Shifter/rear derailleur issue
#1
Junior Member
Thread Starter
Join Date: Oct 2019
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Shifter/rear derailleur issue
My son has a well used diamondback cobra 20 bike. He's having a problem whereby he can only shift from 6 down to 5 and back, but can not shift down to any of the other gears (like the grip was stuck). I have tried adjusting the tension on the cable. I can get to a point where the shifter will shift freely, but it seems that there is not enough tension on the cable at that point to move the derailleur. When I tighten it up again, I am once again in the same boat of not being able to shift through all the gears. Does anyone have any advice on how I might remedy this? This is a 6 gear bike with just a rear derailleur. Let me know what other information may be useful.
#2
Droid on a mission
Join Date: May 2018
Location: Palm Coast, FL
Posts: 1,005
Bikes: Diamondback Wildwood Classic
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 317 Post(s)
Liked 280 Times
in
195 Posts
Does the cable move freely through all control points if you release it from the DER. If it does then check the limit screws for proper alignment. If not then possibly a new cable and/or housing is in order.
This Parktool video should give you some help
https://www.parktool.com/blog/repair...roubleshooting
This Parktool video should give you some help
https://www.parktool.com/blog/repair...roubleshooting
__________________
JoeTBM (The Bike Man) - I'm a black & white type of guy, the only gray in my life is the hair on my head
www.TheBikeMenOfFlaglerCounty.com
JoeTBM (The Bike Man) - I'm a black & white type of guy, the only gray in my life is the hair on my head
www.TheBikeMenOfFlaglerCounty.com
#3
Senior Member
Join Date: Sep 2010
Location: Roswell, GA
Posts: 8,319
Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1438 Post(s)
Liked 1,092 Times
in
723 Posts
Which gear are you calling 6, big cog or small? My suspicion is that the cable is frayed inside the shifter, or it may be time for a cable and housing replacement.. I would shift to the small cog, detach the cable from the derailleur, check the cable for fraying along its entire length and check the shifter/cable system for free movement. Then check the derailleur for free movement by pushing it by hand while turning the crank; watch your fingers. If all checks out OK, set the system up by following this procedure: https://www.parktool.com/blog/repair...eur-adjustment
#4
Senior Member
Join Date: Jun 2014
Location: Ontario, Canada
Posts: 4,624
Bikes: iele Latina, Miele Suprema, Miele Uno LS, Miele Miele Beta, MMTB, Bianchi Model Unknown, Fiori Venezia, Fiori Napoli, VeloSport Adamas AX
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 1324 Post(s)
Liked 927 Times
in
640 Posts
Is t he derailleur hanger bent?
Cheers
Cheers
#6
Senior Member
Join Date: Feb 2012
Location: Golden, CO and Tucson, AZ
Posts: 2,836
Bikes: 2016 Fuji Tread, 1983 Trek 520
Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 675 Post(s)
Liked 741 Times
in
430 Posts
If it was working before and suddenly stopped working, the problem could be failed cable housing, broken shifter, or badly bent hanger.
You can easily disconnect the three major components from each other and test them individually. Does the shifter click five times each direction? Does the cable move freely through each piece of cable housing? Can you manually push the derailleur through all its gears (while pedaling in a stand or upside down on the ground) without hitting spokes?
You can easily disconnect the three major components from each other and test them individually. Does the shifter click five times each direction? Does the cable move freely through each piece of cable housing? Can you manually push the derailleur through all its gears (while pedaling in a stand or upside down on the ground) without hitting spokes?
#7
Junior Member
Thread Starter
Join Date: Oct 2019
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Thanks for all of your responses. I'll tell you what I know so far.
The cable does seem to move freely along with shifter, if I unhook the cable from the derailleur. I can see the cable getting shorter as I shift from 6...5...4...etc...
I need to read up on how the limit screws work to check those.
I have a new shifter and cable. Even with these, I am seeing the same problem that I saw with the old shifter and cable.
I am calling the small cog gear 6. That's where the chain is currently positioned.
I can flip the bike over and push the derailleur in by hand to get the chain to go on each of the cogs as i move the pedals.
I just checked the hanger and it looks properly aligned to me.
The cable does seem to move freely along with shifter, if I unhook the cable from the derailleur. I can see the cable getting shorter as I shift from 6...5...4...etc...
I need to read up on how the limit screws work to check those.
I have a new shifter and cable. Even with these, I am seeing the same problem that I saw with the old shifter and cable.
I am calling the small cog gear 6. That's where the chain is currently positioned.
I can flip the bike over and push the derailleur in by hand to get the chain to go on each of the cogs as i move the pedals.
I just checked the hanger and it looks properly aligned to me.
#8
Junior Member
Thread Starter
Join Date: Oct 2019
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I watched a video on the limit screws and those are in a good spot now. I did a very slight adjustment, so the alignment on the small cog and the large cog look good when adjusting the derailleur by hand.
It is working a little bit better now, but still problematic. i can shift all the way up into 2nd gear now. however, the derailleur doesnt move at all when i go to 5 and only a little when i go to 4. when i go to 3, the chain moves to the next cog. it takes a lot of pressure to get into 2nd gear, and i cant get shifted into 1st at all while attached to the derailleur currently.
It is working a little bit better now, but still problematic. i can shift all the way up into 2nd gear now. however, the derailleur doesnt move at all when i go to 5 and only a little when i go to 4. when i go to 3, the chain moves to the next cog. it takes a lot of pressure to get into 2nd gear, and i cant get shifted into 1st at all while attached to the derailleur currently.
#9
Senior Member
Join Date: Jun 2019
Posts: 580
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 254 Post(s)
Likes: 0
Liked 182 Times
in
141 Posts
One possibility (among many) is that the cable is not attached to the derailleur correctly so you don’t have good leverage and also the derailleur doesn’t move as much as it’s supposed to with each click. Can you take a picture of how the cable is attached to the derailleur?
#10
Junior Member
Thread Starter
Join Date: Oct 2019
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I tried to post the image, but this forum will not let me post an image or a URL, so you've gotta love that. Hopefully words will be helpful enough. I ran the cable straight across. If there is any bending needed at the nut, then that could be my problem.
#11
Half way there
Join Date: Sep 2015
Location: North Carolina
Posts: 2,956
Bikes: Many, and the list changes frequently
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 986 Post(s)
Liked 880 Times
in
527 Posts
Long shot: Check all of your cable housing, especially where it goes through a cable stop. It may be that under tension, the housing is pulling through the hole in the stop. New housing with proper ferrules should fix that.
#12
Junior Member
Thread Starter
Join Date: Oct 2019
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I found a hi res pic of one of these bikes online and the cable routing matches mine, so i think i can rule out incorrect cable routing.
Since a couple of people have mentioned cable housing, I will likely look at that next. I have one of the sections, as it came with my shifter. The other section is perhaps a custom size, as it does not match the size of the second housing that came with my shifter. Do housings come in standard lengths or do you generally need to get those from the bike manufacturer?
Since a couple of people have mentioned cable housing, I will likely look at that next. I have one of the sections, as it came with my shifter. The other section is perhaps a custom size, as it does not match the size of the second housing that came with my shifter. Do housings come in standard lengths or do you generally need to get those from the bike manufacturer?
#13
Senior Member
I found a hi res pic of one of these bikes online and the cable routing matches mine, so i think i can rule out incorrect cable routing.
Since a couple of people have mentioned cable housing, I will likely look at that next. I have one of the sections, as it came with my shifter. The other section is perhaps a custom size, as it does not match the size of the second housing that came with my shifter. Do housings come in standard lengths or do you generally need to get those from the bike manufacturer?
Since a couple of people have mentioned cable housing, I will likely look at that next. I have one of the sections, as it came with my shifter. The other section is perhaps a custom size, as it does not match the size of the second housing that came with my shifter. Do housings come in standard lengths or do you generally need to get those from the bike manufacturer?
#14
Junior Member
Thread Starter
Join Date: Oct 2019
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Thanks again for all your feedback, folks. I replaced the cable housing and still no luck. At least I know how to replace cable housing now.
#15
Senior Member
Join Date: Jun 2014
Location: Ontario, Canada
Posts: 4,624
Bikes: iele Latina, Miele Suprema, Miele Uno LS, Miele Miele Beta, MMTB, Bianchi Model Unknown, Fiori Venezia, Fiori Napoli, VeloSport Adamas AX
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 1324 Post(s)
Liked 927 Times
in
640 Posts
Whereabouts are you located?
Cheers
Cheers
#16
Junior Member
Thread Starter
Join Date: Oct 2019
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I'm near Cincinnati, OH. There are bike shops near me, and I could take the bike there, but it will cost more than the bike did. With that in mind, I may end up just giving up on it and leaving it as an essentially single gear bike.