Chain slipping on my new build?- Mtbr.com
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  1. #1
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    Chain slipping on my new build?

    When accelerating hard or climbing the chain tensioner is moving up(giving the chain more slack) causing the chain to skip. Do you think I need to shorten up the chain one link or is it something else? Everything is assembled correctly & it's a Origin8 single speed conversion kit. Any help would be much appreciated, thanks!

    I'll try to take some photos tomorrow and post them if you think this will help by looking at it.
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  2. #2
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    Are the chain and cogs new?

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    Yes they are, KMC chain & whatever cog came with the Origin8...looks a little "cheesy" to be honest...but it still shouldn't skip.
    I was watching the tensioner move up when pedaling hard & that's when the chain will skip.
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  4. #4
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    I had that problem a couple of times in muddy conditions. Not enough chain rapped around the rear cog. I shortened the chain AND changed the tensioner direction so that it pushed up instead of down and that seemed to remedy the problem.

  5. #5
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    Quote Originally Posted by GT554
    Yes they are, KMC chain & whatever cog came with the Origin8...looks a little "cheesy" to be honest...but it still shouldn't skip.
    I was watching the tensioner move up when pedaling hard & that's when the chain will skip.
    The usual suspect of a skipping chain is a spring loaded tensioner. Most spring tensioners work by pushing the chain down and away from the rear cog. This results in very poor chain wrap. When peddling the majority of the torque from the chain is on the front chainring is on the teeth at 12:00 –0300 and on the rear cog it is the teeth from 6:00- 9:00. What this means is the very area of the rear cog, where chain wrap is necessary, a push down spring tensioner pulls the chain off the cog. This transfers the torque to the tensioner pulley wheel, which in turn pulls the tensioner arm upward. The chain then rides up in the cog teeth in the 9:00-12:00 position. Since it takes a great deal of torque to turn the rear wheel and there is practically no chain warp in the area, the tensioner will fail and the chain will jump over the teeth at the 9:00-12:00 position on the cog, causing it to “skip”. The answer is to first make sure your chain is as short as possible (a half link is a good idea but it will create a weaker link). Next use a spring tensioner with a push up mode or even better a tensioner without a spring so the arm can be locked up; this way tensioner cannot be defeated by overcoming the spring tension. A quick fix is to zip-tie the tensioner arm to the chain stay. This will create a tensioner in a push up mode that does not rely on spring tension.
    Last edited by aka brad; 07-02-2009 at 12:57 PM.
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  6. #6
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    Quote Originally Posted by aka brad
    The usual suspect of a skipping chain is a spring loaded tensioner. Most spring tensioners work by pushing the chain down and away from the rear cog. This results in very poor chain wrap. When peddling the majority of the torque from the chain is on the front chainring is on the teeth at 12:00 –0300 and on the rear cog it is the teeth from 6:00- 9:00. What this means is the very area of the rear cog where, chain wrap is necessary, a push down spring tensioner pulls the chain off the cog. This transfers the torque to the tensioner pulley wheel, which in turn pulls the tensioner arm upward. The chain then rides up in the cog teeth in the 9:00-12:00 position. Since it takes a great deal of torque to turn the rear wheel and there is practically no chain warp in the area, the tensioner will fail and the chain will jump over the teeth at the 9:00-12:00 position on the cog, causing it to “skip”. The answer is to first make sure your chain is as short as possible (a half link is a good idea but it will create a weaker link). Next use a spring tensioner with a push up mode or even better a tensioner without a spring so the arm can be locked up; this way tensioner cannot be defeated by overcoming the spring tension. A quick fix is to zip-tie the tensioner arm to the chain stay. This will create a tensioner in a push up mode that does not rely on spring tension.
    Thanks for the very detailed explanation. That helped a lot. I'll get to work on it today!
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    Unless you're using a full suspension frame, I don't understand why someone would just a spring tensioned tensioner. We finally got away from the a rear derailleur and you're just going to out another spring on there? A fixed arm tensioner is just so much better.

  8. #8
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    *update*
    Well I got more tension on the spring & the problem is now fixed!
    Bad Mechanic, I hear where you're coming from but this is my first SS build & really just wanted to get it working to see if I enjoy it. This bike came out great but it's basically a parts bin bike. I got this SS conversion kit for close to nothing. I'll post a couple photo tonight.
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  9. #9
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    Quote Originally Posted by aka brad
    The usual suspect of a skipping chain is a spring loaded tensioner. Most spring tensioners work by pushing the chain down and away from the rear cog. This results in very poor chain wrap. When peddling the majority of the torque from the chain is on the front chainring is on the teeth at 12:00 –0300 and on the rear cog it is the teeth from 6:00- 9:00. What this means is the very area of the rear cog, where chain wrap is necessary, a push down spring tensioner pulls the chain off the cog. This transfers the torque to the tensioner pulley wheel, which in turn pulls the tensioner arm upward. The chain then rides up in the cog teeth in the 9:00-12:00 position. Since it takes a great deal of torque to turn the rear wheel and there is practically no chain warp in the area, the tensioner will fail and the chain will jump over the teeth at the 9:00-12:00 position on the cog, causing it to “skip”. The answer is to first make sure your chain is as short as possible (a half link is a good idea but it will create a weaker link). Next use a spring tensioner with a push up mode or even better a tensioner without a spring so the arm can be locked up; this way tensioner cannot be defeated by overcoming the spring tension. A quick fix is to zip-tie the tensioner arm to the chain stay. This will create a tensioner in a push up mode that does not rely on spring tension.
    Brad,
    Awesome post. I just got a tensioner and had the same problem. That's a really nice explanation!

  10. #10
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    this is great info! I just bought a bike that was converted into a single speed with a orgin 8 conversion kit, and on the first ride, when I crank down hard, I notice the skip, and became concerned on how to fix it.

    would it be a problem if I just removed the tensioner, and took out excesss links?

  11. #11
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    Amazing! I just finished a conversion with the Origin 8 conversion kit and have the same skipping problem. I thought of the cause mentioned above and I already took out a couple of links but it is still skipping. Can the O8 tensioner be run to push up or did I just waste some money on it?

  12. #12
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    I'm wondering the same thing(about reversing it from pulling down to pushing up)

    or possibly getting rid of it all together and just riding it like a bmx?

  13. #13
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    Quote Originally Posted by desertrider83
    I'm wondering the same thing(about reversing it from pulling down to pushing up)

    or possibly getting rid of it all together and just riding it like a bmx?
    You need a certain amount of chain tension (about 1/2" vertical deflection, max) in order to keep the chain seated on the teeth of the cog and chainring. Otherwise, it'll skip like a mofo and you won't be going anywhere.

    How to tension that chain? Well, that's where the chain tensioner (fixed-arm) comes in. I use my old derailleur personally, but it's a budget build and I put a little length of cable through the derailleur so it functions as a fixed-arm tensioner. We use tensioners to keep the tension on the chain (funnily enough) on most conversions because they'll have vertical dropouts (the part where the skewer goes into the bike frame). If you're very lucky, you can sometimes figure out a magical gear which will allow you to have the proper chain tension on vertical dropouts, but 99% of the time that gear doesn't exist.

    So you'll end up with a chain that's just barely too short, or just barely too long if you can't find the magic gear. Either case is bad. Singlespeed-specific frames will have either horizontal dropouts or sliding dropouts, so you can move the wheel fore and aft so that you can score the proper chain tension with whatever gear ratio you want (mostly).

    I've never seen this Origin8 tensioner, but I'm sure you could use it in whichever orientation you want. It just may require some fiddling.
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  14. #14
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    I took two more links out of the chain but then the tension on the idler wheel seemed too much (noisy). I tried to reverse the spring to make it push up but the little dealio in the back is asymmetric so you can't just flip it around. I relived some of the tension by just flipping the arm so the bulge at the end that the idler wheel axle attaches to is pointing up. Took it for a ride and no skipping and not too much noise. I think I'll run this for a while and if I decide to stick with the SS I'll get one that pushes up.

  15. #15
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    Quote Originally Posted by st-rider
    I took two more links out of the chain but then the tension on the idler wheel seemed too much (noisy). I tried to reverse the spring to make it push up but the little dealio in the back is asymmetric so you can't just flip it around. I relived some of the tension by just flipping the arm so the bulge at the end that the idler wheel axle attaches to is pointing up. Took it for a ride and no skipping and not too much noise. I think I'll run this for a while and if I decide to stick with the SS I'll get one that pushes up.
    I also took 2 links out of my chain, had to get the chain on old school bmx style (get a link on a tooth, then turn) still about a inch of slack, so I pulled the tensioner up to take up the slack.

    I've got about half the cog covered (18t) and quick test ride (in flip flops) showed no skipping. soon as I finish the laundry, will take out for a clipped in test run.

    I'm hoping Im going to enjoy my ss hard tail now. (newb to ss, came over from a 27spd all mountain fs)

    oh yea, only problem I have now is the back wheel is def not going to come off easily. but how often does the back wheel need to come off anyhow.

  16. #16
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    I posted this on another thread about the first ride. No slipping by the way.

    Just went for the first ride on my freshly converted Fat Chance. Loved it! I get it. I'm sold. At one point I just started laughing out loud. The bike felt so much lighter and more crisp without all that noisy stuff banging around.

    I was over geared for the hilly trails here 36/18 but I still had fun and was able to ride 99.99% of it. Came home and swapped out to a 36/22. Much better. I immediately figured out a lot of the things I've heard the SS converts saying about momentum, picking lines, etc.

    Also got to ride my friend's Karate Monkey 29er SS geared 34/24. What a nice ride that was. I'm going to be shopping for a 29er SS for sure.

  17. #17
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    update: took it out for a clipped in test run. before, couldn't even put down enough force to pop a wheely, now, I can take off like im stealing it.

    thanks you guys.

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