I'm disappointed with my new Cannondale and it's 105 group, I expected this to be a major upgrade from my previous trouble free bike with the bottom end group set. It's done about 500 miles, had new cables, a new chain and rear derailleur re-alignment and numerous adjustments over the 5 service visits between 2 dealers and it still doesn't shift smoothly every time. Over a 2 hour mixed terrain ride it will miss-shift several times.

It seems to be mainly an issue with the 3 black colored gears in the center of the cassette, regardless of small or big chain ring. Sometimes when up or down shifting the lever clicks as normal but the chain does not move to the adjacent gear, click again and it moves and stays there until the next shift. Other times I would down shift in anticipation of a hill, the chain appears to have moved, but when I stand it slips.

Both of these issues happen randomly and spoil my riding pleasure, does anyone have any thoughts on what the issue might be?

  • 5
    This definitely isn't true to form, a 105 groupset should be pretty slick. You say you've changed the chain, did you ever change the cassette? I'm just trying to get a complete picture of what you've done here - at the end of the day 500 miles is nothing for this level of gear. Another question is whether you changed the chain to address the problem, or whether the problem started after you changed the chain. I'm just thinking compatibility between different parts.
    – PeteH
    Commented Jan 3, 2015 at 22:02
  • Pretty much agree with PeteH, the new 11speed 105's are pretty slick, I've found them to be at least as reliable as the previous generation Ultegra's. One question I would add to the ones Pete asked is which model Cannondale do you have? Commented Jan 3, 2015 at 22:44
  • Is this on a new bike or a (used) new to you bike
    – mikes
    Commented Jan 3, 2015 at 23:00
  • 2
    Are you sure the derailleur is not bent?
    – Batman
    Commented Jan 4, 2015 at 5:03
  • I don't know what's wrong, but I will tell you a story. My SRAM Rival front shifting never worked properly. Despite having SRAM cranks, chain, everything matching. From when the bike was new, every few months it would start throwing the chain outside. I had it adjusted in two different shops, and it would be fine for a few months then back to broken. Eventually I convinced SRAM to replace the front derailleur and it has been magically OK ever since. So, defective derailleurs are apparently possible...and not easy to diagnose. Commented Jan 4, 2015 at 12:13

5 Answers 5


Assuming that the cabling is clean, that the derailleur is nicely indexed and well alligned, the derailleur hanger not bent, and the chain correctly moves lateraly +/- 4mm for each gear up or down, then I would have a look at the distance between the upper jockey pulley and the sprockets.

The distance should be on all sprockets less than 25 mm and more than 12 mm. I suspect that your distance is slightly too high, meaning that the chain has too much room and can flex.

The way to adjust this is by loosening the B screw, as described on this page.

I had the same problem on a 105 derailleur on one of my bikes. B screw was loosened to the max, and I was still too far from the sprockets compared to my other bikes. I managed to file the part of the derailleur hanger touching the support of the derailleur where the B-screw is, to shorten this distance even more. Now it shifts very well.

  • Gidday and welcome to SE Bicycles. Excellent first answer, I look forward to your future contributions.
    – Criggie
    Commented Jan 15, 2016 at 21:57

Chris- first culprit is the barrel adjuster. New cables tend to stretch. As a result, small adjustments need to be made to cable tension to keep shifting 100% dialled in. Doing this at home is fairly simple, and there are many great tutorials online about how to do this yourself, here is a link to a great video from Art's Cyclery.

if you still have trouble dialling in your shifting the next most likely culprit is a slightly bent derailleur hanger. This can actually be a quick and cheap fix at a bike shop, as they have a tool to bend it back into alignment (instead of totally replacing the hanger).

In summary, try watching the video, and if you still have trouble try visiting a new shop!


As previously stated - the mileage you have done - should not affect the gear change. Your drive-train is still very young. Check the cabling - in particular the gear cabling entering the lever. The newer 105 (5700 onwards) use under bar tape cabling. In some cases - I have seen the inner gear cabling can end up being pulled through the gear ferrule cap. This will cause the unreliable shifting you are describing. It will need replacement of the section of gear cable from lever only.

  • The shifter cables were replaced already, but I did double check as you described and they look ok. I guess I need to find a different bike shop. Commented Jan 25, 2015 at 18:28

Silly question, but have you tried indexing your gears? I had hell with my 105 groupset (Cannondale too) when I first got it a couple of years ago.

The problem I find with gears is that if you start messing with all of the different settings, it can throw the whole system of entirely. It took me forever, partly because I was a novice at the time, to get them shifting properly again. Double check all of your alignments and positioning of your dérailleurs and then perform and indexing on your gears.

Put the chain on the inner chain-ring and on the largest cassette, ensuring that your gear lever cannot go down in gears any further. Now click your rear gear lever once, and once only. If it doesn't change gear to the next one on the cassette, use the barrel adjuster located on the rear-derailleur until the gear correctly shifts to the next gear and doesn't make any rough, catching noises. This should automatically progress through the whole range of gears without any further adjustment.

If you're convinced that the rest of it is set up correctly, I would be inclined to make sure that your rear axle isn't bent. I have an old wheel where the rear axle was made from a soft metal and subsequently bent whilst riding. This had a knock-on effect of causing my rear cassette to wobble with every wheel revolution and sometimes throw the chain's position off when shifting.


Certain-year 105 shifters fit POS category. 2011 105 set, after 4500 miles. Downshifting wasn't happening. Saw signs of a cable-strand failure, figured it must have been broken in shifter. Pulled back hood and multiple strands had failed. Pulled cable as best possible, many strand-ends in shifter cable path. 20 min just digging strands out of plastic innards with needle-nose pliers and tweezers. Went to LBS for cables, seller said "that's what happened there," pointing to a gorgeous white cannondale. She also mentioned "check cable first when shifting gets gunky."

  • Could you please use Edit and expand "POS" ? I can't understand it from the context.
    – Criggie
    Commented Oct 8, 2016 at 23:05
  • POS is probably "Piece of Shit". I don't see any reason why this shifter would have accelerated cable wear -- sometimes you just get unlucky and the cable goes.
    – Batman
    Commented Oct 9, 2016 at 0:01
  • Welcome to Bicycles! We recommend that new users take the tour so that you can make best use of the site. Writing clearly in full sentences is appreciated too.
    – srank
    Commented Oct 9, 2016 at 14:53

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