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  1. #1
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    New question here. Flash 29er Granny Gear

    Pardon my ignorance if this has been covered and I missed it.

    I have a 2012 FLASH ALLOY 29'ER 1
    Front SRAM X7 with 39/26 Sprockets
    Rear SRAM X9 with 10 Sprockets 11/13/15/17/19/22/25/28/32/36



    I love this bike dearly, but it just doesn’t have the tight, singletrack, monster climb granny gearing that I need. My other bike is a 2005 Scalpel, and I find it much easier on my old knees.

    Anybody have experience and insight into the best way to modify this for my needs? According to my LBS, you can't just swap the front 26 tooth for a smaller one.

    Thanks!

  2. #2
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    Flash 29er Granny Gear

    I changed the 39/26 tooth chain rings on my Scalpel to a 38/24 and it works a lot better for me. You need a new spider in 104/64mm bolt center diameter (BCD) to replace the 120/80mm BCD on your existing bike... Plus new chain rings. You'll gain two extra climbing gears though, so it's worth it. LBS can help you. (The 2014s are all 38/24 now .... This is generally recognized as a better gear setup for 29ers.)

  3. #3
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    Thanks Scott, the 38/24 sounds a lot better for my situation. I will check with the local LBS again to see what they have to say about your excellent advice.

    Cheers!

  4. #4
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    My suggestion to you is to work on improving your pedaling force and get used to the 39/26...
    The gain that you will achieve by reducing 2 teeth in the front is not substantial enough = it is only 1.4 gear inch
    F24/R36= 19.4 Gear Inch
    F26/R36 = 20.8 Gear Inch

    For comparison one higher cog in the rear will set you back 2.6 gear inch..
    F26/R32 = 23.4

    Save the money for better/lighter wheels.

    Check out the gear calculator at BikeCalc.com - Bicycle Gear Inches Chart
    Flash29C2
    Scalpel 29C1
    Niner One9 SingleSpeed RDO fork
    Supersix Evo 1 Hi Mod D/A

  5. #5
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    Where I ride the 39/26 paired with 11-36 cassette just didn't cut it on those long grueling climbs.

    Lower options as mentioned are 38/24 , 36/22.

    I went 1x11 with a 28t ring and 10x42 cassette....perfection.

  6. #6
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    I would go this route, makes a bigger difference and cheaper too.

    42T GC cog for Shimano ? wolftoothcomponents.com

  7. #7
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    Quote Originally Posted by Flucod View Post
    I would go this route, makes a bigger difference and cheaper too.

    42T GC cog for Shimano ? wolftoothcomponents.com
    Agree - bigger difference and less cost - does anyone have real experience with it ?
    I guess that a long cage derailleur will be required and most likely a longer chain ?

    That combo 26F/42R will create approx 18 gear inches vs the 20.8 G.I. of the 26F/36R and therefore be much more substantial than changing the front chain-ring
    Flash29C2
    Scalpel 29C1
    Niner One9 SingleSpeed RDO fork
    Supersix Evo 1 Hi Mod D/A

  8. #8
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    Huh... me and my 25.9 Gear Inch lowest gear...

    DAN.GEROUS.NET : MOUNTAIN BIKING : CYCLOCROSS : ROAD :

  9. #9
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    Quote Originally Posted by Dan Gerous View Post
    Huh... me and my 25.9 Gear Inch lowest gear...
    LOL
    My SS is 41.9 GI @ 32/22 ...


    Seriously, 39/26 front CW works great.
    As I said to the OP, IMO it really worth the time to develop the required strength to use it.
    Flash29C2
    Scalpel 29C1
    Niner One9 SingleSpeed RDO fork
    Supersix Evo 1 Hi Mod D/A

  10. #10
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    Quote Originally Posted by StumpyElite2010 View Post
    LOL
    My SS is 41.9 GI @ 32/22 ...


    Seriously, 39/26 front CW works great.
    As I said to the OP, IMO it really worth the time to develop the required strength to use it.
    I'm serious too, 36T single ring, 11-36 cassette, 26" wheels and I rarely cried for a lower gear (there are no 25km long steep climbs around here though).

    Early in the season, before base training, I pedal a lot on big gears at super low cadences, always seated. It builds leg strength but also lower back strength. Then during base, I mostly spin at more normal cadences... But year long, I include some fast spinning and the slow grinding so I have no problem hitting 190rpm but I can go at a ridiculously slow cadence too.... It's good to have a wide range in the legs even if you do have a big gear range on your bike.

    DAN.GEROUS.NET : MOUNTAIN BIKING : CYCLOCROSS : ROAD :

  11. #11
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    Quote Originally Posted by StumpyElite2010 View Post
    As I said to the OP, IMO it really worth the time to develop the required strength to use it.
    It's not a leg strength issue, it's a permanently damaged knee issue. If I didn't have the weak link in my knee, the gearing would be fine. My old 2005 Scalpel with 26" wheels, 22 tooth front, and 9-Speed 11-34t cassette in the rear is perfect when I hit those really long, steep climbs. Drop into granny and spin away.

    I've put about 2500 miles of riding on the Flash so far, not a lot, but enough to know that gearing it down is safer for me than risking further injury. I do agree with you that the gearing isn't that bad, and should be useable for most people, but unfortunately for me, that's not my situation.

    Probably a dumb question, but is there a way to calculate gearing that takes the 26" vs 29" wheel issue into account? In other words, what would the exact ratio need to be on the Flash 29" to equal what my Scalpel 26" is when I've dropped down to 22 front and 34 on the rear on the Scalpel?

    Thanks

  12. #12
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    DAN.GEROUS.NET : MOUNTAIN BIKING : CYCLOCROSS : ROAD :

  13. #13
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    Sorry to hear about your knee...
    The link I provided earlier allows you to input the wheels size as well as the tire...
    29" wheels makes it a bit more difficult compares to the 26"
    Flash29C2
    Scalpel 29C1
    Niner One9 SingleSpeed RDO fork
    Supersix Evo 1 Hi Mod D/A

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