channelz28

i have an 80's steel frame road bike with shimano golden arrow shifters and derailleurs. im going to swap out the double crankset for a triple for the sake of loaded touring. will i need to switch out the front derailleur or will it work? how about the shifter?
thanks.

cny-bikeman

Difficult to get a derailleur designed for two chainrings to work well on three. With friction shift you will get better results even with a medium level triple derailleur than with that double, and at a very reasonable cost. No idea if the levers have enough throw to cover 3 rings, perhaps someone else does, though.

bobotech

Doubtful on using a double for a triple chain ring. Mind you, people do it but it won't be smooth. A triple derailleur has extra bends in the cage that compensate for the 3rd ring. A double is much simpler and has smooth sides since it only needs to move the chain from low to high to low, it doesn't have the extra bends/channels that help move the chain to the 3 different positions.

You will most likely have to use a friction shifter for it to work at all.

cycle_maven

With a friction shifter, you'll be fine. I've done this many times, and a double shifts a triple crank just fine. Just adjust the limit screws and pay some attention to chainline when selecting a crank. Maybe even better than a "triple" derailleur- but you'll have to trim it more often while in the small chainring to keep it from rattling.

The reason for the crazy-looking cage design of the triple derailleur is so that the cage can be narrower when the chain is on the outer ring and wider for the chain on the inner ring. The main reason for this is index shifting- one size cage wouldn't work with three hugely different chainrings; if the cage were narrow enough to keep the chain from throwing off the big ring when shifting up, then it would be so narrow that the chain would rattle in the granny gear on most of the back cog.

Friction shifting doesn't have this problem- you can adjust the derailleur to any position relative to the small chainring to prevent rattling. Look at a triple derailleur from the friction shifting days, and the only difference from a double is a slightly longer and beefier cage.

brooklyn_bike

+1 my friends and i have done this many times for long tours no problem.

FBinNY 

Even with friction shifting the answer may not be yes. Most doubles have cages designed around chainrings no smaller than 36t. If you're using something like a 26 or 28t granny, the cage won't reach low enough to clear the chain. So odds are that you'll need a new FD.

The good news is that many index shift levers sold as doubles are actually triples, with the granny position ignored, so you might save there as long as you get the correct compatible (same pull ratio) FD

With index,

cny-bikeman

Exactly right. The OP can always try out the current derailleur first of course, but the cost of a triple is very modest.

channelz28

thanks. they are friction shifters, i was assuming that the shifter would probably work.

i dont know much about front derailleurs, this is the first time i have ever looked at them. i will take a close look at the differences between doubles and triples. if it will work, im sure i can adjust the screws to get it to work as well as can be expected. im used to trimming even with the double, so thats not a problem. im patient. thanks for the responses.

also, how much is a "modest cost?" is this looking at used ones on ebay?

cny-bikeman

eBay does not necessarily mean used. I think $25 and under is modest cost, lots of those even new on ebay.