Posted over in road, but realized this might be a better place. I need to replace my left 105 brifter. Says it's a 5600 under the hood cover. What is the difference between a 5600 and a 5601? I see them both for sale on ebay and such, can't find an explanation.

Per bike.shimano.com

ST-5600: can be set up with double or triple cranksets

ST-5601: double cranksets only

See https://techdocs.shimano.com/media/te...9830686067.pdf

shimano 105 sti..jpg

Thanks. But I don't see how you get that from that chart. It shows the 5601 for front double, 5603 for front triple, and 5600 for rear.

You are right, the chart isn't explicit, but desertdork is correct -- you need to read through all of the technical documents to confirm this. There is some confusion on this issue because previously, the 105 and Ultegra models were all double-triple compatible, but Shimano made a mid-course correction on the 10-speed series and introduced double/triple-specific models.

Sorry, I meant to post the chart for the 5600 levers, too. Like deperreno stated, you can find each lever's application in Shimano's documents. If you run a double crank, you'll want a 5600 or 5601 lever; a triple crankset requires a 5600 or 5603 lever.

How come you're replacing the shifter? Tried degreasing it?

There is a small metal spring loaded ratchet arm on top just under the cover that is in 2 pieces.