Is there a special way other than consulting the LBS to measure the wear of a chain? When do you guys exactly replace it?
A chain tool you mean? http://www.chainreactioncycles.com/dk/en/park-tool-chain-checkerr-cc-3-2/rp-prod5784 Other than that, I think its just visual.
Step 1 - fly to England or the US for you metric loving folks Step 2 - by a ruler, yard stick, or a measuring tape with those great English units, aka inches Step 3 - fly home Step 4 - measure the chain across say 10 links Step 5 - if you are 1/16" to 1/8" past the 10 inch mark, you may want to change your chain The obvious alternative to the above is to use your god awful metric ruler, tape measure, etc and measure 10 links.Ideally you'll be at 254mm, but if you are 2-3mm past that, you may want to follow step 5! Admittedly, I don't do that. If I did, I'd be replacing chains way too often. There's always the risk that if you let your chain wear too much you'll wear out the cogs and chainrings prematurely. I just do the $$$ trade and determined I could let my chain go 5000-8000 miles and replace the chain and cassette together. It actually costs less than replacing the chain more often. And look at https://cyclingtips.com/2016/09/how-to-check-for-chain-wear-2/
I use a eh... schuifmaat. On a new chain it is 146 mm, easy to check the stretch with this tool. I know it is arbitrary but any number of links will do. I guess the more links, the more accurate. At 147 mm I start thinking replacement. But it is easy to check quickly and more accurate then those fixed measure things.
