Why aren't my gears shifting smoothly?

[ives]

Hi,
I have Sora 8 speed STI's (new) with new cables,stops,etc. Sora front and rear mechs, with a shimano 8 speed cassette block (12-23) and chain.

All adjustments have been made as per the manuals ( Adjusting high and low stops on the rear mech, B-tension adjustment, greasing the cables etc)
However, the gears won't shift smoothly at all. In fact it seems like the top three sprockets cause the problem (12,13 and 14). The other gears shift fine, it's just I can't dial in these gears no matter what I try. The chain and block have done about 6 months of riding with each other and worked perfectly on my old indexed downtube shifting setup.

Any one heard of this or can think what it could be?

Ives

 

[demirh]

Hello Ives,

I had a similar problem. I finally found that the cable housing was the culprit. Once they were replaced, the shifting was vastly improved. Good luck. Demirh

 

[ives]

Hello Ives,

I had a similar problem. I finally found that the cable housing was the culprit. Once they were replaced, the shifting was vastly improved. Good luck. Demirh

Well, my cables and cable housing are brand new.

 

[drewski]

Well, my cables and cable housing are brand new.

paradoxically enough, new cables/housings are often when shifting issues occur! with the greater shifter-cable length of STI vs. downtubes as well as the additional housing that the cable needs to go through, you've added the need for more accuracy as well as more points of failure . . .

make sure the ends of the housing are cut squarely and that there is nothing that the cable can snag on. if it's not cleanly cut, there could be excess friction on the cable that can cause shifting issues. if it's not squarely cut, increased tension on the shifting cable could cause the housing to angle and either change housing length slightly or have the cable bind a bit.

also, try some dry lube under the bottom bracket where the cables contact the frame and make sure that the housing you're using is appropriate compressionless shift cable housing. if you have housing that could compress, this will dramatically impact shifting.

good luck!

 

[ives]

paradoxically enough, new cables/housings are often when shifting issues occur! with the greater shifter-cable length of STI vs. downtubes as well as the additional housing that the cable needs to go through, you've added the need for more accuracy as well as more points of failure . . .

make sure the ends of the housing are cut squarely and that there is nothing that the cable can snag on. if it's not cleanly cut, there could be excess friction on the cable that can cause shifting issues. if it's not squarely cut, increased tension on the shifting cable could cause the housing to angle and either change housing length slightly or have the cable bind a bit.

also, try some dry lube under the bottom bracket where the cables contact the frame and make sure that the housing you're using is appropriate compressionless shift cable housing. if you have housing that could compress, this will dramatically impact shifting.

good luck!

Hi and thanks for the response.
Lube under the BB has been done with no improvement.
The cables are the cables that came with the STI Soras, so I presume they are the right sort (compressionless)

I've taken the inner cables out and lubed inside the outer cables so that there is practically no friction there at all.If I put the inner through the outer cable now and tilt it, the outer cable will slide off, that's how low in friction they are.

Although the outers were cut slightly, they were done with proper cable cutters and the ends were rounded so as not to provide any friction points.

I'm at a real loss with this one.

Just one question:
Should the shifts using STI be instantaneous....what I mean is, as soon as you hear the click ,should it be changing into the next gear?
On the problem 3 top sprockets (12,13,14), I have to hold the gear lever/brake lever in the shift position for a second or two after the click is heard before it will shift. Whereas on the other sprockets, the shift occurs as soon as the click is heard.
On my old indexed down tube shifters, I was used to the gears changing as soon as the click occured. Maybe it's not like that with STI's?

 

[e_guevara]

I have a bike equipped with a Sora drivetrain which I use for training rides and I haven't had any problems with it.

Some suggestions:
- Check for chain wear. You said that you used your chain and cassette on your old friction shifter.
- Does the chain flex enough? Some gear combinations (big chainring-big sprocket / small chainring-small sprocket) may not engage properly because of the chain. Again, this may be due to an old chain.
- If you're going to adjust your drivetrain, see www.parktool.com or www.sheldonbrown.com. They provide better procedures than the one included with the equipment.

Hope this helps.

Cheers

e_guevara

 

[GuyStevens]

Are the STI cables cut too short?

Is the chain too short?

 

[ives]

Well, thanks for all the suggestions but really, everything that has been suggested here has been tested and checked.
Nothing oestensibly seems to be at fault with the set up.
As a last resort,I might try a new block and chain, although mine is less than a year old.

 

[RC2]

How about taking it into a good LBS for a check up? A good tech would probably be able to pinpiont the issue(s) quickly and tell you how much it would cost to fix...it may be very inexpensive from what you are describing.

 

[boudreaux]

Just one question:
Should the shifts using STI be instantaneous....what I mean is, as soon as you hear the click ,should it be changing into the next gear?
On the problem 3 top sprockets (12,13,14), I have to hold the gear lever/brake lever in the shift position for a second or two after the click is heard before it will shift. Whereas on the other sprockets, the shift occurs as soon as the click is heard.
On my old indexed down tube shifters, I was used to the gears changing as soon as the click occured. Maybe it's not like that with STI's?

STI/ERGO will shift as fast as downtubes if everything is right.As suggested,take it to someone who knows what they are doing.

 

[drewski]

STI/ERGO will shift as fast as downtubes if everything is right.As suggested,take it to someone who knows what they are doing.

with STI, i believe shifts to larger cogs happen immediately, while shifts to smaller cogs happen after the "click" occurs and lever is released.

could be wrong, this is just my work-siesta recollection.

 

[boudreaux]

with STI, i believe shifts to larger cogs happen immediately, while shifts to smaller cogs happen after the "click" occurs and lever is released.

could be wrong, this is just my work-siesta recollection.

Obviously you have to release the lever. Shift to the larger cogs doesn't happen till you push the lever.

 

[ives]

Shift to the larger cogs doesn't happen till you push the lever.

What's this?????
You have to move the lever in order to shift gears???
And there was I thiking it was all done telekinetically.
Perhaps that's where I'm going wrong.

 

[boudreaux]

What's this?????
You have to move the lever in order to shift gears???
And there was I thiking it was all done telekinetically.
Perhaps that's where I'm going wrong.

We were talking STI.

 

[drewski]

Obviously you have to release the lever. Shift to the larger cogs doesn't happen till you push the lever.

i guess what i meant to say was that going to larger cogs happens when you push the lever (immediately), going to smaller cogs doesn't happen until you release the lever (after having pushed it).

are we saying the same thing?

that is to say, it doesn't work the same way in both directions. IIRC, Ergo shifting happens with the press of the lever for both up and down-shifting.

it's been over a year since i rode a campy ergo equipped bike so a bit foggy, but i tought it behaved a tiny bit differently (other than the thumb thing)!!

 

[boudreaux]

i guess what i meant to say was that going to larger cogs happens when you push the lever (immediately), going to smaller cogs doesn't happen until you release the lever (after having pushed it).

are we saying the same thing?

that is to say, it doesn't work the same way in both directions. IIRC, Ergo shifting happens with the press of the lever for both up and down-shifting.

it's been over a year since i rode a campy ergo equipped bike so a bit foggy, but i tought it behaved a tiny bit differently (other than the thumb thing)!!

It doesn't matter what we're saying.It has nothng to do with his issue.

 

[ives]

I think I might have made a bit of a breakthrough in what might be wrong.
Despite greasing the cables before I installed the STI's and despite running some light oil into the STI outer cables when I initially dismantled the system looking for what was wrong, I decided last night to squirt some WD40 into the outer cables.
This flushed out all the grease that I had put on the outer cables.
Now, it seems that the gears shift adequately.
They are not absolutely 100% perfect but pretty good and certainly I can live with them as they are now.
The tollernaces for friction on these cables must be tiny. I mean, they were well lubed before.