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  1. #1
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    Anyone running an Actiontec 20t small ring on the Tallboy?

    I just installed one, but it wants to skip unless I'm in the 34T in back. Just wondering if anyone has gotten around this.

  2. #2
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    I'm running the 20/30/40 on my S-works epic 29r SRAM system with no problems and also on my giant XC2 29r Shimano with no problems. Coverted the 2*10 system to a 3*10 system to give me the same overall gearing as a 26r (see specialised discussion for how). If it is shifting ok to the 20T but skipping in the 20*34 combo - make sure the chain isn't A) too long; B) the chain isn't fowling on the lugs or bolt heads holding the 20T on the spider; C) the cage isn't rubbing the chain when in the 20*34 combo. What brand shifter/derailleur you running?

    See Converted 2011 S-works 29r 2*10 to 3*10 system for the 'how to'convert 2*10 to 3*10 for a SRAM XX eqipped 29r.

    FWIW

  3. #3
    I Tried Them ALL... Moderator
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    The ActionTec 20t granny ring works great, scaling those pesky, 20-25% grades in the 34t cog. However, the OP's underlying issue is really a bent rear derailleur hanger....not the 20t ring. Have it checked ASAP.
    "The mind will quit....well before the body does"

  4. #4
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    Thanks for the response. I took the cranks back off and inspected the posts. Sure enough the posts have some marks in them where the chain is hitting. I'm going to take it in to work tomorrow and grind the posts down a bit.

    I did shorten the chain by two pairs of links already. I think I actually have it too short now because (even though I shouldn't) the chain isn't long enough to go on the big ring and the 11T in back without putting the rear derailer in bind.

    I adjusted the height of the front derailer a bit, so that it would only touch the bottom of the derailer cage as the chain went a little bit slack on the top. That's the closest I could get it and still be able to clear the big ring as well. Everything with the exception of the ActionTec 20T is XT.

  5. #5
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    Zach, you really think it's a bent rear derailer? I'm trying to picture in what way it could be bent that would cause the chain to skip on the front.

  6. #6
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    I got XT on my Giant HT - I use the 20T actiontec no probs - BUT I also use the anderson machine 30/40 rings so there is not such a large jump from the 40>30>20 rings compared to 42>32>20. This gives the same overall gearing in each chain-ring as a 26r with the smaller dia. wheel, if you compare cadence(revs) * speed.

    I had no need to shorten the chain even though it now needed to cope with the 40T ring which is about 10mm less OD than the 42.
    HTH

  7. #7
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    When I installed an ActionTec 20T ring, I had to file down edges of the bolt heads and mounting posts that the chain was hitting. I think that's pretty standard on most spiders. I also had a problem with skipping when the chain was highly tensioned while climbing. I noticed that the valleys on either side of the 4 bolt holes were shallower than the others. I presume they do this for strength around the bolt hole. I used a round file to deepen them to match the other valleys, and my skipping problem went away. That was about a year and a half ago and I haven't had a problem since. Incidentally, I just replaced the 32T stock ring with a 30T Extralite Octaramp, and love that as well..
    Use it, use it, use it while you still have it.

  8. #8
    I Tried Them ALL... Moderator
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    If its skipping on the front - I recommend flipping the ring...even though there is no indication of directional application.
    "The mind will quit....well before the body does"

  9. #9
    I Tried Them ALL... Moderator
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    Quote Originally Posted by astrahsburg
    Zach, you really think it's a bent rear derailer? I'm trying to picture in what way it could be bent that would cause the chain to skip on the front.
    Still would not hurt to have it inspected. Did you get the steel, or titanium 20t ring? Makes a huge difference....the ti ring refuses to bend if installed correctly, despite the incredible tension on steep climbs.
    "The mind will quit....well before the body does"

  10. #10
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    So, I finally got this thing straightened out. I had taken the crankset to work the next day, and used a grinder on the bolt lugs hoping that would be enough.

    Put everything back together, and it was still skipping. I stupidly though that maybe if I make the chain another pair of links shorter, maybe it will work better. Thinking back, I must have been really tired when I though that because right now it doesn't make any sense at all. In fact, after removing a pair of links, I promptly skipped again, and tore the chain in half.

    2 days layer, a new chain and a Dremel tool have left me with an incredibly smooth and very high torque first gear. No skipping or chain suck. With the dremel tool I depend the valeys of the chain ring like Gasp4Air did. They still aren't quite as deep as the others, but they seem to be deep enough now. After deepening the valleys the chain was no longer clearing the mounting posts I had tried to grind down before and the chain ring bolts which were clearing before were no longer clearing, so I shaved the edge off those a little bit too.

    Overall I'm pretty happy with how it turned out. I'm also glad the chain broke, because it reminded me that I really should put a new one on anyway.

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