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  1. #1
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    Crankset for N360

    Hello all,

    I have been successfully using my N360 for 2000 nearly-trouble free miles (one mishap where both axle nuts came loose and one fell off the bike due to insufficient tightening, yikes!) and so far I've been using a Sugino RD2 or 'messenger' crankset and a Phil Wood square taper bottom bracket. My bicycle has 75* dropouts (nearly vertical) so I cannot use the dropout to adjust chain tension, nor do I want to due to the use of disc brakes. This leaves me with the option of chain tensioners or eccentric bottom brackets. I have been using a Surly Singleator to tension the chain so far, and I hate it. Rear wheel removal is a complete hassle because I need to use a 6 mm hex key to remove the tensioner, screw it back on, and use an 18 mm cone wrench to reapply tension. When you commute every day to work, and flats are inevitable, this system gets tiring.

    I have begun to explore other tensioning solutions. I am willing to change out any component of the drivetrain to get it the way I want. The YESS ETR/B is one solution, but after using a spring loaded tensioner I am just not a huge fan of external tensioners. One more part to fail / snag on crap. My frame does not have the ability to use an eccentric bracket, but I have found a few aftermarket solutions in the Phil Wood Philcentric and the Excentriker bottom brackets. Personally I feel like a doofus for not considering a frame that supports eccentric bottom brackets, but the bike is built and is here to stay. Both use OBB cranks. I have a square taper crank.

    My question is: how do I achieve the 49 mm chainline specified by Fallbrook? What crankset is known to work? I know OBB cranks have a fixed chainline but I know some Nuvinci users have cranks that fulfill this requirement. I have never used outboard bearings so any knowledge in this area would be most helpful. Thank you all!

  2. #2
    Frt Range, CO
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    Quote Originally Posted by crazylemurboy View Post
    ...My question is: how do I achieve the 49 mm chainline specified by Fallbrook? What crankset is known to work? I know OBB cranks have a fixed chainline but I know some Nuvinci users have cranks that fulfill this requirement. I have never used outboard bearings so any knowledge in this area would be most helpful. Thank you all!
    There is chainline flexibility with an OBB by using the three 2.5mm spacers. If your bb width is 68mm then you have quite a bit of flexibility of chainline. Even if your bb is 73mm there's still room to shift the chainline around. Stock MTB triple cranks have 50mm chainline for the middle ring. That should be close enough for a 49mm chainline, if you feel the need for exactly 49mm then I'd use three 1mm bb spacers in place of a 2.5mm spacer.

  3. #3
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    I'm using a Truvativ Stylo 1.1 crank/OBB (68mm shell) and the chain line is really close out of the box with my Nuvinci.
    As for tensioning, I am not aware of the options for your setup other than finding a "magic ratio" or the tensioner.

    IMO a frame is a commodity that can easily be sold and replaced with one that better suits your needs.

  4. #4
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    I think I have a setup that would work for you and you won't need to replace your crankset.

    Here's a link to a post I put up about it. I forgot that I used to have a sprung tensioner in this system until I looked up the old post. My current setup has an idler pulley that is in a static position, and it pushes up on the chain a bit. Mine is an N171, so it's not exactly your situation, but it seems like a similar problem.

  5. #5
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    Thank you everyone for your input.

    jtrops - I like your solution quite a bit. A similar thought occured to me, by bolting my tensioner somewhere along the chainstay I would have clearance at both the bottom bracket and rear wheel. My issue with spring loaded tensioners is that I am a large rider (6' 4", 220lbs) and I'm not getting smaller any time soon. When I was using smaller chainring / cog combo I could cause the chain to jump the teeth at will, even with the tensioner cranked down. Using a larger combo results in almost no slip, but it is still there. This is with brand new PC-890 chain and Surly stainless gearing.

    canyoneagle - I was looking at your Gryphon a while back. That is probably the frame I should have picked originally. Your build is similar to mine but I fell in love with the Vaya frame and I was able to source it locally. The only downside on your bike I see is the lack of fender & rack eyelets on the front fork, but that can always be overcome if you want. I don't even know if you care for them, but for me I need them as I love my front panniers! I am a bit envious of your build, came out very nice. I am considering buying a different frame, but this time it must fit all my criteria. An EBB has been added the list.

    pursuiter - Thanks for the OBB information. I did a bit more research and I have a better understanding now. If I'm not mistaken, road triples have their chainlines at 45mm. Given typical 5mm spacing, this gives 40, 45, and 50. If so, I can put 3mm spacers on the left side cup (this is for a 68mm british threaded shell) and 2mm on the right side, giving me an extremely close approximation of what I'm looking for. If this is not true, then a mountain crank will work too. I'm only concerned about the smaller rings used overall since I have had problems with chains slipping under full load even when everything was brand new. This was with a 38T aluminum chainring and 20T stainless steel cog.

    My current thought is to get a Shimano 105 FC-5703 triple, using the outside position, and the Phil Wood Philcentric. This is still cheaper than a new frame, eccentric, and crank/bb. Thoughts?

  6. #6
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    I'm not using the spring tensioner any more either. I'm still using the basic setup, but my current tensioner is more like this one. If I was going to buy a tensioner I think I might try the Kore Chain Reactor that mounts to the chainstay. Honestly though I don't know if it would work better than the DIY, although it's probably lighter. I guess the Kore doesn't play well with oversized stays though, so back to the DIY.

  7. #7
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    Quote Originally Posted by crazylemurboy View Post
    Thank you everyone for your input.

    canyoneagle - I was looking at your Gryphon a while back. That is probably the frame I should have picked originally. Your build is similar to mine but I fell in love with the Vaya frame and I was able to source it locally. The only downside on your bike I see is the lack of fender & rack eyelets on the front fork, but that can always be overcome if you want. I don't even know if you care for them, but for me I need them as I love my front panniers! I am a bit envious of your build, came out very nice. I am considering buying a different frame, but this time it must fit all my criteria. An EBB has been added the list.

    My current thought is to get a Shimano 105 FC-5703 triple, using the outside position, and the Phil Wood Philcentric. This is still cheaper than a new frame, eccentric, and crank/bb. Thoughts?
    That's the only downside of the Gryphon, IMO - no front rack/fender brazes. The rear has rack mounts, which made fenders very easy (zip tie on brake bridge and P-clamp on chainstay bridge). I used P-clamps on the front fork at about the same spot where lowrider mounts would be - obviously not suitable for a rack, but they are great for fenders. Here's the gryphon in commuting mode:


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