Lowering Gears for Touring Bike

PatC wrote in
6:



Second question, can I buy smaller chain rings for the 105 triple
crank, or should I just buy a Sugino touring crank and BB and be done
with it?

Everybody's addressed the chanring size limits of your 105, but let me
put in an enthusiastic plug for the Sugino XD 300/600 (only difference
is steel vs. aluminum rings). Pair it with a UN52 or UN73 if your 105 is
Octalink and you'll have a beautiful crank with great gearing for
everything but racing (or fast rides with jerks who'll drop you) for
under $100.


My logic is, replace the crank with something like a Sugino 48/38/28
(if anyone has suggestions for others), change to an LX mtn rear
derailleur (or maybe a SRAM?), and use a mtn cassette of my choosing.
Leave the bar end shifters and front derailleur the same.

Not a SRAM. If they're still making any RDs that are Shimano-compatible,
they don't list them on their web site.

And if you go with an LX, remember that the 580 is top-normal, so you'll
either need to remember that when shifting; or get an older LX or a
Deore (all three options seem OK to me).


I also don't know whether a ratio like a 28 or 26 small ring / 32 rear
cog is too low to be useful, but truth is I haven't loaded it up yet.

FWIW, My current low gear is 26F/24R and I really need something even
lower,

Good luck!

-Hank

Sheldon Brown wrote:
PatC wrote:

First question, how big can a 105 triple rear derailleur handle? Can it go
mountain-type cassettes like an 11-32? My guess is probably not.

Peter Chisholm replied:

Probably easily handle a 30t biggest cog. Anything bogger, need a MTB
rear der with a longer cage.

Right.

remember the longer cage is just for more
chain so a big-big combo won't break a chain.

That's not correct. No chain will break in big-big unless it is too
short. The longer cage is to prevent droop in small/smallish, when the
chain is properly sized for the sprockets installed.

C'mon Sheldon, we are saying the same thing. Use a too short cage on a
set up, eliminate chain droop in small-small, and shorten the chain so
the top pully doesn't hit the cog in the small ring/biggest cog, and it
will probably be too short for big-big. Add more chain and the oing
cage and everything is OK.

Yes a long cage setup can have a chain too short or too log but going
from a short cage double to a long cage triple, it's for the need for a
longer chain.


The reason the 105 won't work with bigger than a 30 isn't the cage
length (droop is pretty much harmless, and only occurs in gear
combinations that you shouldn't use anyway), but the height of the
jockey pulley. It is too high to clear a larger rear sprocket. The
jockey pulley will bump up against the big sprocket when you're in low
gear, causing unpleasant noise and vibration.

If you make the chain too short, it will work. I have put a 11-32 with
a DA 8s rear der/shifters and it was fine, as log as the chain was too
short.

Third question, I'm using DuraAce bar end shifters. If I use LX or XT
shifters (if I have to), is there a problem with compatibility?

Nothing barend from shimano except DA.

True for 9- and 10-speed, but not the answer to his PatC's question.

Kinda grouchy today ehhh Sheldon. No barend controls now being made
from shimano except DA, yes 9s and 10s. Are there 7 and 8s barends
somewhere 'outthere' yep but they haven't been made since about
1998....

There will be ZERO compatibility problems with 9-speed Shimano barcons
and ANY Shimano 9-speed system.

I also don't know whether a ratio like a 28 or 26 small ring / 32 rear cog
is too low to be useful, but truth is I haven't loaded it up yet.

If you're heavily loaded, not in a hurry, and have good balancing
skills, this can be useful in steep terrain.

Sheldon "Gears" Brown
+------------------------------------------+
| The lower your gear, the more of your |
| riding time will be spent going uphill. |
+------------------------------------------+
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

An 11-32 will work fine with a 105 triple; it's what I have on my bike
and is standard equipment on several cross bikes. I would suspect an
11-34 would just barely work but I think getting the chain length right
would be tricky and the jump across gears feels too large at times even
with an 11-32.

I combined it with an ISIS 48/38/28 Nashbar touring compact:
http://www.nashbar.com/profile.cfm?c...eid=&pagename=

The black anodized finish on the cranks has proved more durable than I
would have thought though I'd still prefer something polished.

I ended up using a Deore LX bottom pull front derailleur that I
already had up front. I tried a regular road derailleur (Centaur
triple) but even with the long stays of a touring bike I had to do a
fair amount of trimming to eliminate chain rub. No similar problem with
Deore. Regular road FD will work with bar ends or Campagnolo where you
can easily trim front derailleur position but I found it fussy.

Now that things are setup, I find the gearing excellent. However, the
drivetrain takes a beating riding in the rain. We've had a lot of bad
weather here in New England and my chain is very worn after only a few
months. The cassette even has bits of rust in places too and is pretty
ground up from dirt so get more than one when they are on sale if you
plan on riding in the rain much.

Justin