rear derailure help asap pls

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  • rear derailure help asap pls
  • Hey guys can someone please help with setup on my rear derailure ?

    Problem seemed to start last time out at Llandegla the chain was getting caught between the swingarm and bottom chain ring,

    so tonight I thought I would have a little play about with adjustable skrews but nothing seems to move if you get me ?? So slowly turning the crank is sending the rear mech into a bouncing fit and throwing it of the rail cog ??

    Plz help as going riding in morning

    jekkyl
    Member

    Again in English?

    Premier Icon boriselbrus
    Subscriber

    I’d love to help but I really don’t understand what you are asking. What is a rail cog?

    Ino , I am sorry its hard to explain. The rear mech needs adjusting but when I am turning the adjuster skrews and looking at the mech nothing appears to change or adjust therefore I am struggling to work out what I am doing as I dont know what skrew does what ??

    Sorry railcog = guide pulley !!!!

    Premier Icon DezB
    Subscriber

    Problem seemed to start last time out at Llandegla the chain was getting caught between the swingarm and bottom chain ring,
    = chain suck?

    Not sure how the rear mech will help chain suck… either worn chain rings or poor shifting technique (shifting when chain under load) are usually the causes.

    dantsw13
    Member

    Take the chain off. start again from scratch.

    Follow the PARK TOOLS GUIDE here and you won’t go wrong.

    It might also be worth checking your mech hangar isn’t bent or loose before you start.

    I will have a read thrpugh the guide now ๐Ÿ˜‰

    jekkyl
    Member

    Is the lower rail cog (jockey wheel) very worn? & skrews are spelt screws. ๐Ÿ™‚

    Premier Icon midlifecrashes
    Subscriber

    Is the mech screwed tightly onto the frame? Also, any sign of the mech hanger being bent so the pulley/jockey wheels are not parallel to the rear cogs when moving across the block?

    Jamie
    Member
    Premier Icon midlifecrashes
    Subscriber

    These are mech hangers and usually bolted on to the frame around the dropout where your axle slots in.

    Im not sure what do you think ๐Ÿ˜‰

    3feet jamie???

    Midlifecrsshes thnks for pic, my rear hanger looks pretty good ?

    jekkyl
    Member

    That’s the upper jockey wheel mate, if your bike was the right way up.

    Jamie
    Member
    Superficial
    Member

    Isn’t this what bike shops are for?

    Jamie
    Member

    Isn’t this what bike shops are for?

    I’m sure the OP appreciates your input, but bike shops are probably not open at 10pm.

    Superficial
    Member

    I’m sure the OP appreciates your input

    Do I even need to point out the irony, given your previous input into this thread?

    Is the OP trolling? I don’t even know any more. Skrews? Seriously?

    PeterPoddy
    Member

    I’ve had a quick skin read of the thread.

    Kenz – Not taking the pee, but it sounds like you don’t have the foggiest idea how to adjust a mech. There’s lots of things that need checking and adjusting and I’d suggest taking it to someone who knows what they are doing – your LBS – as trying to explain on here is going to tie you in knots. If you’re anywhere near Farnborough, Hants, I’ll gladly do it for you. ๐Ÿ™‚
    Email in profile.

    Premier Icon boriselbrus
    Subscriber

    The screws only affect the limits to which the mech can move. If the chain doesn’t sit on the sprockets correctly each time you change gear then you need to adjust the barrel adjuster (where the cable goes into the mech)

    Read the park tools guide and see how you get on. Good luck!

    Premier Icon martinhutch
    Subscriber

    You haven’t really posted a pic which helps show the situation for us, but if the problem is contact between the upper jockey wheel and the cassette sprockets, read the Park Tools guide linked and try to locate the ‘b’ screw on your mech and see if you can adjust it to provide more clearance.

    Personally, if you’re determined to get it sorted tonight, I’d take everything off and start again.

    andyl
    Member

    as Boris says – the screws are just to set the end points (max and min). There is also the b-screw which sets the clearance of the derailleur from the cassette sprockets.

    Max should be set so you can’t push the chain off into the drop out. Min should be set so you cannot push the chain off into the spokes.

    In between that there is no effect and that is done with the barrel adjuster.

    if you are experiencing chain suck – ie the chain getting jammed up between the chainring on the crank and the frame then it is often a case of bad shifting but also a sign of worn or just dirty components.

    check the wear on your chain (look up chain measuring instructions) and also look for any shark fin shaped teeth.

    Jamie
    Member

    Do I even need to point out the irony, given your previous input into this thread?

    I dunno. Seemed quite helpful.

    Jamie:

    http://www.parktool.com/blog/repair-help/rear-derailler-adjustments-derailleur

    http://www.madegood.org/bikes/repair/index-a-rear-derailleur/

    Premier Icon wwaswas
    Subscriber

    Seemed quite helpful.

    Yes.

    I think that caught everyone out, tbh ๐Ÿ˜‰

    Jamie
    Member

    I think that caught everyone out, tbh

    Myself included.

    Reluctant
    Member

    Sounds like chainsuck to me. As the chain hooks on the ring, it’ll pull the rear mech forward and spring back as the chain lets go ~ creates a juddering effect in the rear mech arm. Looking at the pics, it’s an old XT 750 era rear mech which could be anywhere up to 14 years old ~ if the rest of the transmission is the same age, it’s gonna have problems :~)

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