hows it working out for ya? how often are you in the highest gear available? if the answer is "a lot" then you could switch to a 53x39 but if its "not a lot" then you're fine. I actually switched from a 25 to a 27 on my P2C because of the terrain I ride. I know its kind of immasculating to need an "easier" gear but living in PA there arent too many flat rides. I also like the ability to spin more instead of using more leg muscle to get uphill, it saves your legs for the run.

If it makes you feel any better, I use a triple :P

Long story short... if you spend a lot of time going 30+mph, you need a 53x39.

All in all, you are going to shift to a gear you can comfortably ride, and whether it is 53x15 or 50x12 (frontXrear) its the same effort. (I dont know if those 2 gears are equal, but its just an example)

The deal with a 'compact crank' which you have is that it is closer to a triple in front, BUT you dont lose much. You lose about 1mph over a 53x11 vs 50x11, and you end up gaining a few lower gears you didnt have.

I am a big guy who is strong on the bike, and if I could get a compact crank on the cheap (because i am on a budget) i would definitely ride one.

a 12x23 cassette is more like a 12x25, and therefore your gears are closer together.

I have compacts on both my bikes - wouldn't change for anything (with 11-23). "Both my bikes" I like how that sounds - it makes me so happy that I have 2 bikes now.

This is a great thread... I'm actually not super happy with my gearings, and I am thinking of going compact.

But, if I have DA cranks, couldn't I just switch out the rings, or do I have to get a whole new crank? Right now it's 53x39.... I actually like the 39, but it's the 53 that I'm not such a fan of... would I be a total freak for switching the 53 for a 50 and leaving the 39? Would that somehow give me too little differential between the two rings?

http://www.sheldonbrown.com/gears/

Use that calculator, and you can see how the changes will affect your ride

this has all been great info...thanks guys! exactly what i was hoping for...i learned some new stuff!

now, i need to go sit on someone's bike and see the difference...i suspect it's going to be in moving up to the 39, not moving up to the 53: the 53 sounds like it's all fun and puppies; the move up to the 39 makes hills seem a little more daunting (i have some in mind)

i'm going to check out the sheldon brown link too...i also have been wondering what the equivalent gearing to a 42x16 on my bike would be (i'm interested in getting a fixie for my commute and i'd like to feel that on some of the hills along the way)

I use 53x39 on two bikes. With my old 7-speed in the back, I'm rarely in too tall a gear, despite some rolling hills here in PA. On my newer 10-speed, I don't really use the lower cogs in back, so a compact might help. Or, even a 48 tooth single, since most of the tri's around here don't have huge hills. I put a 45T single on my commuter and really love it. It's simpler, lighter, easier to clean, and only a minor inconvenience on the few steeper hills I encounter. With one smaller cog in the back I'm also just as fast (spinning a little faster) on the downhills.

I've just bought a new bike (Cervelo Team). My previous bike had standard cranks - 53/39. During a service I'd had the cassette changed to a 12-27 because 1) I'm old, 2) I have a bad back and don't like to grind and 3) because some rides I do have nasty hills.

I've never regretted the decision to go 12/27 but there were still some hills that were killing me and I found I spent about 80% of my time in the small ring. I've never really run out the big gear because I can spin pretty quickly.

Based on these things, I went compact (50/34) and 12-27 for the Cervelo. My cranks are a couple of mm longer. I now find I spend most of my time in the big ring and when I do ramp up in speed I don't find I'm missing all that much top end (at 50/12 @ 100rpm I'm seeing low-mid fifty kms). It's unlikely I'll ever average close to that in a tri.

I also figured it was easier (and cheaper) to change a rear cassette than a crankset. So far I'm happy with the decision and I will just swap the cassette if I get a lot stronger. At the end of the day, I'd rather sacrifice a bit of top end speed for the ability to ride (rather than walk) up a tough hill.

cheers
/k

I'm pretty sure the smallest inner ring you can put on an FSA 130BCD crank is a 38-tooth, which is a bummer for me as a weakling on the hills who currently has a full-size FSA-SLK crankset.