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Rear D/R angle and chain length

jeremyrundlejeremyrundle Posts: 1,091
edited December 2010 in The workshop
I have only just noticed that in some gears the rear DR on my mountain bike (that I use for commuting) is almost at the same angle (running paralell) to the chain itself, is that right, surely this is putting extra strss on the DR, would alonger chain cure this, and how DO you woek out the correct chain length :?:

Thank you
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Banish unwanted fur - immac a squirrel
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Posts

  • nicklousenicklouse Posts: 81,520 Lives Here
    so what have you changed?

    and do you know how to use your gears?
    http://www.bikeradar.com/forum/viewtopic.php?t=12647117

    PS do not multi post topics.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Nothing, just something I have noticed now, , also yes saw that today, useful.
    Peds with ipods, natures little speed humps

    Banish unwanted fur - immac a squirrel
    http://www.dailymail.co.uk/news/article ... heads.html
  • Having a chain a bit too long is not necessarily a problem, but having one too short is.

    Put the chain on small/small and tighten up on the pedals/cranks. You want the situation where the RD doubles back on itself and takes up the slack of the chain so that it is taught. You want the situation where the RD is fully doubled back and keeps the chain just taught. The trype of situation where if you were to add a link it would be too long and the chain would fall slack.
  • THANK you
    Peds with ipods, natures little speed humps

    Banish unwanted fur - immac a squirrel
    http://www.dailymail.co.uk/news/article ... heads.html
  • I have my mtb's chain length set so that when in big/big it looks like it's about break the mech, and yet it doesn't. Short chains weigh less and don't fall off so often.
    I also run a medium length cage as I've ditched the 'granny ring' because I'm not a granny and can still climb the Goat Trail at 'tress in middle, also it makes the bike lighter still!

    Interestingly, full-sus bikes with a 'positive-pedal-platform' normally move the rear wheel away from the BB when the suspension compresses. Which means your pedal force damps the travel. And snaps the short chain or mech clean off!

    Much against all advice, I often hold onto big ring, even when in big (1st) on the back for psychological reasons: I rather kill myself than drop down at the front, and then proceed to kill myself for next 2 miles because I'm turning too big a gear uphill or into a headwind.
    FCN16 - 1970 BSA Wayfarer

    FCN4 - Fixie Inc
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