Triaxtremec

I currently run a 2x10 compact crank but still find myself always having to drop into my small ring. Thinking of swapping out for a 46t chainring in hopes that it may reduce how often I actually need to drop to the small ring and hopefully allow me to spin more. Thoughts?

pdedes

Do the gear/inch calculations first

rpenmanparker 

Why don't you get a standard 53/39 crank and stay on your small ring all the time?

Triaxtremec

getting a new chain ring is a lot cheaper

Velo Dog

Should work fine. I went through a long illness and hospitalization a couple of years ago, and when I got back on the bike, I was really weak. I swapped the 52-39 rings for 46-34, and I'm never going back. I live in the mountains and rarely used my highest gears anyway.
Be sure to check your bolt circle diameter (BCD) before you order, and you may need to move the front derailleur down a hair. If the rear Der. won't take up the slack you might have to take a link or two out of the chain, but that's easy.

evan938

you live in Nebraska and spend THAT much time in your small ring?

sounds like you just need to work on the motor more than changing out parts.

TrojanHorse

Yep

cks

This may seem shocking, but Omaha is not pancake flat like the rest of the state west of Lincoln. There are hills. To give you and idea, on the other side of the Missouri River is Coucil Bluffs, Iowa. From national geographic:

A bluff is a steep cliff, or wall of rock or soil. Most bluffs border a river or its flood plain. .

RollCNY

OP, going from a 50 to a 46 will be a very small change, essentially less than one cog shift on the cassette. Not knowing what you have for a cassette, you might receive more bang for the buck, and meaningful difference, by a cassette change, or may choose to look at both.

KevinF

It works fine. I switched from a 50/34 to a 46/36 last season. You'll have to lower your front derailleur a bit. I like that a lot more for the constantly rolling terrain of New England.

rpenmanparker 

How do you figure? You have the whole thing backwards. You are thinking Nebraska is somewhat flat, I presume. cks says it is not, but never mind that. How much time in flat country do you spend above 25 MPH, the common limit for the small ring with 11 tooth cog for those who pedal at reasonably high cadence like 90-100 RPM. For many folks the big ring is needed mainly for sprinting and descending, not rolling on the flats.

CrankAndYank

Many climbs there in Omaha??

evan938

from what I found online, the elevation for the Omaha area has a difference of about 140m, so we'll say 425'. that does not sound like there is a lot of climbing involved.

but lets go with it. 50/34 and we'll say a 11-25 cassette. I'm going to assume the OP can/will ride above 15.6mph, which is what he would be at in a 50/25 @ 100rpms. he could switch out the cassette to an 11/28 and still spin the hell out of a 50/28 and be at 14mph. an area with that little elevation change should not need anything smaller than a 50 big ring. unless the OP is painfully slow, he should either switch out the cassette to be able to spin more, or get stronger.

a 46/34 is going to limit him to ~33mph @ 100rpms in his biggest gear. remember, you can always slow your pedaling to go a lower speed. when you're out of gear, you're out of gear. you're going to have a limit your legs can move at, and if you want to hammer down a hill or sprint and reach that limit, theres nothing you can do.

id rather have gears i dont need or use much (ie, 50x11) than need gears i don't have. my fairly flat 55 miles yesterday here in OH (14-1500' and a **** ton of wind), i stayed in my 50 ring all day "rolling on the flats". im usually right around 84-86rpms and stay in the 13/15/16 range...i have an 11-25 cassette i use pretty much every day, and put on a 12-28 when we head out to the ski area and there are some hills that average over 10%, even thought they're usually not more than 1/2 mile long or so.

not to mention. switching out a cassette for different terrain is a whole lot less hassle than a chain ring and moving a FD and readjusting everything.

rpenmanparker 

You missed my point. I agree OP should not change his rings. But not because he can make do with the 50. Rather because he should be on the 34 most of the time. If its flat and he is not descending, then when is he going to be doing more than 25 MPH? Sprinting, tail wind, aggressive group ride. Okay so then shift up. But most of the time, the 34 will do him fine.

RollCNY

These are some great posts. First post says you know OP's topography, and his gearing question suggests he needs to improve his motor. You got all of that from his question.

Now second post says that you checked the internet to confirm your original insulting assessment of terrain, and you clearly see no need for his small gears. Then you use your scientific and mathematical skill to express concern about the OP's sprint speed. First, he was too weak to be on the big ring, now he is so strong that he is going to spin out a 46/11 combo on the ground you have twice determined to be flat. And if he has the wattage to travel at 33 mph at 100 rpm, how do you know he couldn't spin 120 rpm or 140 rpm, and reach a higher speed? Hey, did you notice that rpm is already plural, and doesn't need the "s"?

Have you ever ridden a bike with a 46/11? I have, and have never experienced a significant difference between a bike set up with that, a compact or standard crank.

cosmonhat

I recently switched out my 50/34 compact double for a 46/30 on my road bike with a 11-28 cassette. I'm not a racer by any means, but so far this has been a good decision. I ride in the hilly SF Bay area and very rarely find myself using the 50/11 combo (occasionally during flat sprints), and I typically coast downhill. The 46/11 ratio is nearly identical to a 50/12 ratio, which I used much more frequently before the change. So at the end of the day, with the 46 big ring I utilize the smaller range on my cassette much more evenly. The 30/28 combo is great for the super steep stuff, but that's a topic for another time.

datlas 

You are posting like it's a shame to "drop" into your small ring.

That's what it's there for.

Of course, you can play around with an online gear calculator to see if the proposed new setup will work well for you, but what's wrong with using your FD??

clausen

I would change the cassette first.What cassette are you using?

akansaskid

Unsaid is the best reason for me to consider going from my 34-50 compact to 36-46 cross bike gearing: less than 3-4 shifts on the cassette when you shift from one chain ring to the other.

99Klein 

Omaha is HILLY. It may not look lokrwit online but I would not ride a standard crank there.

Can you switch cassette? Maybe you can put an 11/27 on and stay in the small ring? The 50 will be nice coming down:-)

Triaxtremec

Thanks for the post everyone. The bike is currently running a 12-27 cassette, its a CAAD 10 105. I live in West Omaha and their isn't a flat piece or land anywhere, hard to believe I know, but its either up or down a hill. Some are bigger than other, I just don't have the leg endurance to keep it in the large ring and go up many of the smaller hill. I'd like to be able to keep it in the large ring more often. Many times I'm in the small ring but in the smaller rear cog sprockets so I'm having a lot of chain noise with the odd angles of the chain. Also being in the small ring means I have no chance in hell of keeping up with the majority of the riders I try to ride with who are all typically using a 53t.

99Klein 

Maybe swap the 34 for a 36. Nothing wrong with the small ring. I ride about 50% of the time in mine. 36 would make you front shifts much nicer too.

rpenmanparker 

I don't understand. Why would you try to keep up with folks mashing on the 53t front ring by riding your small ring? First you need a cassette that goes up to 11 teeth so you can ride 34/12 without serious cross chaining, AND so your high gear 50/11 is better than their 53/12. Second you need to adjust your FD and learn to "feather" the front derailleur setting to allow noise free running with mild cross chaining. No reason for any but the smallest rear cog (which should be 11) to cause a noise problem in combination with the small front ring. But here is the point: it is appropriate to run on one front ring for long periods of time due to extended riding situations like climbing or the opposite, a fast run of the pack down wind. Shifting between rings to accommodate such a situational change is perfectly normal. Shifting between rings while in the middle of such a situation is not normal and should be avoided. Also staying on the big ring because you are going fast enough to need those gears is proper. Staying on the big ring because it is what you see others doing is BS.

Altbark

The OP is asking a classic question about gearing that is very easy for him to answer.

I built up a road bike last year - nothing fancy. I'm not a racer. Nor am I a member of the elite club rider group. So before I decided on the gear ratios I wanted on my new bike, I figured out the gear inch range on the old stead and what I was actually using when I was solo and club riding. The results found me going with a 50/34 compact crankset married to a 13-25 10 speed junior cassette. My bike tops out at 101.5 GIs and bottoms out at 35.9 GIs.

Some will argue that you will spin out with only 101 GIs at the top while on a good downhill but I have found that a good tuck at that point works better for me. My point is that a good analysis of what is being used now will provide a more usable and realistic set up when the OP is actually riding his bike. Personally, I like to stay relatively standard in drivetrain parts. Going with the standard compact crank allows me to radically change the drivetrain by doing a simple cassette change - not that I see that happening anytime soon. Al

Looigi

Pretty much. Also, going fast downhill rarely last very long at all. Climbing that same hill, on the other hand, can take quite a while. The low gear might be necessary while the high gear may only be nice to have on rare occasion.