Double Chain Device alignment issues

chimp007_uk
chimp007_uk Posts: 13
edited October 2012 in MTB workshop & tech
I'm new to the forum, I'm on RetroBike, but recently sold my 99 GT XCR STS in favour something newer...

I've got a 2010 Trek Remedy 8, and converting it from a 22,32,44T triple to a 22,32T double. I've fitted an E13 bashring and a DMR chain device. However I'm having some issues with alignment... I have a 73mm BB casing with XT cranks and a single 2.5mm spacer on the drive side as per.

The dmr chain device has replaced the drive side spacer, but then I'm left with this for alignment to the granny and middle ring...

photo9.jpg
photo8.jpg

I played with the BB spacing adding another 2.5mm spacer and ended up with this...

photo10.jpg

Obviously this isn't a good thing to do.

I'm stumped! All of these type of chain device are the same, a steel or ally plate with a roller at the end.

Anyone got any ideas?!

Cheers
Chris

Comments

  • nicklouse
    nicklouse Posts: 50,675
    looks like it is an ISCG mount device. is attached to the frame or to a BB mount adaptor?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • chimp007_uk
    chimp007_uk Posts: 13
    It is indeed a duel ISCG (old/03) and BB. It's mounted on the ISCG mounts, but then is also clamped on the external BB.
  • nicklouse
    nicklouse Posts: 50,675
    chimp007_uk wrote:
    It is indeed a duel ISCG (old/03) and BB. It's mounted on the ISCG mounts, but then is also clamped on the external BB.
    right so it is dual mount.

    what is its thickness where it mounts? IIRC it is only about 1mm or less. and your requirement is for a 2.5mm spacer to be there.

    Now you are lucky that you are using a shimano crankset as they are quite flexible on the amount of spacers you use.
    yes it changes the chain line a little but that in not always a bad thing.

    running the device and a 2.5mm spacer will be fine you could add a 1mm spacer if you find one.

    I have run about 5mm on a 73mm BB with no issues.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • chimp007_uk
    chimp007_uk Posts: 13
    nicklouse wrote:
    chimp007_uk wrote:
    It is indeed a duel ISCG (old/03) and BB. It's mounted on the ISCG mounts, but then is also clamped on the external BB.
    right so it is dual mount.

    what is its thickness where it mounts? IIRC it is only about 1mm or less. and your requirement is for a 2.5mm spacer to be there.

    Now you are lucky that you are using a shimano crankset as they are quite flexible on the amount of spacers you use.
    yes it changes the chain line a little but that in not always a bad thing.

    running the device and a 2.5mm spacer will be fine you could add a 1mm spacer if you find one.

    I have run about 5mm on a 73mm BB with no issues.

    Oh right, I thought it was a big NO NO. With the 2.5mm spacer and the chain device it looks better. The plate thickness of the DMR is 2.5mm, measured that with some calipers.

    I have been told to try swapping the roller, but it's designed to be that way round.
  • nicklouse
    nicklouse Posts: 50,675
    also the roller is too close to the bash can you swing it away from it.

    and then after tightening it all up bend it out wards as it does look a little skew in the pics..
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown

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