frothyllama

what speed is the shimano 105????

JiveTurkey

From: https://sheldonbrown.com/k7.html#roadmtb

Note, also that rear derailers do not care how many gears you have. You do not need to have a so-called "10-speed" derailer to use a 10-speed cassette. This is true of all Shimano derailers with the exception of 1996 and earlier (pre-9-speed) Dura-Ace units.

Panthers007

What does matter is your shifter. A friction-shifter setup will shift through all ranges. But an indexed-shifter has to match the number of gears you have in the rear, and how many chainrings you are running up front. So if you have a 9spd cassette in the back - you need a 9spd shifter. 3 chainrings? You need a 3spd shifter for the crankset.

operator

At least 5 million.

FFS, it even says 5600gs in the image name. Please.

Lawrence08648

If anything, that looks like a long cage derailleur which means it will work on a double or a triple.

JiveTurkey

Generally, yes. But when you say 18-speed, do you mean 2x9 or 3x6?

Also, what's the range of gears (cogs) in the back? That rear derailleur is rated for up to 27-teeth, but that may be able to be exceeded somewhat.

Panthers007

You can bet on it. A "medium" RD is more like a long-cage. The "long-cage" you see - rarely - are really long and designed for all-out mountain-bikers. Mediums will handle most situations. And Shimano shoots itself in the foot by saying 27T is maximum. Nonsense. I run Ultegra RD's and have seen them easily take on a 30 - 32T in the rear. Apparently the max-size is referring to the largest size in that particular gruppo.

Shimano discourages customers in this way, and the max-size they list should be ignored. I just installed a FD (Shimano) that was max at 44-48T (FD-M961). I put this on to work with an Ultegra triple - 30-39-52. It has plenty of room to spare and shifts flawlessly.

Wake up, Shimano!

BearSquirrel

If you're going to take that tact, the precise answer is uncountably infinite (the cardinality of the real number set).