Spring loaded tensioner questions

biknut

biknut

Well-Known Member
Hope I'm posting in the correct forum. I want a spring loaded chain tensioner. After doing a thorough search I can't see where this question had been addressed.

My question is this. If you run a spring loaded tensioner, won't you need one on both the top and bottom chain run? Most of the ones I'm seeing only run one on the bottom. What happens when you let off the gas on a downhill. If there's only one tensioner on the bottom run of the chain, won't the top chain run go slack and possibly jump the sprocket?

Am I missing something here?
 
I know it seems like the upper portion of the chain would go slack, and it does, to an extent but, if your chain tension is correct, 1/2 to 3/4" when measured on the upper chain when pushing the bike forward, clutch engaged, then you shouldn't have excessive slack when in deceleration. This would be especially true if you opt for a spring tensioner. Proper drive chain tension and alignment is the most important facets of these bikes.
Tom
 
I see. That makes since.

That's a relief, because all the good tensioners I'm looking at are about $80. I really didn't want to have to buy 2 of them.

 
the chain needs to be installed so that the chain slack mentoined above by 2door is all the slack allowed "without" the spring tentioner installed,,,the spring tentioner is just for cleaning up the last 1/2 -3/4 slack after proper chain instalation
 
corgi1 said:
the chain needs to be installed so that the chain slack mentoined above by 2door is all the slack allowed "without" the spring tentioner installed,,,the spring tentioner is just for cleaning up the last 1/2 -3/4 slack after proper chain instalation
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Tha man is correct. The 1/2 to 3/4" slack measurement is when a kit supplied tensioner, or no tensioner is used. A spring tensioner will take up that slack, more or less.
The advantage to a spring style tensioner is to keep you from manually adjusting the chain tension as the chain wears (sometimes called stretch). The trick is to find the proper spring tension for the application. Too strong and it will make the chain too tight. Too weak and the chain will be loose. Proper alignment can not be stressed enough also. As I said above; tension and alignment are critical to a reliable chain drive.
Tom
 
The man is not correct, I run my chain real loose 1 to 1 1/2 inch, never had the chain come off ever. When I was younger I raced motorcycles and nobody had there chains tensioned up, it's more stress on the chains. It creates more resistance and friction this is probably the worse advice.
 
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Well on these a loose chain will wip during misfires etc and beat them to pieces,and if the links bunch going into the small sproket area it can (and does)damage the clutch shaft
 
keep in mind I'm a novice, and am in the steep part of the learning curve.

This is what I'm thinking about doing now. Since my bicycle has horzontal drop outs I'm going to use the frame drop outs to adjust the motor drive chain like a motorcycle, and I'll put a tensioner on the peddle chain.

i think this will work, but I do have a coaster brake.
 
Horizontal drop outs, awesome. Comes in real handy! I would agree with Tom and Corgi. Right and tight.

Just the way I do it and not intended as advise. I mount engines with a slight lean to the rear. As the chain wears-in, level it correctly or even slightly forward. literally takes up some of the slack. But my usual goal is to lose the tensioner which is a whole other debate.

Have seen pics of using the tensioner on the bike chain. Folks said it worked fine.

Looking forward to seeing your build and welcome to the crazy.

What do you have for front brakes?
 
Dan said:
Horizontal drop outs, awesome. Comes in real handy! I would agree with Tom and Corgi. Right and tight.

Just the way I do it and not intended as advise. I mount engines with a slight lean to the rear. As the chain wears-in, level it correctly or even slightly forward. literally takes up some of the slack. But my usual goal is to lose the tensioner which is a whole other debate.

Have seen pics of using the tensioner on the bike chain. Folks said it worked fine.

Looking forward to seeing your build and welcome to the crazy.

What do you have for front brakes?
Click to expand...

Only have a coaster brake right now, but I'll probably end up with a front disk.
 
fm2200 said:
The man is not correct, I run my chain real loose 1 to 1 1/2 inch, never had the chain come off ever. When I was younger I raced motorcycles and nobody had there chains tensioned up, it's more stress on the chains. It creates more resistance and friction this is probably the worse advice.
Click to expand...
To give FM2200 some credit here I'll say this. Chain/sprocket alignment is important. If the alignment is perfect, or near perfect, you can get away with the slack that he mentions. It's when there is some slight lateral misalignment, easy for a newbie to have, then that's where the trouble shows up with too much slack.
Also I'll repeat something here that I've said over and over: You should not compare mechanical features of a motorized bicycle built by a man with limited skills, as many of them are, with a motorcycle that was designed by engineers and built in a factory. They might look similiar but looks is where the similarities end. Just because something works on a motorcycle doesn't necessarily mean it will work on a motorized bicycle. They ain't the same animal.
Tom
 
This is my fix,Not advice just what I do!I'm working on something better.Kip.
 

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I use the supplied nylon wheel and thru bolt shortened and held in place in the top block with a set screw.Works great but I've been working on something better.
Tried it out today and it's worked super so far!I even noticed a smoother ride.Stay tuned!!Kip.
 
It's my opinion.If you don't have any type of tensioner your going to stretch your chain and hook your sprockets prematurely and you guy's that don't use a tensioner or a chain guard are NUTS!Kip.
 
After going back and forth on which side to put the chain tensioner on I've decided to put it on the power side. Thanks to everyone for helping me understand the options and pitfalls.

My plan is to leave the peddle chain alone. Cut the drive chain as short as possible and use a ZTR tensioner to take up the rest. I replaced the rear motor mount studs with extra long ones that I'm planning to attach some kind of mount for my tensioner that I'm yet to fabricate.


I'm thinking this will be a little less maintenance than putting the tensioner on the peddle side. Hopefully I'll have all the rest of my parts by the end of the week to finish my install.
 
This is how I did it.Kip.
 

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