Beach Bob

Its getting to be time to change chain rings and I'm contemplating going from 34/50 to 36/52 (staying 12-28 on rear). I know I'll lose a little bit of low end for climbing, but I think I should be OK as I don't see much above 8%; and realistically, no long climbs above 6-6 1/2%.

My main reason for doing this is just because I'm finding that I'm spinning out lots on mild descents and flats with a tail wind. Would it be worth the small hassle to adjust the FD and lengthen a chain? or just stick to 34/50?

Thoughts?

Cyclist0108

Lengthen the chain by getting a new one.

You should ride whatever gearing you find best.

If it were me, I would change the 50 to 52 and keep the 34T chainring, if your derailleurs can handle it. (If the shifting is wonky, you can always change the 34T to 36T later.)

rm -rf

Is it 12-28 in 10-speed? That's kind of unusual.

The 52 vs 50 is only 4% higher, less than one rear shift (which can range from about 5% to 12% or more, depending on tooth counts.)

Here's a 12-27 in 10-speed, showing the 34 chainring in red, the 50 chainring in black, and the 52 chainring in blue. I changed the cadences to a little higher range, 90-102 rpm, since you mentioned spinning out. You'll gain maybe 2 mph with the 52-12 high gear.

It's a pretty minor change, less than a half shift at the same cadence.

I'd guess that your chain is fine, unless the big-big combination has the rear derailleur arm completely stretched straight already. With a quick link, I'd reuse the same chain, but "carefully" test the big-big combination with the bike in a stand!

From the very useful Mike Sherman's gear calculator.




~~~~~~~~~~~~~
Comparing 34 and 36 rings. 34 in red, 36 in black, 52 in blue. Showing more typical flat road cadences, 86-97 rpm.
You lose about 1/2 shift at the lowest gear.
With a 36 chainring, it's usable past 20 mph, so you don't need to shift the front if you are staying at 20 or less.



~~~~~~~~~~~
I wouldn't go 36-52 on my bike, since I ride some very steep hills. I have a 34F-32R low gear, and even lower would be useful.
But this looks good for flatter terrain like yours. There's reasonably close shifting from 15 mph up through 25 mph.

I made a custom combination 11-speed 14-32 that I use for fast group rides. It has the very low climbing gears, and 1-tooth cog shifts from 18-25 mph, where I'm trying to hang onto the group. (I have 14,15,16,17,18,19,20,22,25,28,32) I spin out at 29-30 mph, but that tradeoff is worth it for me. (On rides with very long downhills, I change back to 11-32, so I can soft pedal the downhills.) Your 52 and 12-28 would be good for me on the fast rides.

Banzai

I prefer 36-52, and have been running that for years. The progression is smoother up front.

ksryder

You probably won't notice the 2-tooth difference on the bottom end.

But make sure the BCD is correct for the new chainrings. I don't know what the BCD is on semi-compact cranks and my 5-second google search didn't tell me right away, but it's just something to check before you buy.

Edit: OK did some more research and apparently they make 52-tooth chainrings with 110 BCD now so disregard everything I said.

Racing Dan

50t > 52t 4% higher top gear.
12t > 11t 9% higher top gear.
50/12 > 52/11 13.4% higher top gear.

bikebreak

Spin faster or get an 11-28 cassette. 50->52 is 4% faster, barely noticeable.
Even assuming you run a shimano crankset that can handle 50 or 52 big ring with a quick swap, the new chainrings cost as much as a cassette.

Jofu

I recently bought a new bike with 52/36T 11-30t, whereas my other commuter/climber has been 50/34T 11-32t. I switched to 52/36 for the same reason as you, to get a bit more gears on fast descents. In hindsight though, I honestly can't say why I went 11-30t instead of 11-32t in the back, as it only hurts my climbing... 36/30 is nearly 13% harder than 34/32, and I definitely felt it the first few times I tried my usual hills/mountains. Having gone 11-32t would have meant only 6% worse.

I was seriously considering buying a 11-32t cassette, which isn't cheap (SRAM Red), but I'm slowly getting used to it now, so I'll probably just tough it out and get stronger

Anyway, just one data point!

Geoff

79pmooney

Go for it! Don't listen to the guys who say it's only a tiny whatever percent change. It's your bike. You ride it. (I change my chainrings on my fix gear for more subtle changes than I can get with rear cogs.)

Nominally, you want a chain 1 link longer. That's hard to do unless you can find a half link (and for a 9-speed or higher, it would have to be a quick-link style half link and you might have to wait a few years for someone to come up with one. I'd break my new chain 1 pair of links longer than the old and put it on. Maybe tweak the "B" screw back just a touch. You may then find that the chain really does want to be the old length. No big deal, You can always make a chain shorter but going the other way doesn't work so well.

You may have to move the front derailleur up a touch. If it is working well now, take a careful sight down the outer cage plate and see where it lines up on the cassette. Raise the derailleur so it does not quite hit the large chainring as you shift. Adjust the rotation around the seattube to get the same alignment after you move it up. (You still will probably want to tweak the inner and outer limit screws a touch to get best shifting/security from the chain falling off.

I am a huge fan of riding exactly the chainrings and cogs that suit me best and those were often not what others rode.

Ben

TrojanHorse

I know SRAM makes a cassette like that because I have one. and instead of the 11, you get a 16, filling in the gap between 15 and 17 very nicely. Works great on flats and my rationale was that I don't care if I spin out going down hill, I'm not racing.

Mechanically, it probably wouldn't work but it wouldn't bother me if a cassette went from 11 to 14, and then up one at a time.

MattyMurdah

I just switched from 50/34 & 11-25 to 52/36 & 11-28 and much prefer it. Granted, that's a different shift from what you would be making. However, if you can afford buying a replacement cassette/chainring if you decide it isn't for you, I would 100% say give it a try! No real way to know if you like it better or worse unless you actually try it .

Lazyass

I have no problem with a 50T. But a 34 is just too wussy, sorry. I don't cruising in my smallest cogs and having to shift to the big ring every time I accelerate. In the one month I had a compact crank before I yanked it off I rode in the 50 most of the time.

colnago62

redlude97

that's funny, I see plenty of compacts on Cat3 and higher race bikes here in the PNW. Plenty of light riders too

colnago62

Dean V

So any better than average cyclist needs similar gearing to Pro's even though they have a power/weight ratio that is at least 25% more.
Why is that?

kbarch

Can't say what's "worth it" to you, but I find that the 4-5% difference in speed realized for a given cadence that folks are talking about can be VERY noticeable, and from the sound of it, I suspect you will too.

I ride all three sizes (compact, mid and standard), and definitely notice the difference between each on rolling terrain. In fact, just yesterday, when I rode the compact for the first time in a couple of weeks after riding just the mid - on the very same roads - I was again struck by the difference. But perhaps folks who ride on less roller-coaster-y roads, where the transitions between gears aren't as broad, frequent, or rapid, wouldn't notice the difference as readily. What's noticeable first is how much sooner I'm ready to get on to the big ring after finishing a climb. With a standard or mid, when the road is more uphill than not, I often stay on the small ring for all the but the longer descents, but with the compact, I'm going back and forth between the big and small rings more often. When riding flat routes, no, I don't notice the difference between the setups much unless it's a very spirited ride.

By the way, on the mid and compact, I have 11t cogs, which is what I'd recommend if the longer descents are an issue.

Bah Humbug

It's funny how I always either fiercely agree or disagree with you.

@Beach Bob, asking other people for gearing opinions is almost worthless; all they can tell you is what they like and what they think you should ride. Me, I switched from 50/36 to 52/36 when I got my Quarq, and dmanned if I don't miss my 50 front. Yes it's only a 4% change, but that 4% is often the difference between being just comfortable enough staying in the big ring over minor hills instead of needing to change or my cadence going lower than I'd like over them. Conversely, I don't much mind spinning out or brief forays above 110rpm, so losing 4% off the top doesn't hurt me.

All of which has eff-all to do with what gearing you should be using or would find most helpful.

It's also hilarious how many people think a 52/36 with an 11-28 is tougher than a 50/34 with 12-25 because the bigger chainring is obviously more manly.

Lazyass

Similar gearing would be like a 53-44. And riding in the big ring most of the time. Nobody is suggesting that.

rm -rf

Yeah, a 16 cog is good.

That 15-16-17 tooth series is great for 20-25 mph speeds on the flats. I want close shifts there, where I'm working hard to keep up with the group.
For me, the 50 chainring puts these three cogs at 21-25 mph, which is fast for me.
The 52 chainring moves them up to 23-27 mph, faster than I can maintain for very long.

But I can see why some riders really like the 36-52. Riders have big differences in flat roads speeds, and variations in their preferred cadences.

redlude97

froome using a 34x32????madness
https://mobile.twitter.com/ShimanoRO...65373029056512

fietsbob

back when freewheels had 13t high gears I liked my 52 - 36 double crank

problems, inconvenience mostly, come when your sequence of favorite gear ratios

require a double shift of both front , & rear.. to go between them ...

Dopefish905

Lazyass

Mmmkay, Lance. Perhaps you should reread the replies and see why some of us don't like compact cranks. No, it's not because we're ready to be signed by Team Sky.

caloso

My Tarmac came stock with a 52-36. Didn't think I'd like it, but I really did. You don't lose anything on the flats and the 36x27 little gear is more than enough for anything I need climbing. Unfortunately, I wanted to keep my Quarq with its 130bcd spider so I'm limited to a 38t small chainring.