I am registered for Escape from Alcatraz, and am looking for mechanical assistance for my climbing. I was advised to go compact and 12/27 cassette. Can I get the same compact benefit by changing out the chainrings to 50/34? I will be going back to the 53/39 double and 12/23 cassette after the race.
What do you guys think?
On a regular crankset you can’t go below a 38-tooth small chainring.
My wife runs a 50/38 on her road bike. That’s as small as you can go with a 130mm bolt pattern. I’ve tried to talk her into 50/34 110mm compact cranks like I’m running but she doesn’t want to give up her beloved DA cranks.
That was my original thought, but when I was recommended the compact I was left with some doubt. I don’t have enough experience to know how much of a difference there is between the 53/39 with a 12/27 vs a 50/34 with a 12/27.
I guess i have to go 12/27 either way, so I may as well swap out the cassettes first and see how that feels.
Read this. I’m using a 50/34 with 12-25 cassette. Way better up steep hills than was 53/39. I’d never go back.
51/38 or 52/38 with a 12-28 would get you really close.
except that you lose the middle gearing.
i ran a 12-27 on a 53/39 at IMC 2 years ago…ran an 11-23 on a 50/34 last year, and it was much much better, and the hill climbing was better.
I agree that the compact crankset is a wonderful thing. I have a 50/34 with 11-23 or 12-25 depending on the course. I have been thinking of going to 52/36 on a 110 bcm set though. Trying to get the best of both worlds. 34 is really small.
For many people a 50/36 compact is probably just about right. I keep my 34 only because of this one mutha of a hill we have in our area. It it wasn’t for that I’d probably go 50/36.
Is the “mutha” hill the airport hill Cerveloguy? I still have my 55-42 with 11-21 cassette on my bike for riding up that nasty climb 
I’ve been contemplating dropping the gearing on my Wheeler and trying to up my cadence to see how it works for me.
Yup.But don’t forget you’re on 650’s on the Wheeler. Plus I’m old and weak and need every advantage I can get to try to keep with the youngun’s on the hill rides.
I actually find that climb a lot easier on my road bike with a 53-39 setup and 12-25 on the back even though it has got big wheels.
It’s the geometry. Tri bikes aren’t designed for hill climbing otherwise the TDF teams would be using them in the mountain stages.
I used to use the same gearing as you on the hill rides before discovering the compacts. The stronger riders like you and some of the other guys in the group don’t need them but they are a godsend for us older guys since they keep us a little closer to you guys on the uphills. Also being skinny also helps.
I agree. I think a 50/36 is a better choice. It preserves the same difference in teeth as the 53/39. I wouldn’t want to go with a bigger difference- that just means more shifting in the rear when you shift the front (i.e. shifting from big to small ring, you’d have to upshift several times in the rear or you’ll spin out like crazy). There is also potential for chain rubbing issues with the smaller rings. I have heard from several people that they get rubbing on the big ring when they’re in the small ring and smaller (not smallest) cogs. If I ever decide to try a compact it will be a 36/50. Now I just have to wait until someone makes it in a 180mm crank…
" Now I just have to wait until someone makes it in a 180mm crank… "
How tall are you Greg? NBA size.
I just noticed that the Truvativ Rouleur Carbon compact is available in 177.5 and the Rouleur (non-carbon) is available in 180.
actually…the don’t use them b/c they don’t fit the UCI regulations - for both geometry and aerobars 
i run compacts on my race bike and regular cranks on the road bike…can’t climb standing worth a damn on the tri bike, so the compacts are nice.
Thanks for the table, I have been thinking about going from a FSA 53/39 campy 11-23, changing the inner ring to 38. A LOT cheaper then a new rear.
Not a single response in this thread has addressed the only 2 things that determine what gearing you need. The 2 things (and the only 2 things) are how much power you generate on the hill you are worried about (at actual race intensity) and what cadence you like.
That is an individual perscription. Without knowing those 2 factors, anyone who says you need a 12-27, compact, triple, whatever is just blowing smoke.
Compacts haven’t ‘caught’ on in the pro cycling community becuase they don’t need them. At their watts/kg they can climb really steep hills with relatively large gears and still reach their desired cadences. What you need has no more to do with what they need than what the other readers of this forum need.
Find a hill that is similar to what you expect to face in your goal race. Climb it at what you anticipate to be race pace. If your cadence is below what you like, you need more gear, if your cadence is ok, your gearing is ok.
Take 2 people who generate the same w/kg, one who likes to climb at 75rpm and the other who likes to climb at 100rpm. They will have drastically different gearing needs despite the fact they will climb the hill at the exact same speed.
Scott
One use for compact gearing, which I did not realize until this winter, was for (systems training) riding high RPM in climbing while keeping the heart rate under 80%. At first it can be difficult to do with a 40/27, easier with compact 36/27. I do not use compact cranks however.