Old FD + New Shifters = Shifting Problems?
10-14-09, 12:03 PM
#1
Junior Member
Thread Starter
Join Date: Sep 2009
Posts: 17
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Old FD + New Shifters = Shifting Problems?
I'm sure this has been answered a dozen times on this forum but after a few searches I didn't come up with an answer for just this situation. Here's the low-down:
I recently bought a used 1994 Rockhopper and the left shifter was more or less shot. I just got in some new Shimano trigger shifters and put the left one on last night. I'm new to bike mechanics but everything has been going reasonably well so far and I even managed to get the front Canti brakes working better than before with the new levers and included cables. Here's the issue. I ran the FD cable and tightened it onto the FD and everything seems to move and function correctly but the indexing seems off. When I up shift, the FD moves enough to really rub the chain on the next chainring rather than fully shifting. Slight pressure on the up shift after it says "2" will push the chain perfectly onto the ring (same with the largest "3" ring). My question is, is there an adjustment for how far the cable pulls or perhaps is there some place on the frame that the wire is catching and preventing the complete shift? I figured the cable was properly tightened but perhaps its not quite tight enough? I started trying to straighten the FD thinking that may be the issue and have yet to find the "perfect" alignment of that either.
Any help would be greatly appreciated!
I recently bought a used 1994 Rockhopper and the left shifter was more or less shot. I just got in some new Shimano trigger shifters and put the left one on last night. I'm new to bike mechanics but everything has been going reasonably well so far and I even managed to get the front Canti brakes working better than before with the new levers and included cables. Here's the issue. I ran the FD cable and tightened it onto the FD and everything seems to move and function correctly but the indexing seems off. When I up shift, the FD moves enough to really rub the chain on the next chainring rather than fully shifting. Slight pressure on the up shift after it says "2" will push the chain perfectly onto the ring (same with the largest "3" ring). My question is, is there an adjustment for how far the cable pulls or perhaps is there some place on the frame that the wire is catching and preventing the complete shift? I figured the cable was properly tightened but perhaps its not quite tight enough? I started trying to straighten the FD thinking that may be the issue and have yet to find the "perfect" alignment of that either.
Any help would be greatly appreciated!
10-14-09, 12:23 PM
#2
Bianchi Goddess
Join Date: Apr 2009
Location: Shady Pines Retirement Fort Wayne, In
Posts: 27,858
Bikes: Too many to list here check my signature.
Mentioned: 192 Post(s)
Tagged: 2 Thread(s)
Quoted: 2930 Post(s)
Liked 2,923 Times
in
1,491 Posts
Hello. it is not likely the cable is catching on the frame. first check you limit screws. turn the cranks and pull down on the cable just to make sure the derailluer can freely move the chain both up and down. if it does and the cable is not too slack there should be an adjusting barrel on the shifter. give it a turn or two and this should solve your problem
__________________
“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
10-14-09, 12:29 PM
#3
Junior Member
Thread Starter
Join Date: Sep 2009
Posts: 17
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I did set the limit screws both high and low to make sure the chain wouldn't go flying off the chain ring. I'll look at the adjuster near the shifter, I tried turning it a little last night though it didn't seem to change anything at all. Perhaps I just wasn't turning it right or it wasn't sitting in the shifter correctly when I installed it. I'll post a picture tonight if I get a chance.
Also, how do I make sure my FD is in the right place? I think I read somewhere about the front part of the housing being a penny's width from the teeth on the largest chain ring?
Also, how do I make sure my FD is in the right place? I think I read somewhere about the front part of the housing being a penny's width from the teeth on the largest chain ring?
10-14-09, 12:33 PM
#4
Bianchi Goddess
Join Date: Apr 2009
Location: Shady Pines Retirement Fort Wayne, In
Posts: 27,858
Bikes: Too many to list here check my signature.
Mentioned: 192 Post(s)
Tagged: 2 Thread(s)
Quoted: 2930 Post(s)
Liked 2,923 Times
in
1,491 Posts
that sounds about right. are these type of shifters new to you? in my experience sometimes you need to push just a little past the click.
__________________
“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk
10-14-09, 12:36 PM
#5
Fresh Garbage
Bicycletutor.com can help on the last question if you think you'll learn more easily from a video.
10-14-09, 12:58 PM
#6
Junior Member
Thread Starter
Join Date: Sep 2009
Posts: 17
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
They are the same style of shifters on my new Trek 7.3FX so I've used them without problem on the Trek. Just can't seem to get the adjustment just right on the Rockhopper.
10-15-09, 01:38 AM
#7
Senior Member
Shimano did some changes around the mid ninties on their MTB front derailleurs when STI took over. This is an excellent tutorial on Trim from the late great Sheldon Brown. It might be of some use. Good luck.
Originally Posted by Sheldon Brown
Trimming
As you shift the rear from side to side, the angle of the chain changes where it approaches the front. Sometimes, this results in the need to "trim" the front derailer.
For example, you may start out in the lowest gear, with the chain on the innermost chainring and innermost rear sprocket, and everything is running smoothly. As you build up speed, you typically shift the rear derailer outward, toward the smaller sprockets for successively higher gears. At some point, this may cause the outside of the chain to rub against the outer plate of the front derailer's cage. This is noisy and will wear a groove in the derailer cage if you persist.
With traditional systems, you would deal with this issue by "trimming" the front derailer, that is, you would pull back very slightly on the front derailer's shfit lever, to nudge the cage a bit outward to eliminate the rubbing.
That works fine if your front derailer is operated by a friction shifter.
With the advent of indexed front shifters, such as Shimano's STI and RapidFire units, the possibility of trimming the front derailer is limited by the number and spacing of the indexing detents ("clicks.") Earlier indexed front shifters had little or no ability to trim, but most newer ones have extra detent positions to provide a limited trim capability.
In most cases, if you use the specific chainring sizes that the front derailer was designed for, and front derailer is adjusted very carefully, trimming won't be necessary if you follow good shifting practices.
If you customize your chainring sizes, you are more likely to have a problem with indexed shifters, so you might want to use bar-end shifters, GripShifts , or Campagnolo Ergo shifters. These are indexed on the rear, but not in front. The Ergos and GripShifts are not strictly "friction" shifters, as they do "click" when you shift them, but they have many "micro clicks" permitting considerable "fine tuning" of front derailer position. (GripShifts sold in the aftermarket use non-indexed fronts, but O.E.M. GripShifts sold with new bikes frequently are indexed.)
The need to trim is largely dependent no the chainstay length...the shorter the chainstays, the greater the need for trimming, because the chain angle is greater for a given amount of sideways movement in back. This is one of the areas where recumbents have a real advantage, as their very long chains result in minimal angle variation in different gears.
By contrast, the super short chainstays found on many racing-type frames often require trimming of the front derailer. (There's an unfortunate near-superstitious belief that short chainstays somehow make a bike "faster" or more maneuverable.)
As you shift the rear from side to side, the angle of the chain changes where it approaches the front. Sometimes, this results in the need to "trim" the front derailer.
For example, you may start out in the lowest gear, with the chain on the innermost chainring and innermost rear sprocket, and everything is running smoothly. As you build up speed, you typically shift the rear derailer outward, toward the smaller sprockets for successively higher gears. At some point, this may cause the outside of the chain to rub against the outer plate of the front derailer's cage. This is noisy and will wear a groove in the derailer cage if you persist.
With traditional systems, you would deal with this issue by "trimming" the front derailer, that is, you would pull back very slightly on the front derailer's shfit lever, to nudge the cage a bit outward to eliminate the rubbing.
That works fine if your front derailer is operated by a friction shifter.
With the advent of indexed front shifters, such as Shimano's STI and RapidFire units, the possibility of trimming the front derailer is limited by the number and spacing of the indexing detents ("clicks.") Earlier indexed front shifters had little or no ability to trim, but most newer ones have extra detent positions to provide a limited trim capability.
In most cases, if you use the specific chainring sizes that the front derailer was designed for, and front derailer is adjusted very carefully, trimming won't be necessary if you follow good shifting practices.
If you customize your chainring sizes, you are more likely to have a problem with indexed shifters, so you might want to use bar-end shifters, GripShifts , or Campagnolo Ergo shifters. These are indexed on the rear, but not in front. The Ergos and GripShifts are not strictly "friction" shifters, as they do "click" when you shift them, but they have many "micro clicks" permitting considerable "fine tuning" of front derailer position. (GripShifts sold in the aftermarket use non-indexed fronts, but O.E.M. GripShifts sold with new bikes frequently are indexed.)
The need to trim is largely dependent no the chainstay length...the shorter the chainstays, the greater the need for trimming, because the chain angle is greater for a given amount of sideways movement in back. This is one of the areas where recumbents have a real advantage, as their very long chains result in minimal angle variation in different gears.
By contrast, the super short chainstays found on many racing-type frames often require trimming of the front derailer. (There's an unfortunate near-superstitious belief that short chainstays somehow make a bike "faster" or more maneuverable.)
10-15-09, 09:43 AM
#8
headtube.
Join Date: Sep 2008
Posts: 803
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 3 Times
in
3 Posts
If you have 1994-era crankset, it probably doesn't have the ramps and pins you find on newer sets. A lot of the time upshifting the front needs a little overshift. You push the lever a little *past* the click until it catches, then release.
10-15-09, 10:08 AM
#9
Wrench - Racer - Fanatic
Join Date: Oct 2007
Location: Baltimore, Maryland, USA
Posts: 47
Bikes: 2007 Novara BigBuzz, 2001 Trek Y-1, 2007 Gary Fisher HiFi, 2006 Cannondale CAAD8, 1986 Peugeot Fixie Tourmalet PH10-LE, Kuwahara Road Tandem, Marinoni Corsa, Trek 810 Steel, 1998 Cannondale m300, Cannondale m600
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
as previously stated, fine-tune the barrel adjuster...
10-21-09, 12:33 PM
#10
Junior Member
Thread Starter
Join Date: Sep 2009
Posts: 17
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I got it working! Thanks everyone. I had to turn the barrel 2-3 revolutions to get it straightened out. I didn't even realize it could turn that far the first time I was messing with it. Thanks again.
