|How often does one need to replace the chain?||hammer_cycle|
May 20, 2002 5:17 PM
|Someone who works for a shop told me that typically one needs to replace the chain on a bike around 2k miles to avoid excessive wear on the cassette. Is that correct? I have 2 bikes with easily over 5k miles on each of the Dura Ace chains. They *seem* to be working flawlessly and I notice no difference between when they were new and now. I also swap out cassettes/wheels often if that mitigates any potential problems.
Any input is greatly appreciated! Thanks.
May 20, 2002 5:59 PM
|At $40-50 for a cassette and $20 for a chain, it's hard for me to see the math that you are "saving" your cassette by replacing the chain 3X more often than when it is worn out. Standard for a worn out chain is 0.5% elongation, which is 1/16" in 12" of original chain length. If your chain is elongated, it will chew the cogs faster and shifting will deteriorate. My experience is to replace chain and cogs simultaneously, but that gets complicated with multiple wheels in rotation.|
May 20, 2002 7:10 PM
|Say you have two new chains, would it make sense to alternate them (Clean one and ride with the other etc back and forth)or just use one until it wears out then use the next one? What makes more sense???|
|call me crazy, but...||dustin73|
May 20, 2002 9:46 PM
|i don't think that would work. either way you're working each chain the same amount.
say you had 2 beers, one in the L hand, one in the R. whether or not you drank the L first, then the R, or drank them together, you're still taking the same amount of sips. and the last will always taste like poo.
|When chains cost $5 and freewheels cost $20||dzrider|
May 21, 2002 5:05 AM
|I replaced chains to save freewheels, only changing the freewheels when the new chain jumped around. Sometimes, especially if it was just one cog, I'd change the offending cog. Now, your arithmetic looks better, but I use the chains considerably longer than 0.5% elongation since I'm not concerned with preserving the cassette. I don't notice much degradation in the shifting as stuff gets older and, surprisingly to me, the chainrings still last quite a bit longer than the cassettes.|
|When chains cost $5 and freewheels cost $20||hammer_cycle|
May 21, 2002 5:11 AM
|If only cassettes and chains were that cheap! A shimano 9spd chain runs around $23 and a DA cassette runs around $70.
I'll measure the chains this week at the shop and check for stretch.
|I have a Park chain measuring tool||speedisgood|
May 21, 2002 6:18 AM
|One of the best investments I've made (other than that pesky Enron stock.) It actually measures % elongation. My new chains are usually .25-.5%. I replace whenever it reads around 1%. That's what Park recommends (and I think most chain manufacturers.) This way, I don't need to keep track of miles/cassette (I run 4 different sets of cassettes and they see different wheels a lot.)
Also, wear is affected by dirt on the chain, how often you lube it, how often you ride in the rain, etc. You can't account for those variables very accurately (well maybe Kerry can) so I figure measure elongation directly and you'll be ok. I've done it this way for around 3 years and have replaced chains only, no cassettes needed replacing in that time.
May 21, 2002 8:16 AM
|I've got a Park tool myself, but I'm not impressed with it's accuracy. As you've noted, new chains may check as partially worn.
I've had better luck using a 12" machinist's scale or a carpenter's measuring tape. With the measuring tape you can measure over 4 feet in length, which improves accuracy. Measuring 1/4" in 4 feet is a lot easier than measuring 1/16" in one foot.
I change chains annually (up to 4000 miles) even theough the stretch may only be 1/16" in four feet, or 1/4 the acceptable limit. Bicycle chains also suffer from sideplate wear, which can deteriorate shifting performance long before they reach the maximum stretch.
|mech wrong my new chain and old casette werent working together||ishmael|
May 21, 2002 11:22 AM
|You say you switch the chain every year or when it's only 1/16 an inch streached. Mine total drive train is the same age and my chain wasnt even that streached(its hard to measure as you say) and when i put the new chain on it wouldnt work with the casette.|| |