Shimano 7 spd rear derailleur compatability on 8 speed bike?

JaiRo
JaiRo Posts: 64
edited February 2012 in MTB workshop & tech
Hello all,

would it be possible to swap without much modification, a 7 speed derailleur in place of an 8 speed?

I currently have:

Shimano Acera / RD-M360
http://www.chainreactioncycles.com/Mode ... tedKingdom

but have noticed its slightly bent. The chain rubs on to the side that holds the bottom cog in place and it makes the chain run at an angle rather than straight.

Would it be okay to do a straight swap with

Shimano Tourney
http://www.camdencycles.co.uk/index.php ... ductId=383

?

or.....what slight modifications are needed?

thanks in advance for your help.
Scott Aspect 40 2011

Comments

  • nicklouse
    nicklouse Posts: 50,673
    is it the mech that is bent? or the mech hanger?

    that tourney will not mount on your bike.

    but to answer your question in most casses yes.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • JaiRo
    JaiRo Posts: 64
    Thanks nick.

    Its the mech hanger, the bottom part of the actual unit.

    The meaty part looks straight, the part that is screwed on to the actual frame is straight, just the 'hanger' part which holds the cog nearest to the floor.

    So for better example, in the link I gave for the tourner, its the metal part that is holding the red cog.

    ah damn it, either way, it wont fit :(

    Cheers.
    Scott Aspect 40 2011
  • nicklouse
    nicklouse Posts: 50,673
    the mech hanger is part of the frame and often is replaceable. nothing to do with the mech other than it attaches to it.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • The Rookie
    The Rookie Posts: 27,812
    JaiRo wrote:
    The meaty part looks straight, the part that is screwed on to the actual frame is straight, just the 'hanger' part which holds the cog nearest to the floor.

    So for better example, in the link I gave for the tourner, its the metal part that is holding the red cog.
    That is part of the mech, not the mech hanger!

    Simon
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • JaiRo
    JaiRo Posts: 64
    Thank you guys.

    Okay cool, looks like Ill need a totally new one then.
    Scott Aspect 40 2011
  • The Rookie
    The Rookie Posts: 27,812
    Or a good condition used one........but nothing like that Tourney if your bike does have a mech hanger!

    Simon
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • JaiRo
    JaiRo Posts: 64
    ahah thanks.

    the tourney is from a bike thats been in the garage so just wanted to find out if it can be used instead of just thrown away.
    Scott Aspect 40 2011
  • The Rookie
    The Rookie Posts: 27,812
    You can get Tourneys designed for use on a mech hanger or without, so is yours like the one in that link with the 'horseshoe' bracket or not?

    Simon
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • nicklouse
    nicklouse Posts: 50,673
    so yet again the parts show have nothing to do with the question that was not even asked.

    so Yes/No/Maybe take your pick.

    who knows as you are the only one who knows what you actually have and ESP does not work yet.

    ;)
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • JaiRo
    JaiRo Posts: 64
    Hi Simon,

    from the link, is it the top part that attaches to the frame, if so, then yes.

    Nick, I dont understand your last post.
    Scott Aspect 40 2011
  • cooldad
    cooldad Posts: 32,599
    JaiRo wrote:
    Nick, I dont understand your last post.
    Because your ESP is equally weak.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • supersonic
    supersonic Posts: 82,708
    7/8/9 speed mechs will work, with allen key bolt fitting to the frame's mech hanger.

    I have quite a few that wil do the job in the classifieds.
    GT ZASKAR CARBON TEAM

    VOODOO CANZO

    Come and see me at https://www.facebook.com/biketyke/
  • nicklouse
    nicklouse Posts: 50,673
    JaiRo wrote:
    Hi Simon,

    from the link, is it the top part that attaches to the frame, if so, then yes.

    Nick, I dont understand your last post.
    Your first post had absolutely nothing to do with what you actually wanted to know.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • JaiRo
    JaiRo Posts: 64
    Not go off topic but it did.

    I just wanted to know if it was a straight swap with little mods, you said no and you asked a question about the mech to which I responded.

    thanks for your responses all.
    Scott Aspect 40 2011
  • The Rookie
    The Rookie Posts: 27,812
    You wanred to know if parts at a shop would swap in, but the parts you have are not at the shop and may not be the same parts, so the original post was pretty pointless.

    If your Tourney has the hook shape part that "attaches to the frame", it won't fit your bike with a mech hanger.

    Simon
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • JaiRo
    JaiRo Posts: 64
    Nothing was mentioned about a shop or finding out about a purchase, just wanted to know if 1 part can be swapped for another, thats it. Nothing more to it.
    I only posted links to give a better example for what I had.
    Scott Aspect 40 2011
  • mattv
    mattv Posts: 992
    You would need the one with the code d-att. But running 8 on a 7 mech may behave badly. Technically 7sp chains are slightly fatter than 8sp, and the total range a mech needs to travel is slightly further on 8 compared to 7. In reality it will probably work.
  • supersonic
    supersonic Posts: 82,708
    Most modern 7 and 8 speed chains are exactly the same, and are 3/32 overall width. Many manufacturers use 8 speed mechs on 7 speed set ups too.
    GT ZASKAR CARBON TEAM

    VOODOO CANZO

    Come and see me at https://www.facebook.com/biketyke/
  • The Rookie
    The Rookie Posts: 27,812
    My daughters bike is running a tourney off a (quite old) 7speed on an 8 just fine....

    Simon
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.

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