hockey

I put 50-34 compacts on my Trek 5200 and the Wife's carbon TCR 2. I have two cassettes, 12-25 and 11-23 and the wife uses a 12-27. She prefers the simplicity of the setup and yet she can spin up the steepest hills. Both work well with the standard ultegra front derailleurs, although they must be adjusted. My touring bike is a triple and it shifts well, but I must admit, if I thought I could get away with a compact double I would. I see no reason to diss this setup. Know yourself, your strengths and weaknesses, the terrain you ride and adjust gear inches as needed. A knowledgeable rider is a better rider.
Hockey

The Weak Link

Hmm. Had a bad case of chain drop today. Shoulda gone with the compact double......

Retro Grouch 

Agreed.

I think that compact crank users sometimes overlook the flat-road gear question. I think that's a serious mistake.

Whatever gear you prefer to use on a flat road with no wind, you'd like for it to fall right in the middle of the cassette. That way you have a couple of "trim" gears in either direction before you have to shift the front chainrings. If your favorite flat road gear falls close to the point where you have to make a chainring shift, the frequent shifting coupled with the associated rear shift that the compact double makes necessary will drive you crazy.

That said, I really like the compact double on my road bike. In my case I switched from a 53/39 double. I lost a couple of fast gears that I never used and gained a couple of hill climb gears that I needed. In most cases I'm able to do all of my flat road riding in the big ring so I generally only use the small ring for hill climbing.

rideon7

Great insight. Now must take a closer look at the gears I ride in most often and calculate from there using the SheldonBrown site (whose URL I don't have at hand right now).

Tom Bombadil

I could probably go with a compact double, but it would have to be something like a 44/32 on the front with an 11-34 cassette. I think I'd be okay with that setup.

maddmaxx 

As far as I know, you cannot do 44/32 on a compact double. I'm pretty sure that it puts gear teath in proximity with chainring bolts. I could be wrong but I believe that 46/34 is the best there is.

for a 44/32 keep the MTB gearset and remove the granny.

hunyak

I just got a compact 50/34 - 12/25 on my new bike. My old rig had a 53/39 - 12/23.
The compact gives me a little lower gearing which helps in the hills. On the flats I do less cross chain shifting now. As Retro Grouch says, it puts me more in the middle of the cassette on the flats. I love the compact.

jppe

I have a 53/39 and a 50/34. I converted a 52/42/30 triple to the 50/34 compact crank and have been very, very pleased with it. I'm not a racer so I don't know if I can help you much on pros and cons of the two setups though. I do find the compact easier to keep the front derailluer adjusted for smooth shifting-however both shifted fine when both were tuned properly.

I find I spend a lot more time in the 50 than the 34, especially riding in groups. It's not often that I spin out on the top end using a 12/27 cassette, and find I can climb most stuff using the 34/27. I have converted my RD to a XT so I can run a 11-32 rear cassette for the really steep hills. That has really come in handy lately for me too. I believe that provides a little easier gear than even the 30/27 so in my opinion I have the best of all options. The only trick is to do the mountain bike rear setup you have to run 9 speed and not 10. You can run a 12/27 in a 10 speed though so unless you really wanted the easier gears as I did the 10 speed will work fine. If I were racing I'd like to have the 10 speed for the tighter gear ranges.

If you choose a compact I'd highly recommend the Shimano R700 over other models.

SteveE

Yes. Lost one gear at the low end. Gained one gear at the high end (went to 50/34 x 11/23 from 52/42/30 x 12/26)

BluesDawg

I'm guessing you lost more than one gear on the low end going from 31 gear inches to 40 for a lowest gear, unless your 2nd largest rear cog on the 12/26 was a 20.

ftsoft

I switched to a compact last year (50/34) . I love it! I used it on the Hilly Hundred last year with a 25 on the back and just cruised up 20% grades. I decided to do it because I practically fell over on Oakville Grade out of Napa the year before in a 39/26 and I needed to replace all the parts anyway. I normally run an 11/23 and I have no trouble staying with fast group rides.

Frank

SSP

In Wisconsin!!?? Good thing you don't live someplace hilly, like say, Nebraska.

SteveE

Yeah, I meant to say was I went from a low gear of 30 x 23 to 34 x 23 and a high gear to 52 x 12 to 50 x 11.

BSLeVan

My two bikes with double chainrings both have a 50-43 up front and 12-27 in the rear. The third has three chainrings. For most rides the compact double does me fine. For some reason, I feel like I already responded to this post... I think I need to get me and the laptop in out of the heat! Maybe I'll follow my dog's lead and take a nap.

Trsnrtr

I agree, and a triple allows one to use a closer range cassette. A compact requires a big cassette which means big cog jumps and/or lots of front ring shifting.

BluesDawg

Different setups for different bikes and different situations.

I have triples on some of my bikes, doubles on others. I'm thinking seriously of setting one up as a 1x8 to avoid front shifting altogether.