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14486Re: [rootsradicals] That whole chain tension thing again

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  • Brian Livelsberger
    Dec 6, 2012
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      Not the solution you're looking for, but I used an internally geared hub with a $15 single speed conversion chain tensioner. The tensioner has a pitifully inadequate spring, so I attached an old bed spring  to the bottom of the tensioner arm with the other end of the spring attached via a strong piece of cord to the rear of the Xtracycle frame. Excellent tension (though fiddly to adjust), and no chain slap whatsoever. Doubt that would work on a derailleur system, but some other form of spring tension augmentation might be doable.

      Perhaps more practical is to finagle your own bracket to approximate the effect of the kit you mention by using an inexpensive idler pulley such as (http://www.amazon.com/DMR-STS-Chain-Tensioner-Stainless/dp/B001GSKORE/ref=sr_1_3?ie=UTF8&qid=1354810348&sr=8-3&keywords=chain+tensioner+single+speed)?

      Brian.


      On Thu, Dec 6, 2012 at 9:22 AM, David Backeberg <dbackeberg@...> wrote:
       

      If you're balking at $120 for (very, very nice) idler pulleys, I have a far cheaper solution:


      Just accept the chain slap, and wrap your chainstay with handlebar tape. Lots of people do that even when they're NOT worried about the chain jumping around; it's just a good precaution to protect your frame.

      Another tip, if you get the xtracycle kickstand, that gets slapped before your stay because it rides closer to the chainline.

      take a look at this picture:

      the the terracycle idler on a dummy, the chain goes over the stand. Normally it goes under on the return side and over on the pull side. In my experience, only the return side slaps, so that's the side you want to worry about.


      On Thu, Dec 6, 2012 at 12:02 AM, kiltie_celt <kiltie_celt@...> wrote:
       

      So, I have the chain mounted on my Xtracycle and I've been playing with shifting the front chain ring with the chain on the smallest ring in the back. I can't shift the rear since I'm waiting on a replacement rollamajig since my kit seems to have not come with one. However, just the bit of playing I've done makes it clear that there is enough slack in the chain that my chainstay on the donor bike as well as part of the FreeRadical are going to see a lot of rubbing and damage from chain slap. So, I'm thinking idler pulley. I searched for quite a while on here and on the web but I don't seem to be coming up with any kind of good solution other than buying the grievously overpriced Terracycle Big Dummy idler kit. It looks great and seems like it really does the job, but dang! I'm not paying $100 or more for one of those kits! Has anyone built anything similar to this idler arrangement where the pulley is mounted to a shaft that allows it to move from side to side with the shifting gears? I ran across a post on a recumbent forum that mentioned using modified inline skate wheels as pulleys as well as v-belt pulleys purchased from McMaster-Carr. I like the McMaster-Carr pulley idea because they appear to somewhat similar to the Terracycle pulleys, albeit a larger diameter. Specifically I'm looking at the nylon v-belt pulleys: http://www.mcmaster.com/#idler-pulleys/=kgvyfs
      Besides a complete scratch build on a tensioner setup, has anyone had luck with adapting something recumbent/tandem-wise for use on the Xtracycle without having to pay $100 or more?



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