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  1. #1
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    1983 Bianchi Randonneur Drive Train issue

    Hi there,
    This is my first post, and I am not the most knowledgeable about bikes, but am learning fast so please bear with me.
    I purchased a 1983 Bianchi Randonneur on saturday, and whilst it is in beautiful working order in 80% of ways, the drive train is causing me some problems.
    I took it down to my local bike co op for a workshop last night, and we discovered that their is some misalignment between the chain rings.
    Some basic info:
    Suntour Friction shifters and derailleurs the rear derailleur is a 3000, not positive of the front. It has a 3 ring casette on the front, 22-36-48, and a six speed on the back.

    The issue is presenting in that when I am in the lowest gear up front and try to upshift, it will not go onto the second ring, and will only shift all the way to the largest ring. We tried replacing the chain with a newer one with little jumps on it to help the shifting along, didn't work. We also replaced the front derailleur with a Shimano 600 as there was a little bit of a wiggle in the original, again, this did not fix the issue.

    We then looked at the chain alignment. When it is in the lowest gear front and back the chain is definitely veering to the right, as if it were cross-chaining. This means that the front and back casettes are misaligned, with the front casette being further out than the back.

    The mechanic suggested that we move the rear casette out by moving some of the spacers around and re truing the wheel. This is a big job and I am a little hesitant to leap into it. He seemed to think this issue was caused by someone converting it from a two ring to a three ring up front causing the casette to be pushed out, but researching shows me that these bikes came with a 3 ring casette.

    I guess my main question is, has anyone ever experienced this issue before, both the chain jumping the second ring and the misalignment.

    Any recommendations?

    Please excuse any abuse of terminology. I am learning, but if I am incorrect please call me on it, how else do you learn?

    Further side note: I am doing these repairs myself at the co op with a bike mechanic teaching me what to do, I am planning on riding to San Francisco this summer so am trying to educate myself prior to that.


    ETA: Both derailleurs were aligned properly as well, and the front chain ring cannot get any closer to the frame without the chain rubbing.
    Last edited by bianchi83; 04-09-13 at 12:25 PM. Reason: grammar, ETA

  2. #2
    Senior Member gyozadude's Avatar
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    If you are trying to shift from the small/small (F/R) to middle/small, you were indeed cross chaining and the chain will pull to the right towards the back. To check the chainline roughly, without going through the rulers and calipers, the easiest way is to site from the middle of the back to the middle of the front. Does it look sort of straight? If it is, and looking down at the crankset, is there a reasonable amount of space between the right chainstay and the small chainring? Is that gap more than 1cm? Is it less than 5mm? That can give you a rough determination if your chainline is causing major problems with shifting.

    Most likely, your issues are:

    1. Improper positioning of the FD - needs to be adjusted to the optimal height so it still clears the chainrings but the bends in the FD cage are at the correct height to move the chain from chainring to chainring.

    2. Improper FD for the application - The FD needs to be studied to determine if it was for a 2spd application, a half-step touring application, or for an MTB application. You have an MTB type of crankset with a super low granny 22. It's unusually and not a stock config. Older 1980's cranksets usually came stock with equal number spacing, like 28-38-48, or 26-36-46. Unless of course you had a touring bike config which would be 50-44-28, and then you'd be mostly using the top two chainrings with a fast, "half-step" FD. The small ring would be a bail out gear. So someone stuck a modified MTB crank. So that might be a likely cause because you have the wrong FD cage for the purpose.

    3. Check the orientation of the middle chainring. Is the bevel of the ring facing the same direction as the other big ring? Is the profile of the teeth the same as on the big ring? Shifting up on the front is the hard part and requires the ring and teeth present a profile that aids shifting. If the ring is flipped the wrong way, that can be an issue.

    There may be other issues, but those are the top 3. Spending effort to re-align the chainline is unlikely the cure. Also, you may want to avoid cross chaining in the first place.
    Yes, I can roll my own potsticker skins!

  3. #3
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    When siting from middle to middle the chain is definitely not straight. It looks straight when the front is at the lowest and the rear is mid/high, which is definitely not good. The distance from the right chainstay the smallest chain ring is almost 1.5cm.

    The crankset is definitely older, not a MTB though, as each of the rings is removable and reversable, something to Mechanic made a point of.

  4. #4
    Senior Member gyozadude's Avatar
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    I have an older 5 spoke MTB crank set with removable rings but my rings are not reversible. So beware. Back in the day, those were the only cranksets they had for MTBs. It does sound like your crankset is too outboard. What;s the clearance on the crank to chainstay when you back pedal and line the two up? What the crankset placed on a long spindle because of chainstay clearance issues? Is the gap the same on the other side? Sounds like you may want to try a narrower spindle. But we still don't know if the cage on the FD is for half-step gearing and this is an MTB style set of chainrings that was installed onto the same spindle without any thought about chainline. Or if the FD is set at the right position. Got a picture?
    Yes, I can roll my own potsticker skins!

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