Chain tensioner bracket is too large for the frame.

Discussion in 'Transmission / Drivetrain' started by Eden, Jul 25, 2016.

  1. Eden

    Eden New Member

    Hi, I have a 20" Schwinn Stingray Bicycle. I have successfully installed every aspect of the 2 stroke engine kit I purchased off eBay onto my bike... except the chain tensioner. It is the stock one that came with the kit.
    • I have tried putting it onto the frame, only to fail time and time again. It fits loosely on the frame, even when tightened.
    • I have tried various methods to allow it to fit on the frame, including placing metal (up to multiple layers), rubber pads and even hard plastic, but no matter what, the power and force of the chain always manages to make the tensioner move inwards and onto my tyre, causing the chain to fall of the sprocket and stall my bike.
    • Recently, I tightened the bolts so far that they snapped from the pressure.
    I need to find a way to either make it stay on without moving.

    Can anyone offer any suggestions?
     

    Attached Files:


  2. FurryOnTheInside

    FurryOnTheInside Active Member

    I would try it with no tensioner at all.. Looks like there is clearance at the chainstay. You will probably need to buy a half link to get the tension reasonably good on both chains. The kit chain will stretch anyway. You don't want the tensioner getting dragged into your spokes. Maybe you can use the/a tensioner to push the return side of the pedal chain down or pull it up, there is less power going through that chain.
     
  3. bakaneko

    bakaneko Active Member

    have you try wrapping an old tire tube around it? make sure it is oversized so when you tighten there is a lot of room to spare. you can also try duck tape. again oversize and tightened
     
  4. crassius

    crassius Well-Known Member

    hammer the curve in it a bit flatter, then saw about 2 inches off an old handle bar and split that into 2 "C" shaped sections to put under the mount (hammer these a bit flatter if needed) - tighten with good steel bolts (I use 10.9 grade)
     
  5. CrazyDan

    CrazyDan Member

    After using whatever needed to get it to fit tightly to your frame use a self tapping screw or drill a small hole through the tensioner and frame and bolt that sucker up. Should keep it in place.
     
    Cozmik Mezzenger likes this.
  6. FurryOnTheInside

    FurryOnTheInside Active Member

    Drill through the frame?!?? :eek:
    I see now why you have that nickname.
     
  7. CrazyDan

    CrazyDan Member

    Just a lil hole o_O you can fill it with epoxy if it worries you :D
     
  8. Eden

    Eden New Member

    Thanks for the answer. We have tried without but there is so little clearance that it drags on the frame and/or the tyre. Only at a very tight tension will it clear it and only with the tensioner pulling it out of the way. Thank you though.
     
  9. Eden

    Eden New Member

    We did try that yes. We tightened it a number of times with rubber, etc and it just kept pulling out of alignment. We got to the point where we tightened so much that the bolt for the tensioner sheared in half! Thanks though
     
  10. Eden

    Eden New Member

    T
    Thank you but the frame is very small and any hole will make it too weak in my opinion.
     
  11. bakaneko

    bakaneko Active Member

    Oke, the ugly way to do it is to run a small steel rod across the plate of the tensioner using hose clamps or some type of bracket to tighten. I can mock up a diagram in the morning if you need. Essentially the metal bar will hold the tensioner in place using two tubes as an achor. Cost about 5-10 bucks to do
     
  12. FurryOnTheInside

    FurryOnTheInside Active Member

    Last edited: Jul 26, 2016
  13. bakaneko

    bakaneko Active Member

    Another way to do it is to run a metal bar (steel best) across either the inside or outside of the chain tensioner and secure it to the frame tubes using hose clamps. If the metal bar has to be on the outside then you will need to get a hose clamp to secure it to the chain tensioner.

    I did this for my last bike because the tube was too small however my current bike has a big enough tube to securely affix the tensioner. It ain't pretty but it does work, plus your bike is a nice silver so it wont look that bad as opposed to a black colored bike. You might have to play around with the orientation of the chain tensioner nuts and bolts to get the bar to fit just right and aligned with the rear sprocket. My chain tensioner nuts is on the outside while yours is on the inside.

    The metal bars (steel best) are available at Home Depot, Menards for about $2. Find one that does not bend much usually steel but there are more cheaper metals that bend too much. You will need atleast two small hose clamps for $1 each and possible one more for $1.50 or so.

    Also, you would want to keep the roller wheel as low as possible. Your chain will stretch and you will have to remove the extra slack from the chain. Keeping it low initially allows you to possible not change the position of the chain tensioner to remove slack.
     

    Attached Files:

    FurryOnTheInside likes this.
  14. gary55

    gary55 Active Member

    Take a look at the spring loaded chain tensioners that attach to the engine. I have had good luck with the one sold by turbobuick1 on ebay. they last a long time, and every body seems to like them.
     
  15. Purple Haze

    Purple Haze Active Member

    Ditto what gary55 says. That stock tensioner is nothing but trouble, and ugly to boot. Purchase the turbobuick1 tensioner, money well spent. You'll love the high-quality parts (comes with stainless allen head bolts) and it makes the chain much more quiet. Never have to worry about adjusting chain slack ever again. If you are into looks, it polishes up nicely. P.S. NEVER drill holes in the frame, especially the chainstay.
     
    gary55 likes this.
  16. FurryOnTheInside

    FurryOnTheInside Active Member

    I believe the tubobuick tensioner would work with a 34t sprocket but as the OP says the chainstay is getting hit by the chain and in doing so it's pushing the chain over onto the tyre.. The Tubobuick won't lift the chain at the critical point, I think.. The solution suggested by banenko would work with the 44t if a 44t on a 20" wheel (lots of torque, low top speed) is what the OP wants.
     
  17. gary55

    gary55 Active Member

    Your probably right about the chain stay clearance with the tensioner so far forward. Hard to tell chain alignment and clearance from side view. One more option might be the arch chain tensioner that runs from the chain stay to the seat stay. Lots of leeway in mounting location and adjustment. 24 bucks on e bay or 19 + shipping at kings. looks like a good solution, and might be a little cleaner than hose clamps.
     
    FurryOnTheInside likes this.
  18. JGH122

    JGH122 Member

    Here is the solution for this problem and loose gas tanks, etc.
    Go to a hardware store, automotive store or a Caterpillar dealer and buy a roll of self sticking non-skid tape.
    Put a layer on either side of the chain tensioner brackets that squeeze the frame and wrap a single layer around the chain stay.
    Problem should be solved.
     
  19. JunkyardDog

    JunkyardDog Active Member

  20. gary55

    gary55 Active Member

    I agree no holes, but as furyonthe inside mentioned with the tensioner so far forward there could be clearance probs with the part of frame that stock tensioner attaches to " chain stay". Check out the arch chain tensioner on ebay or kingsmotorbikes. It attaches to the seat stay and the chain stay with U bolts so no holes solid mounting and no clearance issues. May require some shimming for chain alignment.
     
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