105 shifter

[roadiewill]

Hi, just been out on my new tarmac (105 groupset). The right hand shifter for the small chainring was shifting smoothly through he gears. However, the left hand shifter for the big chainring didnt want to shift down...it felt almost stuck.

Anyone know what the problem is/how to solve it?

 

[Mortiroloboy]

Disconnect the cable where it goes into the FD and this should release the spring mech, re-connect the cable and it should work again, I had this happen to me in the summer at the foot of Walbury Hill, my Campag FD stuck on the big ring, I took the cable out, the FD spring released, after connecting the cable back again no further problems.

I was told it occurs when you try to change down under extreme load, hence my problem on Walbury Hill!

Always try and avoid changing under exteme load.

 

[Radius]

Mortirolo is right, but when you release the cable, if it's in the biggest chainring and a high sprocket (as it should be in that combination), the front mech will spring downwards a bit and get stuck most likely. It's best to adjust cable tension at the front in lowest gear, even if this means (in your case) shifting down slowly, and physically moving the chain until it's on its lowest combination...hope that makes sense.

 

[roadiewill]

Disconnect the cable where it goes into the FD and this should release the spring mech, re-connect the cable and it should work again, I had this happen to me in the summer at the foot of Walbury Hill, my Campag FD stuck on the big ring, I took the cable out, the FD spring released, after connecting the cable back again no further problems.

I was told it occurs when you try to change down under extreme load, hence my problem on Walbury Hill!

Always try and avoid changing under exteme load.

Whats the FD?
thanks

 

[Radius]

Front Derailleur

 

[roadiewill]

By disconnecting the cable do you mean undoing the allen key clamp the holds it taught?

 

[Radius]

Yeah, the bit being pointed at by the allen key here:

and in your case, it can be seen at the top here:

But note again, that if you remove the cable in the highest chainring, you wont be able to reconnect it to the correct tension, because up there the tension is too high. That's why you need to be in a lower gear at the front (and back)

 

[roadiewill]

OK i did that but now I seem to be stuck in the small chainring... i.e it wont shift up to the large chainring.

 

[Radius]

What exactly have you done so far? You may have pulled the cable too tight when you reconnected it.

 

[roadiewill]

OK, the chain was stuck on the big front chainring.
I shifted the chain onto the smallest rear cog to reduce tension.
Then I undid the FD cable.
The FD sprung back inwards as it should.
I pulled the cable as taught as I could, which isnt really taught -I can still bend it.
Tightened the allen key clamp.
Went to shift the front chainring from the small one to the large one and nothing happened.
The FD didnt make contact with the chain to scoop it up.

 

[Radius]

Ok, what you need to do is get the chain down to the smallest chainring to adjust the tension properly. I know you can't shift, so, shift down one position by clicking (don't turn the wheels), then physically (with your hands) lift the chain down a ring, and so forth until you're on the smallest. Make sure your rear mech is on the smallest sprocket as well.
Then adjust the cable tension, pull it through with your hands, but not quite as tight as you can pull it (at least I don't have to), then check by shifting up and down. If the problem persists, re-adjust as necessary. If it's not quite reaching enough to shift up, there is too little tension (unless the levers are hard to pull to shift up, then there's too much, but it doesn't sound like that)

 

[roadiewill]

so small on the front and on the back?

 

[Radius]

Yes. That will basically eliminate any existing cable tension, meaning that to increase it doesn't involve having super human strength and a big wrench thingy.

 

[roadiewill]

ok thanks il let you know how it goes

 

[Radius]

Good luck