Comparing 50/34 to 53/39

There is a slot on the braze-on, isn't there? You should have some range
of positioning.

Some bikes have enough leeway to move it down, some do not.
B

(remove clothes to reply)

There is a slot on the braze-on, isn't there? You should have some range
of positioning.

Some bikes have enough leeway to move it down, some do not.
B

(remove clothes to reply)

TRG- Does getting a compact road double (50/34 or 48/34 or 50/36) means
having to
change the FD on a Trek 5200 with a braze-on Campy Chorus 10? BRBR

No-

TRG- Does this
setup require a triple FD in order for the chain to clear the small ring
(which is 3 or 5 teeth smaller than the 39 double I have now)? BRBR

No

I have put the FSA 'Tyler' crank onto shimano and Campag systems, clampon and
braze on and they work fine-

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

TRG- Does getting a compact road double (50/34 or 48/34 or 50/36) means
having to
change the FD on a Trek 5200 with a braze-on Campy Chorus 10? BRBR

No-

TRG- Does this
setup require a triple FD in order for the chain to clear the small ring
(which is 3 or 5 teeth smaller than the 39 double I have now)? BRBR

No

I have put the FSA 'Tyler' crank onto shimano and Campag systems, clampon and
braze on and they work fine-

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

According to campy manuals (Record 2003) the short cage derailleur has
a maximum capacity of 14-tooth difference in the chainrings. And
27-tooth total capacity (biggest chainring - smallest chainring) +
(biggest cog - smallest cog). Right now I am using a 13-26 cogset and
i'm planning to get a 49/33 up front. 33 is the smallest that would
fit in 110 bcd, and i'm just going 16 teeth more for the big ring.
This is already 2 teeth more than the stated max. My question is, will
this combination work? Can I go with an even bigger difference, say
53/33?

Peter, you say you've used up to 29-tooth cog with a short cage campy
derailleur? But the max tooth for the short cage is supposedly only
26. How did you make your setup work?

Btw, i also have a campy front derailleur which i believe is a double
(how do i tell if its a double or a triple?). The double supposedly
has capacity of 14, and the triple has capacity of 23.


"David L. Johnson" wrote in message ...
On Tue, 16 Sep 2003 11:13:24 +0000, Lanny R. Levenson wrote:

How would performance change using the medium cage with 50/34 and 12x25,
13x26? Is this a situation that one would have to change the chain?
Also, what kind of shift performance change would you see if you stayed
with a short cage while using a 13x29 or would that not work at all?

I am surprised Peter says it would work with a short cage. Maybe he was
focussing on the 13/29 cassette rather than the total teeth. Most short
cage derailleurs can handle maybe 28 or so total teeth, new Campy ones
maybe more. But certainly 32 teeth is tight. You don't want loose chain
on the small-small combination, but you really don't want it to be too
small on the big-big.

dennis wrote:

According to campy manuals (Record 2003) the short cage derailleur has
a maximum capacity of 14-tooth difference in the chainrings. And
27-tooth total capacity (biggest chainring - smallest chainring) +
(biggest cog - smallest cog). Right now I am using a 13-26 cogset and
i'm planning to get a 49/33 up front. 33 is the smallest that would
fit in 110 bcd, and i'm just going 16 teeth more for the big ring.
This is already 2 teeth more than the stated max. My question is, will
this combination work? Can I go with an even bigger difference, say
53/33?

See: http://sheldonbrown.com/gloss_ca-m.html#capacity

Sheldon "50/28" Brown
+-----------------------------------------------------------+
| Always listen to the experts. |
| They'll tell you what can't be done, and why. |
| Then do it. --Robert A. Heinlein |
+-----------------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

On Tue, 23 Sep 2003 11:37:17 +0000, dennis wrote:

According to campy manuals (Record 2003) the short cage derailleur has a
maximum capacity of 14-tooth difference in the chainrings. And 27-tooth
total capacity (biggest chainring - smallest chainring) + (biggest cog -
smallest cog). Right now I am using a 13-26 cogset and i'm planning to get
a 49/33 up front. 33 is the smallest that would fit in 110 bcd, and i'm
just going 16 teeth more for the big ring. This is already 2 teeth more
than the stated max. My question is, will this combination work? Can I go
with an even bigger difference, say 53/33?

Well, I've used things like a 48/30 front with no trouble, although right
now I have a 46/30. My front derailleur is a mid-80s (guessing) Record,
so meant for a double. Up until last Fall my rear derailleur was also a
mid-80s Record, short cage. I do use a chain watcher, since I had trouble at
one point missing the little ring, but that was due to too-small spacing
between the rings. Still, I leave the chain watcher on, but with it I
have no trouble shifting. I*think a 14-tooth limit in the chainrings is
very conservative. Your 49/33 should work well for you.

Btw, i also have a campy front derailleur which i believe is a double (how
do i tell if its a double or a triple?). The double supposedly has
capacity of 14, and the triple has capacity of 23.

I sometimes use a triple for touring. Last time I had a 46/30/20 (94/58
bolt circle). I have gone to a Racing T rear just to get enough capacity,
but the front is still the old Record. No trouble with the front
derailleur. I used a 12-23 cassette with that, for a total of 37 teeth.

--

David L. Johnson

__o | And though I have the gift of prophecy, and understand all
_`\(,_ | mysteries, and all knowledge; and though I have all faith, so
(_)/ (_) | that I could remove mountains, and have not charity, I am
nothing. [1 Corinth. 13:2]

Thank you sheldon and david for your responses. You have given me
confidence to go even wider with 50/33. Otherwise I would have gone
down to 48. This is because the 49 tooth TA chainring I just learned
is not pinned and ramped. Also I looked closely at my FD and there's
definitely enough space to go even wider than 14-tooth difference in
chainring size without the chain dragging on the bottom of the FD
cage.

As for the rear derailleur, I like what sheldon said in his webpage:

"Competent riders can considerably exceed the official rated capacity,
since they will not misuse the granny ring by running it with the
smaller rear sprockets, so it doesn't matter if the chain hangs slack
in those gears. "

dennis- My question is, will
this combination work? Can I go with an even bigger difference, say
53/33? BRBR

a 16t diff is no problem, a 20t difference may be.

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

On Wed, 24 Sep 2003 09:54:10 +0000, Peter Storey wrote:

C) Less convenient shift pattern.

Depending on the precise combinations of chainrings and sprockets, both
"before" and "after", you may find that the lowered top gear in the small
ring forces you to make the cross-over front shift more often. Also, a
number of these combinations would require you -- as part of the
cross-over -- to shift across more sprockets in the rear to reach the
"next" gear. Depending on what you are used to, you may or may not
care.

It may depend on the equipment you have, but I don't find it a problem.
If I am near the end of what I can get with my big ring, but I don't want
a much lower gear, I shift both front and rear at once (with Ergo it's
just a matter of pushing with both thumbs). Again, with Ergo, shifting
across several sprockets is also not a problem.

I played around with this concept for a while earlier this year, and I
never could get a range that dropped the lowest gear far enough without
either (i) forcing the cross-over into the midst of my cruising gears or
(ii) widening the intervals between ratios. And I wasn't the least bit
hesitant to give up 53/11! Or even 52/12!

This happens if you use a standard close-ratio cassette and a big big
ring, like a 52 or 53. What I do, instead, is to use a smaller big ring,
a 46 for me, and a 12-23 cassette. Then, my cruising gears are the middle
of the cassette. I also don't have wide jumps. The 46/12 is big enough
for my needs. With a very small inner ring I can still get nice low lows.

--

David L. Johnson

__o | It is a scientifically proven fact that a mid life crisis can
_`\(,_ | only be cured by something racy and Italian. Bianchis and
(_)/ (_) | Colnagos are a lot cheaper than Maserattis and Ferraris. --
Glenn Davies