105 STI shifter - front ring shifter keeps breaking

[Newton]

I have a road bike that is about 8 months old, it's running full 105, 2 months ago the left hand shifter (the front derailleur shifter) appears to strip out the internals, so the break part works but the shifter feels like nothings inside. I take it back to the LBS and they order a new LHS shifter, they install the new shifter, check the cables and adjustment, the bike mechanic shifts the lever live 8-10 times and then the shifter strips out again, that's at the LBS & before I've even picked it up (this is about 4 weeks ago), they order another new shifter from Shimano and install it - test it about 10 times appears OK.

I take it to another bike shop for another opinion - the bike mechanic checks it and says it appears OK. So today I take the bike out for it's first ride since it's been repaired, 30 minutes into the ride the shifter breaks again, that's like another 10-20 shifts.

Has anyone had problems with the current crop of 105 shifters. I've found enough posts from other forums to know that Shimano have a problem with the current 105 shifters.

 

[chas0039]

I have a road bike that is about 8 months old, it's running full 105, 2 months ago the left hand shifter (the front derailleur shifter) appears to strip out the internals, so the break part works but the shifter feels like nothings inside. I take it back to the LBS and they order a new LHS shifter, they install the new shifter, check the cables and adjustment, the bike mechanic shifts the lever live 8-10 times and then the shifter strips out again, that's at the LBS & before I've even picked it up (this is about 4 weeks ago), they order another new shifter from Shimano and install it - test it about 10 times appears OK.

I take it to another bike shop for another opinion - the bike mechanic checks it and says it appears OK. So today I take the bike out for it's first ride since it's been repaired, 30 minutes into the ride the shifter breaks again, that's like another 10-20 shifts.

Has anyone had problems with the current crop of 105 shifters. I've found enough posts from other forums to know that Shimano have a problem with the current 105 shifters.

I read somewhere there was a batch of defective 105s and some sort of recall. Good luck with this, see if your shop will move you out out 105.

 

[alfeng]

A few things may be happening ...

Of course, you could be encountering a bad batch of shifters ...

It is possible that there is actually a problem with your front derailleur. I had two Ultegra 6500 front derailleurs which were fine (with downtube shifters) until I tried to use them with some 6500 STI shifters ...

After I contacted Shimano's Customer Service, they asked me to return the two front derailleurs & they sent me replacement front derailleurs -- 'my' problem was solved.
​

It is also possible that you are inadvertantly pushing BOTH levers at the same time and thereby destroying the mechanism.

OR, something else may be occurring ...

 

[kdelong]

Check the cable guide on the underside of your BB. If it is the plastic one, you might try replacing it. I had one that had a small groove worn in it that made shifting the FD extremely difficult. I discovered it when the cable casing finally blew out.

 

[cyclocommuter]

Has anyone had problems with the current crop of 105 shifters. I've found enough posts from other forums to know that Shimano have a problem with the current 105 shifters.

It appears there is a design defect with the latest 105 left brifter... I first read about this on the roadbikereview website where at least 2 recent reviewers gave poor marks because of this exact same problem. Since then I have read other complaints in other forums as well.

As a result, I will be getting either Ultegra Shifters (old 6600) or SRAM Rival gruppo instead of 105s for my all-weather/hack bike build.

 

[oldbobcat]

2 months ago the left hand shifter (the front derailleur shifter) appears to strip out the internals, so the break part works but the shifter feels like nothings inside.

I haven't had to deal with defective 105 front shifters, but I'm not saying they don't exist. I have learned a couple of tricks to setting them up right, though.

First, make sure the cable is seated properly. Getting the barrel end in its slot is no problem but the cable can be routed through the hole in the control lever without being properly seated in its slot.

Second, remember that all 105 levers are now designed for triple chainrings. If you have a double, the outer limit screw on the front derailleur is the only thing that prevents the shifter from thinking you have three chainrings. If cable tension and limit screws are not right you can overshift against the limit screw. Too many downshifts against a tightly wound cable will eventually cause the ratcheting mechanism to strip.

If you're using a double you should have four distinct derailleur positions, reachable using a light tap on the levers. On a triple make that six. If you can't find these positions, or if initiating downshifts requires a lot of force on the paddle, chances are the cable is tensioned too tightly against the outer limit screw.