Derailleur PROBLEMS
03-12-15 | 01:26 PM
#1
Thread Starter
Junior Member
Joined: Oct 2012
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Derailleur PROBLEMS
Hi folks,
Today I swapped my 6-speed setup for a 7-speed(shifter, freewheel, derailleur, all Shimano except freewheel, DNP 11-30) and I'm having a hard time getting the mech to shift nicely.
I haven't installed many derailleurs but have gotten a couple on without difficulties.
The problem I'm having is this:
I've adjusted so that the shifting is smooth from the smallest sprocket and up to the largest. But when I try to shift the other way I have to release the tension screw a bit for the chain to drop from the largest to the second largest sprocket; otherwise it requires two downshifts for it to drop. If I release the tension and manage to shift, then I can't shift from the smallest sprocket and up again, and need to tighten the tension again(and I'm back where I started).
I'm pretty sure I did everything correctly at the start, setting the limit screws properly, correct tension on the wire, so on..
I hope I'm making sense, I'll try to explain better if I need to!
Simon
Today I swapped my 6-speed setup for a 7-speed(shifter, freewheel, derailleur, all Shimano except freewheel, DNP 11-30) and I'm having a hard time getting the mech to shift nicely.
I haven't installed many derailleurs but have gotten a couple on without difficulties.
The problem I'm having is this:
I've adjusted so that the shifting is smooth from the smallest sprocket and up to the largest. But when I try to shift the other way I have to release the tension screw a bit for the chain to drop from the largest to the second largest sprocket; otherwise it requires two downshifts for it to drop. If I release the tension and manage to shift, then I can't shift from the smallest sprocket and up again, and need to tighten the tension again(and I'm back where I started).
I'm pretty sure I did everything correctly at the start, setting the limit screws properly, correct tension on the wire, so on..
I hope I'm making sense, I'll try to explain better if I need to!
Simon
03-12-15 | 01:43 PM
#2
Senior Member
Joined: Nov 2014
Posts: 27,576
Likes: 5,452
From: Eugene, Oregon, USA
I assume you have some kind of indexed shifting.
I'm a little new to the indexed shifting... been using friction shifting for years. But, I've noticed a few things that seem to have a bit of a bearing.
The "B-Screw" adjustment more or less sets the distance of the derailleur from the cassette/freewheel cogs. You want this set as close as possible without it rubbing to minimized the flex in the chain between the jockey wheel and the cassette.
The Jockey Wheels also have a little of float in them. A little float may be good to help center the chain. Shimano still uses bushings on their upper jockey wheel, even with 11s, but now with a lot less float. Too much float, and the derailleur doesn't shift properly. On my "frankenbike", I ended up using one of those Chinese aluminum jockey wheels which helped a lot with shifting.
Perhaps a worn chain would also have more flex and negatively impact shifting.
The newer derailleurs also seem to have a lot stronger of a spring which may lead to more positive shifting.
Extra friction in your cables/housing could also negatively impact shifting.
I'm a little new to the indexed shifting... been using friction shifting for years. But, I've noticed a few things that seem to have a bit of a bearing.
The "B-Screw" adjustment more or less sets the distance of the derailleur from the cassette/freewheel cogs. You want this set as close as possible without it rubbing to minimized the flex in the chain between the jockey wheel and the cassette.
The Jockey Wheels also have a little of float in them. A little float may be good to help center the chain. Shimano still uses bushings on their upper jockey wheel, even with 11s, but now with a lot less float. Too much float, and the derailleur doesn't shift properly. On my "frankenbike", I ended up using one of those Chinese aluminum jockey wheels which helped a lot with shifting.
Perhaps a worn chain would also have more flex and negatively impact shifting.
The newer derailleurs also seem to have a lot stronger of a spring which may lead to more positive shifting.
Extra friction in your cables/housing could also negatively impact shifting.
03-12-15 | 01:47 PM
#3
Nigel
Joined: Mar 2011
Posts: 2,991
Likes: 7
From: San Jose, CA
Bikes: 1980s and 1990s steel: CyclePro, Nishiki, Schwinn, SR, Trek........
1st check your RD hanger alignment. If that is good continue. If not good, the drivetrain will never work well.
Set the derailleur in the middle cog (of seven that is easy, on a even number you have to chose one side or the other as there is no middle cog). Adjust the cable so that it runs the quietest on the middle cog. That should do it, unless there are spacing issues on the freewheel (been there with a Shimano 14-28 7 speed), or a kinked cable.
Set the derailleur in the middle cog (of seven that is easy, on a even number you have to chose one side or the other as there is no middle cog). Adjust the cable so that it runs the quietest on the middle cog. That should do it, unless there are spacing issues on the freewheel (been there with a Shimano 14-28 7 speed), or a kinked cable.
03-12-15 | 01:50 PM
#4
Senior Member
Joined: Apr 2009
Posts: 39,897
Likes: 3,865
From: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
A few possibilities come to mind.
The first is that the chain and freewheel aren't ideally matched for clean shifting. Index shifting requires good matching because down shifting counts on the chain's outer plate snagging a tooth and beginning to climb up without much overshifting. By the same token, upshifting requires the chain to release and drop without overshifting in that direction.
So there's a possibility that your specific combination of chain and freewheel is working against you a bit. OTOH, they often settle in and shift better after some miles.
Before spending dough here are a few other, easier to play with things to try.
1- B-screw adjustment. The closer to the sporcket the jockey wheel is, the crisper the shifting, until you get to close and shifting tends to jam. Try bringing the RD closer via the B-screw (take weight off the screw by pulling the RD back) while you adjust it). Get it as close as possible without coming closer than 5mm or so on the larger sprockets. If this helps a bit, go closer,but never so close that the pulley, chain and sprocket all touch.
2- cable friction. This only affects upshifts, but often people need to bias outward to compensate then have poor downshifts. You can test whether cable friction is an issue, by adjusting the trim based on good down shifts, then upshifting one click, and if/when the RD hangs, plucking the wire like a guitar string. If plucking completes the shift, cable friction is the issue to be corrected.
3- floating upper pulley. Most (all?) Shimano RDs have a floating upper pulley, that can move side to side a few millimeters. This makes trimming easier because the float allows the pulley to center itself. OTOH that loat absorbs travel when you shift and can cause sluggish shifting. Try switching then upper and lower pulleys and see if that improves the shifting. If so. you might find trim a bit difficult to maintain and have a noisier drivetrain. Whau I sometimes do, is use an O-ring, or DIY spacer on the upper pulley bolt to reduce but not eliminate the float. This is a tials and error process looking for the best balance between crisp shifting and forgiving trim.
So, you now have some things to try, none of which cost anything but time. If these don't resolve the issue, adjust as best you can (I prefer an outward v=bias, bcause I can easily shift beyond the click a half space and let the lever settle back after shifting). Then cross your fingers hoping that some break in solves everything.
The first is that the chain and freewheel aren't ideally matched for clean shifting. Index shifting requires good matching because down shifting counts on the chain's outer plate snagging a tooth and beginning to climb up without much overshifting. By the same token, upshifting requires the chain to release and drop without overshifting in that direction.
So there's a possibility that your specific combination of chain and freewheel is working against you a bit. OTOH, they often settle in and shift better after some miles.
Before spending dough here are a few other, easier to play with things to try.
1- B-screw adjustment. The closer to the sporcket the jockey wheel is, the crisper the shifting, until you get to close and shifting tends to jam. Try bringing the RD closer via the B-screw (take weight off the screw by pulling the RD back) while you adjust it). Get it as close as possible without coming closer than 5mm or so on the larger sprockets. If this helps a bit, go closer,but never so close that the pulley, chain and sprocket all touch.
2- cable friction. This only affects upshifts, but often people need to bias outward to compensate then have poor downshifts. You can test whether cable friction is an issue, by adjusting the trim based on good down shifts, then upshifting one click, and if/when the RD hangs, plucking the wire like a guitar string. If plucking completes the shift, cable friction is the issue to be corrected.
3- floating upper pulley. Most (all?) Shimano RDs have a floating upper pulley, that can move side to side a few millimeters. This makes trimming easier because the float allows the pulley to center itself. OTOH that loat absorbs travel when you shift and can cause sluggish shifting. Try switching then upper and lower pulleys and see if that improves the shifting. If so. you might find trim a bit difficult to maintain and have a noisier drivetrain. Whau I sometimes do, is use an O-ring, or DIY spacer on the upper pulley bolt to reduce but not eliminate the float. This is a tials and error process looking for the best balance between crisp shifting and forgiving trim.
So, you now have some things to try, none of which cost anything but time. If these don't resolve the issue, adjust as best you can (I prefer an outward v=bias, bcause I can easily shift beyond the click a half space and let the lever settle back after shifting). Then cross your fingers hoping that some break in solves everything.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
03-12-15 | 01:52 PM
#6
Thread Starter
Junior Member
Joined: Oct 2012
Posts: 11
Likes: 0
I assume you have some kind of indexed shifting.
I'm a little new to the indexed shifting... been using friction shifting for years. But, I've noticed a few things that seem to have a bit of a bearing.
The "B-Screw" adjustment more or less sets the distance of the derailleur from the cassette/freewheel cogs. You want this set as close as possible without it rubbing to minimized the flex in the chain between the jockey wheel and the cassette.
The Jockey Wheels also have a little of float in them. A little float may be good to help center the chain. Shimano still uses bushings on their upper jockey wheel, even with 11s, but now with a lot less float. Too much float, and the derailleur doesn't shift properly. On my "frankenbike", I ended up using one of those Chinese aluminum jockey wheels which helped a lot with shifting.
Perhaps a worn chain would also have more flex and negatively impact shifting.
The newer derailleurs also seem to have a lot stronger of a spring which may lead to more positive shifting.
Extra friction in your cables/housing could also negatively impact shifting.
I'm a little new to the indexed shifting... been using friction shifting for years. But, I've noticed a few things that seem to have a bit of a bearing.
The "B-Screw" adjustment more or less sets the distance of the derailleur from the cassette/freewheel cogs. You want this set as close as possible without it rubbing to minimized the flex in the chain between the jockey wheel and the cassette.
The Jockey Wheels also have a little of float in them. A little float may be good to help center the chain. Shimano still uses bushings on their upper jockey wheel, even with 11s, but now with a lot less float. Too much float, and the derailleur doesn't shift properly. On my "frankenbike", I ended up using one of those Chinese aluminum jockey wheels which helped a lot with shifting.
Perhaps a worn chain would also have more flex and negatively impact shifting.
The newer derailleurs also seem to have a lot stronger of a spring which may lead to more positive shifting.
Extra friction in your cables/housing could also negatively impact shifting.
03-12-15 | 01:53 PM
#7
Thread Starter
Junior Member
Joined: Oct 2012
Posts: 11
Likes: 0
1st check your RD hanger alignment. If that is good continue. If not good, the drivetrain will never work well.
Set the derailleur in the middle cog (of seven that is easy, on a even number you have to chose one side or the other as there is no middle cog). Adjust the cable so that it runs the quietest on the middle cog. That should do it, unless there are spacing issues on the freewheel (been there with a Shimano 14-28 7 speed), or a kinked cable.
Set the derailleur in the middle cog (of seven that is easy, on a even number you have to chose one side or the other as there is no middle cog). Adjust the cable so that it runs the quietest on the middle cog. That should do it, unless there are spacing issues on the freewheel (been there with a Shimano 14-28 7 speed), or a kinked cable.
03-12-15 | 01:58 PM
#8
Thread Starter
Junior Member
Joined: Oct 2012
Posts: 11
Likes: 0
A few possibilities come to mind.
The first is that the chain and freewheel aren't ideally matched for clean shifting. Index shifting requires good matching because down shifting counts on the chain's outer plate snagging a tooth and beginning to climb up without much overshifting. By the same token, upshifting requires the chain to release and drop without overshifting in that direction.
So there's a possibility that your specific combination of chain and freewheel is working against you a bit. OTOH, they often settle in and shift better after some miles.
Before spending dough here are a few other, easier to play with things to try.
1- B-screw adjustment. The closer to the sporcket the jockey wheel is, the crisper the shifting, until you get to close and shifting tends to jam. Try bringing the RD closer via the B-screw (take weight off the screw by pulling the RD back) while you adjust it). Get it as close as possible without coming closer than 5mm or so on the larger sprockets. If this helps a bit, go closer,but never so close that the pulley, chain and sprocket all touch.
2- cable friction. This only affects upshifts, but often people need to bias outward to compensate then have poor downshifts. You can test whether cable friction is an issue, by adjusting the trim based on good down shifts, then upshifting one click, and if/when the RD hangs, plucking the wire like a guitar string. If plucking completes the shift, cable friction is the issue to be corrected.
3- floating upper pulley. Most (all?) Shimano RDs have a floating upper pulley, that can move side to side a few millimeters. This makes trimming easier because the float allows the pulley to center itself. OTOH that loat absorbs travel when you shift and can cause sluggish shifting. Try switching then upper and lower pulleys and see if that improves the shifting. If so. you might find trim a bit difficult to maintain and have a noisier drivetrain. Whau I sometimes do, is use an O-ring, or DIY spacer on the upper pulley bolt to reduce but not eliminate the float. This is a tials and error process looking for the best balance between crisp shifting and forgiving trim.
So, you now have some things to try, none of which cost anything but time. If these don't resolve the issue, adjust as best you can (I prefer an outward v=bias, bcause I can easily shift beyond the click a half space and let the lever settle back after shifting). Then cross your fingers hoping that some break in solves everything.
The first is that the chain and freewheel aren't ideally matched for clean shifting. Index shifting requires good matching because down shifting counts on the chain's outer plate snagging a tooth and beginning to climb up without much overshifting. By the same token, upshifting requires the chain to release and drop without overshifting in that direction.
So there's a possibility that your specific combination of chain and freewheel is working against you a bit. OTOH, they often settle in and shift better after some miles.
Before spending dough here are a few other, easier to play with things to try.
1- B-screw adjustment. The closer to the sporcket the jockey wheel is, the crisper the shifting, until you get to close and shifting tends to jam. Try bringing the RD closer via the B-screw (take weight off the screw by pulling the RD back) while you adjust it). Get it as close as possible without coming closer than 5mm or so on the larger sprockets. If this helps a bit, go closer,but never so close that the pulley, chain and sprocket all touch.
2- cable friction. This only affects upshifts, but often people need to bias outward to compensate then have poor downshifts. You can test whether cable friction is an issue, by adjusting the trim based on good down shifts, then upshifting one click, and if/when the RD hangs, plucking the wire like a guitar string. If plucking completes the shift, cable friction is the issue to be corrected.
3- floating upper pulley. Most (all?) Shimano RDs have a floating upper pulley, that can move side to side a few millimeters. This makes trimming easier because the float allows the pulley to center itself. OTOH that loat absorbs travel when you shift and can cause sluggish shifting. Try switching then upper and lower pulleys and see if that improves the shifting. If so. you might find trim a bit difficult to maintain and have a noisier drivetrain. Whau I sometimes do, is use an O-ring, or DIY spacer on the upper pulley bolt to reduce but not eliminate the float. This is a tials and error process looking for the best balance between crisp shifting and forgiving trim.
So, you now have some things to try, none of which cost anything but time. If these don't resolve the issue, adjust as best you can (I prefer an outward v=bias, bcause I can easily shift beyond the click a half space and let the lever settle back after shifting). Then cross your fingers hoping that some break in solves everything.
Cheers, I'll come back when I've had a go
Simon
03-12-15 | 02:03 PM
#9
Steel is real
Joined: Dec 2014
Posts: 772
Likes: 17
From: Australia
Bikes: Custom - Record Vortex 8 spd Nexus & Mistral Le Mans 3 spd Shimano. Giant Kronos. Raliegh Single Speed
i just finished doing one
at first i was baffled, the rear wheel that came with the bike had a 7 cog freewheel didnt realize that it wasnt original. the bike has a 6spd shifter
same wheels as the front ..hub colour.. and all. sometimes the universe screws with me
anyway, gave it another wheel with a 6 spd freewheel
and what i found in the end was..the limit screws has to be set spot on to be able to get good adjustments on the middle cogs
as for the high limit screw - while the cable is disconnected... set it so it drops to the fifth gear, which was in my case [second smallest cog]. and while turning the crank adjust the limit screw so the chain just drops on the smallest cog, if there are any noises, only very small adjustments if needed
i think i jagged it with the low limit screw, i adjusted the largest cog by eye, but the same procedure could apply
i think it is very important the limit screws are adjusted correctly so you can get perfect adjustment for the middle cogs
it didnt take me long to finish tuning the derailluer after that. she changes gears sweet
at first i was baffled, the rear wheel that came with the bike had a 7 cog freewheel didnt realize that it wasnt original. the bike has a 6spd shifter
same wheels as the front ..hub colour.. and all. sometimes the universe screws with me
anyway, gave it another wheel with a 6 spd freewheel
and what i found in the end was..the limit screws has to be set spot on to be able to get good adjustments on the middle cogs
as for the high limit screw - while the cable is disconnected... set it so it drops to the fifth gear, which was in my case [second smallest cog]. and while turning the crank adjust the limit screw so the chain just drops on the smallest cog, if there are any noises, only very small adjustments if needed
i think i jagged it with the low limit screw, i adjusted the largest cog by eye, but the same procedure could apply
i think it is very important the limit screws are adjusted correctly so you can get perfect adjustment for the middle cogs
it didnt take me long to finish tuning the derailluer after that. she changes gears sweet
03-12-15 | 03:17 PM
#10
Thread Starter
Junior Member
Joined: Oct 2012
Posts: 11
Likes: 0
I tried all sorts of thing you guys mentioned but still the same dilemma. Checked for cable friction, but that wasn't it, tried the middle sprocket adjustment, that didn't do it. Checked the hanger, seems straight(and the bike is new-ish). Also I find it hard to see any difference after playing with the B-screw, but I got it kind of close after a while. What I can see when I try to shift down is that the amount the RD moves from the largest to the second largest is about 1/2 or 1/3 as much as the rest of the jumps, so it's no surprise it doesn't drop. What could that be caused by?
03-12-15 | 03:28 PM
#11
Senior Member
Joined: Mar 2008
Posts: 2,646
Likes: 2
From: Salinas , Ca.
Bikes: Bike Nashbar AL-1 ,Raligh M50 , Schwinn Traveler , and others
I tried all sorts of thing you guys mentioned but still the same dilemma. Checked for cable friction, but that wasn't it, tried the middle sprocket adjustment, that didn't do it. Checked the hanger, seems straight(and the bike is new-ish). Also I find it hard to see any difference after playing with the B-screw, but I got it kind of close after a while. What I can see when I try to shift down is that the amount the RD moves from the largest to the second largest is about 1/2 or 1/3 as much as the rest of the jumps, so it's no surprise it doesn't drop. What could that be caused by?
03-12-15 | 03:38 PM
#12
Fatty McFatcakes
Joined: Nov 2013
Posts: 986
Likes: 3
From: Krispy Kreme
Bikes: Aero Cheeseburger w/ Sr(h)am eBacon
From your description, your derailleur is not upshifting properly. I know, it seems counterintuitive, but it's correct.
A possible solution:
First, make sure that the high & low screws are set to position the jockey wheels in their proper place directly under the biggest cog and smallest cog respectively.
Next, give the barrel adjuster at the end of the derailleur a turn or two in the direction away from the bike (clockwise). Retry the upshifts.
Rinse and repeat until it upshifts and downshifts correctly. A balance must be struck.
Adjust the B screw tensioner to add shifting crispness
More detail here.
Last edited by velociraptor; 03-12-15 at 03:41 PM.
03-12-15 | 04:02 PM
#13
Steel is real
Joined: Dec 2014
Posts: 772
Likes: 17
From: Australia
Bikes: Custom - Record Vortex 8 spd Nexus & Mistral Le Mans 3 spd Shimano. Giant Kronos. Raliegh Single Speed
Actually you are not shifting down. Downshifting would be going from a smaller cog to a bigger one.
From your description, your derailleur is not upshifting properly. I know, it seems counterintuitive, but it's correct.
A possible solution:
First, make sure that the high & low screws are set to position the jockey wheels in their proper place directly under the biggest cog and smallest cog respectively.
Next, give the barrel adjuster at the end of the derailleur a turn or two in the direction away from the bike (clockwise). Retry the upshifts.
Rinse and repeat until it upshifts and downshifts correctly. A balance must be struck.
Adjust the B screw tensioner to add shifting crispness
More detail here.
From your description, your derailleur is not upshifting properly. I know, it seems counterintuitive, but it's correct.
A possible solution:
First, make sure that the high & low screws are set to position the jockey wheels in their proper place directly under the biggest cog and smallest cog respectively.
Next, give the barrel adjuster at the end of the derailleur a turn or two in the direction away from the bike (clockwise). Retry the upshifts.
Rinse and repeat until it upshifts and downshifts correctly. A balance must be struck.
Adjust the B screw tensioner to add shifting crispness
More detail here.
yeah, i have the barrel adjuster screw about half way out, then tighten down the cable while the chain and shifter is in low gear. edit: HIGH gear {always get that mixed up**
so i can tighten or loosen the cable if needed
03-12-15 | 04:07 PM
#14
Fatty McFatcakes
Joined: Nov 2013
Posts: 986
Likes: 3
From: Krispy Kreme
Bikes: Aero Cheeseburger w/ Sr(h)am eBacon
LOL, I was just about to reply as you edited your post say high instead of low.
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