Problem with 105 shifter

LpPepper

RH side/rear derailleur shifter won't shift into easier (larger) sprockets just this morning. Shifts into harder (smaller) sprockets just fine - will change into easier gear if I go one click into next smallest sprocket and immediately swing lever to shift to easier gear.

Weird thing is that when I put the bike upside down on floor it shifts perfectly.

Only had new cables all around a few months ago as rear derailleur cable actually broke before...

Any ideas??

lissard

Sounds like the cable tension is too low. You should have a barrel adjuster that you can use to fix this. Have a look where the cable meets the rear derailleur. Twisting the barrel adjuster here will tighten the cable and enable you to shift to the bigger sprockets.

LpPepper

lissard wrote: »

Sounds like the cable tension is too low. You should have a barrel adjuster that you can use to fix this. Have a look where the cable meets the rear derailleur. Twisting the barrel adjuster here will tighten the cable and enable you to shift to the bigger sprockets.

No that's not the problem from what I can see. Was shifting perfectly up until I got around the corner on my way to college this morning and just wouldnt shift into larger sprockets. Last day I used it was Sunday and shifted perfect.

Again the odd thing here is when I have it upside down it WILL shift into larger sprockets up until a certain point - nearly looks like cable is snagging on inside of the frame

tuxy

New cables will stretch a small bit and will usually have to be adjusted once after some use.
Also I've often moved the barrel adjuster by mistake when moving my bike around.
The tolerance from going from a smaller sprocket to a larger is lower than the other way around. At least try moving the barrel adjuster beside the derailleur 1/4 to 1/2 a turn anti clockwise to eliminate cable tension as the problem.

LpPepper

tuxy wrote: »

New cables will stretch a small bit and will usually have to be adjusted once after some use.
Also I've often moved the barrel adjuster by mistake when moving my bike around.
The tolerance from going from a smaller sprocket to a larger is lower than the other way around. At least try moving the barrel adjuster beside the derailleur 1/4 to 1/2 a turn anti clockwise to eliminate cable tension as the problem.

Cables are about 6 months old maybe, well over 1,500km on them. Tried turning barrel adjuster both ways but no difference at all

lissard

Are you able to manually push the derailleur inwards so that the chain ends up on the biggest sprocket? If you can do this, then it's definitely your cable that's at fault as it can't apply enough force to move the rear derailleur across the block. If you can't push the derailleur across the block it's the limit screws.

07Lapierre

LpPepper wrote: »

Cables are about 6 months old maybe, well over 1,500km on them. Tried turning barrel adjuster both ways but no difference at all

It should make a difference. A 1/4 turn or more should make a difference. If its not making any difference then there is a problem somewhere.

The fact that it works while the bike is upsidedown (when there is no pressure on the drivetrain) indicates to me that the problem is with your cable and/or the outer cable housing.

When you got new cables fitted, did they replace both inner and outer cables?

NeedMoreGears

I had a similar problem with 105 shifters recently. The cable had frayed inside the shifter causing it to snag. Like you, I could get the smaller gears on the back but not the bigger ones. This happened shortly after I installed a new cable; I assume I messed up somehow. Just be careful to make sure you get all the little bits of broken wire out the shifter or you'll have to replace the cable a second time (like me :o).