• 09-02-2015
    rsaavedra
    SRAM X9 Crankset for 2013 Trek Marlin
    I'm interested in the above crankset for the above bike. I already gathered the chain, cassette, shifters, front and rear derailleurs. The crankset is the only thing I'm not sure on what to get. I think the bb used is bb95, but I'm not sure what all I need to buy, can I use the existing bb on my bike or do I need a new one? Does the bb comes with the crankset? Do I need any additional parts? Is it possible to get part numbers so I can order the right parts? Thanks for your assistance!

    Sent from my SM-G900P using Tapatalk
  • 09-02-2015
    AndrwSwitch
    I really don't think you have an exotic bottom bracket. If I believed in making hyperbolic statements on the Internet, I'd even offer to bet money. I bet you have a 68 mm English-threaded bottom bracket.

    How about some pictures? Particularly from the left. Get up close and personal.

    If I'm right, you need the GXP version of the crankset and a GXP bottom bracket. You can probably get a set that includes the bottom bracket.
  • 09-02-2015
    rsaavedra
  • 09-02-2015
    AndrwSwitch
    Can you embed them?
  • 09-02-2015
    AndrwSwitch
    I'm on my big computer now and two of your images worked. That's an English-threaded bottom bracket shell. I don't know how wide, but it doesn't really matter.

    You can't use your existing bottom bracket. It's the wrong basic design.

    So what I was suggesting in post #2 would be the right approach.

    There are a bunch of different X.9 crank options. That's part of how I ended up with one myself. :) Take a step back, and think about what you want your drivetrain to be. Do you want to do two or three chain rings? Or one? Do you want a bash guard? Are you happy with the length of your crank arms? How many teeth would you like your chain rings to have? Most of these questions only have a few possible answers, so it's not crazy-difficult to make some decisions. But you do need to decide.

    If you haven't looked at this page from SRAM it pretty much lists all your choices.
    https://www.sram.com/sram/mountain/products/x9-crankset
  • 09-04-2015
    rsaavedra
    Quote:

    Originally Posted by AndrwSwitch View Post
    .

    Thanks Andrew! I'm on a triple crank currently 42/32/22 w/ a 11-34 cassette and I'm looking at possibly a double 42/28 or 39/26 w/ a 12-36 cassette. I'm not so sure which one of the 2 combinations will get me closer to where I am currently as I'm not certain of gear combinations. If I don't get a clear answer I'll just purchase the triple crank combo 44/33/22 and move on. The terrain I ride is mostly single track with a lot of fairly moderate climbs, sharp turns, good amounts of rocks, roots and logs along with a few creeks. Any help is certainly appreciated...

    So to make sure I got it so far, I should be looking at a crankset:

    -68mm English thread (excuse my ignorance but would a 68-73mm work?)
    -GXP BB
    -170-175mm

    Do I need to be concerned with spindle diameter as well?


    Thanks for the assistance!
  • 09-04-2015
    AndrwSwitch
    I think triples are inelegant and overkill for drivetrains that can have 11-34 cassettes. It's not worth it to me to go out and buy a double for my bike that has a perfectly good triple, but I'm happy with the double on my newer bike.

    For me, 42/28 would be really high gearing. I like having 22/34 available for climbs bigger than a roller, and I think 44/11 is pretty useless on a bike ridden off-road with knobby tires. I occasionally spin it on the road on the way to a trail head, going down hill, but I don't really care about that, and don't imagine I'd miss it.

    I think 36/22 and 38/24 are more sensible combinations on a mountain bike. Next time you're riding, try to pay attention to which gears you actually use. Figuring out how that translates to different chain rings on a double is just fractions.

    Bottom bracket width mostly stopped mattering when everyone went to external bottom brackets. Just don't buy a crank for a fat bike. :)

    Yes, GXP is basically your only choice since you want X9 and have a frame with English threading.

    You need to decide 170 vs 175. To be honest, it's not that important for most people. People with limited range of motion benefit from shorter crank arms. Many people prefer the feel of longer. You can either measure what you have or see if the length is stamped on the back to at least know what you're coming from.

    24 mm spindle. You don't get a choice about that once you're doing GXP.
  • 09-04-2015
    rsaavedra
    Quote:

    Originally Posted by AndrwSwitch View Post
    I think triples are inelegant and overkill for drivetrains that can have 11-34 cassettes. It's not worth it to me to go out and buy a double for my bike that has a perfectly good triple, but I'm happy with the double on my newer bike.

    For me, 42/28 would be really high gearing. I like having 22/34 available for climbs bigger than a roller, and I think 44/11 is pretty useless on a bike ridden off-road with knobby tires. I occasionally spin it on the road on the way to a trail head, going down hill, but I don't really care about that, and don't imagine I'd miss it.

    I think 36/22 and 38/24 are more sensible combinations on a mountain bike. Next time you're riding, try to pay attention to which gears you actually use. Figuring out how that translates to different chain rings on a double is just fractions.

    I'm leaning more on the 39/26 rather that the 42/28. Tomorrow I'll be doing a 15 mile trail ride with all the conditions mentioned above specifically to pay close attention to what I use the most. I think the 39/26 with either the 11-36 or 12-36 combo will put me around what I enjoy. Soon will report what I find...

    Quote:

    Originally Posted by AndrwSwitch View Post
    Bottom bracket width mostly stopped mattering when everyone went to external bottom brackets. Just don't buy a crank for a fat bike. :)

    Yes, GXP is basically your only choice since you want X9 and have a frame with English threading.

    Thanks Andrew, great information!

    Quote:

    Originally Posted by AndrwSwitch View Post
    You need to decide 170 vs 175. To be honest, it's not that important for most people. People with limited range of motion benefit from shorter crank arms. Many people prefer the feel of longer. You can either measure what you have or see if the length is stamped on the back to at least know what you're coming from.

    I have a 175 and have ridden 170's before and I'm not if I really noticed a difference...

    Quote:

    Originally Posted by AndrwSwitch View Post
    24 mm spindle. You don't get a choice about that once you're doing GXP.

    Cool!!!
  • 09-08-2015
    rsaavedra
    Ok, so I decided that 36-22t w/ 12/36 cassette will be the best option for me.
    I do have the SRAM X9 (lc) rear deraileur, KMC X10L, SRAM PG-1070 12-36, SRAM x9 shifters. I think this is the right combination... any thoughts?
  • 09-08-2015
    AndrwSwitch
    Front derailleur?
  • 09-08-2015
    rsaavedra
    As far as front derailleur right now oem is a TP/LC SRAM X4. I dont know if I am restricted to those specs or if a dual pull/hc ot tp/hc will work or be more beneficial... Also, I'm not understanding the to top swing or bottom swing...

    So, I thought perhaps this would be the right application:

    SRAM X9 2x10 Front Derailleur, Low Clamp- Multi clamp, top pull (SRAM X9 2x10 Front Derailleur | SRAM).

    Now my oem is tp/lc on a 3 crank, when i go to the 2 crank I assume the FD mounting position will change with crank being smaller and not much room on tube for lc fd, so i thought that i may need a hc fd not sure if tp or dp... hahaha I'm just lost in my sea of confusions... hahaha
  • 09-08-2015
    AndrwSwitch
    How about a pic?
  • 09-08-2015
    rsaavedra
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    Andrew pic of the bike?
  • 09-08-2015
    AndrwSwitch
    Yeah - post a pic of the front part of the drivetrain. Needs to be your bike, not a catalog shot or a picture of someone else's bike or anything like that.
  • 09-08-2015
    rsaavedra
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    rsaavedra
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    rsaavedra
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    rsaavedra
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    rsaavedra
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    rsaavedra
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  • 09-08-2015
    AndrwSwitch
    So you've got a top swing/top pull configuration, attached with a clamp. You could also describe it as low clamp.

    You have to stick with a clamp, and it has to be the right size. You might be able to do high clamp, or it might interfere with your bottle cage or the mounting bolt. I think high clamp is a little better if it fits, but it's a pretty marginal difference.

    You can measure the frame tube's diameter to get size, or it might be stamped on the clamp of the existing derailleur. They're mostly all the same size lately, but I think it's still good to check and make sure I'm not getting the wrong thing.
  • 09-09-2015
    rsaavedra
    Andrew thanks for the info, so the FD I linked in post 11 is the right one?

    I forgot to mention earlier that it is a 34.9mm configuration.
  • 09-09-2015
    AndrwSwitch
    The link leads to a page that asks for a bunch of selections.

    So if you make the right selections, yes, it's the right derailleur.
  • 09-09-2015
    rsaavedra
    Great thanks, however I found this and I'm not sure if it means anything or not.

    SRAM Mountain 2x10 Gear Range Bullet point #5, then I looked at SRAM 2016 2x10 MTB Drivetrain Compatibility and it shows the X9 FD NOT listed under the compatible FD with the X9 2X10 36-22t and 38/24t crankset options. Is that correct? Pardon my ignorance regarding the subject but why? If not then what FD? Nan I did't thought this was going to be such an endeavor... Anyways, thanks in advance!
  • 09-09-2015
    AndrwSwitch
    I wouldn't worry about it with a clamp-mounted derailleur. It's a bigger deal with the direct mount models. For clamp, you just put it at whatever height you need it to be.

    I suspect that part of what's going on is that some of the lower-geared offerings came out fairly quickly when people said, "WTF happened to my 36/22 crank?" and some of the documentation hasn't caught up that well. Also, I think we're seeing SRAM reshuffle some of their ranges. A lot of the time, both companies will say their derailleurs are compatible with gear ranges found only within that line - like only X9 stuff - so if 36/22 isn't one of the X9 configurations SRAM had in mind when they released the current derailleur, they're not listing it. A lot of the designations on the chart are fairly new, actually. For a while, SRAM just did 3.0, 4.0, X5, X7 and X9. If they're still doing 3.0 and 4.0, those are only OEM products now. X0 is fairly old, just not as longstanding as X9. XX is kind of old. The newest round is XX1, X01, and GX. I suspect that X7 and X9 are going to be retired in favor of GX. But we'll see.

    None of that matters all that much for what you're doing. Take a look at your front derailleur cage. It's curved to match your chain ring. Imagine if your chain ring had a couple more or fewer teeth. Think that change in curve shape is a big deal? I don't. Double cranks and front derailleurs are pretty forgiving. Hell, I'm running a low direct mount front derailleur for 38/24 with a 36/22 crank, so it's sitting too high. But it works fine.
  • 09-09-2015
    rsaavedra
    hahaha cool Andrew! Man I truly thank you for the time spent helping me sort this out!