Chain Tensioner Do I REALLY need a chain tensioner?

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Questions for motorpsycho...

it's not so much the tensioner that causes these issues...it's poorly made parts. if you get a sprocket that's not machined almost perfectly, you will have issues. almost every kit comes with a poorly made sprocket. Chain alignment, and perfectly centered sprockets are the key.

motorpsycho,

I've finally got my chain tensioning problems under control. I used the kit tensioner bracket. But I attached a 17-tooth idler sprocket from Tractor Supply Co., made specifically for #40 and #41 chain (SKU #: 1182009, $19.99). The idler sprocket has a 1/2" bore, so I had to drill out the top of the tensioner bracket's slot to 1/2" and attach the sprocket with a 1/2" x 2" bolt. On the opposite side of the bracket, the bolt got fitted with: 1) a flat washer, 2) a lockwasher, 3) a nut, 4) a push nut (to hide the end of the bolt).

The sprocket can't move up and down in the bracket's slot because of the larger hole that was drilled in the top of the slot: Now, adjustment of chain tension is done by moving the bracket horizontally on the chainstay.

The kit bracket won't rotate into the spokes because, on my bike, the chainstay portion of the frame that it attaches to is oval-shaped. And, so both the upper and lower bracket fasteners can be tightened evenly, I took up the gap between the two sides of the bracket with flat washers (4 each on the top and bottom).

The black finish that you see on the bracket in the attached picture is tough plastic sheet material (cut from the cover of a 3-ring binder) that is firmly affixed to the bracket with 2-side rubber contact cement. I did the same thing to both sides of the 56-tooth drive sprocket. This is strictly for appearance sake.

Finally, my questions: When you say that a poorly-made sprocket will cause issues, are you referring to the overall production of the sprocket, the accuracy of the drilling of the hub adapter (or rag joint) holes, or both? I've got an aluminum hub adapter that attaches to the sprocket with three bolts. And I DO experience varying tension in the chain as I rotate the rear tire: at one point it's got about an inch of play on the upper run of chain, and at the other extreme it's got virtually no tension at another point in the rotation.

Do you think this is the fault of the sprocket? The chain? And should I be concerned about it?

Thanks for your attention!
 

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I use the two bolt tensioner design on the 410 pedaling chain. You won't have to worry about it going into the spokes on that side. I use the four bolt tensioner design on the drive train side using 10.9 (Grade 8) steel nuts and bolts as well as a 1/2" hex head bolt for the wheel allowing for sufficient torquing. To adjust your sprocket alignment, advance your bicycle until you reach the tightest area of the chain, loosen all of your sprocket bolts until you can adjust the position. Carefully tighten all the center bolts, then right of center bolts, then finally left of the center bolts. It's also a good idea to take a mental note of the tightest and slackest areas so you know where the sweet spot will be. This method has proven to work well for me.
 
Alright then, I've had it with the tensioner. I just had to remove a few links off my chain, after another session with my bro working on the bike, we found out my new chain tensioner didn't quite clear the frame when bolted on to the chain. Lol but its up and running. Now I'm just fine tuning everything and other small tweeks for a good ride coming.:helmet:

We stoped working on it around 8pm, I took it for a test run down the road and back. Now I can feel how smooth the ride is with the heavy duty wheels. And the sprocket adapter works like a charm. Feels good to ride again! Now I just need a day off.

wait what?
the chain tensioner didn't clear the frame when it was bolted to the chain?
you're supposed to bolt the tensioner to the frame, not the chain.
 
wait what?
the chain tensioner didn't clear the frame when it was bolted to the chain?
you're supposed to bolt the tensioner to the frame, not the chain.

Yeah I guess I forgot to edit! What I meant was the frame. I wouldn't even know how to bolt it on to the chain lol. But I guess it was due to my chain being shorter since I took some links off.
 
Old thread, but worth sharing.
I made my own spring tensioners. Only cost about $10, and was very fun :)

 
If it gets tight and lose bad / bent Axel sprocket not centre then the self adjusting tensioner will fix that.
 
IF you can run it straight chain, DO IT!!!
less contact = faster speed, faster excel.
I totally agree.
IF the bike has a derailleur on the right it already has a tensioner.
IF the frame has a J slot for adjusting chain slack for the left side that is by far the best way to go...
You can adjust the chain tension buy moving the wheel.
 
Tinkering around with my chain tensions tonight (who isn't, right!) trying unsuccessfully to get both sides tight without a tensioner using half-link. Then it occurred to me that tensioners for the pedal side are cheap (used), good quality, and readily available in the form of an adapted derailleur. Toss that other dangerous, cheap piece of junk! I think for a lot of us, the pedal side is really mostly the starter and we don't do a lot of unnecessary pedaling around. I'm gonna do it.
 
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