Ultegra 6700 indexing problem

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Defender
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Ultegra 6700 indexing problem

Postby Defender » Sat Dec 15, 2012 18:54 pm

OK this has me stumped - hope that someone has come across it before as I'm sure I've just done something stupid.

Just built up a brand new frame with Ultegra 6700, complete new groupset including 53/39 crankset, chain, levers, mechs, cables etc. OK the cassette is a Tiagra 4600 11-25 10 speed, but I believe that all Shimano 10 speed cassettes are compatible.

Had no problem setting up the limit screws and indexing the RD with the chain in the small chainring. BUT as soon as I shift it into the large chainring, the indexing is out by about one cog at the back. The RD cable is too tight when in the large chainring, but fine when in the small chainring. When in the large chainring and the largest (25) cog at the back, it needs two paddle clicks to shift from the 25 to the 23, and it will never go into the smallest cassette cog even with all clicks used. However if I then shift into the small chainring at the front, it straight away moves from the 12 to the 11 at the back.

I've tried a number of things - increasing the length of the final loop of gear outer (even to a ridiculous length), using a different wheel with a 12-27 DA cassette, checking that the gear cable runs smoothly, various B-screw settings, checking the RD hanger alignment as best I can. Nothing makes any difference. Incorrect routing of the gear cable from the barrel adjuster of the RD to the clamp is an obvious suspect, but I can't see any other way that I would route it.

I've built up a number of bikes with 5/6/7/8/9-speed and 10-speed 6600 and 7800, and never had this problem before. EXCEPT on the recent Tiagra 4600 build I did, where the rear indexing also seemed to depend on whether it was in the large or small chainring. I saw this on two different frames, so I don't think it's down to the hanger alignment or the frame being out of whack.

I'm clearly doing something stupid with these new-fangled 2nd gen Shimano 10 speeds, can anyone suggest what it is? You would make my day.

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JGSI
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Re: Ultegra 6700 indexing problem

Postby JGSI » Sat Dec 15, 2012 19:23 pm

I'm no expert but if I ever need to reset my rear mech (also 6700) I do it with the chain on the big ring at the front.
Checking for perfect at the mech alignment between smallest cog and jockey wheels and starting from there.

thecycleclinic
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Re: Ultegra 6700 indexing problem

Postby thecycleclinic » Sat Dec 15, 2012 20:41 pm

When you shift into the big ring the mech will "extend" as the mech rotates anti clockwise to accomate the "extra chain needed". If your RD cable outer is too short as the mech rotates the cable tension will rise causing the misshifting. Use a longer section of cable outer and you may need a new cable with that extra length and your problem will be solved.
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danmitch
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Re: Ultegra 6700 indexing problem

Postby danmitch » Sat Dec 15, 2012 20:53 pm

Does the chainline look right?

Defender
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Re: Ultegra 6700 indexing problem

Postby Defender » Sat Dec 15, 2012 21:24 pm

JGSI wrote:I'm no expert but if I ever need to reset my rear mech (also 6700) I do it with the chain on the big ring at the front.
Checking for perfect at the mech alignment between smallest cog and jockey wheels and starting from there.


Thanks - have tried setting the indexing up for the big ring. Of course the cable is now too loose as far as small ring working is concerned. Must admit the shifting is poor in the big ring - although I can get to the largest and smallest sprockets, in between there are some horrible missed shifts and double-jumps going on, which makes me think that it's the functionality of the RD when taking the extra chain tension that's somehow the problem.

Defender
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Re: Ultegra 6700 indexing problem

Postby Defender » Sat Dec 15, 2012 21:32 pm

thecycleclinic wrote:When you shift into the big ring the mech will "extend" as the mech rotates anti clockwise to accomate the "extra chain needed". If your RD cable outer is too short as the mech rotates the cable tension will rise causing the misshifting. Use a longer section of cable outer and you may need a new cable with that extra length and your problem will be solved.


Yes that was one of my thoughts too. I already installed (another!) new cable inner to allow a much longer piece of cable outer at the back end. Unfortunately it didn't make any difference :(

The cable outer at the front end has just enough length to allow full turning of the bars. Hate having to put the gear cable under the bar tape - I'm sure it's a bad design.

Thanks for your suggestion.

Defender
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Re: Ultegra 6700 indexing problem

Postby Defender » Sat Dec 15, 2012 21:38 pm

danmitch wrote:Does the chainline look right?


Pretty much straight in 39-19 and again in 53-14 - about what you'd expect?

DaveM399
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Re: Ultegra 6700 indexing problem

Postby DaveM399 » Sat Dec 15, 2012 22:31 pm

Have you got a spacer on the free hub behind the cassette? I believe the Tiagra 10 speed cassette doesn't need a spacer but other 10 speed cassettes (eg 105, Ultegra) do need the spacer. Could this be the cause of the problem?

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smidsy
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Re: Ultegra 6700 indexing problem

Postby smidsy » Sun Dec 16, 2012 07:43 am

Op what u described makes no sense. Put in small ring Disconnect the cables and start again. Set the cable tension on the rear with it in the small ring and start from there.
Yellow is the new Black.

fosst
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Re: Ultegra 6700 indexing problem

Postby fosst » Sun Dec 16, 2012 12:01 pm

I have had a couple of issues with 6700. To me it looks like the shifting is very sensitive to chain tension, to get reliable ( and crisp, immediate) shifts I have been running the chain length a little longer than I normally would, setting the chain length on small/small looking for max chain length and minimal tension on mech until the jockey wheels and sprocket run clear of each other. It probably only works out at 1 or 2 extra links but this is working for me.
Can't help but think that frame/hanger alignment is part of the problem but the hangers are fine (only running 6700 on TCR advanced frames), not tried on any other frames...
Did waste sometime looking for resistance in the cable run and made, unnecessary, mods to rear mech where the cable exits the casting before the clamp because on the limits of travel it made contact with the cable. Don't bother.
Use cables in good condition and decent chains (kmc or da) and this set up works beautifully.

Defender
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Re: Ultegra 6700 indexing problem

Postby Defender » Sun Dec 16, 2012 12:54 pm

DaveM399 wrote:Have you got a spacer on the free hub behind the cassette? I believe the Tiagra 10 speed cassette doesn't need a spacer but other 10 speed cassettes (eg 105, Ultegra) do need the spacer. Could this be the cause of the problem?


Yes there is a spacer. I believe all Shimano 10 speed cassettes are interchangeable - they just get more expensive and less durable as you go up the range. Ok and a bit lighter. And better materials and look better.

Defender
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Re: Ultegra 6700 indexing problem

Postby Defender » Sun Dec 16, 2012 13:20 pm

fosst wrote:I have had a couple of issues with 6700. To me it looks like the shifting is very sensitive to chain tension, to get reliable ( and crisp, immediate) shifts I have been running the chain length a little longer than I normally would, setting the chain length on small/small looking for max chain length and minimal tension on mech until the jockey wheels and sprocket run clear of each other. It probably only works out at 1 or 2 extra links but this is working for me.
Can't help but think that frame/hanger alignment is part of the problem but the hangers are fine (only running 6700 on TCR advanced frames), not tried on any other frames...
Did waste sometime looking for resistance in the cable run and made, unnecessary, mods to rear mech where the cable exits the casting before the clamp because on the limits of travel it made contact with the cable. Don't bother.
Use cables in good condition and decent chains (kmc or da) and this set up works beautifully.


Some good thoughts. I think I'm running the longest chain possible. I had visions of running something like a 29 or 30 rear sprocket for continental sportives, which would give a reasonable mountain-climbing setup without swapping to a compact at the front. But the chain tension was just too low so I had to take a few links out. Maybe I went too far though. These chains only last a few months - I'll try a bit longer next time.

I agree there seems to be excessive contact where the cable exits the casting in the extreme gears. I'm using brand new cable, in fact now gone through 3 new inners!

This morning I took the RD off and lubed the hell out of it, as I did once have shifting problems with my 7800 set-up when the pivot dried out and got gunged up over time. This hasn't solved it though.

My next step will be to swap out the RD and put on my trusty old 6500 one, to see if that makes a difference.

Defender
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Re: Ultegra 6700 indexing problem

Postby Defender » Sun Dec 16, 2012 17:22 pm

Well I swapped to the 6500 RD and still the same problem.

BUT I think I've figured out what the problem is. The frame has internal cable routing. The derailleur wires pass through sleevings inside the downtube and emerge at the bottom bracket. I reckon the sleevings were twisted INSIDE the downtube when the frame was made. This would explain why the rear shifting is so poor when in the big ring, when there is much more tension in the FD cable. This would also be why the tension in the RD cable relaxes when the tension in the FD cable is reduced by shifting to the small chainring, and why it's impossible to index the gears correctly for both big and small chainrings.

Just another one to add to the list of "improvements" that have actually made bikes worse. This is now the third Planet X frame that I've had problems with, so I guess I shouldn't be surprised. :x

I'm going to abandon the internal routing and fit some external barrel adjusters to the downtube. This will also solve another problem in that neither the frame nor the groupset provides any way of tweaking the gears on the move at the moment.

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Paul_Smith SRCC
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Re: Ultegra 6700 indexing problem

Postby Paul_Smith SRCC » Sun Dec 16, 2012 17:48 pm

If all items are compatible then it may indeed be something that you just can't see for looking, or in your case you can't see because it's internal, try just using your fingers when moving the cable through the frame to gauge how smoothly it's moving.

Also, make sure the cable route through the rear mech' pinch bolt is correct as this can pull the mech' slightly differently, infact cable route full stop, as well as the internal routing that you've already concluded may be a miss also make sure the cable stops are secure, as these like the guides can move slightly under tension, resulting in an inconsistent cable tension.

Paul


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