Two chain devices on at once?

dot1
dot1 Posts: 538
edited May 2013 in MTB workshop & tech
I've got a Trek Remedy 7, with no ISCG mounts. It has a SLX chainset and external BB. I am currently running a Blackspire Stinger chain tensioner, but have recently removed the granny ring and front mech and now keep dropping the chain all the time so want to put a chainguide on to help. It will have to be BB mount due to the pivot being in the way of a seat tube mounted guide. I currently have a 2.5mm spacer on the non-drive side of the BB and a 2.5mm spacer and 2.5mm plate of the chain tensioner on the drive side. Could I remove the remaining drive side spacer and fit a BB mounted chain guide and have the 2 guides/tensioners in between the BB and frame instead of the spacers? I don't see why not, but thought I'd ask just incase!
Trek Remedy 7 2009
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Boardman Pro Singlespeed - Sold
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Giant Defy 5 2012

Comments

  • nicklouse
    nicklouse Posts: 50,675
    re fit the front mech and lock it in position.

    using 2 bb mount devices normally ends up not working.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • dot1
    dot1 Posts: 538
    Oh right, is there any reason why it doesn't usually work? Front mech is quite heavy is all.
    Trek Remedy 7 2009
    viewtopic.php?t=12634629

    Boardman Pro Singlespeed - Sold
    viewtopic.php?t=12752297&highlight=

    Giant Defy 5 2012
  • peter413
    peter413 Posts: 5,120
    Why not just buy a full guide? Probably be lighter than two separate guides.
  • nicklouse
    nicklouse Posts: 50,675
    dot1 wrote:
    Oh right, is there any reason why it doesn't usually work? Front mech is quite heavy is all.

    thing just dont line up.

    a device is heavier than most mechs.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • ilovedirt
    ilovedirt Posts: 5,798
    I've PM'd you.
    Production Privee Shan

    B'Twin Triban 5
  • dot1
    dot1 Posts: 538
    peter413 wrote:
    Why not just buy a full guide? Probably be lighter than two separate guides.
    As I've already got the bottom half, so can just get the top guide from superstar for 17 quid, rather than dropping 50 for a whole guide.

    The superstar guide is definitely lighter than the front mech as i had one on my previous bike. So is alignment the only real problems that im likely to come across? As I can play around with the alignments and use various spacers to get it sorted.
    Trek Remedy 7 2009
    viewtopic.php?t=12634629

    Boardman Pro Singlespeed - Sold
    viewtopic.php?t=12752297&highlight=

    Giant Defy 5 2012
  • *AJ*
    *AJ* Posts: 1,080
    Try it, but as Nick says it probably won't line up.

    You currently have the chain device against the frame and then a spacer then the cranks. BB mount chain devices are designed to run in this position, so by replacing your remaining spacer with another BB mount device would result in the chain device being 2.5mm out of line. If that makes sense?....

    You are better off buying another device with both top and bottom guides. Or buy a top device that clamps around the seat tube (exactly as your front mech does). Or just use the front mech as already suggested. Will still function as a chain device, just won't look as good.