Granny ring replacement

ralph1471
ralph1471 Posts: 92
edited June 2012 in MTB workshop & tech
Hi Guys

ill try to keep this brief...

I have had a couple of nasty incidents with chain suck resulting in damage to my frame, i think both times were whilst using my 22t granny ring on my shimano slx double crankset. As the chain was pretty new and well lubricated, I read up about chain suck and apparently a worn inner ring is often to blame. Upon taking a look at the granny ring it did look a bit worn, so I rather stupidly bought a 22t titanium chainring (see link)

http://www.carbon-ti.com/index.php?p1=p ... TBZ22I64SH

as i read that they last a lot longer than aluminum and I was having trouble finding a steel one.

The chainring has arrived but i noticed the teeth on it are much shorter than the Shimano ones, and once it was fitted, consistantly slips when I pedal (resulting in a large lump on my knee which was fun!).

So my question is what have i done wrong?! Any help would be great.

Comments

  • nicklouse
    nicklouse Posts: 50,675
    Sounds like the chain is aso worn then.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • ralph1471
    ralph1471 Posts: 92
    thanks for the quick reply, the chain is brand new! replaced that as well because the last one was damaged in the chain suck incident. cassette is also nearly new.
  • nicklouse
    nicklouse Posts: 50,675
    Ring fitted correctly?

    There are 8 possible ways but only one correct.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • ralph1471
    ralph1471 Posts: 92
    Photo11-06-2012214841.jpg

    it said to have the small arrow facing the crank arm. however this looked slightly different to how the previous ring was fitted but i stuck to the instructions! is there any way to tell which way it should be fitted apart from that? i have pictures of how the old one was fitted as well if that helps.

    thanks
  • nicklouse
    nicklouse Posts: 50,675
    Good.

    Is the chain catching on the middle ring? Causing it not to seat fully?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • ralph1471
    ralph1471 Posts: 92
    heres the picture of the old one -

    Photo05-06-2012194951.jpg

    would it slip like that from being fitted wrong? could the shorter teeth have affected it do you think?
  • ralph1471
    ralph1471 Posts: 92
    sorry i was typing that as you replied! it doesnt shift up onto the middle ring properly no, it doesnt seem to catch correctly. *EDIT just re-read your question, it seems to be seated properly on the ring.
  • nicklouse
    nicklouse Posts: 50,675
    Not what I was asking.

    Does the chain seat fully on the cog? Or us it rubbing on the middle ring?

    Looking at the top of the teeth are they offset? Would flipping the cog move them away from the middle cog?

    Would that help?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • ralph1471
    ralph1471 Posts: 92
    sorry, i did edit it after i realised what you meant. I have had a closer look at it and it doesnt seem to be touching the middle ring at all. the top of the teeth are slightly offset yes, not sure if this would affect it though as it is not in contact with the middle ring? (although the gap is barely visible)
  • ralph1471
    ralph1471 Posts: 92
    I will try flipping it over tomorrow but i'm scared to pedal on the bloody thing now!
  • ralph1471
    ralph1471 Posts: 92
    Any more ideas about this as Ive had a closer look and i don't think the teeth are offset. Also it doesn't seem to be touching the middle ring anyway. I really have no idea what is wrong with it, so any suggestions would be welcome. do you think that I definitely have it on the right way (I.e. maybe I should have lined the teeth up the same way as the old ring rather than as per the instructions?).

    Thanks
  • ricardo_smooth
    ricardo_smooth Posts: 1,281
    If it doesn't shift up into the middle ring properly, your front mech is set up poorly/incorrectly. Set the limit screw to that the mech pushes in further. If you're struggling to get enough initial cable tension push the mech towards the middle ring with your finger whilst you tighten the bolt that holds the cable.
  • ralph1471
    ralph1471 Posts: 92
    thanks but I've sorted that out now, just needed the cable tightened. its more the chain slipping on the granny ring thats the problem.
  • ricardo_smooth
    ricardo_smooth Posts: 1,281
    In what gears? If its more when in the smaller cogs at the rear too, could be just because the chain is slack
  • ralph1471
    ralph1471 Posts: 92
    yeah originally It was too slack but I removed some links, it was still happening even in the 2nd/3rd biggest cogs on the back. (didn't try the biggest after bashing my knee). It seems to be tight enough and if I take any more links out it will be too tight for the big ring.
  • ricardo_smooth
    ricardo_smooth Posts: 1,281
    Possibly worn cassette then as everything else is new.
  • 1mancity2
    1mancity2 Posts: 2,355
    ricardo_smooth wrote:
    Possibly worn cassette then as everything else is new.

    +1
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  • mrmonkfinger
    mrmonkfinger Posts: 1,452
    ricardo_smooth wrote:
    Possibly worn cassette then as everything else is new.

    +2
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  • ralph1471
    ralph1471 Posts: 92
    thanks guys but it is definitely slipping around the front granny ring and not the cassette, i could feel it slip when i tried to pedal. Still no idea why though.
  • ricardo_smooth
    ricardo_smooth Posts: 1,281
    It may appear to slip there, but it's the rear cassette, try it and fine out ;)

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