slackness in chain

jdee84
jdee84 Posts: 282
edited June 2017 in Workshop
My chain seems to be hanging slack when in the 36t front and lower smaller cogs on the cassette, the chains not been on all that long. Could this be a problem with the rear derailleur? Possibly not pulling the jockey wheels back enought to create tension in the chain?

Comments

  • cooldad
    cooldad Posts: 32,599
    Pics help.
    I don't do smileys.

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  • timothyw
    timothyw Posts: 2,482
    Did you fit the chain yourself? Did you trim it to length when you did so?

    The possibilities are that the chain is too long, or that the rear derailleur need servicing (or has inadequate capacity for what it is being asked, and so should be switched to a medium/long cage alternative).

    Fitting a chain on Shimano/SRAM you wrap the chain around the big ring at the front, then the biggest cog on the cassette at the back without going through the derailleur - the ends of the chain should only overlap by a couple of links - it is down to you to remove the excess with a chain tool. There's lots of guides online to explain this better than I have.
  • Bobbinogs
    Bobbinogs Posts: 4,841
    Yepp, sounds like the chain is probably too long. If it is the right length, then shift into a combo that gives some slack on the chain and try moving the rear mech cage (which holds the jockey wheels) to see if the springs are still nice and, err, springy.
  • jdee84
    jdee84 Posts: 282
    I didn't fit it myself it was fitted around 7 weeks ago or 8 weeks ago and I've done about 1400-1500 miles since it was fitted but only had this problem yesterday.

    It's a 52/36 with 11-28 cassette can't take pics right now as the bikes at home and i'm at work.

    I could move the cage back last night when i checked to remove the slack from the chain but it moved back to its original position when I let go, it also seemed like the chain was skipping slightly when in the 36t and the first few cogs
  • The Rookie
    The Rookie Posts: 27,812
    You shouldn't be riding on 36t and smaller (Higher not lower) cogs on the back anyway.

    Some setups are aggressive on rear mech length and it will go slightly slack and risk some slipping if you do that.
    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.
  • jdee84
    jdee84 Posts: 282
    Surely a 52/36 with 11-28 cassette is about as standard as it gets on a road bike these days so is it that aggressive?

    So i shouldn't be 11-14/15 cog when on the 36 at the front?
  • timothyw
    timothyw Posts: 2,482
    Not really, no. The chain tends to rub against the big ring if you do which accelerates wear and is noisy.
  • k-dog
    k-dog Posts: 1,652
    ^agreed. And it's exacerbated by having 52 and 28 as the chain has to be long enough to reach all gears so when you're at the opposite end it's a balancing act getting it not too long.

    Check the big/big combo and if it's not too tight you might be able to lose a link which would help.
    I'm left handed, if that matters.

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