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Do front derailleurs inherently kinda suck?



 
 
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  #1  
Old September 17th 03, 06:05 PM
Mike Kozlowski
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Default Do front derailleurs inherently kinda suck?

A few weeks ago, I bought a bike (Diamondback Topanga Comp '04) for
the first time since the '80s. The most impressive improvement,
obviously, is the indexed shifting. It's deeply cool.

But: It seems to work much more smoothly on the rear than on the
front. Front gear shifts are slower, jerkier, and way more likely to
"miss" (i.e., not shift, and leave the chain rubbing up against the
side of the shifting mechanism; or shift, and leave the chain rubbing
up against the side).

Why is this? Is it because the front derailleur isn't as good as the
rear one (Deore vs. LX)? Is it because the front derailleur is a bit
out of alignment? Or is it just that front shifts are inherently more
awkward than rear ones?

--
Mike Kozlowski
http://www.klio.org/mlk/

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  #2  
Old September 17th 03, 06:14 PM
John Morgan
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Default Do front derailleurs inherently kinda suck?

But: It seems to work much more smoothly on the rear than on the
front.
Is it because the front derailleur isn't as good as the
rear one (Deore vs. LX)?


Yes.

Is it because the front derailleur is a bit
out of alignment?


Yes.

Or is it just that front shifts are inherently more
awkward than rear ones?


Yes.

-John Morgan
--
"I tried lube, careful prying, careful digging and even not so careful
digging. Little chunks of rubber." --Sad Bob


  #3  
Old September 17th 03, 06:37 PM
B. Sanders
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Default Do front derailleurs inherently kinda suck?

"Mike Kozlowski" wrote in message
...
A few weeks ago, I bought a bike (Diamondback Topanga Comp '04) for
the first time since the '80s. The most impressive improvement,
obviously, is the indexed shifting. It's deeply cool.

But: It seems to work much more smoothly on the rear than on the
front. Front gear shifts are slower, jerkier, and way more likely to
"miss" (i.e., not shift, and leave the chain rubbing up against the
side of the shifting mechanism; or shift, and leave the chain rubbing
up against the side).


Jerkiness is the hallmark of indexed front derailleurs. If you're not used
to it, you probably wonder what all the clunking is about. Sounds like
something must be wrong.

Why is this? Is it because the front derailleur isn't as good as the
rear one (Deore vs. LX)?


Deore front derailleurs are kinda flimsy, IMO; but that's probably not the
problem.

Is it because the front derailleur is a bit out of alignment?


There could be problems with alignment (angular), position (on the seat
tube), limit adjustment, or cable tension adjustment. Cable tension is the
most common mis-adjustment, followed by limit screw settings (two screws
that are used to adjust the inner and outer limits of travel for the front
derailleur).

Or is it just that front shifts are inherently more awkward than rear

ones?

Well, that's also part of it. It's often much harder to get front
derailleurs "dialed in" than rear derailleurs. Many riders prefer shifters
that allow the front derailleur to be "trimmed" (adjusted) while riding,
instead of the 3-position indexed shifting that most shifters have nowadays.

-=B=-



  #4  
Old September 17th 03, 07:24 PM
T_Blood
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Default Do front derailleurs inherently kinda suck?


"Mike Kozlowski" wrote in message
...
A few weeks ago, I bought a bike (Diamondback Topanga Comp '04) for
the first time since the '80s. The most impressive improvement,
obviously, is the indexed shifting. It's deeply cool.

But: It seems to work much more smoothly on the rear than on the
front. Front gear shifts are slower, jerkier, and way more likely to
"miss" (i.e., not shift, and leave the chain rubbing up against the
side of the shifting mechanism; or shift, and leave the chain rubbing
up against the side).

Why is this? Is it because the front derailleur isn't as good as the
rear one (Deore vs. LX)? Is it because the front derailleur is a bit
out of alignment? Or is it just that front shifts are inherently more
awkward than rear ones?


Here is my take on the front vs. rear derailer dilemma. First look at the
difference in clearance between front and rear cogs. The rear makes only a
little jump and the front a much bigger jump. Also, rear cassettes are
generally grooved and the "catching tooth" is angled to accept the shift,
providing a smoother almost unnoticeable shift. Then look at the engineering
feat of your rear derailer and then look at the piece of metal consisting of
your front derailer. In my opinion much more concentration and design was
put forth in designing rear derailers. They are where the bread and butter
is. I rarely shift my front, but the rear is in constant motion.


  #5  
Old September 17th 03, 07:53 PM
T_Blood
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Default Do front derailleurs inherently kinda suck?


" Here is my take on the front vs. rear derailer dilemma. First look at the
difference in clearance between front and rear cogs. The rear makes only a
little jump and the front a much bigger jump. Also, rear cassettes are
generally grooved and the "catching tooth" is angled to accept the shift,
providing a smoother almost unnoticeable shift. Then look at the

engineering
feat of your rear derailer and then look at the piece of metal consisting

of
your front derailer. In my opinion much more concentration and design was
put forth in designing rear derailers. They are where the bread and butter
is. I rarely shift my front, but the rear is in constant motion.



Or be like JD and say funk all that technical bull****!


  #6  
Old September 18th 03, 12:03 AM
Van Bagnol
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Default Do front derailleurs inherently kinda suck?

In article [email protected],
"John Morgan" wrote:

But: It seems to work much more smoothly on the rear than on the
front. Is it because the front derailleur isn't as good as the rear
one (Deore vs. LX)?


Yes.


Shifting the rear is far more frequent (and thus subject to wear) than
the front, so the rear derailleur is typically of higher grade
componentry.

Is it because the front derailleur is a bit out of alignment?


Yes.


Front shifts are jerkier than rear, but shifting shouldn't miss or cause
prolongued chain rub. It seems that your front mechanism needs adjusting.

Or is it just that front shifts are inherently more awkward than
rear ones?


Yes.


The front has the task of making 10- to 12-tooth gear changes to a chain
loaded with up to 800 pounds of tension. The rear has to make 1- to
3-tooth changes on the slack part of the chain. What do you think?

Van

--
Van Bagnol / v a n at wco dot com / c r l at bagnol dot com
....enjoys - Theatre / Windsurfing / Skydiving / Mountain Biking
....feels - "Parang lumalakad ako sa loob ng paniginip"
....thinks - "An Error is Not a Mistake ... Unless You Refuse to Correct It"
  #7  
Old September 18th 03, 01:38 AM
Alex Bird
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Default Do front derailleurs inherently kinda suck?

Mike Kozlowski wrote in message ...
Or is it just that front shifts are inherently more
awkward than rear ones?


Yes. The rear derailleur 'de-rails' the returning chain, which is
only under the tension provided by the derailleur spring. The front
de-rails the top of the chain, the part you are pulling at high
tension, AFAIK no front derailleurs are designed for shifting at full
steam, and will work much better if you relax your pedalling until
they're 'in'.
The larger difference between the chainwheels is another factor, and
using a set of parts designed to go together is probably a shortcut to
derailleur joy, but as I never have it's just another of those pipe
dreams ;0)
It's one of those things which may need adjustment as the bike
'settles', and is valuable knowledge anyway, get stuck in.

Alex
  #8  
Old September 18th 03, 02:32 AM
Bill Wheeler
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Default Do front derailleurs inherently kinda suck?

On Wed, 17 Sep 2003 17:05:36 +0000 (UTC), Mike Kozlowski
wrote:

A few weeks ago, I bought a bike (Diamondback Topanga Comp '04) for
the first time since the '80s. The most impressive improvement,
obviously, is the indexed shifting. It's deeply cool.

But: It seems to work much more smoothly on the rear than on the
front. Front gear shifts are slower, jerkier, and way more likely to
"miss" (i.e., not shift, and leave the chain rubbing up against the
side of the shifting mechanism; or shift, and leave the chain rubbing
up against the side).

Why is this?


Nature of the beast. Read, Adjust, Ride...repeat until problem solved.
Or simply get rid of the damn thing.


Peace,
Bill

  #9  
Old September 18th 03, 11:23 AM
Greg P.
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Default Do front derailleurs inherently kinda suck?

"Mike Kozlowski" wrote in message
...
| Why is this? Is it because the front derailleur isn't as good as the
| rear one (Deore vs. LX)? Is it because the front derailleur is a bit
| out of alignment? Or is it just that front shifts are inherently more
| awkward than rear ones?

I am a huge bike rider (all styles), but I am a novice (reading as much as I
can) when it comes to the technical, repair part of bikes. I've had the same
problem you have on two mid-high priced Specialized bikes. I had the dealer
adjust the front der about 8 times until I realized that it was actually
just the way it behaves. Quality and manufacturer are indeed points to
consider, but the front der was not meant (IMO) to be used that often, thus
the lack of consideration when designing them. If you have 8+ speeds in the
back, I suggest to just stay in your middle ring (in the front) and go about
them solely.


  #10  
Old September 18th 03, 02:03 PM
Mike Kozlowski
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Default Do front derailleurs inherently kinda suck?

In article ,
Van Bagnol wrote:

Front shifts are jerkier than rear, but shifting shouldn't miss or cause
prolongued chain rub. It seems that your front mechanism needs adjusting.


Well, if I undo the shift, and then redo it, it's usually fine, which
makes me think that I'm just shifting too tentatively or something.
(I don't know if that's even possible; indexed shifting still strikes
me as magical.)

The only time there's prolonged chain rub is if I have both the front
and the rear in the outermost gears... so I just don't do that.

The front has the task of making 10- to 12-tooth gear changes to a chain
loaded with up to 800 pounds of tension. The rear has to make 1- to
3-tooth changes on the slack part of the chain. What do you think?


Makes sense.

Good to know; thanks.

--
Mike Kozlowski
http://www.klio.org/mlk/

 




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