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  1. #1
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    Floated my chain on my middle chainring

    Shifted my weight onto a pedal on the down stroke (right pedal, actually).

    Immediately went to neutral.

    In my middle chain ring, I've actually got everything adjusted properly. The chain jumped off the chain ring, floated above it (I guess it balanced the part between links on the teeth?) for a few rotations(!), then recoupled to the chain ring again. Didn't do a magic shift (I've had my RDR do a magic downshift when my rear wheel slammed a bump off road), just floated above the chain ring for a second.

    ... what?

    I think I'm going to figure out the FDR this weekend. It's still crap in the lowest ring. I've adjusted and indexed it properly in the middle ring; but my lower limit screw... it's a shimano, it has tilt screws that tilt the bottom in and the top out. Anyway, bottom tilt, if I bring it in close enough to not rattle on my biggest gear in my smallest chain ring (low-low), I occasionally drop the chain between the small chain ring and the seat post. It's adjusted so I don't throw the chain into my frame now, but it actually rattles fiercely in my biggest 2 gears ... oddly enough, it's perfectly smooth in all 8 gears on my middle chain ring.

    I'm doing something wrong I swear.
    Own: 2010 GT Tachyon 3.0
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  2. #2
    bike whisperer Kimmo's Avatar
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    Ah, the joys of attempting to set up front triple indexing. Abandon hope, all ye who enter here.

  3. #3
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    Quote Originally Posted by Kimmo View Post
    Ah, the joys of attempting to set up front triple indexing. Abandon hope, all ye who enter here.
    Wait until I change my crankset (I want a 28-38-48 instead of 30-42-52) and have to do it all over again!

    Also I hate my cheap stock cables, because well... they stretch a lot. Oh god, that reminds me, I need to adjust the brake cable on my front brakes; I've been using my rear brake to compensate. The cables stretch SO MUCH that if I adjust them nice and tight with 1/2 pull giving me brake touch, I can actually loosen them up by squeezing my brake lever all the way 3 or 4 times. I checked the length of cable at the brake itself... I adjusted that nut tight, too... it's not slipping; the cable actually stretches in some impossible way. No way is steel this ductile.

    I'm tempted to buy some higher end cables (possibly smooth or those black coated ones) and redo everything. Shifters, brakes, the works. But I want to get everything adjusted right first so I know I can do it; I don't want to yank my RDR cable off, then come back and go ... oh, you know what? I've only ever messed with my FDR, what the hell am I doing? And now I need to have a bike shop set it up for me...

    REI gives a bike maintenance class for FREE, and I FORGOT to go to it when I signed up. I am dumb. They would have taught me all this crap.
    Own: 2010 GT Tachyon 3.0
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  4. #4
    bike whisperer Kimmo's Avatar
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    It's not rocket science; if you stare at it long enough, sooner or later the problem becomes apparent.

    Although in this case, IMO part of the problem is indexing on front shifters; they should be friction or micro-indexed like Ergos. The available trim positions, if any, are often unsatisfactory. I've resorted to tweaking the derailleur cage in the past.

  5. #5
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    The shimano website has, or at least used to have, good instructions for setting up a front (or rear) derailleur. It is an exacting process. As far as cable stretch is concerned, it's more an issue of properly (firmly) seating the housing within all of the cable stops and barrel adjusters that are encountered. Most bicycle cable is pre-stretched when you buy it. Read about this topic on the sheldon brown site; his article on cables, especially the part about preparing housing, is very good. This applies especially for brakes, but also shifters/derailleurs.

  6. #6
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    I've already said that if I ever have need to replace my shifters, I'm getting friction shifters. At a point I immediately wanted to say indexed is for racing; but it seems to me that skill with a friction shifter would come more naturally, so I don't know. Preference. You learn not to freak out and twist the handle too much, you feel when it shifts, you automatically reflex ... this could be very fast. As fast as a tuned SRAM cage that only shifts on a certain cluster with X gears with specific spacing trigger-trigger-trigger? Don't rightly know.

    I'm not racing anyway. If I was I'd probably blow the gears off my bike; I don't think it handles high torque, because I've had the chain jump off gears or other stupidity several times just by pushing the pedals too hard. It needs adjustments :|
    Own: 2010 GT Tachyon 3.0
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  7. #7
    Elitist Troglodyte DMF's Avatar
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    Ignore the above. The problem is a worn out middle ring.

    Replace and ride.



    There is a chance that it's a mismatched chain. Check your chain wear first.
    Stupidity got us into this mess - why can't it get us out?

    - Will Rogers

  8. #8
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    How is anything worn out when the bike has about 320 miles on it total, brand new? Are my chain rings stamped instead of forged? I'm not that strong, me on a bike is not a 1HP vehicle.
    Own: 2010 GT Tachyon 3.0
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  9. #9
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    Quote Originally Posted by DMF View Post
    Ignore the above. The problem is a worn out middle ring.

    Replace and ride.



    There is a chance that it's a mismatched chain. Check your chain wear first.
    Given the mileage, worn chainring seems like a remote possibility, however it could still be a bent or broken tooth. Also, a worn chainring wouldn't account for brake cable stretch, so some of the above may indeed be relevant .

  10. #10
    Elitist Troglodyte DMF's Avatar
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    Quote Originally Posted by bluefoxicy View Post
    How is anything worn out when the bike has about 320 miles on it total, brand new?
    Well you might have mentioned that before.


    I don't know if it would cause the symptom, but check that the middle ring isn't on backwards.
    Stupidity got us into this mess - why can't it get us out?

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  11. #11
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    http://www.performancebike.com/bikes..._1032122_-1___

    http://www.performancebike.com/bikes..._400002_400928

    Think these are okay for cables? They look way better than the stuff I have now, which I'm wearing gloves to touch because the cables are like handling steel wool; you will get bits of steel embedded in your fingers. My front derailleur cable even snapped off at the derailleur; the bit at the end broke off just from riding (80 miles in), luckily just the excess went and not the side attached to the shifter. <_<;

    Hmm, I think I'll go to a different bike shop though. I don't want to give the one I bought from any more business. The one downtown seems to have competent mechanics, and I'm tempted to just pay them to do all the adjustments for my brakes/shifters. I've already ranted about the shop I bought from, they are simply incompetent.

    At this point, though, I started making my own adjustments ... I could pay a better shop to do it right, but I gotta finish what I started, you know? It's like having a messy apartment and never cleaning it, and the girl next door says she'll clean it up for you... that'd be cool but what good is it if you can't clean up your own mess? I'm just being lazy; I got it to shift up front without constantly skipping and grinding and getting stuck between gears (I had to shift back and forth sometimes or it'd just grind and slip off!) or falling clean off the chain ring, and then I stopped messing with it. Gotta actually get in there and fix it right.
    Own: 2010 GT Tachyon 3.0
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  12. #12
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    Quote Originally Posted by DMF View Post
    I don't know if it would cause the symptom, but check that the middle ring isn't on backwards.
    Before the days of ramped and pinned rings, it was routine to flip the ring in order to double its life. Surly, Salsa, and others make ramp- and pin-less rings for those who choose to use a single ring up front and specifically advertise the ability to flip the ring for increased life. That said, the aforementioned ramps and pins (to aid shifting to a larger ring) likely preclude this possibility. Also, I think some (many?) modern rings are asymmetrical with respect to chainline; this is the case with my Race Face crankset, which uses CNC machined middle and outer rings.

  13. #13
    Elitist Troglodyte DMF's Avatar
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    A lot of modern rings seem to use a counter bore on the bolt holes as positive indicator of which way 'round they're supposed to go.

    But I gotta say, from the way bluefoxicy describes things, this sure doesn't sound like a "brand new" bike. Maybe he's been sold a bill of goods?

    I really want to hear what he measures in the way of chain wear.
    Stupidity got us into this mess - why can't it get us out?

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  14. #14
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    I got my bike from a discount shop that runs on commission and tried to sell me a bigger bike when mine was too high (I wasn't sure about my feet not reaching the ground from the seat, and they said that they can get me an extra large instead of a small so I'd be closer to the ground). I kept the one I was looking at, turns out it's sized correctly anyway. A second associate gave his opinion, asked me my inseam for my pants and eyeballed the bike (which was just "Small" and has no meaningful numerical measurements) and said a larger bike would be bad.

    The bike has linear pull brakes. When I got it, one pad contacted immediately, the other swung in, same issue another poster is having with his brakes that don't provide any braking force. I took it back to them a month later when it threw the chain the first time, as they said after a month the cables would stretch and need adjustments. When i got it back, brakes were still poorly adjusted, with one pad right against the rim and another far away. Also, in the large cog, the chain cage rested against the chain with no clearance, rattle rattle rattle as I pedal, fresh out the bike shop door.

    This is why I'm doing my own half-assed adjustments, trying to figure out how to tune my bike properly. The brakes and shifters are obviously completely out of whack, and sending it back to the mechanic in the shop I bought from gets me really crappy adjustments. The wheels seem mostly straight; if I squeeze the front brake a bit I get a rub-rub-rub at one position on the wheel, which I'm told is normal if it's just a slight deformation, like 1/3 of a mm or something. I've never been able to produce the "musical note" sound out of my spokes, so I'm not sure if the wheel is off true or if I have no clue what I'm doing; I assume at least part of the latter, but that's fixable too.

    At this point, I think they only know how to tug the cable to make sure it's tight enough; I'm unconvinced they even know how to operate any of the other screws that provide fine adjustments for various aspects of the derailleurs or brakes. They sure don't know how to operate a mounting screw, unless you're SUPPOSED to shred it by cross-threading when mounting a bicycle computer (yeah, they destroyed it, I found out when I decided I didn't want it wobbling on my handle bar anymore and examined the mounting screw--it was obviously damaged, and backing it out revealed just how much).

    I'm told that brand new bikes get set up before they leave the shop. With crappy mechanics, maybe a brand new bike seems more like an old garbage clunker from a garage sale. Fortunately, I'm fascinated by everything, and will inevitably become a halfway decent bicycle mechanic. Not yet though. Also I found a decent bike mechanic, but I'm reluctant because I want to figure stuff out on my own....

    So here I am, struggling to be my own mechanic with no tools except a bike pump and a multitool.
    Own: 2010 GT Tachyon 3.0
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  15. #15
    Elitist Troglodyte DMF's Avatar
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    It is MUCH easier to learn when you can do a single adjustment and evaluate the result. As it is now, you might do the correct adjustment but because something else is out of whack you can't tell that you got it right (or not). Pay the mechanic to set it up right, then start "learning" on it. A good mechanic will often answer questions or even show you what he's doing.

    Do you know how to measure chain wear?
    Stupidity got us into this mess - why can't it get us out?

    - Will Rogers

  16. #16
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    Quote Originally Posted by DMF View Post
    It is MUCH easier to learn when you can do a single adjustment and evaluate the result. As it is now, you might do the correct adjustment but because something else is out of whack you can't tell that you got it right (or not). Pay the mechanic to set it up right, then start "learning" on it. A good mechanic will often answer questions or even show you what he's doing.

    Do you know how to measure chain wear?
    +1

    I might add that the trial and error approach will lead to a lot of frustration. That said, you can adjust pretty much everything on the bike with your multi-tool. There are a lot of good online resources in addition to this forum.

    www.sheldonbrown.com and www.parktool.com are highly regarded, well-written, and fairly authoritative resources.

  17. #17
    Senior Member CACycling's Avatar
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    I assume you bought this bike this year. Is this correct? If so, take it back and have them fix it.

  18. #18
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    Quote Originally Posted by bluefoxicy View Post
    The cables stretch SO MUCH that if I adjust them nice and tight with 1/2 pull giving me brake touch, I can actually loosen them up by squeezing my brake lever all the way 3 or 4 times. I checked the length of cable at the brake itself... I adjusted that nut tight, too... it's not slipping; the cable actually stretches in some impossible way. No way is steel this ductile.
    You are correct - steel is not that ductile. Something, somewhere, is slipping. Perhaps the housings was not seated properly in the stops, perhaps the housing or ferrule (housing end cap) is damaged, or maybe the housing was cut too short. Or maybe the pads are moving to allow the brakes to get looser.

    Whatever it is, you are not actually stretching the cable. In fact, what we trationally call 'cable stretch' is not stretching at all, but compression of the housing, which makes it seem like the cable is stretching.

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