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  1. #1
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    Effect of granny ring size on suspension behavior? (5-Spot)

    Anyone try different sizes small rings (specifically 22t vs 24t) on a 5-Spot and notice a difference in how the suspension behaves under pedaling power?

    I've been running a 22t granny on my 2011 5-Spot (with a 32t middle ring on a 2x setup). I find that in the small ring there is a bit too much "anti-squat" for my tastes. Sort of hangs up on climbing bumps (like roots)similar to the way my old Superlight and Heckler did in the small ring. It feels about right in the middle ring.

    I've experimented with comparing how it behaves in similar ratios in the small and middle ring, and there is definitely a difference (better in the middle ring). This, along with my understanding of how the chain tension influences the suspension, leads me to think that a larger small ring would work better.

    I need to replace my rings, and I am considering going with a 24t small ring, in part in hopes of making it a little less "ant-squat-y". I'm pretty confident that it will make SOME difference in how the suspension behaves, but I am unsure whether it will be enough for me to actually notice.

    Thanks
    Last edited by kapusta; 05-07-2013 at 12:24 PM.
    15mm is a second-best solution to a problem that was already solved.

  2. #2
    MK_
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    Only DW himself can answer how much of a difference this will be.

    Here is a general idea about anti-squat and chainring size from DW:
    The amount of anti-squat that a suspension can develop is based on (among other things) the angle of the ground that the bike is riding on and the angle of the chainline. It just so happens that as a bike is climbing a hill, the amount of anti-squat drops because the direction of gravity in relation to the bike changes. What this means is that if you are pedalling along in your 32-18 on flat ground and have just the right amount of anti-squat, then start to climb a steep hill, say 15 degrees or so, the amount of anti-squat is going to lessen. It just so happens that moving the chainline downward, say like if you selected your 22T cog, increases anti-squat. In an Apollo 13 like turn of events, people actually use their 22T cog when they climb hills as steep as 15 degrees (you basically have to). The two changing anti-squat amounts balance out, leaving the rider with very similar riding characteristics while climbing in the granny and riding on the flat in the middle ring. Amazing, huh? As you may have guessed, the same goes for descending with a larger ring.
    And full writeup: dw-link: single chainrings and the detrimental effects on bicycle suspensions used for climbing and all mountain type riding

    _MK
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    "No man goes before his time -- unless the boss leaves early."
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  3. #3
    MK_
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    More info, this from Linkage Design:



    Source: Linkage Design: Turner 5.Spot 2011

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    "No man goes before his time -- unless the boss leaves early."
    -- Marx, Groucho

  4. #4
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    Awesome chart, thanks!
    15mm is a second-best solution to a problem that was already solved.

  5. #5
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    I've used 24, 26, and 28 on a 2x10 set-up on my DW-Link Sultan, I can't say I've felt any difference in suspension behavior as a result. If you plot out the curves on a computer maybe there is a small difference, if you develop bikes for a living and test them back to back on the same hill you might feel a small difference, but for the typical rider out on the trail I doubt it...

  6. #6
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    An Update:

    I replaced the 22t/32t rings I was running with 24t/36t rings.

    I do notice a little difference in the granny, but it is not huge. The difference in the 36t ring is definitely noticeable, and IMO a real improvement. Feels great, actually. In another thread, I saw how the anti-squat of the 5-Spot compared to my old MKIII. I notice that the numbers for the MKIII with 22/32 rings are really close to the 5-Spot with 26/36. This totally jives with what I have been feeling as I ride.

    Only problem is, for me and my riding, the 22/32 rings are more useful. I've been getting away with the 24t granny OK, though I have yet to do any really long rides where a few hours into it I need all the help I can get. But I think it's going to be OK overall.

    Surprisingly, it's the range of the bigger ring that I have some issue with. Since it is about a gear higher than the 32t ring, I need to drop down to the granny sooner. I realized that in my riding, I do climb a lot on the easiest gear in the 32t ring. So now I am dropping down to the 24t ring on many climbs that used to be middle ring climbs, and instead of getting a more active suspension, it is LESS active.

    I'm thinking of trying 24/32. I never really needed more on the high end of the 32t I was running before, anyway. Or I will just HTFU and learn to push the 36t ring. Kind of ticked that 9 speed options with a 36t cog are so limited (I have an Aluminum carrier, and all of the 9-sp cassettes with a 36t separate cogs, not on a spider).
    15mm is a second-best solution to a problem that was already solved.

  7. #7
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    Hmmm would you consider a 24/34 combo? Seems like it might be a good compromise. I'm not that sure if there are ramped 34T rings though.

  8. #8
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    Quote Originally Posted by mikkosan View Post
    Hmmm would you consider a 24/34 combo? Seems like it might be a good compromise. I'm not that sure if there are ramped 34T rings though.
    I had considered it, but I already have a new 32 in the parts bin.

    I think a 24/34 combo with a 36t big cog would be perfect.
    15mm is a second-best solution to a problem that was already solved.

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