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  1. #1
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    Gone through 2 tensioners, and still wire ties do the job right.

    I can't get over this. I have two chain tensioners. One fixed, one spring.

    The spring one, I just... don't get it. I have plenty of tension in the chain. The chain is in perfect line. I checked it with a metal yard stick I have and the gears are in perfect line. Yet when I put pressure on the cranks (I don't even have to be standing up) the tensioner somehow pulls itself up (as if it's getting pulled tight) and skips.

    The fixed one works nicely. Except for the fact it doesn't hold. It has 2 locking positions, 1 with the QR axle and one with the rear derailleur hanger. Today I just got a new derailleur hanger in. Why? Because I was trying to clamp this fixed tensioner in place so it wouldn't slack up the chain under the slightest amount of pressure, so I tightened the hanger bolt so much it just pulled the threads out. Great.

    So what am I doing now? Fixed tensioner in pull-up position with wire ties. Holds nicely. Does the job. I can beat it up and it never skips.

    Why is it wire ties are kicking these 30+ dollar items asses? I just don't get it.

    Would the Rennen Rollenlager be any different than my Sette Chain Guide II? I just don't see how the slightest amount of pressure on the bottom of the chain would be enough to move the tensioner just a bit to slack up the chain.

    Example - I came to a tall step getting on a bridge over the weekend. I got off my bike and walked it up. I pop the front tire over the edge and push forward. Unaware that the chain would hit the edge of the step before the rear tire, I pushed the bike forward. The chain hit the ground when it bottomed out. The weight of the bike + my light walking speed was enough to push the chain up enough to give it slack, plenty worthy of busting out the multi tool to re-tighten it. Again.

    Right now, the way I see it, my only solution is to suck it up and get some black wire ties so they at least blend in with the bike. Besides that, I cannot get this spring tensioner to work, nor can I get the the fixed one to hold its place.

    Any idea? Advice? Input?

  2. #2
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    checking the chainline with a yardstick will not yield you a perfect chainline. try measuring it with a ruler and follow the 67.5 rule.
    everything sucks but my vacuum cleaner.

  3. #3
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    I'm failing to see how it won't.

    You have a solid piece of metal. A non bendable, solid, piece of metal.

    Put it flat against the chainring. This in turn indicates the straight line a chain would take when a chain is placed on the chainring.

    Seat the cog accordingly. Put chain on.

    I'll check our your method, but considering once I set mine straight I lost a lot of chain noise, I'm willing to bet my current chainline is relatively accurate.

  4. #4
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    66.5

    I don't have spacers small enough to give/take another milimeter, and I can't help but to excuse 1 mm having any sort of effect like this.

    What about the DMR STS Tensioner? It's fixed with a roller and requires a 3/32 chain, which I just put on my bike. Is it a good candidate, or should I cut the ******** and get a Rennen? (assuming a Rennen doesn't have the slip problem my Sette has)
    Last edited by Roasted; 07-28-2009 at 05:53 PM.

  5. #5
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    Does your fixed tensioner sit completely flat against the surface of the dropout and hanger? One of my previous bikes had a dropout design such that the outer edge of the threaded hole for the derailleur was not in the same plane as the outer edge of the rest of the dropout, which meant the fixed tensioner that attached to both places was not flat against both surfaces and couldn't grab as well

  6. #6
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    Yeah, that's another kicker. The fixed tensioner actually sits completely flat against the dropout. That's one of the first things I noticed. I even held a flashlight on the other side and didn't see any creeks of light passing through.

  7. #7
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    1mm is alot. more than enough to throw your chain. it's nearly half the thickness of your sprocket

  8. #8
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    Someone explain this to me.

    I have a Sette Chain Guide II. Pretty much identical to the Gusset Bachelor and very "similar" to the Rollenlager by Rennen.

    The Sette Chain Guide, as I've mentioned before, holds decently well but under pressure it'll move, even if I have it torqued down a good way.

    I've heard of people who grind... yes... grind... on the Rennen. Do people actually treat mountain bikes like BMX bikes with pegs and grind on the damn Rennen?

    If that's the case where you can grind and it still holds it's place, I guess that would be a tensioner that would answer my question in terms of having a fixed tensioner that doesn't move under load. Eh?

    Any Rollenlager owners wanna chime in?

  9. #9
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    Quote Originally Posted by ISuckAtRiding
    1mm is alot. more than enough to throw your chain. it's nearly half the thickness of your sprocket
    Well, again, I don't have 1mm spacers so... 66.5 is just going to be the way I run it.

    Besides, I'm running an 8 speed chain so I have some side to side support from that chain. Everything runs perfect until I put that spring tensioner on. THEN I have problems. I'm not thinking it's the chain line whatsoever, to be completely bluntly honest.

  10. #10
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    Yooooooooooooo Rollenlager owners. How's this gizmo hold up for you? Does it move under pressure at all or does it stay put when you lock it down?

  11. #11
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    Quote Originally Posted by ISuckAtRiding
    1mm is alot. more than enough to throw your chain. it's nearly half the thickness of your sprocket
    I'm sorry, but this is just wrong. The amount of angular delection over say 17" with a .040" sprocket displacement just isn't worth worrying about. The frame probably flexes more than that when the chain is under tension during each pedal stroke, especially when you're grinding your way over the top of that almost-too-steep climb.

    Setting chainline by eye or with any straightedge has always worked for me.
    It's possible to get too hung up over that 1mm which doesn't matter a toss.....

  12. #12
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    Quote Originally Posted by Andy R
    I'm sorry, but this is just wrong. The amount of angular delection over say 17" with a .040" sprocket displacement just isn't worth worrying about. The frame probably flexes more than that when the chain is under tension during each pedal stroke, especially when you're grinding your way over the top of that almost-too-steep climb.

    Setting chainline by eye or with any straightedge has always worked for me.
    It's possible to get too hung up over that 1mm which doesn't matter a toss.....
    Well then we'll have to agree to disagree. I've had situations where it mattered (not on my bike). Measuring the chainline with my height gage on my granite surface plate and correcting the spacers has fixed several issues when there wasnt more than .05" error.
    Could also have something to do with the direction in which it's offset when dealing with noodly frames and flex.

  13. #13
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    Quote Originally Posted by ISuckAtRiding
    Well then we'll have to agree to disagree. I've had situations where it mattered (not on my bike). Measuring the chainline with my height gage on my granite surface plate and correcting the spacers has fixed several issues when there wasnt more than .05" error.
    Could also have something to do with the direction in which it's offset when dealing with noodly frames and flex.
    I'm happy to agree to disagree - it's not life or death ! It's just that (like you presumably, with the surface plate and height gauge) I'm a mechanical engineer, and while I'm fussy enough over lots of stuff (wheel trueing, brake set-ups etc) I've never felt the need to do anything but set chainline up by eye and it's always worked for me.

    I have wondered sometimes whether it would be worthwhile (on a flexible frame at least) to set the sprocket .040" inboard to take into account the way that the frame deflects under chain tension - you mentioned much the same thing above.

  14. #14
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    Quote Originally Posted by Andy R
    I'm happy to agree to disagree - it's not life or death ! It's just that (like you presumably, with the surface plate and height gauge) I'm a mechanical engineer, and while I'm fussy enough over lots of stuff (wheel trueing, brake set-ups etc) I've never felt the need to do anything but set chainline up by eye and it's always worked for me.

    I have wondered sometimes whether it would be worthwhile (on a flexible frame at least) to set the sprocket .040" inboard to take into account the way that the frame deflects under chain tension - you mentioned much the same thing above.
    I dunno, i nearly died there lol
    I'm a Manufacturing Engineer, and have been a Toolmaker all my life before that, so we are close to on par there. I agree with ya, i always try to go inboard if anything.
    On a true SS specific bike without a spring tensioner, chainline is not a huge deal, but i've found the tensioners to be a bit picky about chainline, expecially on setups where the person is running ramped chainrings and cogs. A rocky trail doesnt help matters much either.
    And yea, i guess i am guilty of being a little more anal than i need to be

    Also, to the OP, check your chain. I had stetched a master link badly, and it would cause me to drop the chain pretty frequently. It was barely noticable until i checked it out link by link.

  15. #15
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    I don't think I have a master link. I've checked my chain out but I just don't see any problems with it.

    Today I put my spring tensioner back on to give it a shot, it just wouldn't hold. I even used my old derailleur and it too was skipping. I don't know what's happening. It's not like I'm on a noodle frame, so I don't see why it skips.

    I also noticed something weird with my fixed tensioner, which has a roller. I have a 32t chainring and 3 cogs, 14 15 16.

    If I put the 16t cog on, the chain is fine.

    If I put the 14 or 15t cog on, when I pedal forward, the chain "sucks" itself to the one side and rubs horribly against it. I don't understand why, because as we've discussed my chainline is perfectly in line. If you look at the back of the bike and line up the 3 points (chainring, tensioner roller, cog) it's clear the cog and chainring are straight and the tensioner is just doing something weird. Yet the roller is complete T to the aluminum arm.

    I've switched the roller around, thinking something inside must be causing it. But even with flipping the roller, it still pulls to the same side.

    Since I like to run 32-16 for trails, I'm happy with it for now since it's fine with the 16t cog. But what the hell is causing the 14 and 15t cogs to goof up? The chain is the same tension as the 16, I don't see what the issue is.

  16. #16
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    Quote Originally Posted by Roasted
    I don't think I have a master link. I've checked my chain out but I just don't see any problems with it.

    Today I put my spring tensioner back on to give it a shot, it just wouldn't hold. I even used my old derailleur and it too was skipping. I don't know what's happening. It's not like I'm on a noodle frame, so I don't see why it skips.

    I also noticed something weird with my fixed tensioner, which has a roller. I have a 32t chainring and 3 cogs, 14 15 16.

    If I put the 16t cog on, the chain is fine.

    If I put the 14 or 15t cog on, when I pedal forward, the chain "sucks" itself to the one side and rubs horribly against it. I don't understand why, because as we've discussed my chainline is perfectly in line. If you look at the back of the bike and line up the 3 points (chainring, tensioner roller, cog) it's clear the cog and chainring are straight and the tensioner is just doing something weird. Yet the roller is complete T to the aluminum arm.

    I've switched the roller around, thinking something inside must be causing it. But even with flipping the roller, it still pulls to the same side.

    Since I like to run 32-16 for trails, I'm happy with it for now since it's fine with the 16t cog. But what the hell is causing the 14 and 15t cogs to goof up? The chain is the same tension as the 16, I don't see what the issue is.
    I'm pretty new to this, but from my understanding, aren't you supposed to have the chain length as short as possible (removing slack) before putting on a tensioner? For running smaller cogs, perhaps you need to remove a few links from the chain.

  17. #17
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    Quote Originally Posted by el_toro
    I'm pretty new to this, but from my understanding, aren't you supposed to have the chain length as short as possible (removing slack) before putting on a tensioner? For running smaller cogs, perhaps you need to remove a few links from the chain.

    Yes, you're right. With the 14t, I can remove one chain link and it's the magic gear ratio @ 32-14. However, the 15t I cannot remove the chain link, so I'm stuck with the extra link in it. But even still, it's weird as hell that the 14t and 15t act the way they do but the 16t doesn't.

    I'm considering on getting the rennen (still waiting on rennen owners to chime in here). One thing I noticed about the rennen is that you use your typical QR skewer nut, which I think is a bonus, being the skewer nut has slots on the bottom so it should be able to bite into the tensioner more when you clamp it down.

    Not sure if it's worth the 50 dollar jump from what I got, though...

  18. #18
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    Maybe you should try a half link chain to get more adjustability?

  19. #19
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    Quote Originally Posted by el_toro
    Maybe you should try a half link chain to get more adjustability?
    I was thinking that. How are half link 3/32 chains? They pretty beefy or should I expect to drop 10 a season?

    holy high price. I think I'll pass for now.

  20. #20
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    Quote Originally Posted by Roasted
    I was thinking that. How are half link 3/32 chains? They pretty beefy or should I expect to drop 10 a season?

    holy high price. I think I'll pass for now.
    Rennen tensioner= ~$50
    Half Link Chain= ~$20-30

    Cheaper than ordering a tensioner that may not fix your problem!

  21. #21
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    Right, however, is it weird that I'd rather spend 50 on a chain tensioner that I know will be a half decent product as opposed to a half link chain @ 30 when I already have a chain I like?

  22. #22
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    Don't buy a complete half-link chain - there's no point.
    Just get a half link (or a link and a half) like this and use it with your existing chain.

  23. #23
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    Regardless of what I "should" do, I don't understand - "why?"

    Does anybody else here run a fixed tensioner and have random chain issues like this? It's so weird to see my roller straight, chainline straight, and the chain is just like eff you guys I'm gonna go way out of line here and confuse the hell out of ya!

  24. #24
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    Is this happening with any chain, or have you not tried a different one?

    Maybe there's a stiff link, slight side plate distortion or something along those lines. If you've tried substituting another chain and you still have the same problem then forget that I said this....

  25. #25
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    Quote Originally Posted by Andy R
    Don't buy a complete half-link chain - there's no point.
    Just get a half link (or a link and a half) like this and use it with your existing chain.
    Yup and if your chainline is off...it is OFF. Fix it first and then report back. Seems you "think" it is insignificant, but it may not be. That is what I would try first.
    Fat, drunk, and stupid is no way to go through life son...

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