Advertise on Bikeforums.net



User Tag List

Results 1 to 11 of 11
  1. #1
    Member
    Join Date
    Jun 2012
    Location
    The Netherlands
    Posts
    26
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Rival RD with 12-32t cassette

    Hi,

    Somewhere in this forum (don't remember where) I read that with some fiddling you can get a Shimano RD meant for max 27t work with bigger cogs. I have a Rival RD, could I use a 12-32t cassette with this? Or would the largest cog hit the upper derailleur wheel?

    Thanks!

  2. #2
    Galveston County Texas 10 Wheels's Avatar
    Join Date
    Nov 2007
    Location
    In The Wind
    Posts
    25,391
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Last edited by 10 Wheels; 07-12-12 at 11:14 AM.
    [SIZE=1][B]What I like about Texas[/B]
    http://www.youtube.com/watch?v=PGukLuXzH1E

    Set F1re To The Ra1n ( NY Night Rain Ride)
    http://www.youtube.com/watch?v=W7jfcWEkSrI

  3. #3
    coprolite fietsbob's Avatar
    Join Date
    Jun 2010
    Location
    NW,Oregon Coast
    My Bikes
    7
    Posts
    40,134
    Mentioned
    28 Post(s)
    Tagged
    0 Thread(s)
    Sometimes you can fudge a bit cranking in the B screw.

    you need a longer chain, with the bigger cog, and big ring needing it.
    then it will go slack on small ring/smaller-cog combos
    the long-cage RD will take up that slack.. so you pick..

    [Maybe-Not if you fit a smaller outer chain ring, too,
    with the same number less, as you add teeth on the back]

    [10 wheels went with a longer cage type]
    Last edited by fietsbob; 07-12-12 at 11:15 AM.

  4. #4
    Member
    Join Date
    Jun 2012
    Location
    The Netherlands
    Posts
    26
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    This is exactly what I was wondering, I have a 42 teeth as an outer ring. So am I correct if I say that means that chain length wont cause a problem and that therefore cage length is not a problem?

    That means the only issue is whether I can fit the 32t to not touch the upper derailleur wheel.
    Last edited by raymond82; 07-12-12 at 11:36 AM.

  5. #5
    Senior Member
    Join Date
    Sep 2010
    Posts
    2,648
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by raymond82 View Post
    This is exactly what I was wondering, I have a 42 teeth as an outer ring. So am I correct if I say that means that chain length wont cause a problem and that therefore cage length is not a problem?

    That means the only issue is whether I can fit the 32t to not touch the upper derailleur wheel.
    Not exactly. There are two separate specifications for rear derailleurs.

    The first is the maximum cog size that the derailleur will clear which, as has been mentioned before may not be a hard limit and can possibly be slightly exceeded.

    The second is the chain take up. It is not the size of the large outer ring which matters for this but the difference of the largest and smallest front chain rings' teeth (if not a single) PLUS the difference of the largest and smallest cogs. This limit can also be exceeded slightly with the understanding that the smallest cogs will not be able to be used with the small chain ring since the chain will go slack. You shouldn't be using those combinations anyway.

    You will still have to size the chain to fit on the big-big combination even though you shouldn't use that one either. If you forget, and you will, and shift to that combo you risk damage to your derailleur and/or frame.

  6. #6
    Member
    Join Date
    Jun 2012
    Location
    The Netherlands
    Posts
    26
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Thank you, that's a very clear explanation! I have 34/42 chainrings and the cogs would be 12-32, can you say anything about whether this would be a problem?

    I'm aware of the importance of keeping a straight chain, I always keep a close eye on it. Actually, one of the reasons I have the 34/42 is because that way I can keep the chain quite straight while riding the speeds I usually ride on the flat.

  7. #7
    Senior Member
    Join Date
    Oct 2007
    Location
    West Yorkshire, United Kingdom
    Posts
    3,274
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    You don't say what spec of RD you have, SRAM make a WiFLi version for their road range which is designed to use the larger capacity cassette (11-32) http://www.sram.com/sram/road/technologies/wifli_tm

  8. #8
    Member
    Join Date
    Jun 2012
    Location
    The Netherlands
    Posts
    26
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I have a normal Rival RD with a short cage. I'm aware of SRAM's WiFLi RD, it's just that since I read it might be possible to get away with the short cage RD, it would save me some money!

  9. #9
    Senior Member
    Join Date
    Sep 2010
    Posts
    2,648
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    SRAM's 210 Technical Manual - downloaded from this page http://www.sram.com/service/sram/3,381
    states that the Rival rear derailleur is rated for 28 teeth max cog and 33 teeth takeup. So you are 4 teeth over the rating with the 32 tooth cog but OK with the takeup (42-34) + (32-12) = 8 + 20 = 28 teeth. So I would expect that your problem would be having the derailleur clear the large cog but it would take up the chain OK.

  10. #10
    Senior Member rdtompki's Avatar
    Join Date
    Nov 2008
    Location
    Hollister, CA
    My Bikes
    Volagi, daVinci Joint Venture
    Posts
    3,934
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by dsbrantjr View Post
    SRAM's 210 Technical Manual - downloaded from this page http://www.sram.com/service/sram/3,381
    states that the Rival rear derailleur is rated for 28 teeth max cog and 33 teeth takeup. So you are 4 teeth over the rating with the 32 tooth cog but OK with the takeup (42-34) + (32-12) = 8 + 20 = 28 teeth. So I would expect that your problem would be having the derailleur clear the large cog but it would take up the chain OK.
    I'm running an 11-32 with Rival RD on my single without problem. It's probably a long cage to achieve the take-up with my 50-34 chainrings, but the LBS did nothing special to get the RD to work flawlessly. I will change to an X9 to give me an 11-36 option when nasty climbs are contemplated.
    Rick T
    --------
    Volagi - Triple"ized" and Tubeless
    daVinci Joint Venture

  11. #11
    Member
    Join Date
    Jun 2012
    Location
    The Netherlands
    Posts
    26
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Thanks dsbrantjr for showing me how to calculate it. So now I guess that with a short RD, it is possible to put a 30t (like 10Wheels shows) but like you say, 4 teeth is probably too much.

    I'm running an 11-32 with Rival RD on my single without problem. It's probably a long cage to achieve the take-up with my 50-34 chainrings, but the LBS did nothing special to get the RD to work flawlessly. I will change to an X9 to give me an 11-36 option when nasty climbs are contemplated.
    I've been studying the pictures on SRAM's website and it looks like the WiFLi RIVAL RD not only has a longer cage but also a longer parallelogram (is that what it's called?). I guess that's required then to clear the large cog. But when I look at 10Wheel's first picture, the parallelogram doesn't look longer than normal.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •