country joe said:
The gears are shimano 105 but i don't know the make of chain
What you need to do is buy the correct quick-link/power-link for your chain. That doesn't mean the same brand, just the same size. So an SRAM power-link for a nine-speed chain will work fine on a Shimano nine-speed chain. Shimano say that they don't recommend it but they're just covering themselves, it works fine.
Then you take one link out of your chain, basically you knock the pins out of both ends of one outer link. Any chain tool should do, if the chain is similar to MTB ones, but I don't know much about road bike chains.
Once the link is out you just replace it with the SRAM quick-link. That's it. One tip is to carry another quick-link and chain tool with you. That way if your chain snaps you can pop the link out and be running again in minutes, I've bailed out a mate with my quick-link and saved us a long walk.
Another tip is to use short length of coat hanger wire bent into a hook at each end to hold the chain together and give you a bit of slack when you take the link out and fit the quick-link. You can also use this to help re-fit the chain after removing it for cleaning. I don't bother, I've done it so often I've got the knack of doing it with my fingers.
