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  1. #1
    Transition Blindside v5
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    New question here. Q: shift ramps and pins on middle chainring ?

    I have a silly question here...

    When installing a middle chainring that has shift ramps and pins, does it matter at all as to where they're placed, in relation to the direction of where a crankarm is pointed at?

    I ask this because I'm thiniking of rotating the ring once in a while (for an even wear), but... In the case of 4-bolt ring like the pic below, the ramps/pins are not evenly spaced per the chainring-bolt holes. (Maybe rotating 180 will probably be the same, but rotating 90 will change the ramp/pin locations in relation to the crankarms.) So, just wondering if that makes any difference in shifting, etc.

    Thanks for your feedback in advance,
    - PiroChu
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  2. #2
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    Yup. Only rotate it 180 degrees to take advantage of them.
    A 90 degree rotation will defeat their purpose.

  3. #3
    Transition Blindside v5
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    New question here. And, just to be sure...

    Quote Originally Posted by Elzippo
    Yup. Only rotate it 180 degrees to take advantage of them.
    A 90 degree rotation will defeat their purpose.

    Thanks, that makes sense.

    Also, just to confirm, the middlering should be always installed in such a way that the ramps/pins are located like in pic "A" below in relation to crankarms (blue line), not like "B", correct?

    Thanks again,
    - PiroChu
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  4. #4
    All 26.5" all the time!
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    If you look at the inner circumference of the pictured ring, you'll notice a tab (left side of photo A, top of photo B). This tab is usually is positioned under the crank arm, so yes, photo 'A' will work.

  5. #5
    Transition Blindside v5
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    Idea! tabs (x2)

    Quote Originally Posted by Zanetti
    If you look at the inner circumference of the pictured ring, you'll notice a tab (left side of photo A, top of photo B). This tab is usually is positioned under the crank arm, so yes, photo 'A' will work.
    Thanks for the tip on these two opposing "tabs".

    I guess I've never noticed them all these years, while being too preoccupied with the ramp/pin locations...

    I'll check mine when I get home...

    Thanks much again,
    - PiroChu
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    Last edited by PiroChu; 11-30-2005 at 10:51 AM.
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  6. #6
    Xtreme Lounger
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    That is correct

    Quote Originally Posted by Zanetti
    If you look at the inner circumference of the pictured ring, you'll notice a tab (left side of photo A, top of photo B). This tab is usually is positioned under the crank arm, so yes, photo 'A' will work.
    All rings should have a tab that indicates which section goes directly under the crank arm. I've never seen a ring without them.

  7. #7
    Transition Blindside v5
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    New question here. Are all brands interchangable? (Truvative steel rings on XT crank)

    Quote Originally Posted by steiny
    All rings should have a tab that indicates which section goes directly under the crank arm. I've never seen a ring without them.
    So, are those "tabs" & "ramps" & "pins" pretty much similarly shaped & located for all brands (ie. Shimano vs Truvative vs Raceface, etc)? Meaning, are they all "mix-and-match" interchangable (so long as the spider length and the bolt count match)?


    For example, I have a Shimano XT FC-M751 crankset (44-32-22T, 64mm/104mm, 4-bolt). And its original 22T was replaced with a Shimano LX M570/M571 "steel" 22T ring, its original 32T replaced with a Shimano Deore M480/M440 "steel" 32T ring, and its original 44T replaced with Truvative RockGuard bash ring. This combo has been working well.

    But, now it's almost time for new chainrings again, and this time I'd like to try Truvativ TruShift "Steel" Ring on my XT crank. I know that they'll simply "fit" fine in terms of size (length/bolt), but I just want to make sure that there possibly won't be any unforeseen shifting problems/glitches (with a certain way Truvative may shape/place its tabs/ramps/pins, if different from Shimano's) with this particular combo. (And I'm using PC-69/971 chain & X.9 rear derailleur & FD-M751 front derailleur.)

    Thanks again,
    - PiroChu
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  8. #8
    Transition Blindside v5
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    New question here. tab (x1)

    a tab
    Just realized something...
    Did I previously mislocate the "tab(s)" in my above post (marked by 2 blue rectangular boxes, pointing out the bigger center grooves)?
    Was it actually meant as a "single" tab, as in this pic (marked by a green circle), below?
    Now I'm confused a bit...
    - PiroChu
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    Last edited by PiroChu; 11-30-2005 at 10:57 AM.
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  9. #9
    Xtreme Lounger
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    Green circle is a winner

    Quote Originally Posted by PiroChu
    Just realized something...
    Did I previously mislocate the "tab(s)" in my above post (marked by 2 blue rectangular boxes, pointing out the bigger center grooves)?
    Was it actually meant as a "single" tab, as in this pic (marked by a green circle), below?
    Now I'm confused a bit...
    - PiroChu
    That green circle is it - that's the index tab. That is supposed to go under the crank arm.

    IF you use all Shimano, all RF, all [fill in the blank] rings, you definitely want to arrange the rings so the index is under the crank arm. They've gone through the trouble of designing the ramps and pins to work nicely together so just go with it. If you mix/match brands, you're on your own. I don't think you'll get any guarantees of flawless shifting even if you try all 4 possible orientations of certain rings. Placement of the shifting ramps and pins could be one area of difference between manufacturers - ring thickness and therefore spacing between rings might be another.

    Maybe others have some advice about the whole mix/match thing.

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