QUESTION: It’s time to replace my chain. My Ultegra cassette has 10,000 miles on it, so should I replace it, too? Of course, the shop says to put on a new cassette. They say worn cogs will wear out a new chain quickly. The teeth have no visible wear, but I want the drivetrain to function as efficiently as possible. What to do? — Bill M.
RBR REPLIES: If you’d been changing your chain each time it started to show stretch, then your cassette would probably still work fine with a new chain.
But it sounds like you’ve been using your chain for a ton of miles. If so, it’s probably badly stretched and the cassette will have to go into the wind chime bin. Worn cogs don’t always look worn, so here’s how to tell.
Put on a new chain with the current cassette and then very carefully take a test ride.
Do it in a place where you don’t have to worry about traffic or plate-glass windows. Stay seated and pedal hard in each cog from the small chainring, with the brakes dragging for extra resistance. Be ready for skipping when you get to the smaller cogs because they’re usually the most worn.
If the chain jumps and slips on any cogs, replace the cassette. Then replace the chain more often to give the new cogs maximum life.
Rohloff and Park Tool both make a cog-wear checking device, but the test ride will let you know what’s up in real-world conditions.
Remember, stay seated and be careful or you could also get a chance to check your helmet’s MIPS rating.
Putting on a new chain whenever there is any measurable stretch is cheap drivetrain insurance and makes for a happy cassette.
I ride Campagnolo (3 bikes, 9, 10, and 12-speed). A new 12-speed cog set costs at least $300. I can get a Campy Record chain for less than $60. A Park chain checker is less than $15. Clean and check the chain frequently, and chances are you will never need to replace the cogs!
agree. I check my chain fairly often as I ride sometimes 200 mi/wk. My cassette lasts a long time.
It sounds like you don’t trust your LBS. Second opinions are a good idea, but if you don’t trust them it is time to find a new LBS.
The advice of the LBS is not actually bad. 10,000 k on chain is way too long and as there is no indication that the chain has been changed before they are probably both worn even if there does not appear to be visible wear. In most cases the LBS reccomends changing both because they don’t know the usage history. There is nothing worse than putting on a new chain and having to go back because the cassette is worn too. Plus it is dangerous. Having said that I check chain wear probably once a month and try to change before the wear gets too bad (0.75 to 1.0 is worn) and find I can get to three chains before the cassette is done too.
I check my chain with a tool and replace it when needed. It has saved my cassettes.
I use a Park cc-2 chain checker. I use Rock-n-Roll Extrame lube, keep my Shimano Ultegra chains fairly clean and they are usually ready to be replaced at the 3,000-3,500 miles or so. A heavier cyclist and/or a racer wannabe who sprints a lot probably won’t get that many miles out of a chain. I have three road bikes, average around 5,000 miles each year and (knock wood) have never had to replace a cassette.
A ruler is a more reliable chain checker than most of the specific tools on the market. And while a worn (elongated) chain will indeed wear a cassette faster, the cassette will still wear even with frequently replaced chains. It’s a simple fact of how metal-on-metal wear works. If you are wearing out the smallest cogs on your cassette, consider riding in the big rind and with the chain on bigger cogs in the back. Same gear ratio but way more cassette and chain ring teeth engaged by the chain so all three elements will wear more slowly. Finally, if the “new chain skips” test requires significant force, you might find that a couple of hundred miles with a new chain will eliminate the chain skip problem and allow you to get a lot more miles out of the cassette.
The rule-of-thumb recommendation to replace a chain after X number of miles is poor advice, IMHO. Get an accurate chain checker. The Park CC-4 is more accurate than the Park CC-2. (The cc-2 will indicate more wear than what is actually present, because of the way it pushes the rollers in opposite directions. The CC-4 pushes the rollers in the same direction, so the roller-wear dimension is not doubled, meaning you’ll have more wear left in your chain than if you used the CC-2).
Regardless of which type of chain checker you use, measuring the actual stretch gives you a more precise evaluation of what’s left in the chain. Chain wear varies considerably among cyclists due to a number of variables (the kind of weather you ride in, how you ride, how well the chain is maintained, etc.). If you go just by mileage alone, you can be waiting too long to replace chains, or be replacing them more often than needed.
As mentioned by someone above, all cassettes will wear out regardless of how well they’re maintained. I have found, over my 30 years of cycling, that I can expect to get (with good chain maintenance), about 5,000 or more miles/chain (riding in SE Iowa), and usually 15,000 mi on a cassette (a lot more on chainrings). I don’t change the cassette until there’s skipping on the cogs, or measuring cog wear with a tool shows a lot of wear. When I do put on a new cassette, I like to start with a new chain, but if my current one has low mileage, I’ll use that one.
I certainly don’t follow your LBS’s advice. I clean and measure my chains regularly and replace them when they are 0.5% worn, which for me is around 6,000 kms. I replace the cassette if the new chain skips cassette teeth, which can be after as much as 20,000 kms. Performance will vary with the quality of chainsm cassettes, lubrication and type of riding, of course. I buy expensive cassettes, but if you don’t, and you don’t care to pay that much attention yourself, replacing the cassette when you replace a chain might suit you.