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  1. #1
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    monocog bottom bracket question...

    I'm going to pick up my monocog tomorrow and was just trying to get my head around bottom bracket sizing and crank upgrades.

    I was looking at the Truvativ stylo crankset, which is ISIS splined. The stock mono comes with a JIS spline, so obviously to run the truvativ's, I'd have to get a bottom bracket that has the ISIS spline. (Right?)

    Now, the stock mono also has a bottom bracket dimension of 68x116. Will the frame take a bottom bracket that is narrower than 116mm? Like, for instance, a more standard 108 or 113 width? Or am I stuck with trying to find a bottom bracket with the 116 width and an ISIS spline? (As far as I can tell, they don't exist...)

    Argh.

    Thanks.
    matt

  2. #2
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    Why upgrade?

    Why upgrade the Monocog. It is what it is, a good entry SS for a good price. I owned one and rode it the way it was. The monocog hooked me on SS and when I needed more I bought a better bike. There are some things about the monocog that make upgrading it a bit of a challenge. I would suggest riding it until you need more and have your $400 of fun out of it and then sell it and upgrade the whole bike.

    You can easily upgrade the saddle, tires, bars, stem, post, pedals though and all those items could likely transfer to another bike later.


    My name is Matt and I suffer from upgradeitis. I buy decent bikes and spend a lot of money to try to make them into great bikes. I know I have this problem and part of my cure is to try to help others avoid my disease.
    Two Wheeled and Too Big

  3. #3
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    Fair enough. :)

    Yeah, I'm (obviously) also prone to this condition. And your point is well taken.

    But from an academic, would-like-to-learn angle, would it be possible to put a shorter spindled bottom bracket on any bike? Or are frames designed only to work with certain length bb spindles?

    And I promise, no upgrading until I've broke at least one crank arm completely off.
    Last edited by homestar; 05-10-2005 at 05:38 AM.

  4. #4
    hands up who wants to die
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    My 04 Monocog (steel) has plenty of room between each crank arm and the chainstay. Accounting for frame flex, I'm guessing you can go a few mms narrower on the BB spindle with no problems. I can measure it tonight if you'd like.

    However, I believe there are differences in profile between square and ISIS. In other words, 113 spindle ISIS and 113 square taper may not end up spacing out the arms the same distance. I'm not sure on that exactly.

    I suggest you stick with the stock Monocog cranks until you break them. Going weight-weenie on a Monocog makes little sense, and if you are a big guy worried about flex, you will probably be flexing the frame and fork if you are getting the cranks to move much distance. And, if you blow the bearings on the stock BB, how much is a good square taper replacement? I bet you can find one pretty cheap.

    Upgrade the hubs first.

    -rob in NY

  5. #5
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    i love my monocog hubs... they roll strong and solid infact i just hosed my rear wheel and i am thinking i'll re-use the old hub to build the new wheel.

    why do you not like the hubs rob (i ain't questioning your logic more i would just like to know if you have any bad experience with them)???

    and personally i wouldn't consider an isis BB an upgrade at all. i bet your square taper would last twice as long and is much cheaper to replace.

    the monocog may be a cheaply priced bike but it rides super nice IMHO and i love mine!!!!

  6. #6
    "A black kid on a bike?"
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    Quote Originally Posted by max-a-mill
    i love my monocog hubs... they roll strong and solid infact i just hosed my rear wheel and i am thinking i'll re-use the old hub to build the new wheel.

    why do you not like the hubs rob (i ain't questioning your logic more i would just like to know if you have any bad experience with them)???

    and personally i wouldn't consider an isis BB an upgrade at all. i bet your square taper would last twice as long and is much cheaper to replace.

    the monocog may be a cheaply priced bike but it rides super nice IMHO and i love mine!!!!
    Sorry to hi-jack.......

    So then what is the final verdict on the Monocog? Taking into consideration it's frame limitations (110mm rear hub, portly weight, BB size, etc) is the Monocog still a good buy. I know it lacks the big bling factor of most of the bikes on this site but based on info I've gathered from the this forum I'm still a little confused as to whether this Monocog is a decent bike or just a high end dept. store clunker. I liked the idea of a simple do it all machine so I've actually ordered a monocog from my LBS while they were on sale for $375. I'm beginning to wonder if I would be better served taking my $$ and investing in a IRO or Surly frameset and building up my own SSpeed.

    Thoughts?

  7. #7
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    Quote Originally Posted by homestar
    I'm going to pick up my monocog tomorrow and was just trying to get my head around bottom bracket sizing and crank upgrades.

    I was looking at the Truvativ stylo crankset, which is ISIS splined. The stock mono comes with a JIS spline, so obviously to run the truvativ's, I'd have to get a bottom bracket that has the ISIS spline. (Right?)

    Now, the stock mono also has a bottom bracket dimension of 68x116. Will the frame take a bottom bracket that is narrower than 116mm? Like, for instance, a more standard 108 or 113 width? Or am I stuck with trying to find a bottom bracket with the 116 width and an ISIS spline? (As far as I can tell, they don't exist...)

    Argh.

    Thanks.
    matt

    I ran a 113mm Race Face Evolve XC and a Truvativ Gigapipe ISIS BB on my '02 Monocog (used RF Turbine LP's) with no spacing problems. I destroyed the RF BB in 6 months (split the bearing cases), but the Truvativ held up for okay. You do have to keep an eye on the rear hub. Mine were junk in about 8 months and that was with regular maint.

  8. #8
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    Monocog is OK

    Quote Originally Posted by Joe Rocket
    Sorry to hi-jack.......

    So then what is the final verdict on the Monocog? ........... I'm beginning to wonder if I would be better served taking my $$ and investing in a IRO or Surly frameset and building up my own SSpeed.

    Thoughts?
    The mono cog is a great first single speed if you'd rather buy one all set to ride then mess around building one. However, there is a lot to be learned from from either converting a geary or building up an SS bike from the frame. There are also other complete bikes for just a bit more. I have done it each way and eventually you should too. I started with a Monocog, a year later I upgraded to a Solo-one (worth every penny of the $100 more), then I converted a bike for a townie, recently I have built a bunch of high end and lower end SS bikes from the ground up.

    If I were you, and can spend the extra get a Solo-one over the Monocog for about $100 more, or for probably $200-300 more you could build up a nice IRO Higlander or Surly 1x1.
    Two Wheeled and Too Big

  9. #9
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    I've got the original BB in my 03? monocog, and its a 88x113. Hubs are holding up fine too, did dissasemble and grease the front recently. This bike is more than adequate and a great deal IMO..

  10. #10
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    upgrading monocog

    The Monocog is a good deal -- inexpensive, durable and of solid design -- but the upgrade path is more limited and less fruitful than on something like the KHS Solo-One.

    Achieving proper chainline is always an issue when changing cranks and BBs, and is more so on the Monocog because of the unusual (for a MTB) rear axle spacing of 110 mm. You can achieve proper chainline but in the absence of specific crank and BB recommendations from other Monocog owners who've done it themselves, some trial and error will likely be involved.

    As others have opined, It might make more sense to either ride the monocog more or less as is or spend a bit more on something like the Solo-One. The upgrade path on that bike is less limited because of its typical 135mm rear axle spacing. It's also more fruitful because the frame isn't so heavy. No amount of chi-chi upgrades will make a Monocog light.

    btw, I've found the Monocog's Redline hubs to be quite good.

    -- singleminded

    Quote Originally Posted by homestar
    I'm going to pick up my monocog tomorrow and was just trying to get my head around bottom bracket sizing and crank upgrades.

    I was looking at the Truvativ stylo crankset, which is ISIS splined. The stock mono comes with a JIS spline, so obviously to run the truvativ's, I'd have to get a bottom bracket that has the ISIS spline. (Right?)

    Now, the stock mono also has a bottom bracket dimension of 68x116. Will the frame take a bottom bracket that is narrower than 116mm? Like, for instance, a more standard 108 or 113 width? Or am I stuck with trying to find a bottom bracket with the 116 width and an ISIS spline? (As far as I can tell, they don't exist...)

    Argh.

    Thanks.
    matt

  11. #11
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    Thanks everyone!

    I just went by the shop to pick up my monocog. A five minute jaunt around the lot was all I need to mellow me out. As the geometry numbers suggested, she fits perfectly - and as the first well-fitting bike I've ridden in almost a year, I'm reminded how much that matters.

    I'm going to ride this puppy into the ground.

    Quote Originally Posted by singleminded
    The Monocog is a good deal -- inexpensive, durable and of solid design -- but the upgrade path is more limited and less fruitful than on something like the KHS Solo-One.

    Achieving proper chainline is always an issue when changing cranks and BBs, and is more so on the Monocog because of the unusual (for a MTB) rear axle spacing of 110 mm. You can achieve proper chainline but in the absence of specific crank and BB recommendations from other Monocog owners who've done it themselves, some trial and error will likely be involved.

    As others have opined, It might make more sense to either ride the monocog more or less as is or spend a bit more on something like the Solo-One. The upgrade path on that bike is less limited because of its typical 135mm rear axle spacing. It's also more fruitful because the frame isn't so heavy. No amount of chi-chi upgrades will make a Monocog light.

    btw, I've found the Monocog's Redline hubs to be quite good.

    -- singleminded

  12. #12
    Mama Tried
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    05 monocog BB question

    I just picked up a 05 monocog frame and if the original bb says 110.5 leghth on it and I want to upgrade with a better bb for my cranks, can I use a 68 X 113 or should I just buy a 68 x 110. Will I run into any issues with the 68 x 113?

  13. #13
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    Depends on the cranks...

    Here is my understanding of bb spindle length, someone can correct me if I am wrong.

    The spindle length is determined by the cranks. Most cranksets are designed to work with a certain spindle length to achieve proper chainline. Some cranksets will work with a couple of different lengths, but best chainline is achieved using the design specific spindle length of the cranks. Hope this helps.

    DIrt

  14. #14
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    You got questions, I got answers...

    On a 2005 steel Monocog, you want a crankset that will give you a 47.5mm chainline (from center of seat tube to tip of your SS chainring tooth), if you want a perfectly straight chainline with your 110mm spacing rear Redline hub. The original square taper BB that came in my Monocog was a 68x110.5, and that measured a 47.5mm chainline with the original Redline square taper cranks. You can't go by BB spindle length alone, you need to know the chainline of any given crankset (for the middle ring mounted on the inside of the largest spider bolt holes). So in an ISIS, you may need a different length than the square taper to get the same chainline with ISIS cranks. Check the manufacturer's website or call them for chainline specs for the cranks you want, they will tell you which width BB to use to get it.

    As far as the steel (and aluminum Flight) Redline Monocog goes, 2005 was the last year for a 110mm spacing rear hub, the 2006 models all have a 135mm rear spacing.

    And in refference to Monocogs being cheap, yes, mine was, but now I wish I would have bought just the frame and built it up rather than the whole bike. I ended up upgrading/replacing literally every part on it except the frame and seatpost clamp. I love the bike, the steel feel, the geometry (with a different fork) and the paint. So it's a cheap frame, but I like it perfectly. Enough that I put a Fox Talas fork, King headset, Thomson stem and post, Easton bars, Avid brakes, XT cranks (changed only because I wanted 180s), eggbeaters, Blackspire chainring, Terry Fly seat, Phil Wood hubs (yes, I got the last 110mm spacing freewheel BMX Phil Wood hub), 819 UST rims, Maxxis tubeless tires, new grips, etc. on mine. Oh well, I like that frame. If I ever crack it, I'll have a custom steel frame built to those exact geometry specifications (except change the seat angle by 1/2 degree steeper) and with Surly rear dropouts. (I'd consider a top quality custom steel WaltWorks frame, but not after the nightmare a friend just went through with Walt's choice of frame painter botching up an expensive custom paint order, not Walt's fault, but that painting company in the Springs will never get any of my business, nor will I ever buy a Yeti while that company paints their frames).

    So where were we?... oh yeah, I like my steel monocog.

    If I were going to put new cranks in it all over again, I'd get a set of RaceFace Deus or Atlas cranks and install with the spacers per the instructions for a 68mm BB shell width, except move one of the two (2mm) black spacers to the left side, which will give you a 48mm chainline. Original cranks were 47.5, you'll be fine. My outboard bearing XTs are 48mm chainline with two 2.5mm BB spacers on the left and one on the right which is fine, but the Q-factor is rediculous, feels as wide as a DH bike with a 100mm wide BB shell. Next time, RaceFace. Or Tru-Vativ Stylo SS cranks. But couldn't find 180mms around here (or any Stylo SS ISIS cranks left anywhere).

    If you get a new 2006 Monocog with the "standard mtb" 135mm rear spacing, you want a 49mm chainline. Most mtb cranksets now are 50mm chainline, some with spacing options down to 48mm, so you should be fine if you install them correctly.

    BTW, my 110mm spacing Phil Wood BMX rear hub chainline measurement is the exact same as the original Redline 110mm spacing hub. If I wanted to put either of these 110mm spacing hub rear wheels in a 135mm spacing frame, I would need 12.5mm of spacer washers on each side of the bolt-on axle (for the Redline hub, and possibly a longer threaded axle), or the spacers and longer mounting bolts on my Phil hub. Assuming I wanted to do that and didn't have my Phil axle replaced or steel frame respaced (and 25mm is too much to respace a steel frame regardless of what some people have done in their garages, the metal will bend, but you will cause all kinds of alignment problems including rear brake posts, and that frame is not worth reworking in my opinion.

    Get on a Monocog and ride it. Upgrade what you feel you need to if you like it, or buy another similar bike if you feel the size and geometry were right, but not the parts spec.

    Cheers,

    Dave
    Last edited by mtbdirteater; 11-15-2005 at 05:14 PM. Reason: failed ebonics
    Just Passing Through: eatin' dirt & crappin' dust

  15. #15
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    YOu'll crack your steel monocog when??

    Quote Originally Posted by mtbdirteater
    On a 2005 steel Monocog, you want a crankset that will give you a 47.5mm chainline (from center of seat tube to tip of your SS chainring tooth), if you want a perfectly straight chainline with your 110mm spacing rear Redline hub. The original square taper BB that came in my Monocog was a 68x110.5, and that measured a 47.5mm chainline with the original Redline square taper cranks. You can't go by BB spindle length alone, you need to know the chainline of any given crankset (for the middle ring mounted on the inside of the largest spider bolt holes). So in an ISIS, you may need a different length than the square taper to get the same chainline with ISIS cranks. Check the manufacturer's website or call them for chainline specs for the cranks you want, they will tell you which width BB to use to get it.

    As far as the steel (and aluminum Flight) Redline Monocog goes, 2005 was the last year for a 110mm spacing rear hub, the 2006 models all have a 135mm rear spacing.

    And in refference to Monocogs being cheap, yes, mine was, but now I wish I would have bought just the frame and built it up rather than the whole bike. I ended up upgrading/replacing literally every part on it except the frame and seatpost clamp. I love the bike, the steel feel, the geometry (with a different fork) and the paint. So it's a cheap frame, but I like it perfectly. Enough that I put a Fox Talas fork, King headset, Thomson stem and post, Easton bars, Avid brakes, XT cranks (changed only because I wanted 180s), eggbeaters, Blackspire chainring, Terry Fly seat, Phil Wood hubs (yes, I got the last 110mm spacing freewheel BMX Phil Wood hub), 819 UST rims, Maxxis tubeless tires, new grips, etc. on mine. Oh well, I like that frame. If I ever crack it, I'll have a custom steel frame built to those exact geometry specifications (except change the seat angle by 1/2 degree steeper) and with Surly rear dropouts. (I'd consider a top quality custom steel WaltWorks frame, but not after the nightmare a friend just went through with Walt's choice of frame painter botching up an expensive custom paint order, not Walt's fault, but that painting company in the Springs will never get any of my business, nor will I ever buy a Yeti while that company paints their frames).

    So where were we?... oh yeah, I like my steel monocog.

    If I were going to put new cranks in it all over again, I'd get a set of RaceFace Deus or Atlas cranks and install with the spacers per the instructions for a 68mm BB shell width, except move one of the two (2mm) black spacers to the left side, which will give you a 48mm chainline. Original cranks were 47.5, you'll be fine. My outboard bearing XTs are 48mm chainline with two 2.5mm BB spacers on the left and one on the right which is fine, but the Q-factor is rediculous, feels as wide as a DH bike with a 100mm wide BB shell. Next time, RaceFace. Or Tru-Vativ Stylo SS cranks. But couldn't find 180mms around here (or any Stylo SS ISIS cranks left anywhere).

    If you get a new 2006 Monocog with the "standard mtb" 135mm rear spacing, you want a 49mm chainline. Most mtb cranksets now are 50mm chainline, some with spacing options down to 48mm, so you should be fine if you install them correctly.

    BTW, my 110mm spacing Phil Wood BMX rear hub chainline measurement is the exact same as the original Redline 110mm spacing hub. If I wanted to put either of these 110mm spacing hub rear wheels in a 135mm spacing frame, I would need 12.5mm of spacer washers on each side of the bolt-on axle (for the Redline hub, and possibly a longer threaded axle), or the spacers and longer mounting bolts on my Phil hub. Assuming I wanted to do that and didn't have my Phil axle replaced or steel frame respaced (and 25mm is too much to respace a steel frame regardless of what some people have done in their garages, the metal will bend, but you will cause all kinds of alignment problems including rear brake posts, and that frame is not worth reworking in my opinion.

    Get on a Monocog and ride it. Upgrade what you feel you need to if you like it, or buy another similar bike if you feel the size and geometry were right, but not the parts spec.

    Cheers,

    Dave
    You will need to wait quite a while, or start getting seriously radicial, to break a steel monocog frame. I haven't.
    I put xt octalink cranks on mine for awhile, and whatever spindle length in on a xt octalink bb seemed to work alright for me. My origanal BB was way toast after about a year or less when I upgraded cranks

  16. #16
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    Quote Originally Posted by single1x1
    You will need to wait quite a while, or start getting seriously radicial, to break a steel monocog frame. I haven't.
    Yeah, you're probably right about that. Back in my chromolly frame BMX days I cracked or broke almost every frame that I jumped/raced on, but I never broke that Redline Microline or Proline. Hope that's a good sign. I no longer jump off the roof of my house. And I'm also older, slower and feel like I need a suspension fork now.

    Dave
    Just Passing Through: eatin' dirt & crappin' dust

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