SS Gearing calculation question.- Mtbr.com
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  1. #1
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    SS Gearing calculation question.

    Running a 29er geared at the mo and looking at another SS in the future as well. Question about gearing.

    I noticed that on a really tough climb I spend a lot of time 22T front and 15T back but seated which using Sheldon Browns calculator is 3.1 gear inches. So am I right in thinking a close equivalent would be 32T and 20T which is 3.4 gear inches. Is that how this works? 3.4 being slightly harder I'm guessing.

  2. #2
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    i think you've confused 'gear inches' and 'gear ratio'

    if you're using this site...
    http://www.sheldonbrown.com/gears/
    you need to make sure the 'gear units' category is properly selected.

    a 22 and 15 on a 29er is 42.5 gear inches, and a 32 and 20 is 46.4 gear inches. the higher number will mean its harder to push around....aka, you go further per every rotation of the crank.

  3. #3
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    Oh yeah whoops... I did think the inches looked small haha, thanks for that,

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    I haven't gone SS yet, looking to soon. But you might want to re-think designing your gearing around what you do seated during tough climbs. Sure, you'll be able to replicate that effort, but it will be hard for you to have decent speed on the flats. SS is a compromise and you adjust your speed based on cadence, it seems like you might be centering your range around the low end.

  5. #5
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    Quote Originally Posted by cooleric1234
    I haven't gone SS yet, looking to soon. But you might want to re-think designing your gearing around what you do seated during tough climbs. Sure, you'll be able to replicate that effort, but it will be hard for you to have decent speed on the flats. SS is a compromise and you adjust your speed based on cadence, it seems like you might be centering your range around the low end.
    Thanks heaps, you raise a very valid point.

    I did however SS for two years prior to my new love of 29er geared so I have some idea what I am after. I tend to run lower gears so I can stand and get over the bigger climbs cos I don't really mind spinning out on downhills or on flats that much. I'd rather not get off the bike if I don't have too and in races I find for me 8 times out of 10 I pass people up the hills than anywhere else.

    Basically I have gotten a lot stronger since going geared and was just trying to find a reasonable match to gears I know will work for me. 32-20 is looking more like what I would run. Oddly enough it's what I used to run along with 32-18 but I struggled on some hills a lot. I feel the added strength should help.

  6. #6
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    Lower weight SS, change gear?

    I currently run 32 x 18 on a 29'er and am pondering going rigid, losing 1 1/2 to 2 lbs overall. Does a 2 lb drop in bike weight warrant changing the gearing? thanks. If there's another post on this, please send link.

  7. #7
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    Quote Originally Posted by Swervemonk
    I currently run 32 x 18 on a 29'er and am pondering going rigid, losing 1 1/2 to 2 lbs overall. Does a 2 lb drop in bike weight warrant changing the gearing? thanks. If there's another post on this, please send link.
    1.5lbs = one standard size water bottle full of water.

    do you notice the difference of that? i don't. enough to change the gearing? no way.

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