When to change a chain

[cal scott]

This may be a topic previously addressed ad nauseum, however, my efforts to search the site haven't come up with any answers. This may also be much like oil and tires where everyone has an opinion but there is no common consensus. Despite these shortcomings, I will cautiously ask anyway :teeth.

How do you determine that an O/X ring chain is at the end of its life and needs to be changed? Bike manual states that it should be changed once it has "stretched" a predetermined amount. Other sources state that stretch generally doesn't matter and the state of the links is more the determinant - frozen links and general rusting indicate loss of the sealed chain lubricant. Collective thoughts of the group?

While I am at it, just wondering what the thinking is on changing sprockets...?
- Change both the front and the back every time you change the chain
- Change the front every time but perhaps not the back as that wears more slowly
- They don't need changing every time; depends on wear so assess before making a decision

 

[Junkie]

if the links are sticking, it's done

if the chain is stretching quickly, it's done

surface rust on the outside isn't all that important

I change both sprockets every time I change the chain

 

[mototireguy]

Lift rear of bike or put on center stand.

Spin the wheel.

Do any of the chain links have any visible kinks or does the slack get tight/loose as the wheel spins?

Another check is to grip the chain with 2 hands and flex it side-to-side. There should be zero or very minimal side-to-side play.

And when changing the chain you typically match the new chain with new front/rear sprockets.

 

[dravnx]

Also look for the brown dust of death. It will look like rust but is actually metal dust that has rusted. It's a sign of parts that are no longer lubricated and are eating themselves. Usually you'll see it covering 2-4 links in a row.

 

[Biga]

Whatever you do don't let it get like this one

 

[m0t0_ryder]

Whatever you do don't let it get like this one
View attachment 515286

What....
It's still got half it's teeth... sort of.

 

[Escape pod]

New chain on new sprockets, @ the back of the rear sprocket pull the chain away/ it lifts off the sprocket a little, a worn (drive-train) the chain lifts from the sprocket a lot.








Regina gold gives the best service

 

[HadesOmega]

If the chain stretches to the point the adjusters can no longer keep the chain slack in spec. When a chain is ready to go you will notice it will suddenly start stretching. You'll have to adjust it more frequently all of a sudden.

Also in your service manual it will tell you how to inspect the chain stretch. Usually it is tightening the chain so it is taut or hanging a weight on it and measuring the distance of a certain number of pins. If it is no in spec the chain is done.

Also if you if you chain seems to be stretching inspect your sprocket first it might be worn out. The front one wears out faster than the rear.

I just rode LAB2V on a chain that looked like shit but was still tight inspec but missing o-rings and some of the links are kinking. I punished that chain through 500+ miles of desert terrain and it didn't stretch at all. Modern or good quality chains can take A LOT of abuse. just clean and lube them and they'll last a while.

 

[ichabodnt650]

25,000 miles if well maintained; sooner if not

 

[Aware]

25,000 miles if well maintained; sooner if not

Random number generator?

 

[kuksul08]

There is actually a measurement that tells you plain and simple when it's time to replace it. You measure a certain number of links and if it's long than that, it's due for replacement because the pins have worn passed the acceptable tolerance.

I just replace them when the sprockets start showing wear, or if the links start getting rough.

Also, the 'red dust of death' is an obvious sign the chain is toast. You will see this red/brown powder all over some people's bikes. Once the dust happens, it is ruined.

 

[kuksul08]

Also look for the brown dust of death. It will look like rust but is actually metal dust that has rusted. It's a sign of parts that are no longer lubricated and are eating themselves. Usually you'll see it covering 2-4 links in a row.

That's funny we both call it the brown dust of death. where did you hear that?

 

[ichabodnt650]

Your front sprocket will exhibit 3x more wear than your rear, but you can't see your front as easily (Vstrom has 47 tooth ÷ 15 tooth = 3.13 times more wear to the front teeth)

I've replaced chains ranging from 20,000 ~ 35,000 of use, depending on how abused they have been. 25K is a comfortable interval for me personally.

 

[dravnx]

That's funny we both call it the brown dust of death. where did you hear that?

Meant brown.

 

[Busy Little Shop]

Mileage is a poor standard for wear because of so many variables...

A more accurate standard of chain wear is after the 3rd adjustment because
that is undeniable evidence that the factory installed grease is beginning to
fail to lube the critical pin roller junction hidden behind the X ring... the
length of the chain is growing because of this metal to metal wear... We can
not call a chain serviceable that is grinding on metal...

This is what we don't see behind the X rings... metal to metal wear
every time we adjust the chain that eats into our engine's available
HP... a new pin measures 206.5 and wears down to 205.5 at the 8K mile
mark... looks good to the naked eye but multiply that 1 thousand of an
inch times 108 links and you have 108 thousands of an inch wear or
about the range of the green marks provided by Honda's wear gauge...
202.8 show the very visible wear at the 12K mile mark... the pins are
turning red from extreme heat of grinding dry metal... a chain in this
condition may consume up to 6 to 8% of our RWHP... not to mention it
may snap into and cause case damage...

Some manufactures provided a handy guide to monitor chain wear... stay with
in the green and you'll be looking for a new chain and sprockets at the 8 to
10K mile mark...

What we are lubing are external roller and between the roller and the
sprockets (red area in my drawing)... we are not lubing the X rings
nor behind the X rings so any oil applied in that effort is a waste
and will only fling off...

 

[dravnx]

This would be true if all the pins wear at the same rate. Most chains don't.

 

[Busy Little Shop]

What riders call "brown dust" or "rust" is technically iron oxides of harden metal
at the pin and roller junction behind the X ring that are under extreme heat due
to running long after the factory installed grease is gone...

If you see Red Iron Oxides exploding pass the X ring its tantamount to chain
abuse... because the safety margin of strength built in the chain is expiring with
every turn of the wheel and what a rider risk is tossing the chain which may
crack the primary cover or worst yet foul the wheel and cause an unwanted skid...

 

[cal scott]

Thanks to all who have contributed to this thread. Lot's great information and super helpful. Special thanks to those who took the time to post photos! :thumbup

 

[ScottRNelson]

Some manufactures provided a handy guide to monitor chain wear... stay with in the green and you'll be looking for a new chain and sprockets at the 8 to 10K mile mark...

That guide is only good if you don't change the size of either sprocket. We had somebody on the ThumperTalk XR650L sub-forum all worried about those marking after changing to a different size sprocket. We had to explain that the markings were meaningless after the sprocket change. I run both 14 and 15 front and 45 and 48 rear in all four combinations on my XR650L, so I can use the full adjustment range depending on what's on there at the time.

I haven't had any chains stretch significantly in the last 100,000 miles or so of the various Ducatis, KTMs, and Hondas that I've been riding since joining BARF. I usually end up with kinks in the chain that indicate that it's time to get a new one. Made it to 24,000 on the KTM 990 with only the tiniest hint of kinks in the chain and no measurable stretch. I told the new owner it was probably time for a new chain on that thing.

I guess I actually did have one chain on my Ducati ST2 that stretched in just one part of the chain. I put on a new tire, set the chain adjusters, then rotated the wheel and it was suddenly too tight. I readjusted and then noticed that at about 35 mph it was surging due to uneven chain stretch. I put a new one on there right away.

Rather than measure to detect chain stretch, I just try to pull the chain away from the rear sprocket at the very back of it. If I can see daylight between the chain and sprocket, it's time for a new chain.

The other thing that I do to test for worn sprockets is check if I can hear a difference between rotating the rear wheel forward and rotating it backward. If I can tell by sound which way it's spinning, time for a new sprocket.

 

[Busy Little Shop]

Made it to 24,000 on the KTM 990 with only the tiniest hint of kinks in the chain and no measurable stretch.

This chain was dry fooking way before the 24K mile mark...

A chain kinks and grows when the owner fails notice the factory install grease is
used up and metal on metal wear is happening at critical pin and roller junction
with every turn of the sprockets...