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Strange Shimano ultegra gear shifter intermittent failure

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  • August 16, 2016 at 12:12 am #26144
    terrycojones

    I have an Ultegra groupset and have been experiencing weird intermittent shifter failures and am wondering if anyone else has had the same thing or if people can suggest a possible cause.

    The problem occurs every now and then (half a dozen times on a 120km ride last weekend). The symptom is that on my right shifter (controlling the rear cassette), shifting to a higher (i.e., smaller cog) gear sometimes becomes impossible. The shift lever can be pushed to the left and doesn’t encounter any resistance – no “click” feel when the gear change is initiated, nothing.

    This happens frequently when I have been out of the seat on a climb. I’ll get to the crest of the hill and will go to change up a gear and… nothing. So I’m stuck in the low gear, spinning faster and faster as the road levels out.  It doesn’t always happen after climbing, sometimes it will happen under a fairly normal cycling load on the flat. It just seems that the added power increases the likelihood of the shifter dropping out, but I don’t see how that could be. None of it makes sense to me though, so I mention it.

    I don’t have a way of fixing the shifter. I’ve tried changing to an even lower gear, changing to the small front ring, getting off the bike and moving the rear derailleur around by hand. What works is just to wait – somewhere between 30 seconds and a few minutes – and the shifter returns to normal.

    Last weekend I installed a brand new rear cassette, a new derailleur and a new chain (all of this for other reasons) but the problem persists. So it seems like the problem must be with the shifter, but what could it be?

    There’s one thing I’ve done which I’m told I shouldn’t have: occasionally spray some WD40 into the shifters. Apparently this can cause a residue build up. Maybe that’s somehow occasionaly causing the shifter to drop out?

    I made a couple of videos of the shifter in its non-functioning state, which do a better job of showing what’s going wrong than all the above words: http://jon.es/other/chris1.mp4 and http://jon.es/other/chris2.mp4

    Thanks for any help / suggestions!

    Terry

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  • August 17, 2016 at 11:03 am #876745
    0
    duncanap

    It may not be relevant but I

    It may not be relevant but I had something similar when my hoods (the rubber covers) stretched and moved.

    i seemed like the hoods were providing the return spring so you could shift once but the would just get a soft lever.

    could be worth a check.

    August 17, 2016 at 8:54 am #876743
    0
    TypeVertigo
    terrycojones wrote:
    @TypeVertigo – thanks, that sounds super helpful, and like it could be the cause. I’d never even heard of pawls. I should probably play more Scrabble 🙂 Anyway, I’ll go track down the Art’s Cyclery video.

    Allow me to help point you in the right direction.

    https://www.youtube.com/watch?v=9657OoOY3oE

    The video shows SRAM DoubleTap levers, and the products used are White Lightning Clean Streak for cleaning (vs WD40) and Slick Honey + Boeshield T-9 for relubrication (vs regular Shimano grease + Tri-Flow Superior Soy Lube), but it’s still basically the same method.

     

    There’s also “RJ the Bike Guy,” another YouTube channel. RJ’s hobby is buying old or inoperative bikes and restoring and/or upgrading them to modern drivetrains; some of these projects he keeps while the rest he sells. He mentions the WD40 fix a lot, and he has so many videos detailing the technique – below is one of them. The fix works even with flat-handlebar MTB trigger shifters.

    https://www.youtube.com/watch?v=JbgsJRt-h1A

    https://www.youtube.com/watch?v=49lAdo_vUX4

    I hope this helps.

    August 16, 2016 at 11:17 pm #876741
    0
    terrycojones
    arckuk wrote:
    I’ve had a similar, though less severe issue with my Ultegra (6700 – 10 speed) shifters. It will sometimes be the case that shifting to a smaller cog results in no click, and a lack of the usual slight resistance that is associated with the shift. This is pretty much always solved by repeating the shift action. I’ve assumed it was down to poor engagement of the sprockets in the shifter and/or resistance in the cabling. 

    I’ve also found it difficult to adjust the read derailleur position to get consistent gear indexing – twiddling on the barrel adjuster never seems to get things as perfect as they are on my 105 (5800 – 11 speed) shifters.

    I changed the cable a month ago or so, mainly to try and get the indexing to improve, which it has slightly, but thinking about it I think the failed shifting hasn’t occured since, so maybe this has solved it. Maybe a replacement of the cable outers (which I changed a year or so ago) and perhaps a look at the bend radius in the cables would also improve things. I find the action of both 6700 levers to be significantly stiffer than my 5800 equivalents.

    Sounds like the same thing, but repeating the shift action has no effect for me (see videos). For me it’s just a matter of time until it comes good again. That would be, I think, consistent with the shifter being a little gummed up – something sticks and doesn’t return to its usual place, but after a minute or two it slips and reverts to normal.

    Re gear indexing, I’m getting better at it. There’s no stiffness at all in shifting (when it works). In your case you might have slight cable fraying – that will really cause a big increase in stiffness. I had that happen recently (on the front rings) due to rubbing where the cable entered the frame.

    Thanks!

    August 16, 2016 at 11:12 pm #876739
    0
    terrycojones
    Acm wrote:
    On older Shimano shifters, a similar thing would happen if you put some pressure on the brake lever (started to shift to a larger/easier sprocket) and the pushed the lever for a smaller (harder) sprocket. I’ve no idea if this is the case for the newer shifters but it might be

    if the new shifters do work in the same way, I’d suggest that the cause is something to do with the ratchet not returning properly after shifting to a larger sprocket, which could be because the shifter is gummed up but might also be because the cables need replacing.

    for what it’s worth, I stripped a Shimano STI shifter down once and it was a bitch to get it all back together. It still works, but I had to leave out a return spring in the shifter so my advice would be not to try and take it apart!

    Thanks for this. I think it’s more likely the shifter than the cable, as this (also) happened with a cable that was brand new (was installed the same day by someone who knew what he was doing, not me!). I’ve also heard that you should never try to disassemble an STI shifter… thanks 🙂

     

    August 16, 2016 at 11:09 pm #876737
    0
    terrycojones

    @TypeVertigo – thanks, that

    @TypeVertigo – thanks, that sounds super helpful, and like it could be the cause. I’d never even heard of pawls. I should probably play more Scrabble 🙂 Anyway, I’ll go track down the Art’s Cyclery video.

    August 16, 2016 at 9:47 am #876735
    0
    arckuk

    I’ve had a similar, though

    I’ve had a similar, though less severe issue with my Ultegra (6700 – 10 speed) shifters. It will sometimes be the case that shifting to a smaller cog results in no click, and a lack of the usual slight resistance that is associated with the shift. This is pretty much always solved by repeating the shift action. I’ve assumed it was down to poor engagement of the sprockets in the shifter and/or resistance in the cabling. 

    I’ve also found it difficult to adjust the read derailleur position to get consistent gear indexing – twiddling on the barrel adjuster never seems to get things as perfect as they are on my 105 (5800 – 11 speed) shifters.

    I changed the cable a month ago or so, mainly to try and get the indexing to improve, which it has slightly, but thinking about it I think the failed shifting hasn’t occured since, so maybe this has solved it. Maybe a replacement of the cable outers (which I changed a year or so ago) and perhaps a look at the bend radius in the cables would also improve things. I find the action of both 6700 levers to be significantly stiffer than my 5800 equivalents.

    August 16, 2016 at 9:00 am #876733
    0
    Acm

    On older Shimano shifters, a

    On older Shimano shifters, a similar thing would happen if you put some pressure on the brake lever (started to shift to a larger/easier sprocket) and the pushed the lever for a smaller (harder) sprocket. I’ve no idea if this is the case for the newer shifters but it might be

    if the new shifters do work in the same way, I’d suggest that the cause is something to do with the ratchet not returning properly after shifting to a larger sprocket, which could be because the shifter is gummed up but might also be because the cables need replacing.

    for what it’s worth, I stripped a Shimano STI shifter down once and it was a bitch to get it all back together. It still works, but I had to leave out a return spring in the shifter so my advice would be not to try and take it apart!

    August 16, 2016 at 7:41 am #876731
    0
    TypeVertigo

    I can’t play your video files

    I can’t play your video files because they seem to be corrupt.

    Spraying WD40 into the STI lever internals is actually what you SHOULD be doing – it’s one of the few acceptable uses of the product on a bike. Art’s Cyclery’s Ask A Mechanic video series on YouTube mentions this exact same procedure. Over time the grease gets old and makes the STI levers stop working because the ratchets and pawls don’t catch each other the way they’re supposed to. The pawls are responsible for the clicking per shift. The WD40 acts as a solvent, removing the old gummed-up grease in the internals.

    Work the WD40 into the mechanism using the shift levers, then wait for it to dry out.

    Once dry, you’ll want to regrease the internals – those you can reach from outside. Remember, WD40 isn’t a great lubricant. Ordinary Shimano grease and Tri-Flow Superior Soy Lube works fine for the job, in my experience; the Art’s Cyclery mechanics mention a couple of other spray lubes and greases they use such as Boeshield T-9.

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