Chain - To Change or Not to Change...

[Pedal Wench]

If it shows any sign of stretch, replace the chain. If you wait til there's a problem, there will likely be lots of them, e.g., you may need to replace the cassette, chainrings, etc., as you mentioned. A chain is, what, twenty bucks? The whole system wears together. Changing the chain frequently keeps all your parts happy much longer and saves you money in the long run.

Telling you that it is likely you will need to replace the cassette when you replace the chain is not necessarily true. 3K miles is a good time to do it and chances are you will not have other issues. If you change it and do have other wear issues, you will know right away, and can replace the necessary rear cogs in plenty of time.

What she said!

[ny biker]

I just had this chat with the LBS wrench on Saturday. That Park took almost drops in at .75 on my chain. He said technically I could wait to replace the chain but if I did it at .75 I would be able to only replace the chain rather than having to replace the cassette, too.

[aicabsolut]

you can have the cassette measured... i forget what my friend used.. it looked like a chain whip... but anyway, you can see if the cogs will be too worn to accept the new chain well.

it is probably better to change it now, particularly if you don't want to change the cassette at the same time.

[tantrumbean]

Hmm...thanks for all your input, looks like the overall consensus is that I could get away with just changing the chain....

Rang another bike shop up today, just for a 2nd opinion, who advised I might get away with it, but would then look at having to change the cassette a year or so down the line anyway, so, overall, they again recommended doing both.

Difference was, the price quoted was less than half of shop number 1, so I might go for it... My friend is taking her bike in tomorrow to get it sorted (same issues), so we see how she fares once they have seen the bikes in the flesh. I let her be the guinea pig - if I'm happy with what they do to hers, mine can follow next week!

[woohoo]

Definitely worth changing both if you get a decent quote from your 2nd shop. I left my bike with a stretched chain (ignorance was bliss) a couple of years ago and it very nearly caused an accident. My gears slipped just as I was overtaking a stopped bus - my foot slipped off the pedals, which removed a chunk of calf muscle on the way, and the major wobble that followed ended with me in the middle of the lane just as the bus pulled out without looking. I was lucky enough that it was quiet so I kept it upright and didn't get hit by anything, but I felt pretty silly when I found out that it could've been avoided by changing a few £'s worth of parts out earlier!

[tantrumbean]

After another closer look, a lot of the sprockets had developed that sideways wave profile, so it was time for it to go.

Bike went into shop number 2, came out 24hrs later, serviced, with new cassette and chain and a couple of new cables for the grand total of £50 - which is basically the price of the parts! How good is that?

[PscyclePath]

A cheap way to check your chain is to get a ruler, and lay it with the zero mark centered on one of the pins in your chain. The 12" mark should also be centered on a pin if the chain is new, or in good condition. If the 12" mark is 1/8" or more past the center mark, then it's time for a new chain -- Now. If you keep an eye on your chain wear, you can avoid replacing cassette cogs and chainrings for some time. A worn, stretched chain will cause your cogs to wear unevenly, and if you leave the worn chain on there long enough for that to happen, a new chain won't fit well on your worn cogs. Sheldon Brown has some good examples (and better advice) on this at http://sheldonbrown.com/chains.html .

The Park chain checker is a good little gauge, but I tend to use the ruler method (my spoke length ruler does the job well) to keep an eye on things down there...

Tom