Road Cycling - Moving from a Triple to a Double

currently, my component setup is a 105/ultegra 9-spd with a triple chainring (52/42/30).
i'd like to move to a double (52/39) ultegra setup. what components will i need to replace?

my instinct is that the front derailleur and 1 chainring would need to be replaced. but what
about the rear derailleur and bottom bracket. i've seen RDs advertised as being for "triples"
which implies that there is some difference in the RD depending on how many chainrings
one has.

also, if anyone has a rough estimate for how much this would all cost me that would be great?
parts? labor (if i don't attempt i myself)?

thanks,
-m

currently, my component setup is a 105/ultegra 9-spd with a triple chainring (52/42/30).
i'd like to move to a double (52/39) ultegra setup. what components will i need to replace?


i've got the same setup and looked into it myself. i was told new shifters, crankset (unless you just want to take off the little ring and add a bigger middle and big ring--most double big rings are 53, no?), both derailleurs (the rear is a long-cage on the triple--don't technically have to replace it, it'll just work better). i think with the shifters you can jerry-rig a bit to just take the third click out of the front. but i wound up deciding it was too expensive/troublesome, and am just saving for a new bike with a double already on it. i think how much you buy depends on how comfortable you are with rigging triple parts to work as double parts.

The differance in the rear derailuer is the length of the cage. The triple has a longer cage to take up the chain slack when you shift into the small chain ring. The double has a short cage. You can use the triple rear derailuer on either one.

The front derailuer has a different shaped cage. I am not sure how well it will work.

The bottom bracket is a different length, so it needs to be changed.

I think you need to change the shifter with 105. Ultegra works with both.

Both 105 and Ultegra shifters are compatible with both double and triple.

You'll need a new bottom bracket, middle chainring, and both derailleurs.

Take into account that you can probably sell your current stuff on Ebay and make the change in parts cost almost nothing.

my friend and i swapped parts... he really wanted a triple... and i didnt care what i had. :)

i have tiagra shifters and it works with double as well... 105 FD/RD...

The shops around here would probably charge $40-50.

thanks for the replies!
if my 105 shifters will work, then i'm tempted to make the change. my bb is in
need of replacement anyway.
if the 105 triple shifters wont work on the double, then i think that i will take that
as a sign to buy a new bike......make that an excuse to by a new bike.
-m

I'm not sure if this would work, but how about replacing your middle chainring from a 41 to a 39 (can the the chain climb up from a 39 to a 52?), and just don't use the 3rd ring...
BTW, why do you want to go to dbl?

i want to go to a double because the shifting would be better and the
tuning of the FD/RD would be easier. there is the weight savings, but that
is negligible.

partially it is a mental thing.....when i drop down to the 30 tooth chainring,
i find that my speed tends to drop. often i go faster climbing in the 42, but
it lacks the range in gearing that i need to climb.
-m

I'm not sure if this would work, but how about replacing your middle chainring from a 41 to a 39 (can the the chain climb up from a 39 to a 52?), and just don't use the 3rd ring...
BTW, why do you want to go to dbl?

Sounds like it might be a good time to upgrade to full Utegra - more bang for the buck - just a thought.

partially it is a mental thing.....when i drop down to the 30 tooth chainring,
i find that my speed tends to drop.This might be a dumb questions but have you tried a double shift when you drop into the 30-tooth ? That is, shift to the 30-tooth chainring and simultaneously shift to one or two smaller cogs in the back. There may be some overlap in the gearing depending on what rear cluster you have. I find this sometimes helps me on hills so I don't slow down when I make the big jump from the 42-tooth to the 30-tooth. Otherwise I find myself spinning too much.

why would you need a new fd for a triple? couldn't you just set the limits for two chainrings? the indexing is in the shifters and, anyway, you could set up the front shifting to give a middle position for those small-small gear combos...

ack, forgot about the bottom bracket. there are some seriously cheap year-old ultegra groups around, especially with the new DA on the market. i don't advocate spending money willy-nilly (or any other nilly, for that matter) but it might be worth it if you're going to replace 4 or 5 parts anyway.

why would you need a new fd for a triple? couldn't you just set the limits for two chainrings? the indexing is in the shifters and, anyway, you could set up the front shifting to give a middle position for those small-small gear combos...

i was hoping that this would be the case. if so, i might only have to replace my bottom
bracket, chainrings, and RD (although previous posts suggest that i could make my current
RD work). i don't know if the limit screw will come in far enough.
-m

You can do this many ways depending on how much you want to spend money and how much you want to fiddle with it.

I'm cheap, so my approach would be to leave it as it is and shift gears to maintain my cadence and speed. But if you've decided to change to a double, I'd unscrew the small chain ring, replace the old middle ring and put on a new front dérailleur. You don't have to replace the dérailleur, but double dérailleurs are different from triples in important ways for quickness and precision of shifting, so unless you like to fiddle, it would make sense to do it at the same time. If I had a bit of extra cash and I thought my old BB is wearing out, I would also replace it with a shorter one to improve chainline.

Changing the rear dérailleur is just for show and to loose a few grams. Changing the shifter is completely unnecessary. If there's no third gear to move to, the front dérailleur won't be able to make the extra shift.

Now if you've got money and you want to look cool, get it all replaced, or get Ultegra, or a new bike. In reality, a triple doesn't slow you down in any meaningful way.

i want to go to a double because the shifting would be better and the
tuning of the FD/RD would be easier.

The only thing that might make the shifting a teenie bit better would be the double (short cage) derailuer. And I really doubt that you could tell a differance. The tuning is the same.

if the 105 triple shifters wont work on the double, then i think that i will take that
as a sign to buy a new bike......make that an excuse to by a new bike.

Well, you don't really need to replace anything if you are willing to just readjust you FD so that it doesn't shift down to your granny. This essentially makes it a "double". My brother had this done to his triple. Not because he wanted a double, but because he kept accidently shifting down to granny and it drove him crazy, so he had the LBS reset the FD cable and limit screw so that it wouldn't move beyond the middle ring.

But I really think the problem is your shifter, you'll need to replace your shifters. Better go test ride some new bikes. ;)

New BB, Front Deraillier, crank (the width is smaller for the double), rear deraillier (small cage) and you may need to adjust you chain. You will NOT need to change your STI shifers (unless you want to).

That about covers it. If you want to get the smooth shifting and accurate indexing of the Ultegra you will have to bit the bullet. Anything else will be Jerry rigged and will have problems!!

Later...Bill