Results 1 to 14 of 14
  1. #1
    mtbr member
    Reputation:
    Join Date
    Aug 2013
    Posts
    63

    Rip 9 2014 2x chainring. 24 tooth small ring compatable?

    So, 26front 36 rear, 65+" per rev, doesn't sound too bad until the trail gets real steep, like Strava category 4 or better climb over "short" distances. The kind where you simply can't move the cranks because you've been climbing that hard for 200 yards. The kind where your 40+ year old body is cranking 185bpm and the 20 year old has been walking for the past 50 yards.

    Several of my local trails are just hard to ride an I hate walking. I like the idea of a 24 tooth front ring, but medium cage on a 39 tooth differential? A 24 tooth with the standard 38tooth supplied from Niner? I've hit the gym all winter, done the squats & leg press. Been pushing the trainer hard in the evenings. I don't know that I can gain the strength needed.

    So has anyone tried the 24 tooth up front w/ the 3 star build? How does it work? Do I need to buy different 36 tooth big ring? If so which one shifts as well as the Shimano pair?

    Thanks.

  2. #2
    mtbr member
    Reputation: peteer01's Avatar
    Join Date
    Apr 2005
    Posts
    589
    Quote Originally Posted by Highlander944 View Post
    Several of my local trails are just hard to ride an I hate walking. I like the idea of a 24 tooth front ring, but medium cage on a 39 tooth differential?
    That's what I just ordered. (38/24, 11-36T, medium derailleur) I want a true granny gear, and if I'm dumb enough to try to use gear combinations I really shouldn't use on any bike, regardless of derailleur, there will be too much chain slack.

    As long as you make reasonably intelligent shifting decisions, everything should be within the 35T capacity. Purchase a long rear derailleur if you are really concerned about being within the rear derailleur capacity, but with a double crankset, I'd lean towards the medium regardless of whether you're running 24 or 26 as your small ring in front.

  3. #3
    mtbr member
    Reputation: peteer01's Avatar
    Join Date
    Apr 2005
    Posts
    589
    Some potential pros of a medium cage over a long cage are increased ground clearance and slightly reduced weight of the mid-cager, but I think both of those are overblown, especially on a 29er. The shorter derailleur cages do tend to shift more crisply, but the big pro of going with the medium derailleur in your case is that you already have it.

    The idea that people should go with a long cage on a triple crankset and a medium cage on a double is an over simplification, but generally running medium on a double crankset is fine.

    Hope that helps.

  4. #4
    mtbr member
    Reputation:
    Join Date
    Aug 2013
    Posts
    63
    Quote Originally Posted by peteer01 View Post
    ... if I'm dumb enough to try to use gear combinations I really shouldn't use on any bike, regardless of derailleur, there will be too much chain slack.
    While I get what your saying here, I don't know practical it is. Before ISpec, there was a little indicator which kept you informed about your place on the rear cassette. I, almost subconsciously, checked this to make sure my gear range was within reason. Now with the ISpec, no indicator. Double shift, single shift up/down a few times, hit a nasty bit of track, I can definitely loose my place. Do people really "always" know where they are or have you ever come to the end of a section and been like... oh I didn't think I was there.

    I believe it would be foolish for me to setup a combo which could fail catastrophically. That said, I don't know if the medium cage 2x 24/38 would be a catastrophic failure.

    As far as switching cages, wouldn't it be easier (cheaper) to purchase a 36 tooth front to keep the gear count within working parameters? Hence my remarks about 24/36.

  5. #5
    Carbon & Ti rule
    Reputation: muzzanic's Avatar
    Join Date
    Apr 2009
    Posts
    5,155
    Lol this is why I have built up my wife's New Rip9 the way I have.

    She loves it.

    XX1 cranks with 26 tooth Wolf tooth direct mount front ring, 11/36 XT cassette with Oneup 42 tooth cassette gear ( remove 17 tooth ring ) to get back to 10 speed )

    X9 Type 2 rear derailieur ( Long cage )

    Sram double tap shifter ( only has the 1 lever that is used for both going up & down gears, It also has the gear indicators with numbers on so she knows what gears she is in.

    I'm sure that she will end up with XTR Di2 on any new bike from here on.


    Quote Originally Posted by Highlander944 View Post
    While I get what your saying here, I don't know practical it is. Before ISpec, there was a little indicator which kept you informed about your place on the rear cassette. I, almost subconsciously, checked this to make sure my gear range was within reason. Now with the ISpec, no indicator. Double shift, single shift up/down a few times, hit a nasty bit of track, I can definitely loose my place. Do people really "always" know where they are or have you ever come to the end of a section and been like... oh I didn't think I was there.

    I believe it would be foolish for me to setup a combo which could fail catastrophically. That said, I don't know if the medium cage 2x 24/38 would be a catastrophic failure.

    As far as switching cages, wouldn't it be easier (cheaper) to purchase a 36 tooth front to keep the gear count within working parameters? Hence my remarks about 24/36.

  6. #6
    mtbr member
    Reputation: JimmyC's Avatar
    Join Date
    Dec 2005
    Posts
    243
    I am not sure if you care about your high end gearing, I certainly don't on the steep and extended climbs we have here in Tahoe. I just installed 22T/33T Wickwerks chainrings (from a 26T/38T setup) on my new Rip9 RDO's M785 XT crankset. I had made an initial change to a 24T/38T setup, which worked well on flatter/rolling terrain (i.e. the Bay Area), but I really missed my 33T when riding in Tahoe.

    I had to change the front XT shifter from a 2 ring setup to 3 ring setup (easy to do) to accommodate the change from a 26T granny to a 22T granny. At least for me, the new setup gives me the climbing range that I enjoy using up here in Tahoe. The loss of the high end gearing may be a significant issue on flatter terrain. However, I generally use the 33T chainring for most of my riding---and use the 22T chainring as a bailout gear when I am beat. Good stuff.

  7. #7
    mtbr member
    Reputation: kragu's Avatar
    Join Date
    Jun 2011
    Posts
    1,670

    Rip 9 2014 2x chainring. 24 tooth small ring compatable?

    Wow, muzz. 26/42 is lowwww. I just set up my Lunchbox with X01 and a WT DM 28t because I can't get a bigger ring on the 'box without shaving some chainstay. That, and I don't feel the need for a gear higher than 28/10. I feel like I could pedal Everest in my granny.
    '14 Lenz Lunchbox
    '08 Gary Fisher Ferrous 29

  8. #8
    Carbon & Ti rule
    Reputation: muzzanic's Avatar
    Join Date
    Apr 2009
    Posts
    5,155
    Quote Originally Posted by kragu View Post
    Wow, muzz. 26/42 is lowwww. I just set up my Lunchbox with X01 and a WT DM 28t because I can't get a bigger ring on the 'box without shaving some chainstay. That, and I don't feel the need for a gear higher than 28/10. I feel like I could pedal Everest in my granny.
    Yes it is low.

    The thing is we do climb some very steep stuff (all be it not for that long ) & because she will never need more top end on this bike, It is nice climbing a steep tricky track & know you have 1 or 2 gears up your sleeve if needed.

    She has her Jet9 RDO for the trails she needs more speed.

  9. #9
    mtbr member
    Reputation: peteer01's Avatar
    Join Date
    Apr 2005
    Posts
    589
    Quote Originally Posted by kragu View Post
    Wow, muzz. 26/42 is lowwww.
    Actually, while it sounds low, 22/36, which is a pretty standard triple ring option, is actually lower. On a 29er, there are definitely times (climbs) I have been very grateful for that granny gear on my 3x9 XC bike.

  10. #10
    mtbr member
    Reputation:
    Join Date
    Jun 2004
    Posts
    626
    I've got 22/36 on my RIP, mainly because I'm weak and out of shape. Need all the climbing help I can get.

  11. #11
    mtbr member
    Reputation: peteer01's Avatar
    Join Date
    Apr 2005
    Posts
    589
    Quote Originally Posted by rufus View Post
    I've got 22/36 on my RIP, mainly because I'm weak and out of shape. Need all the climbing help I can get.
    I like riding long enough and hard enough that I want/need 22/36 on my XC bike at the end of a good ride. My trail bike won't have that granny gear, but I probably don't want to be riding really technical/treacherous stuff completely exhausted.

    I road a 38.5 mile race today and was very glad to have 22/36 at a few climbs in the last hour.

  12. #12
    mtbr member
    Reputation: kragu's Avatar
    Join Date
    Jun 2011
    Posts
    1,670

    Rip 9 2014 2x chainring. 24 tooth small ring compatable?

    Quote Originally Posted by peteer01 View Post
    Actually, while it sounds low, 22/36, which is a pretty standard triple ring option, is actually lower. On a 29er, there are definitely times (climbs) I have been very grateful for that granny gear on my 3x9 XC bike.
    I guess it's just been a while since I've run that low. Over the last 4 years, I ran 22/36 on a SRAM 3x, 24/36 on a SRAM 2x, 26/36 on XT, 32/36 on a 1x, 32/42 with a Wolf Tooth GC, and now what feels like a big step down to 28/42.
    '14 Lenz Lunchbox
    '08 Gary Fisher Ferrous 29

  13. #13
    mtbr member
    Reputation:
    Join Date
    Aug 2013
    Posts
    63
    Hi all, thank you for your replies.

    I'm very analytical, I have a spreadsheet which calculates the distance traveled per crank revolution for every gear ratio. Here is my design process:

    The current 65.8" distance per crank is a little difficult on STEEP climbs. A 10% reduction sounds nice. A 24 tooth front ring yields 60.7" per crank, a 10% reduction. -> Low gear set.

    As I approach 30mph I would like to keep my rpm around 100. 100 cranks per minute @ 314.7" per crank (38 / 11 on a 29er) is 29.8mph. -> High gear set.

    So my design constraints... 60" per crank in low gear to keep big climbs more manageable but near 300" per crank in big gear to keep near 30mph possible. -> 24 / 38 front - 11 / 36 rear.

    @Muz: 26 front - 42 rear = 56.4" per rev. Yes this is a nice low range, and I have considered this path. The cost of a 1x conversion is around $100-$150. If I can simply replace the 26 w/ a 24, my cost is $30. The 24 would get me 60.7" per rev, or about a 10% reduction and allow me to keep the top end. If I go 1x10, my high gear is 26 / 11 and I'd have to crank 150 rpm to hit 30mph...

    Hence my original question. Can I simply swap out the 26 for a 24 while maintaining the "nice" front ring shift? Is there a 24 tooth which plays better or best with the Shimano? How bad is this for the stock medium cage rear XT derailleur.

    Thanks.

  14. #14
    mtbr member
    Reputation: peteer01's Avatar
    Join Date
    Apr 2005
    Posts
    589
    Quote Originally Posted by Highlander944 View Post
    Hi all, thank you for your replies.

    I'm very analytical, I have a spreadsheet which calculates the distance traveled per crank revolution for every gear ratio. Here is my design process:

    The current 65.8" distance per crank is a little difficult on STEEP climbs. A 10% reduction sounds nice. A 24 tooth front ring yields 60.7" per crank, a 10% reduction. -> Low gear set.

    As I approach 30mph I would like to keep my rpm around 100. 100 cranks per minute @ 314.7" per crank (38 / 11 on a 29er) is 29.8mph. -> High gear set.

    So my design constraints... 60" per crank in low gear to keep big climbs more manageable but near 300" per crank in big gear to keep near 30mph possible. -> 24 / 38 front - 11 / 36 rear.

    @Muz: 26 front - 42 rear = 56.4" per rev. Yes this is a nice low range, and I have considered this path. The cost of a 1x conversion is around $100-$150. If I can simply replace the 26 w/ a 24, my cost is $30. The 24 would get me 60.7" per rev, or about a 10% reduction and allow me to keep the top end. If I go 1x10, my high gear is 26 / 11 and I'd have to crank 150 rpm to hit 30mph...

    Hence my original question. Can I simply swap out the 26 for a 24 while maintaining the "nice" front ring shift? Is there a 24 tooth which plays better or best with the Shimano? How bad is this for the stock medium cage rear XT derailleur.

    Thanks.
    The Shimano options for a 38 big ring are 24 or 26, at least for XT, so I would think the 24 tooth Shimano ring would be the only difference between the 38/24 and 38/26 double cranksets.

    As for the medium cage, you get 35T, and if you're 11-36 and 24/38, your maximum differential is 39T, so you just need to avoid those smallest rear gears when you're in 24 in the front.

    I just intentionally ordered a medium cage with a 38/24 double and 11-36 cassette. My math behind the low and high gear combinations wasn't nearly as detailed as yours, it was more of just knowing I wanted the 24 front, 36 rear granny gear on a 29ers, but your post confirms that I'm happy with what I'm getting. The XT shifters show what gear I'm in, so unlike X9 shifters, I'll be able to look at the bars if I'm not 100%.

Similar Threads

  1. Replies: 0
    Last Post: 05-29-2014, 10:54 AM
  2. Replies: 5
    Last Post: 02-16-2014, 12:38 PM
  3. Chain jumping from small chainring to middle chainring
    By menusk in forum Drivetrain - shifters, derailleurs, cranks
    Replies: 6
    Last Post: 04-07-2013, 10:31 PM
  4. Shimano small chainring tooth design
    By Pableras in forum Drivetrain - shifters, derailleurs, cranks
    Replies: 5
    Last Post: 10-04-2011, 12:24 AM
  5. 26 tooth small ring on a Mojo?
    By d-bug in forum Ibis
    Replies: 2
    Last Post: 03-29-2011, 10:50 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •