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  1. #1
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    Finding 'magic ratio' worth it?

    I'm riding a 30 x 18 with a plastic Disco. The chain has good tension, but my wheel axle only goes about 1/4" into my semi-vertical dropouts. The QR is CRANKED, but is it just a matter of time before my rear wheel leaves the dropouts, while riding?

    Believe it or not I can't get proper tension when I add another 1/2 link. I'd like to try and stick with no tensioner, is that possible? I'm trying to keep things simple (cheap) until I decide how deep I'll get into SS; although from the last few rides it's gonna get real deep!
    Going down to the LBS tonight and will 'discuss' the Fisher Rig. Anyways how to set up that magic gear?

    Thanks

  2. #2
    giddy up!
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    I personally don't think the magic gear thing is worth it in the long run. Sure the chain might be perfect with a new chain or a really used chain but that's really limiting. What happens when you want to change to a different ratio? What happens when you need a new chain, ring or cog.

    I think the best bet in your situation is to use a derailleur as a tensioner to see if you like SSing.

    Then if you dig it you can look into a new frame or eno your existing frame.

    Hope that helps!

    B
    www.thepathbikeshop.com

  3. #3
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    Counter point... kind of...

    I have a pretty nice Jamis Dakota that I loved as a geared bike... so naturally I wanted to use this frame for SS as well. I bought a tensioner and did a few rides, which worked out pretty well but there was always a bit of chain bounce and noise / friction with the brand that I have. I then opted for the "magic gear"... which worked out pretty well for me after changing cog & ring set-up. I tried the half-link option too but that little pin clip just made me nervous on the climbs; I kept envisioning the link popping off at the worst possible moment.

    After a bit of chain stretch I'm securely seated in the drop outs and have expereinced no problems thus far. Overall, I think that the "magic gear" route is a viable option if you have an existing frame that you really like. I also have a mid-90's Merlin that's 'magic' too.

    If I had the extra $$$ right now, I'd like to try out the White Eno hub for the Merlin. It looks very clean IMO. Anyway, if you've got a new chain and your forward in the drop out, a bit of stretch should set you straight. There are other options too, such as filing axles, drops, etc. but in the end if you're not crazy about your current frame a dedicated SS, like the Rig is a nice option.

  4. #4
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    I say go for a taller gear and grow into it. Ain't nothin' wrong with gettin' stronger.
    Your fear of looking stupid is holding you back.

  5. #5
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    Quote Originally Posted by hrcon
    I'm riding a 30 x 18 with a plastic Disco. ..
    Whats a plastic disco?
    Quote Originally Posted by hrcon
    .... Anyways how to set up that magic gear?...
    Up in the right hand corner of this page is the <b>SS FAQ</b>, in the middle of it is a link to Fixmeup. Its super simple to use, measure your chainstay length, chainrings you want to use, maybe click the halflink option, and it shows you all the "magic" gear combos. I prefer the Java version because the html one doesn't show the "good" range as clearly.

    I really like the look of my bike without a tensioner, much more clean looking. I accidently ran into the "magic" combo while trying to fit gears to my bike so that i can clean <i>that Hill</i>. I cannot tell the difference between a 16t and 18t on my bike or at least i can't clean any more hills with the 18t that i could with the 16t, so the ability to change gears in 1 tooth incrememts doesn't seem that important to <i>me</i>. On the first SS i put together the chain was so loose that it would slap the chainstay in the rough sections but i never dropped a chain on that bike, so i wonder what the right tension is.

  6. #6
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    If you just wanna get the feel for SS and you can find a decent magic ratio, it'll probably work fine short term.

    Once you decide you are gonna commit get an ENO eccentric hub, an EBB or horizontal dropouts of one form or another.

    The two biggest drawbacks to magic ratios are:

    1. chain wear or 'chain stretch'

    2. not having the wheel fully in the dropout.

    In general with a magic ratio setup I would be very hesitant about mashing. Dropped chain while mashing = no need for condoms for a week or two.
    To air is human, to dig is divine.

  7. #7
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    No magic Here!

    Try a Rennen! This thing works great...
    Attached Images Attached Images

  8. #8
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    It looks like you got some good advice here so far, so I won't reiterate what others have said. If you started with a new chain, it will stretch and let you get the wheel all the way in the dropout. If the chain has already been used for a while, you might need to find another ratio. If you are running a 30-18 right now, try 32-20 or 34-22, they just might work. But if you don't have rings and cogs sitting around, just buy a Rennen and be done with it!

  9. #9
    Get out of town!
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    Quote Originally Posted by MC9.5
    Try a Rennen! This thing works great...
    That looks a lot like the Convert.

  10. #10
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    Can you not fit your Rennen in "push up" mode? Should give you a little more chain wrap and protect the Rollenlager a bit more.

    Another note on the Rennen Rollenlager: It did not fit perfectly on my 96-97 Kona Explosif and I had to file out the part that bolts to the derailleur hanger to make it fit. That said, I think it is the cleanest-looking "tensioner" you can get.

  11. #11
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    The bike is a MC Rumble with....
    -Gusset single speed conversion kit spacers.
    -Surly SS 32t front cog
    -Chris King SS 17t rear cog
    - Rennin Rollenlager
    I did not need a tensioner with a 32tx16t but I did not like the combo.
    The 17t made the chain too short so I had to add a half link which then made it too long, thus the need for the Rennen.
    The Rennen would hit my chainstay in the UP (ideal) position, so down it went.
    No filing required, But I did add a longer bolt and spacer to the roller in order to line up
    with the chain.
    I have not had a problem yet with dropping the chain or the Rennen taking a hit in the down position.

  12. #12
    Tribe Member
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    Disco's are here: http://www.offcamber.com/menu.htm

    and then hit the link for Disco's on the left.....Travis Brown use's them so they must be good
    Proud Tribe member since 1992 - looking for better singletrack to be ridden year round

  13. #13
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    Well I am surprised there seems to be no love for the magic gear. I have been riding an old Kona explosif for about 6 months this way. Initially the chain was a bit too tight and probably contributed (along with the complete lack of maintenance) to bearing failure in my rear hub. Now a lot of miles and rides later the chain is about right. My chain does not seem to have lengthened very much.

    Perhaps I have been lucky and I guess I have not cared abot gearing. Although I am starting to worry about snow rides and being able to gear down....

  14. #14
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    You could try a phantom cog too. If you pull it out of your old cassette, it won't cost you anything at all.

  15. #15
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    Might be too bling free

    Quote Originally Posted by Marrkie
    Well I am surprised there seems to be no love for the magic gear....
    Me too. I have only been at it for a couple of months but magic gear seems to work great. I had more problems and noise using the tensioner. I don't really get the chain stretch reasoning, if it stretches past a 1/4 link maybe its time for a new chain.
    Quote Originally Posted by Marrkie
    ...Although I am starting to worry about snow rides and being able to gear down....
    Ya i was thinking about this too. I was going to use 2 power links to add and take out links but leaning towards 2 chains instead. Only using $4 novatech and dx cogs so plenty of money left over for a cheap bmx chain.

    The only draw backs to magic ratio i see is that you can only move your gearing in 4t and 2 tooth (with 1/2 link) increments. If you want 1 tooth changes you are out of luck. And if you aren't lucky enough to use even numbered tooth count chainrings and cogs you have to spend extra $$ for SS specific cogs or chainrings with odd numbered tooth counts.

  16. #16
    Don't be a sheep
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    Quote Originally Posted by Ratt
    I don't really get the chain stretch reasoning, if it stretches past a 1/4 link maybe its time for a new chain.
    Yes, If it stretches to the point where you need to buy a new chain to keep it from derailling, maybe you actually need to buy a new chain.
    "Do not touch the trim"

  17. #17
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    Thanks.

    Thanks everyone for the great replies. Well I ordered the Rennen last evening. Sounds like it can be a bear to get it to fit, and might require a new QR, but I played with FIXMEUP and I would need at least a new chainring and cog, and that wouldn't be a guarantee. My LBS convinced me that running the way I do, with the wheel barely in the dropouts, is not such a good idea! Oh, I checked and I'm running a 32 x 20. Perfect for around here, maybe abit too tall for some areas. Running a harder gear will make me stronger: a stronger hiker! I've been riding fixed on the road for 3 years and I think I'm developing a feeling for what gears work best for my legs,given the massive hills and wind here.

    Thanks again.

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