Drivetrain wear

[blindwilly]

how are people assessing the wear/lifespan of their drivetrain components. specifically cassettes and chainrings. I have a crankset that i was thinking of pulling off one bike and putting on another but i dont want to bother if the chainrings are at or near the end of their usable lifespan. Are most people changing cranksets/chainrings after a specific amount of miles or is there another way of telling how worn the rings are? I have put roughly 7,000 dry miles on the crankset but it came on a used bike and i am not very good at keeping it clean. I mostly just ride till its noisy then squirt lube and then ride till its noisy again. I haven't experienced any chain slipping yet. I am basically just looking for tips on how to assess drivetrain wear. Thanks

[K3RRY]

If you’re not noticing anything wrong then keep riding it.
As far as looking for wear for cassettes and chainrings - sharks teeth shape and broken teeth and for the chain - get a chain tool checker gauge or pull on it on the chainring side and see if there is excessive slack.

[Dave]

A cassette is usually considered to be worn out if you get NEW chain skip on one of more of the most-worn cogs, when pedaling with heavy pedal pressure ( usually standing). You may then find that a slightly used chain works just fine with that cassette.

Chain ring are worn out when you get chain suck, where the chain does not comes loose from the bottom teeth and tries to go up and around.

I edited to add NEW, which is important.

You'll get more cassette life by alternating the use of several chains with one cassette. Slightly used chains are unlikely to skip on a worn cassette.

[Mark McM]

As noted, chainrings have to be very well worn before their performance degrades. I usually judge chainring wear by eye. Brand new chainrings typically have symmetrical teeth. As they wear, only the leading edge of the teeth wear down, and the teeth begin to assume a "shark's fin" shape. When the "shark's fin" shape becomes distinct, I replace the chainring.

Note: Chainrings wear faster on the teeth that are at perpendicular orientations from the crank arms (these are the teeth that are under load when the cranks are horizontal). Rotating the mounting orientation of the chainrings can help to even out tooth wear and extend the life of the chainring. Unfortunately, the outer chainring has shift pins and an anti-jam pin that are at specific orientations, so the outer chainring cannot be re-oriented to even out wear. But inner chainrings (and most single chainrings) don't have specific orientations, so they can be re-oriented to extend their lives. (Since small chainrings wear faster than large chainrings, it is probably a good idea to rotate inner chainrings.)

One of the biggest factor in chainring and sprocket wear is chain elongation. Chains elongate as they wear, and that accelerates wear of sprocket and chainring teeth. Replacing chains before they elongate too much can dramatically extend the life of the sprockets and chainrings, so frequent chain replacement can end up being economical.

[zmalwo]

good info from everyone

[blindwilly]

As noted, chainrings have to be very well worn before their performance degrades. I usually judge chainring wear by eye. Brand new chainrings typically have symmetrical teeth. As they wear, only the leading edge of the teeth wear down, and the teeth begin to assume a "shark's fin" shape. When the "shark's fin" shape becomes distinct, I replace the chainring.

Note: Chainrings wear faster on the teeth that are at perpendicular orientations from the crank arms (these are the teeth that are under load when the cranks are horizontal). Rotating the mounting orientation of the chainrings can help to even out tooth wear and extend the life of the chainring. Unfortunately, the outer chainring has shift pins and an anti-jam pin that are at specific orientations, so the outer chainring cannot be re-oriented to even out wear. But inner chainrings (and most single chainrings) don't have specific orientations, so they can be re-oriented to extend their lives. (Since small chainrings wear faster than large chainrings, it is probably a good idea to rotate inner chainrings.)

One of the biggest factor in chainring and sprocket wear is chain elongation. Chains elongate as they wear, and that accelerates wear of sprocket and chainring teeth. Replacing chains before they elongate too much can dramatically extend the life of the sprockets and chainrings, so frequent chain replacement can end up being economical.


Good info. I check the chain somewhat regularly by pulling it from the large chain ring to see how much play there is. Ill keep an eye on the tooth shape and look out for chainsuck and chain slippage as well.

[Mark McM]

Good info. I check the chain somewhat regularly by pulling it from the large chain ring to see how much play there is. Ill keep an eye on the tooth shape and look out for chainsuck and chain slippage as well.

The problem with the "pulling the chain away from the chainring" test is that it depends on many variables, many of which are not related to chainring wear. A worn chain will pull further away from the chainring than a new chain. Not all chainrings have the same shape teeth, so the same chain will pull different distances away from the chainring. This is one of those things that sound good on the surface, but don't pass muster when examined more closely.

[Mikej]

I recently purchased the Shimano chain checker tool to keep on top of this. Turns out even though my chain passed, I put a new one on anyway ( I love that new chain feel) Cassette slipped on 2 smallest cogs. Go figure-

[K3RRY]

I recently purchased the Shimano chain checker tool to keep on top of this. Turns out even though my chain passed, I put a new one on anyway ( I love that new chain feel) Cassette slipped on 2 smallest cogs. Go figure-

It slipped after your new chain? Maybe reindexing the rd will help if you haven’t tried it yet

[9tubes]

how are people assessing the wear/lifespan of their drivetrain components. specifically cassettes and chainrings. I have a crankset that i was thinking of pulling off one bike and putting on another but i dont want to bother if the chainrings are at or near the end of their usable lifespan. Are most people changing cranksets/chainrings after a specific amount of miles or is there another way of telling how worn the rings are? I have put roughly 7,000 dry miles on the crankset but it came on a used bike and i am not very good at keeping it clean. I mostly just ride till its noisy then squirt lube and then ride till its noisy again. I haven't experienced any chain slipping yet. I am basically just looking for tips on how to assess drivetrain wear. Thanks

With that method I'd guess that your rings and cassette need replacing after 7000 miles. Take the bike to a good mechanic for an evaluation.

Chains are cheap in a relative sense (I ride SRAM Red and the cassettes are really expensive) so I replace chains pretty often, like 1200-1500 miles, rather than spend on cassettes and chainrings.

[godfrey1112000]

With that method I'd guess that your rings and cassette need replacing after 7000 miles. Take the bike to a good mechanic for an evaluation.

Chains are cheap in a relative sense (I ride SRAM Red and the cassettes are really expensive) so I replace chains pretty often, like 1200-1500 miles, rather than spend on cassettes and chainrings.

Send me those chains, 3000 miles easy,

Just replaced a DA chain operating on DI2
5750 miles, wasn’t still shifting smoothly
Clean after every ride

[Mikej]

It slipped after your new chain? Maybe reindexing the rd will help if you haven’t tried it yet

I tried- everything-

[Dave]

Using a chain for too long is an invitation to chain skip, when a new chain is installed. I did that with a Campy chain that had 6000 miles of use, but little elongation. The rollers were severely worn and the side clearance twice that of a new chain.

Likewise, tossing chains prematurely is wasteful. Rather than toss them, but 3-4 in a rotation and use them much longer.

[Mark McM]

I recently purchased the Shimano chain checker tool to keep on top of this. Turns out even though my chain passed, I put a new one on anyway ( I love that new chain feel) Cassette slipped on 2 smallest cogs. Go figure-

Sprocket wear can be measured with a sprocket wear indicator tool, such as the Rohloff HG-Check. Unior also makes a similar sprocket wear indicator.


https://www.rohloff.de/fileadmin/_processed_/6/6/csm_hg_check_big_9ae9e29581.png


These tools can be used to estimate how much life remains in the sprockets, and whether they should be replaced when replacing a chain.

[K3RRY]

Sprocket wear can be measured with a sprocket wear indicator tool, such as the Rohloff HG-Check. Unior also makes a similar sprocket wear indicator.


https://www.rohloff.de/fileadmin/_processed_/6/6/csm_hg_check_big_9ae9e29581.png


These tools can be used to estimate how much life remains in the sprockets, and whether they should be replaced when replacing a chain.

Didn’t know about this tool. Thanks!

[Blue Jays]

Nice new chains are essentially expendable "cheap insurance" in my experience.
I prefer to replace every 1500-2000 miles to help preserve cranks and cassettes.

[El Chaba]

Sprocket wear can be measured with a sprocket wear indicator tool, such as the Rohloff HG-Check. Unior also makes a similar sprocket wear indicator.


https://www.rohloff.de/fileadmin/_processed_/6/6/csm_hg_check_big_9ae9e29581.png


These tools can be used to estimate how much life remains in the sprockets, and whether they should be replaced when replacing a chain.

I have one of these tools and it is a fiddly thing to use. It gives a pretty good idea about wear. In practice, I try to replace chains early in the wear cycle to prolong cassette cog and chainring life. It's flat-rolling around here, so I spend a lot of time using relatively few cogs 15-16-17. Even with replacing the chain early, those cogs are frequently worn (at least the 15-16) with roughly every third chain or so. It's almost as easy to just put on a new chain, put down the pressure in the small chainring on a short hill and see if anything skips.
Another observation about wear...With the proliferation of cog numbers on the rea and people using smaller chainrings, more riding time is spent in lower tooth count cogs in the back. In my experience, cog wear is an exponential function so you are WAY more likely to wear out a 15 or 16...Tooth counts lower than 15 are just not suited for extended hours of use. Combine this effect with thinner cogs/chainwheels, etc and the lifespan of wearable items in the drivetrain has really gotten pretty short as of late.

[Seramount]

Nice new chains are essentially expendable "cheap insurance" in my experience.
I prefer to replace every 1500-2000 miles to help preserve cranks and cassettes.

hmm, so you're replacing chains based on mileage and not wear...?

I use a steel ruler to measure and can typically get 8-10K miles from a $30 KMC.

have ~50K miles on DA7800 chainrings, shifting is still flawless.

[Mikej]

hmm, so you're replacing chains based on mileage and not wear...?

I use a steel ruler to measure and can typically get 8-10K miles from a $30 KMC.

have ~50K miles on DA7800 chainrings, shifting is still flawless.

Steel ruler measuring pin to pin? That will only give you side plate stretch, not pin and roller wear.

[bikinchris]

KMC makes a cog wear tool for 11 speed bikes.

It should be noted that pro race teams ride tens of thousands of miles per year and never wear out their very expensive cassettes. They replace their chains before they are worn out.

I use the Rohloff chain checker and replace 11 speed chains at .75 wear. 11 speed cogs are thinner and wear out easier.

[Dave]

Steel ruler measuring pin to pin? That will only give you side plate stretch, not pin and roller wear.

A 12 inch precision rule can be placed with one end on the edge of a pin. The pin at the other end will be completely covered, when new. As the chain wears, the covered pin will be exposed. When the exposure reaches nearly half the pin, you've reached .5% elongation.

Side plates don't stretch. The wear is between the pins and the bushing formed into the inner plates.

Using a single chain for many thousands of miles will nearly always cause enough sprocket wear to cause new-chain skip. It's false economy. Alternate the use of several chains and you'll never have new-chain skip.