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  1. #1
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    whered all the Chain Tensioners go?

    i may not be looking at the right images, but many if not most of the ss mountain bikes i am seeing are without a chain tensioner... i have a C-dale f400 69 rigid and am about to convert it over to ss. From all the research ive done, since i have vertical dropout, im under the impression that a chain tensioner is required to keep the chain tight.

    my question is how is it soo many MB are able to go without a CT? do the bikes have horizontal DOs? are we cutting into the Verts and boring out to be Horz? ive done simular things like that before but not on 6061 Alum and i am alittle weary since its not at strong at Cro-Moly. has anyone modded a 6061 dropouts succuessfully?

    side question
    i am tech going to have a dual speed set up(45t in front with a 12t/14t or 14t/16t in the back, so i can pop the wheel off and switch depending on terrain) so a CT may be necessary regardless, but i dont know anyone who has ever tried this set up and any advice/encouragement would be greatly appreciated.

  2. #2
    What could go wrong ...
    Reputation: Zoke2's Avatar
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    I used to ride to Win ... Now I ride to Grin

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  3. #3
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    with chain stretching being inevitable, is it just a matter of popping half-links in and out as needed?

  4. #4
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    half links are no good they are literally "half" the strength of a reg link
    try a CT im running a Surly Singelator
    you dont sacrifice style with it+its a good conversation starter : D

  5. #5
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    Brandon,

    With the popularity of SS flourishing, many specific bikes are being produced.

    That being the case, EBB's (eccentric bottom brackets) and sliding dropouts have become quite common.

    Conversions have been bolstered by the White Industries ENO hub, an eccentric axel hub that allows chain tensioning on vertical dropouts...sweet.

    There have even been a small offering of EBB's that fit inside a standard 68 or 73 threaded bottom bracket.

    Lots of options for ya,

    rody
    As requested by the MTBR gods, I am the voice of Groovy Cycleworks, check it out... http://www.groovycycleworks.com

  6. #6
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    Since when are they half the strength? If that were the case, why on earth would there be so many different heavy duty BMX chains made entirely of half links? These are chains designed for extreme abuse, including grinding etc. I've been running a 3/32 half link on a fixed gear through all weather for well over a year without problems.

    Quote Originally Posted by Gearsequalqueers
    half links are no good they are literally "half" the strength of a reg link
    try a CT im running a Surly Singelator
    you dont sacrifice style with it+its a good conversation starter : D

  7. #7
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    I'm building a SS and thought i needed a EBB. Don't really want a tensionor or to build a set of rims. What are the odds i can get away with using 1/2 links. I'm set on 34/16 and don't really want to change gears to fit the chain? Thanks again

  8. #8
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    i dunno, i think chain tensioners are cool, just dont skimp and buy a cheapo.
    good way to get in w/o buying a frame, see if you like with minimal risk.


    half link chains are actually STRONGER. but mainly just for easier dial in on chain length.
    no chain no gain.

  9. #9
    What could go wrong ...
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    Quote Originally Posted by henrymiller1
    I'm building a SS and thought i needed a EBB. Don't really want a tensionor or to build a set of rims. What are the odds i can get away with using 1/2 links. I'm set on 34/16 and don't really want to change gears to fit the chain? Thanks again

    I have 2 SS bikes that run 34/16 and it seems to be a "magic gear" as I do not need to run a CT or a half link with either one ... YMMV
    Last edited by Zoke2; 09-12-2009 at 09:15 AM.
    I used to ride to Win ... Now I ride to Grin

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  10. #10
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    Do you know your chainstay length? I know on my old GT frame with 426mm chainstay length, a 32/16 gearing was the magic gear and I didnt need to use a tensioner.

    Just make sure your chainline is dead straight before you start trying to find a magic gear.

  11. #11
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    Here's my thoughts on this (for what they're worth...)

    While you might get lucky with a particular combination of chainstay length, chainring and sprocket sizes and be able to get away (with or without a half link) with not using a tensioner, your chain tension will only be correct at one point in the life of your chain - as it wears it will run slacker and you have no way of taking this up.

    I'd rather use a decent tensioner than have to put up with being stuck with what may turn out to be a less than ideal ratio - and also the risk of throwing a chain.

    A half link is not the "universal panacea" that some people seem to think it is - it allows you to alter the chain length by 1/2" and that is far too much to just take up a bit of wear.

    If you want to use an existing frame (without a bolt -on tensioner) then the choices are - White Industries ENO hub or either a Forward Components or Trickstuff Excentriker BB. All are far better than relying on this "magic gear" stuff. If you have rim brakes I'd go with the ENO hub and if you have disc mounts the EBB would be a better option IMHO.

    Or modify the frame with retrofitted track ends - easy with rim brakes but more problematic with discs as you need some sort of caliper adjustment too.

    If you want to try SS with the least possible expense then use a tensioner - a fixed one seems a better idea than a sprung one. And tension the chain upwards for better chain wrap.

  12. #12
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    Here's probably a dumb question but I'll ask anyway because I enjoy looking like an idiot:

    How much effect on the efficiency of running singlespeed does adding a chain tensioner add? I want to try singlespeed and I really like the idea of the chain only contacting the crank and the cog in a nice straight line for maximum efficiency. I suppose a chain tensioner wouldn't be quite like the zig-zag of running through a normal rear derailer but is it particularly noticeable when compared to a bike that's designed to be single speed (ebb, horizontal dropout, sliding track dropout)?
    I hate 650b because it's not as fun as 26 inch wheels and because it doesn't have the rollover ability of 29 inch wheels.

  13. #13
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    Quote Originally Posted by Buster Bluth
    Here's probably a dumb question but I'll ask anyway because I enjoy looking like an idiot:

    How much effect on the efficiency of running singlespeed does adding a chain tensioner add? I want to try singlespeed and I really like the idea of the chain only contacting the crank and the cog in a nice straight line for maximum efficiency. I suppose a chain tensioner wouldn't be quite like the zig-zag of running through a normal rear derailer but is it particularly noticeable when compared to a bike that's designed to be single speed (ebb, horizontal dropout, sliding track dropout)?
    To actual drivetrain efficiency I would say that it makes next to no difference - certainly nothing that I could notice anyway. Most tensioners make a little noise, which may or may not bother you (and if it generates noise then obviously it must use a little energy...) , they are something else to get branches, grass and ferns caught in and they make getting the wheel in and out a bit more difficult (or more difficult than with sliding vertical dropouts or EBB anyway).

    But if you use one in the push-up configuration it's fairly well tucked up out of the way of trail debris anyway - so to try singlespeeding without having to commit loads of money to it, that would be a good solution.

  14. #14
    Recovering Weight Weenie
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    Quote Originally Posted by Gearsequalqueers
    half links are no good they are literally "half" the strength of a reg link
    try a CT im running a Surly Singelator
    you dont sacrifice style with it+its a good conversation starter : D
    My Singleator lasted 1/2 a ride until it snapped off.

    My chain with 2 half-links is a year old.

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