years, so maybe I'm just
being too picky. But my questions are:

1) With proper adjustment, which rear sprockets should I expect to be usable
for each chainring and trim setting?

All except for large large and small small. Make sure your front
derailleur cage is set up right:

http://parktool.com/repair/readhowto.asp?id=75

Barry said:

I have a 2005 Trek 1500 with Shimano 105 triple front derailleur and 9-speed
cassette. No matter how much I fiddle with front derailleur adjustment, I
find that chain rub limits the usable rear gears enough that there's less
overlap than I would like between one chainring (52-42-30) and the next. My
LBS doesn't seem to do any better. This is my first bike with indexed
shifting, and the first I've even owned in almost 20 years, so maybe I'm just
being too picky. But my questions are:

1) With proper adjustment, which rear sprockets should I expect to be usable
for each chainring and trim setting?

In general, whether 9- or 10-speed:
-Small chainring, all except smallest two sprockets.
-Middle chainring, all sprockets
-Large chainring, all except largest two sprockets.

....is reasonable, though you can often do better, i.e. one extreme
sprocket not available at each end, rather than two.
Even if you can get down to only one sprocket rubbing at each end, not
using the last two is a good rule of thumb when riding.
The crossover combinations normally produce a ratio that is available
elsewhere (particularly on a triple), and the harsh angles on the
chain are thought to increase wear and be marignally less efficent.

Quoted message said:

2) Same question for a Shimano double with 10-speed cassette.

As above, ignoring the middle ring.

Quoted message said:

3) When adjusting the front derailleur, which factors are most important in
getting the maximum number of usable gears? Any special tricks?

1. Check that the cable is taking the correct route at the pinch bolt.
2. put in a fresh cable and outer if there's any doubt as to condition
3. setup from scratch as per
http://sheldonbrown.com/derailer-adjustment.html

Don't assume that the clamp position of the front der. is correct,
even from the factory - check and reset per the instructions.

....there's not much else to do - ya get what ya get at that stage.

If you want to go beyond that, you're looking at tweaking the cage
shape (files, pliers etc.), as Phil suggests above, or looking at
swapping components. Shouldn't be necessary with a good setup.

Quoted message said:

Thanks.

Barry

hth,

regards,

bookieb.

Barry said:

I have a 2005 Trek 1500 with Shimano 105 triple front derailleur and 9-speed
cassette. No matter how much I fiddle with front derailleur adjustment, I
find that chain rub limits the usable rear gears enough that there's less
overlap than I would like between one chainring (52-42-30) and the next. My
LBS doesn't seem to do any better. This is my first bike with indexed
shifting, and the first I've even owned in almost 20 years, so maybe I'm just
being too picky. But my questions are:

The fact that you or the shop haven't gotten it right yet, doesn't
mean it can't be done, but triples are hard to get right. Do you need
a triple?

It's probably implied, but you can't let it rub or the friction will
eventually alter the shape and therefore the functionality of the
deraileur. If you need to use *the* particular cog(s) that rubs, you
have to trim, and of course that gets tired fast.

Keep at it, sometimes it takes a lot of tries to understand the minor
mod that will make it right. I'm confindent on most repairs but I'll
admit to struggling with front der and feel fortunate when I finally
get it.

At the price point that most re-acquainted riders enter, mfgs offer
triples, assuming that you'll need one, and maybe a littel marketing:
"You're gettin' more gears!". I ride a 9sp double in New England where
we have lots of hills, some steep but none long. I not only don't miss
the extra gears, I prefer the simplicity of the double but my double
has the cogs I need to climb in my terrain. Whether you can go to a
double depends on how and where you ride. You can handicap your triple
against double here:
http://www.sheldonbrown.com/gears/

I've used an ultegra 12-27 cassette w a 53/39 front for ages, it's got
a good range.

It's not picky to want your equipment to work right, I'd say that's
the minimum actually. Double is easier but clearly it'll cost to make
the change and it will have to be suitable for you and your terrain.

Quoted message said:

1) With proper adjustment, which rear sprockets should I expect to be usable
for each chainring and trim setting?

2) Same question for a Shimano double with 10-speed cassette.

3) When adjusting the front derailleur, which factors are most important in
getting the maximum number of usable gears? Any special tricks?

Unless your racing, the number of gears is unimportant. What you need
is *the* gear for *the* hill and you need one more cog to do that same
hill when you've gotten lost on a Sunday, there's no water anywhere
and you just want to get home. If you have those two, everything else
will fall in place for years to come. What makes you need more gears
is training over a considerable period of time.

If you *have* to have every gear, Sheldon's site, as another poster
recommended, will get you there... if anyone can.

Good luck with it!

Quoted message said:

Do you need a triple?

I don't need a triple anymore, but this is my first bike and that's what it
came with. If/when I get a new bike, I won't get a triple. I do want a
pretty low gear, as I sometimes do very steep (though short) hills, but I
should be able to manage with a 39/27, or maybe a compact crank.

Quoted message said:

Unless your racing, the number of gears is unimportant.

I care about the number of gears only because it affects the overlap between
one chainring and the next. Overlapping gears might be seen as redundant, but
reduce the need to shift the front derailleur.

A couple of posters suggested that I should be able to get all nine sprockets
in the middle chain ring, and seven or eight (all but one or two) in the small
and big rings. I'd be happy to get six of nine without having to adjust the
cable barrel on the fly (accepting the need to trim with the shift lever).

I thank everyone for your replies, but it seems that most of these are generic
advice for front derailleurs as opposed to first-hand experience with a setup
like mine. I'd really appreciate hearing from someone who currently rides a
9-speed Shimano triple, or from a mechanic who works on this stuff.

Barry

On Mar 6, 2:41 pm, "Barry" <[email hidden]> wrote:
<snip>

Quoted message said:

I thank everyone for your replies, but it seems that most of these are generic
advice for front derailleurs as opposed to first-hand experience with a setup
like mine. I'd really appreciate hearing from someone who currently rides a
9-speed Shimano triple, or from a mechanic who works on this stuff.

Barry

OK, to be more specific:
I have a 3x9 105 Shimano setup on one of my bikes.
I can get cleanly to:
8 sprockets from the small ring.
9 sprockets on the middle ring.
8 sprockets on the large ring,
....thobut as I said above, I tend to restrict myself to 7 sprockets
from the big and small rings.

You should not have to tweak the adjuster "in use" to get to that
level.

One reason that the instructions are generic is that the problem (and
solutions) are pretty generic too.

Just as diagnosis:
Did this ever work correctly?

If it ever worked correctly, did you change any components (e.g. new
cranks, new derailleurs etc)?

If it used to work OK, and nothing has been changed, the most likely
cause is that it's just in need of a new cable, cleaning, servicing
and resetting.

hth,

bookieb

Barry said:

I do want a
pretty low gear, as I sometimes do very steep (though short) hills, but I
should be able to manage with a 39/27, or maybe a compact crank.

I'd call that a really, really low gear. You must have some mega
hills.

Quoted message said:

I have a 3x9 105 Shimano setup on one of my bikes.
I can get cleanly to:
8 sprockets from the small ring.
9 sprockets on the middle ring.
8 sprockets on the large ring,

Quoted message said:

Did this ever work correctly?

If it used to work OK, and nothing has been changed, the most likely
cause is that it's just in need of a new cable, cleaning, servicing
and resetting.

OK, thanks for the info. I have never been able to get more than 5 sprockets
cleanly on the big chainring, and even that is touchy (there is no trim for
the big ring - correct?). Bike just came back from general service at the LBS
(plus new chain and cassette), and it's no better or worse than before. I
asked the guy who worked on my bike about this, and he said I shouldn't expect
to get more than 3 or 4 sprockets in the big and small rings. I think they
don't often have to worry about this, as it's very flat around here and most
of the riders with triples are probably like I was a few years ago - novices
or casual riders who don't need many gears and aren't demanding about it. I
guess I just have to keep playing with the adjustments, especially derailleur
angle.

One more question - in the middle chainring, how many sprockets do you get for
each trim setting?

Barry

Quoted message said:

Quoted message said:

should be able to manage with a 39/27, or maybe a compact crank.

I'd call that a really, really low gear. You must have some mega
hills.

Very steep (some over 10%) but short (I haven't done anything more than an 800
foot climb yet). I'm one of the weaker riders in the group. Some of the guys
use a 25, most probably a 27. A couple have a 29, and there are a few with a
compact. I'm one of only 2 triples, I think.

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

Quoted message said:

Very steep (some over 10%)

Giggle :-)

In article <[email hidden]>,

Barry said:

Quoted message said:

Do you need a triple?

I don't need a triple anymore, but this is my first bike and that's what it
came with. If/when I get a new bike, I won't get a triple. I do want a
pretty low gear, as I sometimes do very steep (though short) hills, but I
should be able to manage with a 39/27, or maybe a compact crank.

Quoted message said:

Unless your racing, the number of gears is unimportant.

I care about the number of gears only because it affects the overlap between
one chainring and the next. Overlapping gears might be seen as redundant, but
reduce the need to shift the front derailleur.

A couple of posters suggested that I should be able to get all nine sprockets
in the middle chain ring, and seven or eight (all but one or two) in the small
and big rings. I'd be happy to get six of nine without having to adjust the
cable barrel on the fly (accepting the need to trim with the shift lever).

I thank everyone for your replies, but it seems that most of these are generic
advice for front derailleurs as opposed to first-hand experience with a setup
like mine. I'd really appreciate hearing from someone who currently rides a
9-speed Shimano triple, or from a mechanic who works on this stuff.

Check the chain line. Move the front derailleur
vertically and around the seat tube. Make sure the
front derailleur has full movement inward and outward.

I run Shimano Ultegra derailleurs and 9 gear cluster.
(the cranks and chain rings are TA)

I think a triple chain ring configuration should be full utilized:
* small small chain ring
* closely spaced gear cluster

That is why I run 48,38,24 / 13,14,15,16,17,18,19,21,23.

The chain line is cheated inward, so that the four
smallest cogwheels are unavailable to the smallest
chain wheel. All cogwheels are available to the middle
and large chain wheels; though I only use the cross
chainings for brief periods. Notice that I have actual
low gears and close gearing in the middle and large
chain rings. No hole between 17 and 19.

--
Michael Press

Barry said:

I thank everyone for your replies, but it seems that most of these are generic
advice for front derailleurs as opposed to first-hand experience with a setup
like mine. I'd really appreciate hearing from someone who currently rides a
9-speed Shimano triple, or from a mechanic who works on this stuff.

I run a Shimano 105 triple (50-39-something) with 10 cogs. The middle
chainring can do the full range. I don't know if the big-big and
little-little chainring / cog combos rub because I don't want to put
so much lateral stress on the chain, and I almost never use the little
ring anyway.

The 105 front shifter has a trimming function that allows a small
adjustment on the fly with a single click of the lever, and I
sometimes use that in, say, a big ring / middle cassette combination
but usually it's a sign that I need to drop down to the middle ring.
Information on the trimming function is at:

http://cycle.shimano-eu.com/media/techdocs/content/cycle/SI/105/ST-5600_R700/SI_0024B_En_v1_m56577569830599845.pdf

or

http://tinyurl.com/22e7uw

Colin

Barry said:

...
I thank everyone for your replies, but it seems that most of these are generic
advice for front derailleurs as opposed to first-hand experience with a setup
like mine. I'd really appreciate hearing from someone who currently rides a
9-speed Shimano triple, or from a mechanic who works on this stuff.

Well, if you throw a question out there, you will get the answers that
you get, but I am curious about the chain angles you get at the most
inner and outer rings of your rear cassette. I was always advised to
avoid them to get the most life out of your chain and cassette. Has
your bike shop mentioned this to you? You've said that they have worked
on adjusting your derailler for you.

a nth way of looking at your problem. Riders in competition run more
effective chainline setups than street bikes. Higher levels of
competition run higher than lower levels.
You are at the barrel's bottom. Not only do you not know if it's
running misaligned, you do not know what misaligned is nor what
correct operation is. Not in a position for checking LBS work that's
fersure.
Gotta learn to DIY.
take a look around at street MTB. Where's the average efficency elevl
there?

Quoted message said:

but I am curious about the chain angles you get at the most inner and outer
rings of your rear cassette. I was always advised to avoid them to get the
most life out of your chain and cassette.

Not quite sure what you mean. Are you suggesting always avoiding the smallest
and largest sprockets, or just avoiding the cross-chained combinations? I
never try to use the extreme combinations, and seldom use the largest
sprocket. I do sometimes use the middle chain ring with the smallest
sprocket, to avoid shifting to the big chain ring if I don't think I'll stay
there long.

Quoted message said:

Information on the trimming function is at:

Thanks for the link. I have the older 9-speed version (5500) but found the
proper service instruction on Shimano's website. I do trim in the middle and
small chainrings, but didn't think that trim was available on the large
chainring, too. I'll try to use a lighter touch and see if it works.

Barry said:

Quoted message said:

but I am curious about the chain angles you get at the most inner and outer
rings of your rear cassette. I was always advised to avoid them to get the
most life out of your chain and cassette.

Not quite sure what you mean. Are you suggesting always avoiding the smallest
and largest sprockets, or just avoiding the cross-chained combinations? I
never try to use the extreme combinations, and seldom use the largest
sprocket. I do sometimes use the middle chain ring with the smallest
sprocket, to avoid shifting to the big chain ring if I don't think I'll stay
there long.

I was referring to avoiding the cross chained combinations. Just
thought I would mention it, but glad you have a handle on this already.