Changing Middle and small chainrings

"Javier" <[email hidden]> wrote in news:1147020330.048052.103220
@i39g2000cwa.googlegroups.com:

Quoted message said:

I'm thinking about changing the middle and small chainrings on my
triple so that I can get a bit more shifting room while I climb all the
hills that are on my usual ride. During the steepest part of the climb
I'm in my 30 up front and my 26 in the rear. This isn't bad at all
during the first three loops but after the fifth I start to wish that I
had a slightly lower gear to work with.

My rear cassette is an SRAM 12-26 and my current triple is a 52/42/30.
I'm thinking about going with a 52/39/24 or 52/39/30 while keeping the
same rear cassette. Good idea..bad.. Any comments are appreciated.

Javier

I wouldn't go any smaller than a 26 up front,and I'd keep the 42. A 52-24t
difference is too big, even for most triple FDs, and 52-26 is pushing it.
The two big rings need to be fairly close in size in order for the bulge on
the outer cage to push the chain onto the granny. Too small of a middle
ring, and the chain is below the bulge. I know for a fact that Campy triple
FDs can't handle a 14t gap between big & middle and still be able to shift
to the small. I doubt the 13t gap you're proposing will work, either.

It would be far more effective to get an 11-32 cassette. If you like, you
could mix the cogs with your 12-26 to get close ratios with the small cogs,
and then 2 bail-out gears. Make like a 12-13-14-16-18-20-22-26-32.

Javier said:

I'm thinking about changing the middle and small chainrings on my
triple so that I can get a bit more shifting room while I climb all the
hills that are on my usual ride. During the steepest part of the climb
I'm in my 30 up front and my 26 in the rear. This isn't bad at all
during the first three loops but after the fifth I start to wish that I
had a slightly lower gear to work with.

My rear cassette is an SRAM 12-26 and my current triple is a 52/42/30.
I'm thinking about going with a 52/39/24 or 52/39/30 while keeping the
same rear cassette. Good idea..bad.. Any comments are appreciated.

How about just changing the cassette to a 12-32 with a mountain rear
derailleur?

Art Harris

Hank Wirtz <[email hidden]> wrote in
news:[email hidden]:

Quoted message said:

I wouldn't go any smaller than a 26 up front,and I'd keep the 42. A
52-24t difference is too big, even for most triple FDs, and 52-26 is
pushing it. The two big rings need to be fairly close in size in order
for the bulge on the outer cage to push the chain onto the granny. Too
small of a middle ring, and the chain is below the bulge.

Don't most 9-speed Dura-Ace and 10-speed Ultegra triple cranksets come
standard with 52-39-30 chainrings? The OP didn't say what front derailleur
they are using, but the latest Ultegra or Dura-Ace triple FDs should work
fine with a 52-39 jump. At the low end, I agree that 26 is about the lowest
you would want to try. Paired with a standard 27T cassette, that gives you
lower than 1-1 gearing, which should be enough to climb even the steepest
paved roads.

Ken <[email hidden]> wrote in news:[email hidden]:

Quoted message said:

Don't most 9-speed Dura-Ace and 10-speed Ultegra triple cranksets come
standard with 52-39-30 chainrings? The OP didn't say what front
derailleur they are using, but the latest Ultegra or Dura-Ace triple
FDs should work fine with a 52-39 jump.

Sho'nuff, DA and Ultegra come 52-39-30. 105 comes 50-39-30. Tiagra & Sora
(and I imagine 2203) all come 52-42-30.

But with the ramps and pins positioned based on the size of the adjacent
ring, the OP will see better shifting, and less risk of an incompatible
mech by keeping the 42. Besides, 42 is a better cruising ring. The 39 (or
34 on a compact) makes sense without a granny to bail out to, but the OP
has a granny ring. If he was thinking that having the 39 would improve
shifting, the truth is counterintuitive.

Ken said:

Don't most 9-speed Dura-Ace and 10-speed Ultegra triple cranksets come
standard with 52-39-30 chainrings?

Yes, and that's a good reason to run neither the 9-speed Dura-Ace nor
the 10-speed Ultegra triple cranksets.

52-42-28 or 27 or 26.

--BG

Javier said:

I'm thinking about changing the middle and small chainrings on my
triple so that I can get a bit more shifting room while I climb all the
hills that are on my usual ride. During the steepest part of the climb
I'm in my 30 up front and my 26 in the rear. This isn't bad at all
during the first three loops but after the fifth I start to wish that I
had a slightly lower gear to work with.

My rear cassette is an SRAM 12-26 and my current triple is a 52/42/30.
I'm thinking about going with a 52/39/24 or 52/39/30 while keeping the
same rear cassette. Good idea..bad.. Any comments are appreciated.

Javier

I have a 26/39/52 triple and a 12/28 cassette. I've got a FD-R443 front
derailleur and a Deore XT rear. Everything shifts fine, and it got my
sorry 220-pound ass up a 18% grade without a hitch.

Jeff

In article <[email hidden]>, Hank Wirtz

() said:

I wouldn't go any smaller than a 26 up front,and I'd keep the 42. A 52-24t
difference is too big, even for most triple FDs, and 52-26 is pushing it.

Up to a point, Lord Copper. My trike has 24-42-52 and shifts fine with
an Ultegra triple FD. The rear is a long cage XT, though, and I rarely
if ever venture onto the smaller cogs on the back while on the small
chainring.

Using a smaller-than-standard inner ring with a ramped'n'pinned Shimano
middle, however, may give rise to 'orrible noises as the chain knocks
against the hardware. In contrast, the Campag chainset on the trike is
blissfully silent in this regard, while shifting is as easy as it ever
was with the Shimano one.

--
Dave Larrington - <http://www.legslarry.beerdrinkers.co.uk/>
The elder stoat leads, in all circumstances.

Javier said:

I'm thinking about changing the middle and small chainrings on my
triple so that I can get a bit more shifting room while I climb all the
hills that are on my usual ride. During the steepest part of the climb
I'm in my 30 up front and my 26 in the rear. This isn't bad at all
during the first three loops but after the fifth I start to wish that I
had a slightly lower gear to work with.

My rear cassette is an SRAM 12-26 and my current triple is a 52/42/30.
I'm thinking about going with a 52/39/24 or 52/39/30 while keeping the
same rear cassette. Good idea..bad.. Any comments are appreciated.

Javier

Gearing is a personal choice. If you have STI, you must have a midfdle
with pins and ramps and probably a FD meant for a 39t as well, for good
performance. If ERGO-just put any ring on.

-----BEGIN PGP SIGNED MESSAGE-----

In article <[email hidden]>,

Qui si parla Campagnolo said:

Javier said:

I'm thinking about changing the middle and small chainrings on my
triple so that I can get a bit more shifting room while I climb all the
hills that are on my usual ride. During the steepest part of the climb
I'm in my 30 up front and my 26 in the rear. This isn't bad at all
during the first three loops but after the fifth I start to wish that I
had a slightly lower gear to work with.

My rear cassette is an SRAM 12-26 and my current triple is a 52/42/30.
I'm thinking about going with a 52/39/24 or 52/39/30 while keeping the
same rear cassette. Good idea..bad.. Any comments are appreciated.

Javier

Gearing is a personal choice. If you have STI, you must have a midfdle
with pins and ramps and probably a FD meant for a 39t as well, for good
performance. If ERGO-just put any ring on.

_ I just did this with my bike, I went from a 52/42/30 w 12-25
to a 52/39/26 with a 13-24. With Shimano 105 brifters and triple
front it shifts just fine on the workstand. I haven't had a
chance to ride it yet.

_ Gears are like saddles, you have to figure out the ones that
work for you and where you ride. The cheapest solution would be
to get a wider range rear cassette, you could go as high as 30t
in the back w/o changing the rear derailler. ( Maybe higher
depending on what rear derailler you have. ). Just by an SRAM
MTB cassette and mix and match to get the gears you want.

_ Booker C. Bense

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I just went through this process, so I can tell you my experience.

It sounds like your FD is set for a 10 cog difference between the large
and middle chainrings, so you should probably stick with that. (e.g.
9-speed ultegra/105 fd 52-42-30)

If you want to go to a 39 middle, then I recommend you get the ultegra
10-sp fd, which is set for that jump.

I personally use the 9-spd 105 fd, with 52-42-26. I swapped out the 30
for a 26. I can use 6 of the 9 speeds in the small ring before there is
too much chain slack, but I just shift up to the middle ring. For extra
protection, I added the jump stop chain guard so the chain doesn't drop
off and miss the small ring. That is especially recommended for the
42-24 jump, which some people say works.

Shifting to the middle ring is fine as long as you shift up to the 3rd
or 4th gear in the back. If you try to shift from the lowest couple of
gears, then the pins don't catch well for me.

You might be able to adjust the deraileur, to get better than my
experience.

--Your alternative, which many people seem to do is to go with say
48-38-24 and replace all the chainrings.

I also have a deore RD with 11-34, so my lowest gear is a 26-34.
Yesterday I towed my son in a Burley on a 70-mile "metric" century with
5500 ft climbing, and the low gears helped a lot!

One other note is that when you go outside the recommended
Shimano/Campy range, then it's not dumbproof and it doesn't work 100%,
but for people who think about what gear they are in before trying to
shift, then it works great...

Toshi

Well,

I had this very same idea over the winter with my Ultegra 52-42-30 crank and
SRAM 11-21 cassette.

You see I rode all last year with an 11-32 mountain bike cassette and a
53-38 crank. While this combo gives you a great range and nearly perfect
gear spacing, the down side is that it takes a front shift and several rear
shifts to move up and down the equivelant of a 1 tooth rear cog jump.
Perfectly fine for touring but awful when you're in the middle of that
friendly sprint to the road sign.

So I got a used triple crank/BB/FD (already had a nice long-cage RD and
"luckily" my left Ultegra brifter was a triple even though I was using a
double setup) and put it together with a 11-21 corncob. (I like the 53/11
for standing and stretching while on long rides). The problem was that a
38/32 is 31.0 gear-inches but the 30/21 is 37.3 gear-inches (more like a
38/27 ... not low enough). However, a 26/21 is 32.4 gear-inches ... much
better. So I ordered up a 26 granny, put it on, and found out that I could
only use the big 3 gears in the back before the chain started rubbing on the
pick-up pins of the 42 chainring and downshifting the front would throw the
chain off 1 out of 3 times. This left a big hole in my gearing :-( Ok, I
thought, let's try a 28 granny and a "chain watcher thingy" ... got 5 big
gears in the back before it started rubbing. (Note: The stock 30 lets me
use the 8 big gears in the back before it starts rubbing). That works, but
now there's no overlap between mid and granny chainrings (I sure hope I
don't hit a hill on which I need to switch back and forth) but a 28/21 is
34.9 gear-inches which is very close to the 38/28 I was riding last year,
but is no 38/32! This is not low enough to go up that 3/4 mile 20% grade
hill we have around here.

If I had 10-speed then a 11-23 with a 28 granny would be perfect and would
have the same range as the MTB 11-32 with 53-38 chainrings but would have
MANY more gears in between, but who can afford to upgrade to 10 speed? ...
not me.

I guess the whole point I'm saying is that you can put a smaller granny gear
on there, but you won't be able to use hardly any gears in the back before
the chain will start rubbing on the middle chainring and I haven't seen (or
heard) anyone mention that fact when suggesting a smaller granny chainring.

J.

I calculated that a 26 tooth "granny" would give me
"Qui si parla Campagnolo" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Javier said:

I'm thinking about changing the middle and small chainrings on my
triple so that I can get a bit more shifting room while I climb all the
hills that are on my usual ride. During the steepest part of the climb
I'm in my 30 up front and my 26 in the rear. This isn't bad at all
during the first three loops but after the fifth I start to wish that I
had a slightly lower gear to work with.

My rear cassette is an SRAM 12-26 and my current triple is a 52/42/30.
I'm thinking about going with a 52/39/24 or 52/39/30 while keeping the
same rear cassette. Good idea..bad.. Any comments are appreciated.

Javier

Gearing is a personal choice. If you have STI, you must have a midfdle
with pins and ramps and probably a FD meant for a 39t as well, for good
performance. If ERGO-just put any ring on.

-----BEGIN PGP SIGNED MESSAGE-----

In article <[email hidden]>,

Booker C. Bense said:

Quoted message said:

_ I just did this with my bike, I went from a 52/42/30 w 12-25
to a 52/39/26 with a 13-24. With Shimano 105 brifters and triple
front it shifts just fine on the workstand. I haven't had a
chance to ride it yet.

_ Well after futzing with this on the road for a week, I'd
definitely recommend keeping the 42 if you don't want to
switch to Ergo brifters. It shifts just fine, but there
isn't enough trim in the system to allow me to use most
of the cluster w/the middle chainring. This kind of defeats
the whole point of getting a tighter rear cluster w/a wider
front chainring range.

_ Booker C. Bense

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