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please explain "trim" feature on front derailer



 
 
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  #1  
Old September 17th 03, 02:49 AM
mark watkins
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Default please explain "trim" feature on front derailer

I keep reading about the "trimming ability" benefit of Tiagra and
above front derailers. Could someone explain to me in detail what this
trim ability is, and if it is something that I will be using on my new
2004 Cannondale R600 Triple?
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  #2  
Old September 17th 03, 03:26 AM
David L. Johnson
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Default please explain "trim" feature on front derailer

On Tue, 16 Sep 2003 18:49:19 +0000, mark watkins wrote:

I keep reading about the "trimming ability" benefit of Tiagra and above
front derailers. Could someone explain to me in detail what this trim
ability is, and if it is something that I will be using on my new 2004
Cannondale R600 Triple?


In the old days, once we shifted from one sprocket to another, we would
slightly move (trim) the front derailleur lever so the cage would not rub
on the chain. When Shimano indexed front shifting, you got one position,
and if it rubbed on some rear choices, too bad. Campy came out with a
not-really-indexed front shifter, that allowed you to move the front cage
pretty much like the old days, except that there were clicks involved.
Shimano has now improved its front shifters to essentially allow the same
thing -- an improvement that went back to the way things were 30 years
ago.

--

David L. Johnson

__o | "What am I on? I'm on my bike, six hours a day, busting my ass.
_`\(,_ | What are you on?" --Lance Armstrong
(_)/ (_) |


  #3  
Old September 17th 03, 05:21 AM
Jeff Sutton
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Default please explain "trim" feature on front derailer

I recently bought a new bike with a Shimano Tiagra front derailleur and am
still confused about how the "trim" feature works. Sometimes it appears to
be active, other times not. Appears to work only on the large chainring, and
not in all gears. Can anyone explain how more precisely this is supposed to
work?

It is a nice feature.

"mark watkins" wrote in message
m...
I keep reading about the "trimming ability" benefit of Tiagra and
above front derailers. Could someone explain to me in detail what this
trim ability is, and if it is something that I will be using on my new
2004 Cannondale R600 Triple?



  #4  
Old September 17th 03, 06:59 AM
Mike Jacoubowsky
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Default please explain "trim" feature on front derailer

I keep reading about the "trimming ability" benefit of Tiagra and
above front derailers. Could someone explain to me in detail what this
trim ability is, and if it is something that I will be using on my new
2004 Cannondale R600 Triple?


Grrrr. Makes me angry! No, not because you bought the R600 instead of the
TREK 1500, but because the dealer didn't go over this with you. Happens
once in a while at my own shop as well, despite how often I explain to staff
that they have to assume the "trim" function is something the customer may
not know about.

The "trim" function on nearly all Shimano triple road groups (with the
exception of DuraAce and Sora) works the same way. On the smallest and
middle front chainring positions, you can move the front shift lever
slightly so that it's centered over the chain, eliminating chain rub on the
derailleur. This is really something that should be demonstrated to you, in
person, and if you come across a staff member who's confused by it, by all
means seek out someone else at the shop. Mountain bikes don't have this
feature, and somebody who's totally into mtn biking and nothing else may not
even be aware it's there.

OK, since they didn't explain the "trim" function, here are a few other
tidbits to keep in mind-

#1: Full rated tire pressure at all times (unless you weigh 120 pounds and
ride on roads as smooth as glass). If the tires are rated at 120psi, don't
ride them at 105. At full pressure, you'll get fewer flats and a more
efficient ride. If you want a smoother ride, switch to the next-wider tire.

#2: Make sure you understand how the quick-release wheels work. You
probably already know, but in case you don't, quick-releases are
cam-operated devices that lock in place by flipping the lever open, *not* by
screwing them on. It's the shop's responsibility to make sure the customer
knows this; often times they don't, because they think everybody knows this
and that they'll make it look like they think the customer's an idiot by
showing it.

#3: Keep the seat level, not nose-down. If, to get comfortable on the
saddle, you require a nose-down position, you need to either switch saddles
or look at your fit (quite possibly you're too stretched out, especially if
the bike still has the stock stem on it). The problem with riding with the
nose down is that you're being shoved towards the bars while riding, and
you're actually pushing back with your arms the entire time, trying to
maintain position on the seat. This causes pain in the neck & shoulders.

I think that's about it for now; get back to us if you've got any more
questions. But first get back to the shop (or some knowledgeable friends)
for a demonstration, not just an explanation, of how the "trim" function
works!

--Mike-- Chain Reaction Bicycles
http://www.ChainReactionBicycles.com


"mark watkins" wrote in message
m...
I keep reading about the "trimming ability" benefit of Tiagra and
above front derailers. Could someone explain to me in detail what this
trim ability is, and if it is something that I will be using on my new
2004 Cannondale R600 Triple?



  #5  
Old September 17th 03, 12:12 PM
Gary Mishler
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Default please explain "trim" feature on front derailer


"Mike Jacoubowsky" wrote in message
...

The "trim" function on nearly all Shimano triple road groups (with the

exception of DuraAce and Sora) works the same way.

What about on the DuraAce? I have a DA triple fdr and I *think* I have a
working trim??? Either that, or something needs adjusting possibly.

Why would not there be a trim on DA, but there is on others?

Thanks,
Mish


  #7  
Old September 17th 03, 12:55 PM
David Kerber
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Posts: n/a
Default please explain "trim" feature on front derailer

In article ,
says...
I keep reading about the "trimming ability" benefit of Tiagra and
above front derailers. Could someone explain to me in detail what this
trim ability is, and if it is something that I will be using on my new
2004 Cannondale R600 Triple?


Grrrr. Makes me angry! No, not because you bought the R600 instead of the
TREK 1500, but because the dealer didn't go over this with you. Happens
once in a while at my own shop as well, despite how often I explain to staff
that they have to assume the "trim" function is something the customer may
not know about.

The "trim" function on nearly all Shimano triple road groups (with the
exception of DuraAce and Sora) works the same way. On the smallest and
middle front chainring positions, you can move the front shift lever
slightly so that it's centered over the chain, eliminating chain rub on the
derailleur. This is really something that should be demonstrated to you, in
person, and if you come across a staff member who's confused by it, by all
means seek out someone else at the shop. Mountain bikes don't have this
feature, and somebody who's totally into mtn biking and nothing else may not
even be aware it's there.

OK, since they didn't explain the "trim" function, here are a few other
tidbits to keep in mind-

#1: Full rated tire pressure at all times (unless you weigh 120 pounds and
ride on roads as smooth as glass). If the tires are rated at 120psi, don't
ride them at 105. At full pressure, you'll get fewer flats and a more
efficient ride. If you want a smoother ride, switch to the next-wider tire.


What about my Conti's which have both "Recommended" pressures (95psi)
and max (120 psi) pressures? I run them at 115 for everyday riding
and really like the way they feel (I weigh 185).

.....

--
Dave Kerber
Fight spam: remove the ns_ from the return address before replying!

REAL programmers write self-modifying code.
  #9  
Old September 17th 03, 01:29 PM
Rick Onanian
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Default please explain "trim" feature on front derailer

On Wed, 17 Sep 2003 05:59:07 GMT, Mike Jacoubowsky
wrote:
The "trim" function on nearly all Shimano triple road groups (with the


On my double 105, too.

#2: Make sure you understand how the quick-release wheels work. You


Also, note how to operate the QR for the brakes.
Nobody showed me when I bought my road bike, and it
took me a minute or two to realize it was there when
I first struggled with a tire.

--Mike-- Chain Reaction Bicycles
http://www.ChainReactionBicycles.com

--
Rick Onanian
  #10  
Old September 17th 03, 04:41 PM
Matt O'Toole
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Default please explain "trim" feature on front derailer


"Mike Jacoubowsky" wrote in message
...

The "trim" function on nearly all Shimano triple road groups (with the
exception of DuraAce and Sora) works the same way. On the smallest and
middle front chainring positions, you can move the front shift lever
slightly so that it's centered over the chain, eliminating chain rub on the
derailleur. This is really something that should be demonstrated to you, in
person, and if you come across a staff member who's confused by it, by all
means seek out someone else at the shop. Mountain bikes don't have this
feature, and somebody who's totally into mtn biking and nothing else may not
even be aware it's there.


Mountain bikes used to have this feature, with 7sp XT Rapidfire Plus shifters.
I was dismayed when it was discontinued with the 8sp drivetrains. But these
drivetrains can usually be set up so trimming isn't necessary -- as long as you
use all the parts that were designed to work together. Road bikes often have
shorter chainstays, which makes this more difficult.

Of course, Campy Ergo is infinitely trimmable...

Matt O.




 




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