Ultegra shifting problems

[886014]

I have Shimano 6603 groupset on a bike and am having problems selecting the smallest cogs. The STI doesn’t want to sequence to these gears unless I manually pull the cable to increase the tension. The small lever moves across but doesn’t do anything. In addition, the cable snapped a few days ago.

To me that sounds like a no brainer, too much friction somewhere in the cable run. But I’ve obviously now replaced the cable and it’s identical to before it broke (ie didn’t get better for a while). I’ve checked and re-checked the run and it seems fine. I’ve lubed the derailleur hinge and pivot points and the cable tension seems good. I’m left wondering if the STI lever itself may be cactus and the cable breaking (inside the mechanism, very handy to get out I can assure you!!) was just some sort of bizarre coincidence. I’ve thoroughly flushed the STI lever with WD-40 and spray lube.

Wondering if anyone else has had similar problems with ST-6603? Shimano seem happy to replace (bit under 12 months old with 6,000 km on the clock) but who knows how long that will take and don’t want to rip the thing off unnecessarily (only to discover it’s something else) as clearly the bike is then unusable.

 

[capwater]

Sounds like when you replaced the cable you hadn't clicked the shifter all the way down to the lowest position.

This makes no sense "unless I manually pull the cable to increase the tension". If you pull the cable the RD is going to go inward towards the largest cogs in a cassette.

 

[886014]

Sorry I should have been more specific.

... unless I manually pull on the cable to increase the tension THEN release the tension. In other words if I MANUALLY operate the cable as if I had a downtube friction shifter the derailleur operates normally and will move through all ten cogs normally.

No, when I replaced the cable I didn't forget to move it to the lowest position The system works normally but I have TROUBLE selecting the smallest cogs. In use if I flick the small lever many times it will eventually move to the smallest cogs, but clearly this is not normal.

 

[Insight Driver]

Sorry I should have been more specific.

... unless I manually pull on the cable to increase the tension THEN release the tension. In other words if I MANUALLY operate the cable as if I had a downtube friction shifter the derailleur operates normally and will move through all ten cogs normally.

No, when I replaced the cable I didn't forget to move it to the lowest position The system works normally but I have TROUBLE selecting the smallest cogs. In use if I flick the small lever many times it will eventually move to the smallest cogs, but clearly this is not normal.

I'm thinking you may have a chain line problem. Who built your wheel? It is possible the derailleur hanger is bent. I am asssuming you have the limit screw adjusted properly. I am assuming you are in the big ring with this problem and it's worse if you try to shift to the smallest cog if you are on your small chainring. Is that correct?

Rule out the shifter itself and the cable. It's odd to have broken the cable, though. Exactly where did the cable break? I've got Ultegra on three different bikes and have no shifting problems whatsoever.

I suggest if you don't find a solution yourself consider taking your bike to a shop.

 

[886014]

Nope, problem is identical in either chain ring (the observant may have noticed it's a 6603 ie a triple, but I never use the small chain ring, indeed the way I have my Polar Power sensor setup can't use the small chain ring, in fact having a triple is a pain, but I digress).

The hanger MAY be bent but nothing obvious, I'm having it checked next week. Before taking it there though I want to rule out anything obvious (or not so obvious myself).

The wheels?? Well they're stock Bonty Race wheels, built by robot somewhere in China I expect. The limit screw has been suggested by somebody else, to be honest I haven't tried tweaking it because it's not just the smallest cog, but the final 3 or so. Also if I manually operate the derailleur by pulling on the cable it shifts just fine. Would expect limit screw problem to be the final cog (well unless it's waaay out) and I would never be able to get down there.

Yes the cable breaking is a strange one. May be coincidence, maybe not. As mentioned, it broke inside the STI shifter mechanism. The shifter wasn't in the smallest cog position either so it took a bit of "keyhole surgery" to get the ratchet around to the correct position. Anyone who has had to do this I feel very sorry for, certainly tests the patience.

I'm wondering about other more obscure possibilities, like last time I changed the chain was it too short? I broke this chain (well more like didn't install the link correctly so miles from anywhere it began to work loose. LBS installed one of those removable links, but did they take a few links out of the chain in the process?). Then I would expect large/large problems though. The hanger is certainly a possibility. Also not totally happy with the cable length leading into the derailleur. It seems a wee bit short but notice other bikes are similar. Maybe the B-tension? Another thing I will need to recheck, not sure of the symptoms if this is not adjusted correctly.

 

[Retro Grouch]

When you replaced your shift cable did you replace the housing too? That little piece of cable housing right by the rear derailleur can be particularly troublesome.

Some people have indicated they're had the shift cable bind where it goes under the bottom bracket so you might want to check that too.

 

[886014]

Under the BB is fine, checked that and put some Lith grease on the guide when I put the cable in. I can well imagine it to be a source of problems.

Now the housing you mentioned MAY also be a problem. Where it actually goes into the derailleur, the housing cap is actually designed (it looks like anyway) with a bend in it. Presumably so they can use shorter cable loops there and the cable won't go into the derailleur straight. As mentioned I don't like this and it's not how the Pro's DA bikes are set up. I'll mention it to the LBS when I drop it off

 

[buckybux]

It could be the rear derailer that is the problem. Have you cleaned and lubed the inside of the rear derailer. Sometimes grit can get inside and limit the springs from working correctly. How old is the rear derailer?

 

[886014]

Cleaned, lubed and squeaky clean. Is same age as bike ie 12 months and now just under 6,500km use

 

[Insight Driver]

Cleaned, lubed and squeaky clean. Is same age as bike ie 12 months and now just under 6,500km use

When it does get solved, be sure you let us know what the problem was. This is a good one to learn from.

 

[886014]

Yeah it's a bit of a weird one isn't it. Will post when resolved

 

[886014]

Just as an update, took into LBS and they checked hanger alignment. Said it was pretty good, just a bit out. They also think it's possibly the STI lever but will need to remove and send it in to Shimano. As I need the bike right now will have to wait for a week or so. The saga continues

 

[886014]

For those who may have been interested in the outcome of this. The STI lever was sent to Shimano where it was seen as faulty and replaced under warranty. Not sure if this will be a isolated event but the bike had about 8,000km on it and the shifter gets used a great deal as I ride in rolling hills/hilly area.

Works a treat now ... just in time to convert the lot to DA

 

[flyr]

I have Shimano 6603 groupset on a bike and am having problems selecting the smallest cogs. The STI doesn’t want to sequence to these gears....

I had a similar problem with my Ultegra STI right lever releasing cable tension inconsistently. I found the cable to be quite frayed but not broken. The fraying would bind the releasing of the ratchet. I thought the ratchet was worn/partially stripped but solved the problem with a cable change. This may help those whose cable has not yet broken and shifter is otherwise mechanically fine. BTW...the cable frayed after only approx. 2500 miles.

 

[JCarlos61]

I had a similar problem with my Ultegra STI right lever releasing cable tension inconsistently. I found the cable to be quite frayed but not broken. The fraying would bind the releasing of the ratchet. I thought the ratchet was worn/partially stripped but solved the problem with a cable change. This may help those whose cable has not yet broken and shifter is otherwise mechanically fine. BTW...the cable frayed after only approx. 2500 miles.

I had the same problem here and found the housing to be the problem. The wires inside the housing went out the finishing caps and put pressure on the cable making the shifter and the deraileur to shift erratically.