Forum home Mountain biking forum MTB workshop & tech

Problems with Gears/chain

Makem LadMakem Lad Posts: 7
edited July 2010 in MTB workshop & tech
Hi, having problems with the derailers/chain.

I had intended changing the chainrings, crank & BB but the front mech won't work with the largest chainring so have reverted back to original kit, 44-32-22 with X7 front mech, 11-32 cassette with X9 mech.

The gears were not changing as smooth as I would like and in the process of checking I found that the chain, when on small front/small rear, is so loose (and rear mech is folded back on itself to the point that the chain is touching against the chain round the pulley wheels.

The B screw seems to be adjusted correctly suggesting the chain is too long but changing to the large/large the chain seems fine and any shorter then it would be too short.

Any ideas what's wrong?


  • chedabobchedabob Posts: 1,133
    You shouldn't be using that combination because it puts the chain under a lot of stress. The top 2/3 gears when in the smallest chainring (and the lowest 2/3 on the top ring) are not recommended.
  • Makem LadMakem Lad Posts: 7
    I don't use them when riding but some of what I have read says to use small/small & large/large when checking chain length & some adjustments.

    It is only because the chain is so slack in small/small that the 2" droop in the chain means that the oposing running chain sections are not pressed together hard.
  • nicklousenicklouse Posts: 50,675 Lives Here
    nope. you have read things wrong.

    Large and Large is used to set the chain length, and add a link without the rear mech being used at all.

    re read the how to size a chain on park tools.

    link below.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Makem LadMakem Lad Posts: 7
    Thank for the answers. I have sorted the changing gears problem. Seems that the adjustments were very slightly out (I hadn't done them correctly because I'd tried without disconnecting cables) and once all corrected then no problems.

    I know that the chain catching when on small/small is not a 'real' problem because you never use that combination and have since read that it's more obvious with the short cages fitted to MTBs, the longer cages taking up more of the slack but increasing the risk of the cage getting damaged hitting rocks, branches etc.

    The small/small combo is the rest position of both front & back mech with cables disconnected and this is how the info suggested adjustments should be started, working the mechs by hand as req'd. This is when I did notice the 'problem' and I wrongly assumed that it was causing the gear change problem.

    Learning curve, I'm still low down on the steep bit still it gives you guys up on the top something to chuckle at :D :oops:
Sign In or Register to comment.