Chain Tensioner Slippage Prevention

Discussion in 'Motorized Bicycle General Discussion' started by RonInColorado, Aug 15, 2010.

  1. RonInColorado

    RonInColorado New Member

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    I've seen a number of posts from those with issues related to chain tensioners not gripping the frame well. The best solution that I've come up with is some rubberized/fiber reinforced gasket material from my local auto parts store. it's only a few bucks for a pretty good sized sheet and simply cutting a couple of pieces to line the inside of the bracket where it comes in contact with the frame seems to provide a really good grip.

    I've also used this to line the motor mounts and clamps which provides the added benefit of reducing vibration considerably as well.

    Happy riding to all!!

    cvlt1cvlt1
     
  2. 2door

    2door Moderator
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    Ron,
    I hate to rain on your parade but your solution has been tried, over and over and the results seem to always be the same. Eventually, maybe down the road a ways, but eventually the rubber/gasket material/tape/whatever will loosen and allow the tensioner bracket to move. The only sure was to keep it in place is to either weld it or secure it with a screw/bolt through the chain stay. There is simply too much force applied to the bracket to rely on clamping action alone to hold it. The best option, if a tensioner is absolutely necessary on your frame, is to fabricate a bracket that either welds or is bolted/clamped to the chain stay and seat stay.
    As for rubber mounting your engine...enough has been written here on that subject. In a word: Don't do it. You are not eliminating vibration but instead you're transfering it to the engine mounting fasteners and at some point they can and will fail. Mount the engine as solid to the bike frame as possible. Not gaps, no looseness, but SOLID. Forget resilient mounts. They don't work.
    Tom
     
  3. Al.Fisherman

    Al.Fisherman New Member

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    And that's the way it is....
     
  4. Goat Herder

    Goat Herder Gutter Rider

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  5. Kevlarr

    Kevlarr New Member

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    I agree with 2door, if you have to have a tensioner make one that clamps to both the chainstay and the seatstay, like pic #2 in bearlyawake's thread.
    I think it's funny that the kit builders haven't adopted this design since it can be made out of thinner steel which would reduce costs.
     
  6. RonInColorado

    RonInColorado New Member

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    2 Door, your advise is well taken, however for those with less experience and or lesser equipped the permanent solutions can be a less than ideal option. Personally I'm loath to drill frames having had the experience of a broken frame as a result of drilling and as far as welding, that can weaken the areas around the weld too. Still your recommendations are sound but for me my current engine/kit is now mounted on its third frame in part because of frame breakage and in part due to my simple desire to try out a frame that 'sits' a bit differently. My experience with the rubber/fiber gasket material has been somewhat different from what you describe, the biggest issue I've run into where motor mounting is concerned is that after about 1,000 to 1,500 mile of riding there is enough where on the gasket material to require replacing it. Where the chain tensioner is concerned it just plain works dandy. So, no bubbles burst here but my horizons are broadened.
     
  7. KCvale

    KCvale Active Member

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    Hi Ron, what is your frame design that requires you to use a tensioner on the drive side?
     
  8. RonInColorado

    RonInColorado New Member

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    KC- It's not so much an issue of frame design as jut the usual chain stretch we all experience with a new chain as it wears in. In my particular situation, riding on average of about 275-300 miles per week, the tensioner is a quicker and easier option than breaking the chain down at every turn to take out full links or putting in half links with a high degree of frequency. But as to your specific question the frame that I'm running right now is a basic Specialized Rockhopper Sport 21 speed.

    Typically when starting with a new chain I'll find myself adjusting the tension a couple of times a day the first few days depending on the mileage I'm running and of course beyond that it gets down to a once a day and eventually a once every couple of days deal to adjust the tension.
     
  9. BarelyAWake

    BarelyAWake New Member

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    My Aluminum Comp Schwinn (not recommended for motorizing) requires the dreaded tensioner to reroute the chain up & over the chainstay - some bikes need that redirect or the chain will hit...

    It's true I hate the blasted thing... but it's also true that it makes accounting for chain wear a lot simpler.
     
  10. KCvale

    KCvale Active Member

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    Hehe, I see why you don't recommend that bike. But like you said Barly, on some bikes you simply have to re-route the chain.
    Actually chain doesn't stretch.

    [​IMG]

    Here is an excellent read on it on Diamond Chain's site http://www.diamondchain.com/files/Maint_Guide.pdf

    Most of the initial chain 'stretch' we see on the kit bikes is caused by the big sprocket wearing in.
    That is complete after a 100 miles or so.

    If you are putting 300 miles a week on it, just give this a try for giggles and grins.

    Buy a KMC 410H Heavy Duty 'Freestyle' or similar chain, ~$13 at the bike store.

    Size it up with no tensioner so your wheel is as far forward in the frame keyway's as possible.

    Your rear sprocket is already broke in but will get a little new wear as will the new chain, but one rear wheel adjustment should fix that after a hundred miles or so.
    You don't even have to worry about a pedal side tensioner, the derailer takes care of that.

    I suspect you are having to constantly adjust the chain tension because of the tensioner, not 'chain stretch'. If chains were that inefficient and wore out that quickly there would be tensioners on everything from motorcycles to pedal bikes, and chains would be wearing out like flashlight batteries don't you think?

    What the heck right? It's cheap to try, and easy with your gear bike.
     
  11. Goat Herder

    Goat Herder Gutter Rider

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    I have been very impressed with the KMC 410H lately . Cannot say I have tested it enough to brag about it but it has held up on the Morini J shaft impressively!
     
  12. Al.Fisherman

    Al.Fisherman New Member

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    There is no requirement for a chain tensioner if you can get both chains within tolerances.
    This is not mine (I built it) but the same frame and set up.....
    [​IMG]

    There were issues with the chain hitting the frame where the tensioner is mounted. We have since modified the tensioner mount.
     
    #12 Al.Fisherman, Aug 16, 2010
    Last edited: Aug 16, 2010
  13. Kevlarr

    Kevlarr New Member

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    I remember when my bike looked like that. :D
     
  14. scotto-

    scotto- Custom 4-Stroke Bike Builder

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    Unless it's Made In Chinalaffdance1laff
     
  15. scotto-

    scotto- Custom 4-Stroke Bike Builder

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    That is impressive for a 410 chain, I've always had good luck with KMC's....was my mtn. bike racing chain of choice. They shifted flawlessly.
     
  16. KCvale

    KCvale Active Member

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    So one of the chains needs a tensioners...

    OK, you have two chains you can't match, one has to be longer than the other and require a tensioner.

    Which chain do you put the tensioner on?
    The one that is in constant motion when the wheel turns? Or the one that sits idle 95% of the time?

    The obnoxious hunk of metal and plastic tensioner in the kit will work on the right side too.
    But you can also get something considerably less obtrusive for the seldom used pedal side too like this one.

    [​IMG]

    Note the drive chain that is in motion 100% of the time the bike is motion again has no tensioner.
    Even during that 5% of the time you spend coaster braking and pedal starting, the drive chain is still in motion.

    I know I seem to come across as some sort chain thumping Evangelist against drive side tensioners, maybe I am, but I am no 'Chain Fearing' man (hehe, pun intended) , I just keep making the point that if you are forced to use a tensioner for any other reason than routing the drive chain, put it on the pedal side.
    It becomes a non-issue then.

    And so I repeat...
    If tensioners were a good thing on motorized vehicles, all motorcycles would have them.
    'nuff said until the next exact same topic? hehehe.
     
  17. 2door

    2door Moderator
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    These aren't motorcycles...they're motorized bicycles. There are many of us who run a tensioner and have no issues with them. Installed and aligned correctly they work. Install them wrong and you have problems. Its that simple. Done right, a tensioner will eliminate some of the problems newbies have with chain alignment and the issues it causes. If the chain is aligned correctly, the tensioner wheel aligned correctly and the chain tension is maintained correctly there is no real advantage to running without a tensioner. No you don't gain power. No, the bike doesn't run smoother. If the tensioner drags and is noisy and causes problems you'd better check your installation. The key words here are, "Installed Correctly".
    Tom
     
  18. scotto-

    scotto- Custom 4-Stroke Bike Builder

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    This is true..... and sometimes I'll run no tensioner...sometimes I'll run one, usually on the non-powered side. But then other times I'll run two, one on each side. No big deal really....would anyone like to see some pics? OK then.

    As Tom said: Installed Correctly....and I'll just add: especially with a toothed sealed bearing low friction pulley, or none.
    [​IMG]
     
    #18 scotto-, Aug 18, 2010
    Last edited: Aug 18, 2010

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