Sram red rear derailleur issues

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NiFTY
Posts: 1493
Joined: Sat May 26, 2012 11:26 pm

by NiFTY

Looking got some help w derailleur setup.
Have found worsening shifting with my sram red Rd.
Setup: sram red 2010 levers, 2012 10 speed rd, ilink routed inside bar, kmc x10sl chain. External routing, tarmac sl3w wheel manufacturing hanger. Xg1090 cassette 11-28.



I have found that i can tune the rd to either shift promptly into the 11t and make noise on the largest 3 sprockets or silent cassette except for 12t and won't shift to 11t.

I have straightened the hanger in vertical and horizintal planes. Checked shifter internal for crud and relubed. Replaced inner shift cable and liner. There is a good loop going into the rd. Replaced chain. Tried different cassette - dame result. There is no play in the rd at pivots or cage from wear. Jockeys are as new. B tebsion is adjusted appropriately.

Anyone have any ideas what could be going on. The noise is annoying, it is worst in the 3rd largest sprocket in all cassettes.
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alcatraz
Posts: 4064
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

I had (still have to a slight degree) a similar issue with my old red setup. I thought it was because of my poor choice of housing and cables which are lightweight and standard.

I got some teflon cables to try and reduce the friction. I kept the light housing. I also decided to cross the shift cables of my internally routed frame inside the down tube to minimize the bend radius under the bars.

Here is something that surprised me though. When I took the cable guide under the bb out I noticed the cables had dug into it. They are exposed to the elements there and easily get dirty. I thought to myself that could very well cause the friction and index problem.

Anyway I solved it by cutting two small pieces of liner and now run the cable through a liner there (greased up). It's almost perfect now but I still do have a slight issue with the 2nd cog and the 9th cog to index perfectly. There is still a compromise between them but it's acceptable.

I'm just worried that the cables will eat through the liners at the bb.

Anyway, reduce the friction and the shifting performance should improve. Also check that your derailleur is lining up properly. I had to do some slight adjustments to my derailleur hanger.

Edit: Also check your rear wheel. I noticed my rear wheel when seated in the drop outs is not perfectly centered in the frame which puts the cassette an an angle. Compare the wheel to the seat tube and see that it runs nice and center between the seat stays and the chain stays. Mine isn't but I can get it ok by giving it I slight nudge right before I clamp the skewers on. In the future I might have to file the dropouts to correct it.

Edit2: Check that your cassette is not moving side to side on the wheel. Could be a freehub body issue/bearing or spacer/lockring thing.

/a

Marin
Posts: 4035
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

You can put a washer under the derailleur mounting bold to increase tension on the lowest cog, sometimes this helps when you have sub-optimal cabling.

grover
Posts: 1302
Joined: Mon Jul 26, 2004 1:06 pm

by grover

Things to check. Sounds like you've done most of them.
- limit screws
- b-tension
- chain cassette wear
- derailleur hanger alignment
- cable routing friction
- cable routing compression (especially with ilinks, are all the little segments well compressed together at initial install with no inner cable tension. otherwise they'll compress when inner cable tension is brought on through shifting and the liner is likely to get a little kink underneath and increase friction)
- shifter gunk/lubrication - spray some degreaser in, flush it out, relube
- freehub body play - with wheel in dropout and QR tenstioned is there any slop in the freehub body (grab cassette and rock it up and down)
- rear derailleur spring - worn out, not pulling strongly enough into small cogs (11+12)

I recall working on a number of tarmacs with original red. They derailleur hanger is on the narrower side of specifications so often it helped to do as 'Marin' suggested. Place a washer (1-2mm) onto derailleur mounting bolt before installing on derailleur hanger. This places the derailleur 1-2mm further out and will put the spring on more stretch to provide snappier shifting to harder gears, especially the 11 and 12.

I also recall that the 12 tooth on that cassette was quite often noisy when the rest of the cassette was perfect. Almost as if the spacing in manufacturing wasn't spot on. I accepted it. As long as shifting was good I put up with a little noise.

Marin
Posts: 4035
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

On one bike I noticed that the hanger was so thin that the mounting bolt peeked out of the inside, this is where the washer helped.

numberSix
Posts: 124
Joined: Sun Sep 23, 2012 1:53 pm

by numberSix

IMO SRAM in general is easily impacted by cable drag. With aluminum bars always use the over and around the back route. For internal routing, all I can suggest is try to minimize sharp bends. A test would be to disconnect the cable at the RD, hold tension on the cable with finger pressure while cycling the shifter to test drag.

The other issue, is the right limit start position. It's about 0.5mm--1mm upper pulley to the right vs the smallest cog. With the right start position and cable tension, a smooth test of 11-12-11t results in a noise free cassette.

UpFromOne
Posts: 1181
Joined: Wed Apr 08, 2009 5:23 am
Location: Olympic Nat'l Park, WA

by UpFromOne

Also make sure your der cable is attached on the correct side of the cable securing bolt underneath.
Those older models you can mistakenly attach on the wrong side of the bolt, affecting throw.

NiFTY
Posts: 1493
Joined: Sat May 26, 2012 11:26 pm

by NiFTY

Argghhh. This is driving me nuts. Are any others running sram shirt cage 11-28 i links on the inside of the bars having similar issues. The other thing i noticed is the wheel is straight but offset closer to the left side of the dropouts. I tried to correct for this by spacing the rd pulleys inwards by placing a spacer on the outside of each pulley but it made no difference. I'm almost at the stage of buying a new groupset.
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NiFTY
Posts: 1493
Joined: Sat May 26, 2012 11:26 pm

by NiFTY

OK, think i may have found the culprit. There is no play in the rear derialleur on my other bike (wifli). This seems abnormal and like it would frustrate accurate shifting.

https://youtu.be/Jw3HdDZqZEM
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jobvisser
Posts: 120
Joined: Sun Aug 14, 2016 10:24 am

by jobvisser

have you tried lowering your derailleur with the screw on the back ? is your Hanger straight. if there is a lot of play there should be some kind of spring put in it . my dad's derailleur kept throwing the chain down and it turned out his hanger wasnt superstraight
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NiFTY
Posts: 1493
Joined: Sat May 26, 2012 11:26 pm

by NiFTY

Jobvisser have you looked at the video or read the original post or had a stroke?
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commendatore
Posts: 273
Joined: Mon Dec 30, 2013 1:51 am
Location: North Carolina

by commendatore

+1 on checking chain/cassette wear. KIS

AZR3
Posts: 998
Joined: Wed Sep 12, 2012 9:00 pm
Location: Az USA

by AZR3

NiFTY wrote:Jobvisser have you looked at the video or read the original post or had a stroke?

Sorry, I don't have anything informative to add but ^^that got me going lol

NiFTY
Posts: 1493
Joined: Sat May 26, 2012 11:26 pm

by NiFTY

The cassette is not worn, i have checked the chain for stretch and it is fine too. Did anyone watch the video and look for play in their own red rd?
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by Weenie


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Frankie - B
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Location: Drenthe, Holland

by Frankie - B

I've had exactly that. And still have the derailleur to prove ;) It is toast as the axle is worn, and you need to get a new one. once the new one is installed shifting will be crisp again. I got sick and tired of buying new Red derailleurs as it happend to me twice already, and bought a Force one in stead. 3rd of the price, swapped the CF cage and the alloy bolts from the red to the force and I'm happy with its performance.
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