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  1. #1
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    Rec's on on top vs. bottom swing Front D.

    Hey -

    I am putting together an 8speed drivetrain for an aluminum softtail - essentially standar double triangle design with 34.9 seat-tube - and needs a top pull. I have a xtr 952 rear with 8sXTR cassette, 8 speed chain, and fsa v-drve mega exo cranks, likely. Any rec's on shimano 960 vs. 961 (top swing vs. bottom swing) - im not clear of the advantages or disadvante. Or other recs for FD.

    thanks

    ben

  2. #2
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    Clearance issues

    The determination of whether to use a top swing or bottom swing front derailleur has more to do with clearance issues than anything. For instance, on my full suspension bike, I have to use a top swing derailleur, as the collar position on a bottom swing derailleur would sit above the derailleur cage, and interfere with the linkage for my shock. In that the collar on a top swing sits below the derailleur cage, and therefore several inches below my linkage, it does not interfere with anything.

    On a hardtail, the only thing I can think of that might effect derailleur choice is water bottle cage mounted on seat tube.

    I hope my explanation makes sense.

    Bob
    'If Wal-Mart sold parachutes, who would jump?' Frank Havnoonian (quoting his father) Drexel Hill Cyclery

  3. #3
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    Thanks - That does help. Do you think that there is any shifting advantage (esp. w/8sp) w/top swing - Ive heard the top swings shift more cripsly. I also noted in checking the discussions that the 960/962 xtr may be heavier than the prior XTR's - is there a cost to in that the older 950 series FD arent as stiff (and thus poorer shifting?) than the newer XTR's?

    thanks

    b

  4. #4
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    I don't know

    Quote Originally Posted by shapirob
    Thanks - That does help. Do you think that there is any shifting advantage (esp. w/8sp) w/top swing - Ive heard the top swings shift more cripsly. I also noted in checking the discussions that the 960/962 xtr may be heavier than the prior XTR's - is there a cost to in that the older 950 series FD arent as stiff (and thus poorer shifting?) than the newer XTR's?

    thanks

    b
    Hopefully someone with experience using both can come along and give a definitive answer.

    Bob
    'If Wal-Mart sold parachutes, who would jump?' Frank Havnoonian (quoting his father) Drexel Hill Cyclery

  5. #5
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    Not an expert however-

    My experience is that the bottom swing FD-961 XTR as with all bottom swing derailluer move more in an ARC pattern ( all road bike are eqiuped) and offer a small improvement in shifting compared to a top swing FD -960 XTR that moves more perpendicular relative to the seat stay. So when allowed due to frame type/ mounting and or cleareance etc I run a bottom swing. Hope this helps

  6. #6
    Elitest thrill junkie
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    Bottom swing (traditional) is the way to go.

    Sometimes these can interfear with a linkage, OR the watter bottle cage bolts (on the seat tube) are in the way and can interfear.

    If these are not problems, go bottom-swing because it allows for more adjustment. Much of the time you run into a problem with the top-swing where you can't adjust it any closer inboard, and you have to get a longer BB spindle or put some spacers in the BB to get the rings far enough out to shift. The problem can be that you can't shift to the granny ring, and to make it work you have to push the granny out further.

    Traditional derailers are more versatile in this respect and have a greater adjustment range, they can go further "in" towards the center of the bike. This helps, especially when you may or may not have the correct bottom bracket spindle length.

    If you use the top-swing derailer, you better make darned sure you're getting or have the right bottom bracket.

    I do mods on bikes occasionally and have to fit new derailers on them for various reasons. I always try to make a traditional front derailer work first. The greater adjustment range is worth it, and it's a rarity where a top-swing derailer works and the traditional doesn't. It happens, but it's a rarity.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

    You're turning black metallic.

  7. #7
    Dr Gadget is IN
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    I've used both..

    and definitely prefer the traditional bottom swing. The reason is: Bottom swing moves up as it moves out (so do your chainring hts), top swing moves down as it moves out (DOH!).

    Realistically, if you run ramped/pinned rings in standard sizes (22/32/42or44) either works ok. I like to run things like 20/32/46 instead, and that really makes the compromises of the top swing der obvious. In low ring, the chain wants to drag on the bottom of the cage cuz the cage is in a higher location (moves up as it moves in).

    The only reason top swing exists is the reason already given: suspension stuff using seat tube real estate where the clamp would need to be with bottom swing.
    This isn't a "you're doing it wrong" topic.

    WSS/OSS: Open Source Sealant

  8. #8
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    Thanks for the info - I am definitely going top swing. Does anyone feel that the newer xtr 961 is any better or worse than its predecessor (951?)

    thanks

    ben

  9. #9
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    yup, i feel the older xtr's are better, the new ones are dual clamp which makes for tighter clearances in the bb area (on my bike it made a difference, i couldn't run the new ones) but shifting wise i never noticed a real difference.
    what would rainbow unicorn do?

  10. #10
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    ferday

    thanks for the reponse. ... I fogot to add in my last post, which is best for use with an 8speed chain and cassette, gvien they keep saying they are narrow 9-speed chains...

    In what way are they dual clamp - in the bad picture i have there is one, plus isnt just as advertised "a whole new rhelm of performance" - or ios that bull. It does seem like the prior 953 (if thats right) weighs less., but is essentially not to be found?

    b

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