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  1. #1
    Tech geek and racerboy
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    New XTR- chainline solution: good or no?

    I recently installed new XTR crank/bb on my 01 Schwinn homegrown and came up with what seems to me is a simple solution to the chainline problems people seem to complain about on the review site. I'll describe what I did below, and I'm looking for input on whether this is a good idea or not, and if other people have tried it. If it matters, I'm a smallish (150lbs max) xc guy, and this is my primary race bike.

    I faced the bb shell with the super trick Campy bb facing tool, and chased the threads on both sides to make sure everything was perfect. I then installed the bb per shimano's instructions for my bike (68mm bb shell, non e-type), with two spacers on the drive side, one on the nondrive and attached the crankarms. It looked ok at first, but on coloser inspection I realized that the chainline was visibly off, with the chainrings too far out from the bike. So I reinstalled it with only one spacer on the drive side, and two on the nondrive (since the axle is too long for only one on each side). The nondrive cup still had about 9 threads to enguage with the frame, and the chainline is now as perfect as I've ever seen it on a mountain bike.

    Is this a viable solution to the chainline problem? Do people do this? Is it safe? It seems like a total no-brainer to me as a solution to the chainline problems people have with the new integrated shimano cranks, but it's not talked about by shimano and I haven't heard about it being done by others. What do people think of this?

    thanks in advance

    HTF
    A hardtail is forever

  2. #2
    jonny_mac
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    yeah...

    now check the distance from both crank arms to the chainstays. the non drive will be
    farther away from the stay then the drive side will be as the crank was not designed
    to be run this way. c'dale is shipping bikes like this and it feels weird to me to have
    my left leg further out then my right leg. although the chainline is correct.

  3. #3
    the catalan connection
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    Won´t that make the system sit off center?

    I´m getting a bit paranoïc about the whole integrated system, really.Specially now that I have one coming and will have to install it soon.
    I can´t think of anything going wrong besides you have moved the whole setup 2.5mm to the left, improving chainline, as you said, but moving the left arm out too.Can you feel it?mmm... ...maybe.
    Is the whole thing centered with the frame when installed as recomended ?I would say so.
    "Blessed is the man who, having nothing to say, abstains from giving us wordly evidence of the fact." George Elliot

  4. #4
    Tech geek and racerboy
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    Feels fine...

    Quote Originally Posted by What&son
    I cant think of anything going wrong besides you have moved the whole setup 2.5mm to the left, improving chainline, as you said, but moving the left arm out too.Can you feel it?mmm... ...maybe.
    Is the whole thing centered with the frame when installed as recomended ?I would say so.
    It's centred when installed as directed- 2.5mm off when installed as I did with 2 spacers on the left. I haven't ridden them more than just a hot lap, so I can't speak to the long term affects. I run eggbeaters and they have lots of float and a few mm variability in cleat position when clipped in, so I don't think it'll make much difference. It actually makes me feel better knowing that a major manufacturer (cannondale) is willing to ship bikes that way. It may not be perfect, but it's probably safe. I imagine different pedal systems will affect how much people can feel the 2.5mm offset.
    A hardtail is forever

  5. #5
    mtbr member
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    Space your pedal

    Quote Originally Posted by Hardtailforever
    It's centred when installed as directed- 2.5mm off when installed as I did with 2 spacers on the left. I haven't ridden them more than just a hot lap, so I can't speak to the long term affects. I run eggbeaters and they have lots of float and a few mm variability in cleat position when clipped in, so I don't think it'll make much difference. It actually makes me feel better knowing that a major manufacturer (cannondale) is willing to ship bikes that way. It may not be perfect, but it's probably safe. I imagine different pedal systems will affect how much people can feel the 2.5mm offset.
    I do this with all my cranksets to get a better chain line ! Any LBS that does fittings will have 1,2 or 3 mm pedal spacers just measure from the center of your seat tube and equal out the distance!
    Spin

  6. #6
    83 feet less per minute
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    Race Face has the same directions for the Deus XC crank. By their directions, my chainline was off. I put the spacers on just as you, two on non-drive side, one drive side and ended up with 47.5 mm chainline. This on an '03 Enduro, 68 mm BB shell. So far, so good.

  7. #7
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    5 mm off

    Remember that switching the spacer de-centers the crank by 5 mm, not 2.5. The left crankarm is 2.5 mm closer to the center and the right crankarm is 2.5 mm farther from center. I do this to, and I have a body assymetry that makes this offset of the pedals actually fit me better (caused by a broken ankle along time ago). But you may find that offsetting things in this way will lead to overuse injuries like patellar tendonitis. You can shim the pedal spindles back to center, but that increases the already pretty large Q of the XTR crank. If you run shimano pedals you can shift the cleats over under your shoes, and eggs do allow some sideways movement of the cleat in the pedal.
    I say run it offset because the narrower chainline is better IMO, but as you ride it be aware of any unusual pains in your knees, hips, and ankles. If you do not have any problems then all is good. If you do find yourself getting unusual pain be aware that the offset is probably the cause.

  8. #8
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    Only 2.5 mm

    Quote Originally Posted by barrows
    Remember that switching the spacer de-centers the crank by 5 mm, not 2.5. The left crankarm is 2.5 mm closer to the center and the right crankarm is 2.5 mm farther from center. I do this to, and I have a body assymetry that makes this offset of the pedals actually fit me better (caused by a broken ankle along time ago). But you may find that offsetting things in this way will lead to overuse injuries like patellar tendonitis. You can shim the pedal spindles back to center, but that increases the already pretty large Q of the XTR crank. If you run shimano pedals you can shift the cleats over under your shoes, and eggs do allow some sideways movement of the cleat in the pedal.
    I say run it offset because the narrower chainline is better IMO, but as you ride it be aware of any unusual pains in your knees, hips, and ankles. If you do not have any problems then all is good. If you do find yourself getting unusual pain be aware that the offset is probably the cause.
    All you are doing is moving the chain line in 2.5 mm not 5 mm and therefore only move the
    left arm 2.5 mm out if and when you use a 2.5 mm spacer to center the pedals do you get to 5mm and then with a "Q" factor increase of 2.5mm.
    Spin

  9. #9
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    i changed the chainline on my blur several months ago with no ill effects. just shim the pedal axels and life is good. i did this after a rash of broken chains, and it has worked thusfar.

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