therhodeo

Is there any time that you don't need to change both or is it always good practice? Can leaving a worn out chain on for "trainer season" damage my crankset?

datlas 

General consensus is a cassette should last 3-4 chains. Depends on what you are using, but if 10 speed you should probably get somewhere from 3-5000 miles from a chain.

Using a over-worn chain may wear your cassette prematurely (and mess up your shifting), it's a lot harder to wear out your crank's chainrings from it (although I am sure it can be done if you try hard enough!)

YMMV.

Daytrip

You should be able to get 3 chain changes out of a cassette if you don't let the chains wear down too much. Check them with a ruler. Worn out chains will eventually damage both your crankset and cassette. If you put a new chain on and it skips, then the cassette needs replaced, too.

OTOH, if you've already damaged your cassette and crankset, run the drivetrain until it quits working satisfactorily and replace all three at once. A crank is harder to damage than a cassette, however (I think).

Jed19

The person who comes up with a surefire and simple way to measure cassette wear ala the go or no go chain wear measures is gonna make a lot of dough, provided he/she can get patents.

therhodeo

9 speed chain. I should have somewhere between 2000 and 3000 on it. Its been checked with a gauge and is definitely stretched to the point of needing changed.

Daytrip

If it works like the Park Chain Wear Indicator (doesn't), then the cassette manufacturers and LBS should make plenty of dough as well--just like they do on chains. Of course, my LBS doesn't even need some phony tool to sell you parts you don't need--they recommend replacing chain and cassette at 2K miles--whether they "need it" or not.

Seattle Forrest

I had to change the cassette with the chain on my CX bike after several thousand miles, but the cranks are still going strong. So my bit of experience says you're right.

DaveSSS 

There is a tool available for measuring cassette wear, but IMO, it's not worth the expense or the trouble to use. Just put a new chain on. If you don't get new-chain skip when pedaling under a heavy load, then the cassette is fine. A worn cog on a cassette will shift fine, but it won't drive the bike - the chain will skip over the teeth. Sometimes, only one cog will have enough wear to skip. A little known fact is that a chain with only a few hundred miles of use can be mated to that worn cog and it won't skip. If you have a winter bike, that worn cassette is the perfect place for it. Just don't use a new chain with it.

https://www.cambriabike.com/shopexd.a...m=041700001200

A common misconception is that moderately worn cogs will wear out the chain faster. Not true at all. A stretched chain (1%) or more will accelerate the wear on the cogs by concentrating the load only a few teeth. A new chain on worn cogs will ride at a lower point on the teeth and work just as it does with a new cassette.

The other form of chain skip occurs when a chain is used so long that the elongation approaches 2%. If you do that, then eventualy the chain will also skip over the teeth and not drive the bike. It's entirely different than new-chain skip.

rooftest

no /thread.

wfrogge

3 to 4 chains per cassette huh? Am I the only one thats used the same cassettes for YEARS with no shifting issues?

DaveSSS 

Time means nothing, it's the combination of mileage and riding conditions that matter. I you have several bikes or several wheels that split your mileage up between several cassettes, they should last for quite a few years. I expect 12-18,000 miles from a cassette. If I have 3 cassettes in use, that's 36-54,000 miles. I typically get 5,000 miles from a Campy 10 chain and I've pushed some to 6,000. With 11 speed, I'd be disappointed if I didn't get about 4,000.

Accordion

2400 miles on first chain. Stupid. Was really worn. 1700 miles on second chain and promptly changed. 1300 miles on current chain with some wear but not enough to neccessitate a change.

Same cassette. I figure when I've got 6500 miles I'll change it.

wfrogge

Ok that sounds more like what I am seeing..... I apparently go through chains faster than you guys (up to 3 a year) though.

DaveSSS 

Chain checking tools greatly exaggerate the wear and lead people into the changing chaind more often than needed. True elongation is properly measured with a 12" (or longer) precision rule. A chain that shows 1% elongation with a chain checker may only have .5% or 1/16" per foot, if measured with a ruler.

San Rensho 

Nope, I replace the (cheap) chain a little before it gets to the wear limit and I have easily put over 15k miles on one cassette and it still shifts perfectly fine.

DaveSSS 

I'd be disappointed if I didn't get twice that mileage from the chains and cassette. How are you measuring the wear? Chain checkers are not accurate. There is no point in replacing a cassette if a new chain does not cause skipping with one or more cogs.

DaveSSS 

How many chains were used for 15,000 miles? I'd use 3-4. At some point, changing chains too frequently cost more than using fewer chains and tossing the cassette.

wfrogge

I dont replace until I start getting major skipping or in the case of my last chain.... it starts comming apart. Im still only good for 3-5 months tops with an Ultegra chain

Accordion

Dave -

My CAAD9 was purchased new on April 1st of this year. First real roadbike for me in 20 years.

I didn't even think about the chain until it was skipping all the time. I'd shift down and it would skip one or two gears. Then I started dropping my chain when I'd go from the large chainring to the small chainring in the front. I couldn't figure it out and asked a buddy. He said "CHANGE YOUR CHAIN!!!!". I replaced it with an Ultegra 10-speed chain from Performance on sale at 10% off. I think it was $35 or something like that. Immediate improvement. No more skipping and no more chain dropping.

I do use the Park Chain Tool (even after reading that epic 10-page thread here on proper chain measurement!) but only to verify that the chain is elongated. I changed the second one as soon as it started skipping and showed wear.

I ride hills a lot and push really hard. I think if I tooled around on the flat bike path at 12mph I wouldn't have any issues. I do know that my wife's hybrid bike probably has 3000 miles on the chain over the past 5 years and it's still fine. Cheap components and chain, too.

DaveSSS 

A chain should never skip while it's in use unless worn severely, to about 2% elongation. If that every occurs, a second or third new chain would never work with the cassette. Chain skip from excessive elongation would ruin several of the cogs. Once again, months mean nothing, it mileage that matters.

Chain skip means that the chain stay on the intended cog, but fails to drive the bike when it skips over the teeth. That only happens with a new chain on worn cogs or with the severely worn chain that also ruins the cogs.

Jed19

I have been using chain checkers for a long time. Are you saying I should toss my Park Tool chain checker and rely exclusively on a metal ruler for chain-wear checking?

Accordion

I now understand the distinction. I'm not talking about chain skip then. I'm talking about shifting up and rather than going one cog it jumps three. I know you're going to say that's a function of cable stretch and der readjustment but this happened even after my first tuneup after initial break-in. The front chainring was REALLY problematic. I'd shift and would drop the chain literally 50% of the time. Maybe even more often. All this was cleared up with a new chain.

DaveSSS 

What you have described is NOT chain skip. Chain skip means that the chain remains on the intended cog, but won't drive the bike because it skips over the top of the teeth. If the chain shifts to some other cog, that's probably due to a misadjusted RD. Chain can also suffer from extreme side wear, particularly if the rider cross chains a lot. That still won't cause chain skip, but it might result in the chain drop. The other problem that you describe is usually called ghost shifting.

If a chain skips due to having a true elongation of 2% (measured with a rule), then it most certainly would wear the cogs so they would never mesh with a new chain. If you installed a new chain on the same cassette, and the "skipping" disappeared, it was not true chain skip.

I've used a Campy chain for 6,000 miles and wore it so badly the roller spacing increased from .200 inch to .240 and the side clearance nearly doubled, but it still shifted fine and never skipped. It did wear out one cog enough to skip with a new chain.

7bmwm3gtr

My friend has his stock chain and cassette on his bike still. 10-speed 105 and he has around 10,000 miles on it. He says he doesn't notice anything different about his shifting or anything.

Of course, I'm paranoid so I went ahead and changed my chain at 5400 miles which was on Sunday, but I didn't change my cassette. My 14-25 has about 2.5k miles since I got it in the summer. Prior to that, I had a 12-26 and another 12-26 which is on my trainer wheel. But I only got new cassettes because I got a new wheelset, and because of the Junior gearing requirements.

StanSeven

There are also people that barely get 1500 miles from a chain. A lot depends upon rider weight, how hard they train, their cadence, the amount of hills and climbing, and how often they clean and lube.