Replaced Ultegra drivetrain – Still having issues???

Hi,

Replace the whole of my 6700 drivetrain with full genuine parts:

– compact chainrings (50/34), chain and cassette.

What expecting to be ‘as new’ and smooth, instead struggling for indexing (get i perfect going up, then just not quite right going down or vice vera).

Plus its not super quiet when turning the pedals either like it should be!!

Tried everything, the chain is the correct way round (shimano text outwards), but tried it in all 4 directions/ways with no joy, tried the b tension screw. Even bought and fitted a new mech mech hanger with no joy. Rear mech jockey wheels are fine too.

Any ideas??

Only thing i think of doing is sacking off the shimano chain and getting a aftermarket chain???

Bent mech hanger or a cable strand catching in the shifter.

You don’t mention new cables?

Should run fine, but mine took a while to bed in.
Turns out the cable was about 3 turns out
Also check the cables run smooth

Or you could just be expecting a level of precision that doesn’t exist…

will index up and not down or vici-versa then cables are the prime suspect.

@Rik

what frame is this being used on (internal routing / external routing)?

did you replace the gear cabling when you installed the new parts?

is the new derailleur hanger actually straight (new are often bent)?

unreliable or direction-biased indexing is normally a sympton of cable drag or a bent hanger; we see this a lot on bike with internal routing where the routing has not been done correctly

new and even used 6700 should run very smooth, it was a fantastic group set

Last section of cable outer before the RD needs lubing or replacing. Very annoying fault to track down.

Bends too tight on the handlebars for gear cables gave me the same grief on my 105. So I went DI2 and never looked back. Gears didn’t index, causing chain noises etc.

New cables about a 1000 mile ago when new shifters went on, compressionless ones too

Replaced the mech hanger already, it is straight too.

External cable routing on an s-works, doubt it will get better with time.

The indexing could be the cables I’ll check tomorrow, indexing is odd but the chain sounds noisy even if ite Chainline looks right???

You say the hanger is straight. Is that by eye or have you had a hanger tool on it to check?

Built a bike for a mate last week and brand new out of the box with big plastic blocks around it, the mech hanger was ever so slightly off.

Checked with an alignment tool

You haven’t threaded the chain the wrong way around the metal tab between the jockey wheels have you?

I did that last time I changed a chain and it took me about 3 rides to figure out where the noise was coming from! I felt daft.

My Ultegra doesn’t index either.
New cables ( genuine Shimano inner & outer), new rear mech, hanger straight-checked by me in the shop using the Park alignment tool.

Gives the impression of sticky cables but just doesn’t seem to improve at all.
The Tiagra on my commuter however is faultless, as is the new Ultegra 11sp.

I now just ride the thing & put up with the fact it doesn’t work as well as it should!

Worn jockey wheels give lazy shifting. If you’ve worn out your chainrings, the jockeys will definitely be worn out.

Rik, you say you replaced the cables, did that include the outers?
I tend to find that the outers need replacing more than the inners.

Had all the same symptoms and diagnostics. The cable ferule on the last outer was kinked and this provided the additional tension. Very frustrating. Now I regularly unbolt the cable slide the outer along, lube the cable and replace. 5 minutes and all is good again.

Cables….