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Old Wizard
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Discussion Starter · #1 ·
The principal reason why drive chains fail is from excess tension caused by being installed too tight. Since the swingarm pivot is not concentric with the front sprocket, the chain length needs to accommodate the constantly changing distance between the front and rear sprocket as the rear suspension moves up and down. So the dimension on the swingarm sticker is intended to prevent you from installing the chain too tight. Looser is O.K.

You’ll use the sticker tightness measurement when you need to reassemble after changing sprockets or changing a tire on a bike with double-sided swingarms. Bikes with single-sided swingarms have eccentric adjusters, so no adjustment is required when changing a tire.

Once the chain adjusters are locked down there’s no reason to periodically readjust the chain. Chains get longer, not shorter, as they wear.

As the internal pins and bushings in a chain wear, the chain length of the affected segment gets longer, and when it exceeds 2 mm for a 16-link segment, the chain needs to be replaced. Chains don’t wear evenly, but even if they did, the overall increase in length of a chain needing replacement is less than 11 mm. Consequently, you don’t need any periodic adjustments to compensate for this small amount of wear for the life of the chain. You do, of course, need to periodically check 16-link segments of the chain for excessive wear and replace the chain if necessary.

You’ll need do a chain adjustment when the chain has been loosened to change a tire or sprocket. Also, a 3,000 mile or so tire change interval seems like a reasonable time to check for chain stretch. If you bring your bike to a dealer for a tire change, ask them ahead of time to write down the chain stretch amount for at least three segments of chain. This will put them on notice that you expect them to do it. It’s not often a dealer will actually do the check and a snapped chain is the consequence.
 

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I have always thought that a chain could wear/stretch beyond an acceptable amount which is when one gets too much backlash in the drive, but still have plenty of life in it once re-tensioned to recommended spec/play.

I always thought that if a chain gets too loose, it will create sprocket and worse, gear box damage from backlash. Indeed, for Ducati owners, a chain that might be too loose may jump off the front sprocket enough to damage the engine case.

I pay attention to how my bike takes up the slack/changes gears etc, and if I detect excessive backlash, I will adjust chain tension,as per tighest spot etc. back to spec tension/play, and usually find all is well again re shift quality/no excessive backlash in the drive. If I can't adjust the chain to where it does not get way too tight and then way to loose as it rotates on the sprockets, I change everything.

I always thought that a properly aligned chain with "locked in" adjusters, can still stretch/wear to where it's too loose/excessive backlash, *but still have plenty of life in it.* :)
 

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Beta Tester
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Chains don’t wear evenly, but even if they did, the overall increase in length of a chain needing replacement is less than 11 mm. Consequently, you don’t need any periodic adjustments to compensate for this small amount of wear for the life of the chain.
great! now i know i've been doing it right all these years:D:D
 

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I worry that your statement, "Once the chain adjusters are locked down there’s no reason to periodically readjust the chain. " could be misinterpreted.

Some people may take this to mean that once your chain is OK, there's no need to check it, even though you didn't actually say as much.

Additionally, may take what you posted as saying a slack chain won't present a problem as long as the wear limits are not exceeded. I just read a post about a guy who crashed when his too-slack chain jumped off and locked the rear wheel; thank goodness at low speed.

It is important to check the chain tension often. It doesn't matter how it got to be OK, if it's OK then it's OK. Likewise, it matters not how it might get too slack or too tight. If it's out of adjustment for ANY reason, it's definitely NOT OK. Believing that once it's OK, it will be OK for a long time could cause problems. Again, this isn't what you said, but your post could be misread.

In other words, even though my chain checks OK, knowing that it is highly unlikely to go out of specs once it's locked down is no excuse to ignore my chain tension, especially since it's so easy to check.

On my Monster 696, when the chain is properly adjusted (caution the English translation of the shop manual is incorrect but the Italian and Spanish versions are OK) I can just make it hit the lower rub block by pressing up hard with two fingers. Once you have a feel for that, it's easy to do a quick and dirty check without measuring. I grab a piece of paper (to keep my fingers clean) and quickly check my chain tension every time I refuel.
 

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Chain Adjustment

New to Ducatis, and not had a chain drive for 30 years! I raised the question on the ST page as to the correct method of measuring chain slack. My training was to push the chain in both directions at the midpoint, the difference between the two being the slack measurement. The manual states to push the chain upwards only from the resting point, that measurement being the slack, which is correct? There is 15-20mm difference between the two!!
 

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What I have been doing for a very long time now is: I adjust the chain as per manual, then find a friend close to my weight, have him sit on the bike, check, than call my wife have her sit on the pillion seat and check again. With that load I want to have a minimal slack in the middle.
 

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Different makes and models have different ways to measure chain tension. I happen to believe that following the manufacturers recommendation is the way to go, but others think the factory engineers are stupid and prefer to "eyeball" their chain tension. Suit yourself.

Your bike may require measuring the difference between pushing up and pulling down on the chain. Many bikes specify this procedure. But my Monster 696 uses a different and, I think, a much easier and more accurate method.

Unfortunately, for the Monster 696 the English translation of the procedure is wrong, or incomplete to be more precise. You're supposed to put the bike on the side stand (not a paddock stand) and measure the distance from the bottom of the swing arm to the center of one of the pins. It should be 47mm. The English translation says to pull down on the chain to make this measurement. What it fails to say (and which the Italian version says) is to pull down and then RELEASE the chain before you make the measurement; BIG difference. Of course, if you don't have a Monster 696, this procedure, or at least the 47mm specification, is likely to be wrong.
 

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No one implied that factory engineers are stupid, though there are a lot of them (stupid) just like in any other profession. They have to work through restrictions, limitations and compromises.

What I cannot understand is the stupidity of people to condemn others just for expressing their opinion (right or wrong).

Keep in mind that ''Observation is the mother of science and repetition the mother of knowledge''.

But above all keeping an ''OPEN MIND'' is the most important part in life.
 

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No one implied that factory engineers are stupid, though there are a lot of them (stupid) just like in any other profession. They have to work through restrictions, limitations and compromises.

What I cannot understand is the stupidity of people to condemn others just for expressing their opinion (right or wrong).

Keep in mind that ''Observation is the mother of science and repetition the mother of knowledge''.

But above all keeping an ''OPEN MIND'' is the most important part in life.
Steady there ................ In fact there are PLENTY of folks who believe that factory engineers are stupid, just take a look around the Internet.

But I don't think you can find an example where I said that YOU claim engineers are stupid or evidence that I condemned anyone, especially you, for simply expressing their opinion. In fact, I didn't even read your post until after you indicated that you were upset at my attempt to answer a question from someone seeking recommendations about chain tension.

I was responding to someone else and I simply pointed out a couple of ways people go about setting their chain tension and recommended to the OP, "Suit yourself". If you took that to be a personal attack, I fear you have misinterpreted my post and your vitriol is misdirected.

As far as I'm concerned, you can set your chain to any specification you wish using any method you like. As I said before, suit yourself.

Furthermore, if you want to convince anyone that your method is superior, feel free. After all, this forum is for the free exchange of ideas and opinions, right?

However, my advice to people who have NOT developed a method which they think is an improvement over the factory recommendation remains the same; follow the factory recommended procedure but be sure you know what that procedure is.
 

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Chain maint,cleaning the chain,chain adjustment.I should bought a guzzi or a bmw,not really though,I like my Ducati st2,so much fun to ride.
I believe that most ducati owners feel the same about thier bike,how much do you care,I care alot,they are spendy and rare.
Not to mention,women who drive suv's just seem to stare.Probably wish thier husbands had more balls.Happens all the time,big ego boost.
It is true,the tighest the chain is going to be is when every thing is lined up in a straight line,because the swing arm pivot is behind the cs sprocket.circle deal.
If I push hard on my chain,on the center stand,it will touch the lower rubbing block,when I sit on it,and reach down,it moves 3/4 inch or so,you can hear it if it's too tight it will whine when you let of the throttle.
You don't want it flopping all over the place,jumping sprockets,
And you can pull back on the chain from the center of the rear sprocket,it should not move much,less than a 1/4#, I'd say,other wise it's time for new sprockets and chain.
It's not that much $,everything is 250.00 from sprocket center for my st2.
And no,I don't work for them or care where riders buy there stuff.
So when it's all lined up in a straight line,you want some slack,1/4# at least.
Just my 2 cents.
 

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But I don't think you can find an example where I said that YOU claim engineers are stupid or evidence that I condemned anyone, especially you, for simply expressing their opinion. In fact, I didn't even read your post until after you indicated that you were upset at my attempt to answer a question from someone seeking recommendations about chain tension.

I was responding to someone else and I simply pointed out a couple of ways people go about setting their chain tension and recommended to the OP, "Suit yourself". If you took that to be a personal attack, I fear you have misinterpreted my post and your vitriol is misdirected.

As far as I'm concerned, you can set your chain to any specification you wish using any method you like. As I said before, suit yourself.

Furthermore, if you want to convince anyone that your method is superior, feel free. After all, this forum is for the free exchange of ideas and opinions, right?

However, my advice to people who have NOT developed a method which they think is an improvement over the factory recommendation remains the same; follow the factory recommended procedure but be sure you know what that procedure is.
Would you mind telling me whom were you referring to?
You are still passing judgement and advice (sic), with a lot of arrogance, and then you try to be indifferent ( suit yourself) and at the end you still insist that my vitriol is misdirected.

You should read better what you are writing. A honest proposition to someone who is looking for a second opinion should be , this is how I do it, if it has any logic or agree with it you can do it your self. That's how at least I have been treated all the times I have asked for assistance in this forum. The rest of the comments could have been omitted.
 

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Would you mind telling me whom were you referring to?
You are still passing judgement and advice (sic), .. snip ..........
And a "(sic)" back at ya'.

Let me give you some advice. If you feel like mocking someone when it comes to the subtle nuances of the English language, I advise you to first understand the difference between the words advice and advise before you offer your advice.

An Internet "gotcha'" looses much of it's sting when it reveals a lack of understanding of the matter at hand, wouldn't you agree?

I will continue to advise folks who want to adjust their chain properly to follow the advice given by the factory. If you consider that advice arrogant, I guess you'll just have to live with it.
 

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I'm glad to see I'm not the only one who gets into these lively discussions. Is it you, or is it me ? It's you, isn't it ? It must be you, Because I know it's not me.��
 

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What I have been doing for a very long time now is: I adjust the chain as per manual, then find a friend close to my weight, have him sit on the bike, check, than call my wife have her sit on the pillion seat and check again. With that load I want to have a minimal slack in the middle.
Yaso Stelbo!
I know this is an old thread but just wondering. Yesterday on the first day of an 8 day trip I noticed the chain to be quite tight when the bike was loaded up with passenger, luggage and preload on max so I re adjusted it so there was a bit of slack when I reach down to feel it. In your post where u say when you are loaded up and reach down and look for minimal slack in the middle, wouldn't you want a little bit of slack for when the swing arm moves up and down? Does the chain get tighter when the swing arm moves?

The current adjustment I have will be too loose for solo riding and when I drop the preload again. Does anyone else find they change the adjustment for solo and fully loaded ?

Cheers


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Old Wizard
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Discussion Starter · #17 ·
Does the chain get tighter when the swing arm moves?
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Yes, the chain pivots about the output shaft (small sprocket) but the swingarm moves about its own pivot point. The chain has the least slack when the output shaft, the swingarm pivot and the rear wheel axle are in a straight line. This occurs when the bike is heavily loaded and when the bike moves in its suspension during cornering.

Being in excess of the unloaded chain slack spec marked on the swingarm assures that the chain won't bind under all suspension movements and load conditions. You should have more slack — but not less — than the spec dimension.
 

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Come in Spinner :)
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I'm going to add something else here... I find quite a difference between a cold adjustment and then hot when the bike has been run for a couple of hours and the swing arm, my alloy rear sprocket, and the engine have all expanded to their running size and this is magnified with larger than stock rear sprockets (for instance a 44t rear sprocket is about 30mm larger in diameter than a 38t one)
So I adjust for correct tension hot then re-check to see what it is cold and use that setting for normal checking and maintanance.
The other thing with alloy sprockets is they do wear a little faster than steel so the tension does change quite a bit in the first few weeks of use till the chain and sprocket have bedded together and the alloy teeth have work hardened with use and the chain lube has embedded itself in surface of the teeth

davy
 
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