'Play' in Sram Force RD and poor shifting?

CRAIGO5000
CRAIGO5000 Posts: 697
edited November 2012 in Workshop
I notice that my Sram Force RD is sometimes difficult to tune. When I seem to have it spot on going up the block, it's difficult to come down and vice versa. I noticed today that the body of the RD has about 1mm of play as if it's not locked down to the hanger properly (even though it is) I can feel it click as it moves ever so slightly when wiggled side to side - Is this normal?
I spent a good few hours yesterday tuning both front and rear, degreasing the chain and re-lubing. They are both actually running really well now after a nice 30 mile test ride today. Although I'm still using FinishLine Dry lube in these wet conditions, I have noticed some surface rust on the chain after a few rides and did note some links wouldn't straighten when I bent them. Would that cause these major shifting issues? I did see a YouTube video review of Sram Force and the reviewer loved the groupset apart from the chain as he said when wet/dirty on a ride it would be the cause of poor shifting. He even rode with lube to tackle it when it happened!? After swapping for a DuraAce chain, the problem went away.

So poor lubrication and light dirt build-up mid ride might be a big contribution perhaps to the poor shifting that seems to rear it's ugly head after a few days of riding?

Any other ideas? I'm considering a wet lube now but want one that cleans off easily, doesn't attract dirt build up and has decent anti-fling properties so it doesn't end up all over the frame when the chain gets wet.

Any other theories from anyone - especially if any other Force users have any advice?

Thanks!
Ribble Stealth/SRAM Force
2007 Specialized Allez (Double) FCN - 3

Comments

  • sungod
    sungod Posts: 16,842
    1) if the chain is so dirty/corroded that links are stiff then it needs some attention, if nothing else it's wasting energy, give it a good clean and some nice oil to make it happy

    2) by "going up" i assume you mean to larger sprockets (rather than to higher gear)

    in that direction, cable tension increases, it takes a lot to resist that, and you say shifting is ok that direction

    but it's iffy in the other direction where only spring tension is moving things, it may simply be that the cable and outer are worn/dirty, that'll cause drag/sticking which in turn will certainly cause poor shifting to higher gears

    undo the cable, see if it runs free without any drag/catching, if it's not ok then it may be simplest to replace cable and outer - the outer near the rd is most exposed to bad conditions in the crappy uk weather

    3) once the chain is oiled and the cable running smooooooooooth, follow sram's set-up instructions for the rd, my experience is the b-screw setting is a lot more critical for good shifting than with a shimano rd

    4) ignore the youtube, sram chains shift just fine
    my bike - faster than god's and twice as shiny