SRAM X9 rear mech adjustment problems

manofsteel
manofsteel Posts: 68
edited March 2011 in MTB workshop & tech
Hi I've just complted building my new 456 with SRAM components (Always had Shimano in the past so big leap of faith!)

The rear mech is causing a headache. I have set the L screw correctly to prevent the chain shifting into the spokes. However, the chain will not shift into the smallest sprocket despite the H screw being properly adjusted. This is becasuse the L screw is fouling another part of the mech, preventing it from coming back to it's rest position.

The only solution I can think of is placing a washer between the mech and the dropout to allow the chain to drop onto the bottom sprocket as the L screw won't need to be screwed in so much. However, this seems like a bit of a bodge job and I'm worried that there won't be enough thread going into the frame.

Any advice would be greatly appreciated - I'm going mad trying to figure this out!
Cheers
'Pain is just weakness leaving your body'

Charge Duster SS
GT Zaskar Carbon Expert
'03 Stumpy HT
Ribble Sportive Racing

Comments

  • nicklouse
    nicklouse Posts: 50,675
    sounds like a faulty mech. replace it.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • 02gf74
    02gf74 Posts: 1,168
    strange ... if shmano rear mech worked, there should be no reason a SRAM mech won't

    you definitely have no tension in the cable when trying to shift onto the smallest sprocket?
  • nicklouse wrote:
    sounds like a faulty mech. replace it.
    Thanks for the quick response! It's a brand new mech. I bought a Revolution Triad as a donor bike to build up onto the 456 frame. It worked fine on the Revolution. Could it be because the steel mech hanger on the 456 is narrower than the replacable alloy one on the Triad?
    Cheers
    'Pain is just weakness leaving your body'

    Charge Duster SS
    GT Zaskar Carbon Expert
    '03 Stumpy HT
    Ribble Sportive Racing
  • nicklouse
    nicklouse Posts: 50,675
    and there has been a number of faulty rear X9 mechs.

    send it back. opps.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • nicklouse wrote:
    and there has been a number of faulty rear X9 mechs.

    send it back. opps.

    Cheers Nicklouse - will do
    'Pain is just weakness leaving your body'

    Charge Duster SS
    GT Zaskar Carbon Expert
    '03 Stumpy HT
    Ribble Sportive Racing
  • nicklouse wrote:
    and there has been a number of faulty rear X9 mechs.

    send it back. opps.
    1

    A quick update - I sent it back to the shop and they accepted it wasn't as it should be. However, as it worked fine on a Triad they had in the workshop they weren't prepared to send it back to SRAM for a replacement as it works fine on the bike for which it was originally intended, I hadn't told them I was only using their bike as a donor bike for a different frame as I didn't want to hurt their feelings!
    I have now had the mech returned and have fettled it with an M10 washer that has effectively increased the thickness of the dropout on the 456 frame. There is still plenty of thread going into the frame so I'm happy.
    I've spoken to a few other people who have said that apparently SRAM only tested the mechs on bikes with thick alloy dropouts so this problem never came about before the production run (A bit shortsighted of them) but was rectified on later models when the problem became apparent.

    I got the washers from Wickes for a couple of quid, but they are the same size as the washers on your axle if you or your LBS have any spares kicking around


    I hope this helps other people in the same position
    'Pain is just weakness leaving your body'

    Charge Duster SS
    GT Zaskar Carbon Expert
    '03 Stumpy HT
    Ribble Sportive Racing
  • chris.d.w
    chris.d.w Posts: 43
    My X9 mech works fine on my 456

    If you undo the cable completely and adjust the H screw, will it shift into the lowest gear?
  • chris.d.w wrote:
    My X9 mech works fine on my 456

    If you undo the cable completely and adjust the H screw, will it shift into the lowest gear?

    Hi

    It wouldn't shift into smallest sprocket no matter how much you adjust the H screw as the L screw was fouling the mech. this was a fault with some 2010 X9 mechs but only on frames with skinny dropouts. You must have one of the rear mechs that works okay :D
    'Pain is just weakness leaving your body'

    Charge Duster SS
    GT Zaskar Carbon Expert
    '03 Stumpy HT
    Ribble Sportive Racing