yannisg

RD Ultegra 6800 with 11-32 10 sp SRAM cassette.
I have adjusted the RD so that all sprocket work smoothly except on 11 and 12 cog. When adjust the RD so that those 2 work well I have shifting problems on the larger cogs. These situation happens whether the 34 or 50 chain ring is used. Cranks are Rotor (elliptical).
I had the same problem with a 105 RD and 11-30 10 speed Shimano cassette.
Any recommendation is appreciated.

Andrew R Stewart 

If we are to assume your "adjustments" are cable ones in the attempt to have well indexed shifting in both directions what you experience is a classic cable friction symptom. When the cable route has too much friction along it the der will shift well up the cassette range OT down it but not both. When was the cable and casing replaced? If the cable is fraying, usually inside the shifter so out of sight without looking under the hood, just as it enters the shifter? If so then replace ASAP before that cable fully breaks. Andy

delbiker1 

When Andrew speaks, I listen.

yannisg

Thanks for responding.
Correct cable ones.
I re-lube the last length of cable when I replaced the cassette (today), and cleaned and lubed the wire guides under the BB. The rest of the cable to the shifter is a year old. I don't usually have problems with wire cable friction since my riding conditions are not adverse, but just to eliminate this cause I will replace cable and wire. Probably I change the wire first which is the easiest.

Andrew R Stewart 

If you replace the inner cable then also replacing the last bit of casing that runs from the chainstay to the rear der is also easy and this section of casing if often more worn than the rest of the casing. Andy

Iride01

What you are calling the wire is what most of us call the cable. Unless you have an electronic shifter like Di2. Which I don't think you do. What you seem to be referring to as cable is the cable housing.

yannisg

Ok cable and cable housing I'll use these terms so its all clear.
I'll replace the cable and the last section of the cable housing, and then the cable housing that goes to the shifter. I keep my cables well lubricated (Shimano white cable grease)
Thanks

delbiker1 

IMO, a light oil is better than grease. The grease gets gummed up over time and causes a friction problem.

HillRider

If you have had exactly the same problem with two different derailleurs and cassettes there is a fundamental problem with what you are doing. Any chance the high limit screws are set too tight? If the RD will barely shift into the smallest cog because the high limit is set too close then shifting the remainder of the cassette will be compromised. Try disconnecting the shift cable at the derailleur and shifting the derailleur through it's range by hand while turning the crank. Be sure it's travel is good at both ends, i.e. it goes into the small and large cogs fully but doesn't try to spill the chain. Once that's good, connect the cable and use it's tension setting to adjust the shifting.

cxwrench

Shimano cable grease is excellent and doesn't gum up. At least it doesn't in the 'normal' cable/housing lifetime. Most of the time when someone says 'grease gums up' it's because they leave it way too long before cleaning/regreasing or replacing the cable/hosuing.

dedhed

Same problem with 2 RD on I'll assume the same bike.
Has the RD hanger been aligned?

cxwrench

This sounds much more like a fraying cable than a bent hanger. If the hanger is bent inwards (they way it happens 99.9% of the time) the shifting will get progressively worse as you shift to bigger cogs. It's not at all what the OP is describing. Don't just throw 'bent hanger' out there every time someone is having shifting issues.

shelbyfv

You may need some paper spacers....

yannisg

Upper and lower limits were meticulously set with cable removed.
i don’t think the hanger is bent because I haven’t had a crash.
I will replace the cable and last part of cable housing and see if there is an improvement.
Thanks for the help

shelbyfv

I would double check that I'd correctly assembled any loose cogs in the cassette. That's the sort of thing I could screw up.

SoSmellyAir

Internally or externally routed shift cables?

I recently replaced my shift cables and housings with a Shimano Road Shift Cable Set. This set comes with a specific 240 mm long housing (SIS OT-RS900) for the rear derailleur loop which is more flexible than the housing between the STI levers and the frame. Depending on how tight the rear derailleur loop is, a more flexible housing should theoretically reduce friction with the cable.

Andrew R Stewart 

Unsure if this is a true claim. I'll have to ponder this, but my initial thought is that casing flexibility is WAY down the list of friction causing aspects, if it's on the list at all. Andy

MidTNBrad

6800 series is 11 speed but in your initial post you said 10 speed. Was that a typo? If not you may have a mismatched drivetrain.

yannisg

Hey, good observation, you are right its not a type.
I had the RD-6800 on my 11 sp bike which I replaced with RD-7000-GS to accommodate a 34 sprocket, and I installed the RD-6800 on my 10 speed to accommodate an 32 sprocket.
I wouldn't have thought it would cause a shifting problem since the indexing determined by the shifter.

alcjphil

The RD 6800 will only index correctly for 10 speed if you have a Tiagra 4700 shifter. All other Shimano road 10 speed shifters are incompatible with your derailleur

SoSmellyAir

It is definitely way down in the list, but any mismatch in flexibility between the housing and the cable theoretically increases friction, as one will press against the other.

Otherwise Shimano would not have provided a different piece of housing for the rear derailleur loop in the shift cable replacement kit.

cxwrench

Not true. The geometry of the derailleur also plays a part. That's why you can use 8/9/10 road shifters with 8/9 speed mtb derailleurs but NOT 10. And you can't use 10 speed mtb shifters (Dyna Sys) with 11 speed mtb deraillers (Dyna Sys ll).

yannisg

So the Ultegra 6800 RD will not work with my 10 sp shifter.
I had removed the RD 105 5701 RD which has a short cage (distance between pulley centres is 60mm) to accommodate an 11-32 cassette.
Should I re-install it to see if it will?

cxwrench

The 5701 will work better than the 6800 that's for sure. It most likely won't handle the 11-32 cassette though. If it's SS the spec is max cog of 28. You can probably get away w/ a 30, you'd have to try the 32 and see.

KCT1986

The RD-5701 is the later version of the 5700 series RD and is rated for 30T low gear, so 32T may be possible.

Not sure if the elliptical ring will make a difference since it causes more movement of the cage and the pulley's possible distance to the cog.

Give it a try... Let us know