jnich

Lately have been giving attention to a couple of bikes - getting them in shape. Took my girlfriend's 199x Bridgestone in to get a good tuning as it has sat in a shed for 10 years and the first thing the mechanic said was the chain was worn out - sort of surprised me cause I know she does not ride much. Maybe she got it used....

And he showed me this on a Park tool chain wear measuring thingy. So now I am checking the chain on my 20 year old Cannondale and started wondering about the chain wear measuring procedure. Every description suggest using a 12 inch ruler - then it dawned on me I saw nothing about certain chains not being imperial but metric - are all chains built rivet to rivet 1/2 inch? What am I missing?
thanks

HillRider

All bicycle chains you will ever see are 1/2" link pitch so the wear 12" measurement applies to everything you need to check. The Park Tool chain measurement "thingy" is not the most accurate way to measure chain wear and the 12" ruler is considered the definitive method.

Your girlfriend's chain may not be worn out from use but may be rusted from the 10-years exposure you mentioned to the point it should be replaced. Try lubing it thoroughly and see if that helps.

As to metric chains, years ago Shimano introduces a 10 mm pitch chain and matching chainrings and cogs but it was a short lived product and you are very unlikely to come across one outside of a museum collection.

jnich

thank you - nice complete answer

habilis

Clean and lube before measuring a rusted chain. The rust was once metal that's gone now, and it can dramatically affect chain "stretch."

FastJake

If the chain is rusty, throw it away. Once chains get too rusty they become weak and will break, the moment you're standing on the pedals trying to put power down. Then you'll smash your face/knee/foot/etc into the bike or the ground. Ask me how I know.

dsbrantjr

If you decide to replace your chain I would suggest getting a KMC, SRAM, Wippermann or other chain which uses a master link for closing it. The Shimano "special joining pin" is good for one use only; you need to buy another one each time you need to open your chain. I find that if it is easy (and free) to remove your chain for cleaning, etc. you will do it more often.

DiabloScott

Yeah, I wish someone would invent a chain that only breaks when you're coasting... but no, they always let go when you're stomping on them, and that's not fun.

CliffordK

I've never broken a chain plate. It has always been a rivet popping out, and once a quick link just vanished.

Of course, I never ride really rusty chains, but I'm not convinced that rust would cause one to break unless it has been soaking in seawater for a decade.

To function, the chains have to bend, but I've broken a few loose for other people with WD-40

jnich

thank you all - the hain is not rusty just dry and I left the shop having agreed to get a new chain put on - not sure hat I will end up with - but will note al this

rmfnla

He did mention that it is his GF's bike and she doesn't ride much...

FastJake

Yep, it will. Schwinn Varsity from the early 1970s. Maybe 5 years ago I bought it for $3 and was giving it a test ride in front of my house when it let go. I had just oiled it and it felt fine, no stiff links or anything. Smashed my knee into the bars. Side plate broke. Never again.

habilis

Of course, rust (which should never happen in the first place but sometimes does) is a relative thing. On a newish chain, a small amount of rust may mean it still has enough metal to meet the ruler test. If it's so rusted that a side plate is eaten through, it probably won't pass the ruler test. Just sayin'. Replacement is always the safest option.

CycleryNorth81

One of the first thing I do when I get a used bike is change the chain. Modern chains are inexpensive with a master link included. It is a win win situation.