ambro

My CX rig runs a pretty standard 46/36 but I'm seriously considering swapping it for a compact 50/34 and wanted to get your thoughts. I'm just looking to maximize the utility for cross racing, trails, and road riding and it see the 50/34 may work better all around.

First, when I race cross, I'm usually always in my 36 except for rare occasions on a flat, fast course. So, I don't think a 34 would be much different. I use my CX bike for road riding too(not racing) and sometimes feel the 46 isn't high enough. I was also thinking that the 34 would help with the steep rolling hills I have where I live on the road and maybe even in races up those gnarly inclines.

I don't want to sacrifice anything for racing, so do you think I could use the 50/34 for racing?

aggiegrads

I think that your logic is sound. The only danger that I would have is using my lower gear too much. A larger small ring forces you to grow a pair instead of soft pedaling around the course.

I also wouldn't want a gear that encourages me to ride something I shouldn't. I see lots of mountain bike guys spinning up steep inclines while other people run past them.

Andy_K 

I don't think 50-34 is a good option for racing. The large gap makes it even less likely that you'd switch between rings than usual, so you'd kind of be going 1xN with a 34T ring. I think a better option is switching your crank or rings in the off-season.

fietsbob

Ought to be simple to change chainrings given all 4 are 110 BCD,
and bag up and label the chain for the set.
quick connector links
and the Park special pliers tool makes that a fast change,
during the pre and post race mechanics session.

estimate: it would not take more than 20 minutes in the repair stand.

including moving the FD up and down..

simonaway427

I'm surprised no one has asked this yet....but what cassette are you running?

It is far easier to swap a cassette than chainrings on race day.

ambro

I'm running a 12/27. My current set up with the 36/46 crank works fine in races and trail riding. After doing some research, I may go with a 39/50 crank and keep it in the small gear for cross races and use a cassette up to a 28 or 30 tooth cog.

simonaway427

easier said than done - now you're looking at a potential derailler swap.

cs1

At one time Campy made a 34/48. That seems ideal for what you want. The 14T jump could still shift well. Good luck on whatever you choose.

Barrettscv 

You could install a 50 & 39 and a 12-30 ten-speed cassette and keep your Ultegra or 105 SS derailleur.

fietsbob

46-27 chain would come off , and the 50-30 length chain goes on with the chain ring swap.

of course the N+1 and another bike is the ultimate cure.

Holden McNeil

Velo Orange makes a 34/48: https://store.velo-orange.com/index.p...et-34x48t.html

adam_mac84

why not 11/28 cassette? If you aren't racing on road, 46x11 should be plenty for all but descents...

cs1

Almost too pretty to use.

Cycocross

I run a 50/34 , 11/32. The only problem is zero excuses for not being able to climb the steepest of hills or keeping up with the roadies.

fietsbob

I'd never upshift from the 34 to the 50, anywhere but at the summit of a climb.
smaller difference can be shifted between more readily..

just sticking to the 34 in a CX race, great.

of course, some consideration of the lap the course designer
has laid out for the race itself , matters a lot..

lots of people run a single 42t with chain-guards.

because the course is fast , between climbs
that can be run more efficiently than ridden ..

thenomad

Installed a 34-50 crankset today. Hope to test it out this week. Its an older gossamer isis BB version but it was still lighter than the Ultegra version it replaced.
Want to make it my hill training bike as its the lightest one I have. All the lightest goodies get to go on it. Hope to pick up a modern light weight set soon. RD is next in line as well.

Gears to keep my knees happy on long drags up to the top and CX so I can rip down the dirt trails just as easily.
My other bike will stay traditional road gearing. I think this'll also avoid the overlap in bikes that i have since they are currently geared the same.

ambro

Let me know what you think about that combo

thenomad

I will let you know. I stalled out on the install as I still need to adjust the FD lower and tune it up.
Got them on though, lighter weight than the Ultegra double they replaced.

jbrow1

Thinking of throwing a 34 small ring on my crankset too, currently have a 36/46 with a 14-28 7 speed freewheel. I don't think the 34 would really hurt me, just move the range of gears I use down one, and give me a better total low end. I'm new to cx racing, but don't see myself ever getting into the big ring during a race. Have a spare 34, have to see if it's the same bcd that's on my bike now.

DinoShepherd

You might want to listen to this guy. Or you could look at a gear inches calculator and realize he is a super-genius.

- Z

telebianchi

My CX bike gets used for commuting, trail ride, some mtn bike trails, and a couple of races in the fall. I used to run a 50x34 but bought a new chainring to go 46x34 (11x32 cassette). I don't miss the four extra teeth because I am never screaming down long &/or steep hills on this bike where I would need it. Love the quicker shift between the 46 & 34. Used the 46 in races whereas I never used the 50.

tashi

I use my cross bike similarly to you and want it to be good at everything. It currently has a standard 38/52 crankset with a mountain bike cassette (11-32 8-speed). I raced it that way, and it's all right on trails, and good for road rides, even if the jumps are a bit large with that cassette.

I want to run compact cranks with the mountain cassette, which will give me acceptable road gearing, a wide range with a nice low gear for technical singletrack, and be fine for racing. If I feel like taking the time I'll set it up as a 1x8 for race season.

ambro

It's been a while since I originally posted on this thread - so I thought I'd update everyone. I had been using my standard Cross cranks with an 11-28 Cassette. It worked pretty well but I still felt like I was always in the lower end of the gearing with all the hills I have where I live, or I ran out gear on some fast road rides. I just switched out my chainrings from FSA 46/36 to FSA 48/34. So far, I'm extremely happy with the decision. The 34 chainring is perfect for trail riding and gets me up just about any hill I encounter while remaining seated. The 48 provides a very good gear for the road too. Shifting is perfect - leave it to FSA. I'll see how it performs this year in cross races - but for my level, I don't really think it will make that much of a difference - and 80% of my yearly riding is on the road anyway - so I feel I have the best mix now.

cs1

See, somebody listened to me. How do you like the FSA crank? The only thing that scared me was all the reports on loose left crank arms. Congratulations on the swap.

thenomad

Have been using a 50-36 that I finally finihed up the install on.
Nice because it makes me use the upper end of the cassette with the 50 (opposed to 53) and has a better lower end with the 36 (opposed to 39). The 34 small ring seemed almost unuseable just because it made me jump to the 50 on anything over 16mph (exaggeration) but 34-27 would certainly get me up any hill.