SRAM Red read derailleur shifting adjustment

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ictus
Posts: 13
Joined: Fri Sep 05, 2014 8:29 pm

by ictus

Hey guys,

I just installed a new Sram Red 22 RD and FD.

I already had some Fibrelyte pulley wheels so I went ahead and used them for the install. Used a bit of teflon for the small bolt like I read on another thread here.

I got things mostly adjusted working pretty well. I can shift back and forth up front, and hit all my cogs in the rear and the limits seem good.

The trouble is that I can't seem to find the right tension for the rear derailleur. When shifting up from the smallest to gear ~4ish, there is sometimes hesitation and chatter, but I can overcome this by shifting slightly more deliberately (waiting a second at the click instead of just the quick 'flick' and release). Naturally this causes me to think I need a bit more tension on the cable. My barrel adjuster has plenty of room both ways, so I tried to increase the tension. The problem is that if I add the tension it needs to overcome the hesitation, the chain starts to rub against the next highest cog when in the lower cogs.

Has anybody else run into this issue? Maybe I should try putting the stock pulley wheels back on...

other relevant info:

Cassette: SRAM red 22 11-25
Chain: KMC X11-SL
Chainrings: Fibrelyte 52/36
Powercordz derailleur cable with Swift housing

rijndael
Posts: 402
Joined: Tue Sep 20, 2011 12:54 pm
Location: Haines, AK - Temporarily

by rijndael

Did you make sure your derailleur hanger is straight?

by Weenie


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DuncanS
Posts: 143
Joined: Thu Aug 12, 2010 4:42 pm

by DuncanS

After that, resistance in the rear loop? Too tight a bend/kink?

wojchiech
Posts: 405
Joined: Thu Feb 24, 2011 6:33 pm
Location: bay area, california

by wojchiech

When you adjusted the high limit screw, did you have the cable clamp bolt completely loose? I believe the SRAM tech manuals state that the high limit should be set with zero tension on the cable. With my SRAM stuff I've personally found that a lot less cable tension is required to hit all the cogs in the back once the high limit is correctly adjusted.

When I set rear derailleur high limit screws, I unscrew the cable clamp bolt to relieve all cable tension. I then tighten the high limit screw until you hear it starting to skip a bit into the next cog and back off until the sound stops. Setting the high screw this way allows minimum cable pull from the highest cog into the next, and minimum cable tension required to allow for correct indexing/shifting. I do this method with all SRAM rear derailleurs, but I've found it works for most others as well.

ictus
Posts: 13
Joined: Fri Sep 05, 2014 8:29 pm

by ictus

rijndael wrote:Did you make sure your derailleur hanger is straight?


Just checked and it looks straight. Not sure how to actually verify it, since the frame is a cervelo S5 and the chainstay is fairly shapely... The only other data point I have is that my ultegra RD shifted fine...

DuncanS wrote:After that, resistance in the rear loop? Too tight a bend/kink?


I was curious about what I should do with the Powercordz and the Cervelo S5 bottom cable routing guide. They call it the "single bend cable guide". The S5 manual says no cord liner there, but still I wondered if maybe the powercordz cable would be better with a guide there. The only trouble is that the slots on this S5 cable guide are a bit too thin to fit any linerwithout causing even more friction. I thought about using a dremel to widen the slots and run a full length liner across the bridge.

wojchiech wrote:When you adjusted the high limit screw, did you have the cable clamp bolt completely loose?


I did the limit adjustments before I even had cables routed through the frame or a chain on. I get the point you are making and that also seems like a good way to adjust. The only thing is, wouldn't the high limit screw only affect the shifting when on the smallest cog? Mine seems to have the same hesitation up several gears, and increasing the tension to get good shifting causes lots of noise on the first 3 cogs.

I am wondering if it would be a good idea to undo and re-clamp the powercordz, I heard they aren't meant to be reclamped...

I tried swapping back in the stock SRAM pulleys and couldn't tell any difference. I emailed powercordz about the liner/s5 cable bridge thing. Maybe I'll try that next.

rijndael
Posts: 402
Joined: Tue Sep 20, 2011 12:54 pm
Location: Haines, AK - Temporarily

by rijndael

You can check the alignment with a Park DAG-2 tool.

DuncanS
Posts: 143
Joined: Thu Aug 12, 2010 4:42 pm

by DuncanS

A tool worth owning, IMHO.

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

by Marin

The limit screws will only affect shifting onto the 2 outer cogs.

Try replacing the top pulley with a standard one?

DuncanS
Posts: 143
Joined: Thu Aug 12, 2010 4:42 pm

by DuncanS

You can't adjust tension as such, just the offset in/out. If setting further in causes rub on the larger cog then the lag you are experiencing is most likely either hanger alignment or friction/movement in the cable run. The only other adjustment to look at is b-tension for clearance cog to pulleys. I would start by looking for friction or movement in the line, then check hanger, then go back through the setup procedure which will include b-tension adjust amongst all the other adjustments.

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Rick
Posts: 2034
Joined: Sat Aug 29, 2009 4:30 pm

by Rick

I am not familiar with the Fiberlyte pulley wheels specifically, but I know from prior tries with aftermarket pulley wheels that many are simply not stiff enough laterally to giver the same crisp shifting as the OEM wheels. You might try going back to them and see if that helps.

em3
Posts: 883
Joined: Tue Dec 23, 2008 2:57 pm
Location: NYC

by em3

• make sure that you attached cable only after releasing all clicks from your lever.
• if rear mech hanger alignment was not checked when bike was built then it is out of alignment....ALL new rear mech hangers must be aligned and matched with the dropout on which they are installed (with the proper tool....not eyeballing it)
• DO NOT modify the cable bridge...Cervelo has gone to great lengths to minimize cable bend and friction with their bridge design....your cable should run bare on the bridge
• cable loop to rear mech must be large enough....SRAM seems to be especially sensitive to this issue
* b-screw adjustment and chain length may also be factors
• make sure the upper pulley on your aftermarket pulleys has sufficient lateral play, matching the lateral play of your SRAM pulleys

...post some pics and let us see what you are working with. EM3
______________

MNX1024
Posts: 299
Joined: Thu Apr 28, 2011 1:21 am

by MNX1024

Another thing you should check, though not very likely, is the spacing between cogs on your cassette. I had an issue with my XG1090 cassette once where the overall cassette height was just taller. No idea which cog spacing was the problem because I didn't bother measuring it, but the overall height difference was 3mm..... Spent countless hours and money trying to fix it, thinking it was a problem with the cable/housing because every mechanic I brought to point to my cable and housing.

ictus
Posts: 13
Joined: Fri Sep 05, 2014 8:29 pm

by ictus

Thanks for the tips guys. I ordered and got in my DAG-2 last night and used it right away. I discovered that the hanger was out of adjustment by over 12mm in the left left/right plane and almost as much in the vertical plane. I got it to within ~3mm all around by yanking on it. I also realized I had too much B-tension as there was more space than necessary between the upper pulley and the cassette. With those changes the shifting quality is at least 90% better. I still get a tiny hesitation when shifting between gears 7 and 8, but that only seem to be when pedaling in the stand with no load. When I mount the bike in the trainer and put resistance on the wheel and pedal with my feet it seems to be almost perfect.

Re: rear cable run bend. I got some pictures of my calbe work, but haven't had time to upload them yet. If it helps, the diameter of the cable bend in the rear is around 4". Maybe I should have made it a bit wider. That is the tricky thing about the powercordz, you can't really unhook it and re-tighten it further down the line due to the damaged fibers. I might have to buy another rear cord.

Also I got a response from Powercordz re: the S5 cable bend bridge:

Hi Ryan,

The cables can be installed without the liners. We recommend using the liner
across the bottom to increase the life of the cables.

Both options should be okay. If you are good with a dremel tool, you can
widen the slot. An there is no problem running the cable on the bridge
without the liner. One of the reasons, for using the liners is to reduces
the dirt on the cables. If you do run the cables without the liner, I
recommend adding some grease on the bridge to reduce the coefficient of
friction between the cable and the bridge.

Thank you for supporting Power Cordz!

Best Regards,


I am going to try putting some Squirt lube down there. I am thinking squirt will work well since it is wax based and fairly 'clean' as in it won't attract grime as much as regular grease or oil.

Oh and to reiterate, I had already tried swapping in the stock SRAM pulleys before doing the hanger alignment. Did not seem to make one lick of difference so I will be putting the FibreLyte ones back in, they are both lighter and spin more freely.

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iamuwere
Posts: 2
Joined: Tue Aug 19, 2014 4:08 am
Location: Cleveland, Ohio
Contact:

by iamuwere

12mm or 0.12mm? 12mm is a huge bend.


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rijndael
Posts: 402
Joined: Tue Sep 20, 2011 12:54 pm
Location: Haines, AK - Temporarily

by rijndael

The DAG-2 is not a precision tool, I'd bet that no one using one can tell a difference of .12mm or ~.005", which is pretty close to the thickness of a human hair.

by Weenie


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