chain tension

[glenz]

a constant prob. i have is the cheap- #$%@&%$$#!!??-chinese chain tensioners.anybody come up with a better way?-thanx-G.Z.

[2door]

Glenz,
How handy are you? Do you weld or have access to a welder or a friend who does?
Personally I have three bikes, one has over 1500 miles on the kit chain tensioner with no problems. The tensioner needs to be secured to the chain stay so it can not rotate into the rear spokes and the bracket given a slight twist to align the wheel with the chain correctly, but there are other alternatives. Here are two views of two different approaches to the tensioner issue.

[ADDICTED BICYCLES]

Hello, I like your tensioner ideas. The second one is awesome! My tensioner stripped somehow WHILE I was riding, and loosened the chain a whole lot, which made it hit inside the casing, and snapped one side of my #41 chain!!!! I'm a cursed rider who has a break down EVERY time I ride. I've had everything go wrong, including a snapped frame. I can't begin to express my frustrations, and I literally want to give up on motor bikes. Here's my question, can I use a rear derailler from another bike as a chain tensioner with a #41 chain? And how would I do that? If you can help, that would be excellent, I need this repaired AGAIN asap. Thank you.

[Bmetz]

try the chain tensioner and spring from tractor supply mention in other posts, i used the cheap chinese bracket with new automotive bolts and lots of thread lock, works well now.

to keep the tensioner wheel from sliding down in the slot i added a extra bolt in the slot as a block.

also used some teflon tape where the tensioner turns on the bolt.

[Bmetz]

thats a good idea drilling a hole to keep it from turning. mine got loose a couple of times till i switched to automotive grade bolts and used thread lock where the metal clamps to the frame. i was worried about weakening the frame by welding a cross piece

[2door]

Originally Posted by Bmetz

thats a good idea drilling a hole to keep it from turning. mine got loose a couple of times till i switched to automotive grade bolts and used thread lock where the metal clamps to the frame. i was worried about weakening the frame by welding a cross piece

Welding to the frame, if done correctly by a competent welder will not weaken, but will strengthen the frame. Underline "correctly" here. A bad weld can be a weak area and if the base metal, the frame, is not incorporated into the weld it can fail at that point.
Tom

[bairdco]

i, personally, would never drill a hole in my chainstay.

and i dunno if i'm just lucky, but all the bikes i've built haven't needed a tensioner. i've changed out the rear sprocket or front chainring on the pedal side, added or subtracted chain links, spaced out the wheels, and spent a lot of time figuring out exactly where to put the motor to keep a straight shot.

i realize that this won't work for all bikes, and if i ever need a chain tensioner, i'll probably try to modify something like this:

[soccerrj88]

Try this. Just took the stock Chinese POS and put it on the top chainstay, and put a 10" or so bar stock from tractor supply and extend it to reach the proper length and either drill a hole or make a slot for the wheel to slide up and down. You can even connect it at the end to the frame or I've noticed it works just fine without doing that...

[misteright1_99]

This worked for me......

http://motorbicycling.com/f6/spring-...ioner-890.html

[Junster]

You can also shim between rear motor mount and the seat post with some sheet aluminum to space the motor forward and eliminate the tensioner. You'd be suprized how much slack a 1/16" thick shim will take up.