s4one

I've been riding a standard 53/39 majority of my time on a road bike, sometimes I would ride a compact for awhile until I swap it out for a standard when I get a new bike in the past. However, now I am focusing more on climbs and the area I live in consists of all climbs opposed to my riding style before which was flatter and some rolling hills. I guess I want to work on being able to spin at 80-90 cadence up a 10 mile+ avg grade of 8% climb. I do have trouble on my current 53/39 12-25.

I have a hollowgram crank set, the good thing is that the crank came with a compact spider and i have 50/34 rings laying around. I will try them out since I already have them and don't need to spend extra money.

How is the comparison of a 50/34 to 52/36? I like the 53 on the standard that's why I am looking towards the 52/36 but I just want to make sure that the 36 will be sufficient with a 25t rear compared to the 34. Will the be okay to fit a 52/34, I assume the jump will be too big.

Good thing is that I'll have both a standard 53/39 and 50/34 that i can swap.

Homebrew01

You have the parts. Look up (or do the math) and see which gear matches the 36. Then go ride it and find out first hand.
(edited)

s4one

true but i don't have the 52/36, that's what I'm curious about.

10 Wheels

Get a 12-30 cassette and go get um hills.

Bah Humbug

Why not 50/36? That's my plan for next season. Better shifting than the other two, because of a 14t difference instead of 16t, while still having fairly low gears for climbing. I'd recommend a 12-27 cassette for more climbing power and the ability to hit rollers and mild climbs in your big ring.

Another option would be 52/38 with a 12-27. That's still a nice 14t difference with slightly deeper chainrings than your current setup, and the 12-27 will help you climbing while still being reasonably tight, spacing-wise.

Frankly, I just really think 50/34 and 52/36 are both incredibly flawed gearing combinations, despite their popularity (well, 52/36 seems to have only gotten popular recently). Fortunately, the popularity of 52/36 means plenty of 36t chainrings to swap mine with come spring.

RT

That sounds delicious. I honestly do miss the 2 or 3 teeth on the big ring. My heavy-ass 52t triple blows my compact away. Much less shifting. Not a comment on triples, but a comment on big rings.

rangerdavid

yeah, easier to just change the rear cassette

foresthill

After several years of not wanting to give up my 53, this year I finally acknowledged the steepness of where I live and switched to a 52/36. I couldn't bring myself to go to a 50/36 or 50/34, but the 52/36 has been just right. Climbing a 15%+ grade is a lot less painful, and I've barely lost anything on the top end.

Shifting has been unaffected, and the diameter difference between the old and new large chainrings was small enough that I didn't end up moving my FD at all. This means that if I want to throw my 53/39 back on for the winter or something (since the steep stuff tends to keep snow), it's just a couple of minutes to do so.

My only complaint is that the new exogram crank only came in 53/39 or 50/34, so I had to buy last year's model. Still, worth it.

caloso

I think you'd be exceeding the recommended maximum difference between chainrings, but if you're aware of the issue, take care to adjust the FD, and then shift carefully, I think you'll be alright.

cyclezen

52/36 would need to be done on a 'compact' crankset anyway - since smallest ring you can fit on a normal 130 BCD is a 38...
so if the crankset you have is compact -110 bcd and you already have 50/34 rings, then just determine the cog range you'd need to get the gear range you want ... and get the cassette to fit.
there is no free lunch - a 39x25 is 41 inches, and spinning that at 80 to 90 up 8% ... well good chance you'll need a gear in the mid to low 30's to do the 90 rpm on an 8%, if the 41 won't go...
34x25 is 36 inches, so maybe not quite what you expect
everyone thinks a 'compact' is less macho/big meat, until they have to do a big-ass climb....

catonec 

+1

Bah Humbug

This is why, when I'm picking gearing, I start with the combination that gets as los as I need, then go as tall as I can from there. Rather run out at the top than the bottom, unlike, apparently, most people.

s4one

My current setup is 53/39 12-15, if I change to a 50/34 12-15, will I need to a new chain?

My goal is to go for a 52/36 as the 52 will provide a similar gear to the 53, however I just wanted to make sure that the 36 is good enough with a 25t rear for the majority of climbs.

Racer Ex 

I've won crits on a 50.

cyclezen

chain length change is dependent upon the current length, if you stay with a 12-25, then you might find 1 less link works best. If yo ugo to a larger rear cog, say a 27 or 28, then it's prolly ok the way it is - given the chain is not stretched yet.

39xx25 = 41 inches
36x25 = 38 inches
34x25 = 36 inches
You'll feel some small difference in effort, but I'd be surprised if it's enough to make a significant difference in your climbing rpm. If you can climb in the 39x25 at 80 rpm, then the 36x25 might allow another 5 rpm over an extended period. But to get a significant possible rpm increase you might have to go to a lower 30's inches - as in - 34x27 which is gets you down to 33.5 inches. Assuming that you can hold the higher rpm, regardless.
If I have to climb at 80 rpm, I just detonate. I'm a low rpm climber (hence I can't climb to save my life...) and rpms much over 75 for extended period, make me explode like the Sta-puff'd marshmellow man.

Dean V

How can anyone on a forum answer this for you? Ride the climbs and you will have the answer. As for the chain, it may be or ok, or you might have to take a couple of links out. Put it in the 34-12 and see if the derailleur is still holding tension on the chain.

s4one

How close/similar is a 34x25 vs. 39x28? I have a 12-28 cassette I can use first.

Banzai

So far 50/36 is my favorite. Smaller than a standard double, allows me to run a tighter cassette. Smaller jump than a compact makes for better front shifts. I think there should be a lot more 50/36 offerings. I had to buy a 36t chainring to make mine.

Beaker

They are very close - 35.7 gear inches (34x25) vs 36.6 gear inches (39x28)

Fox Farm

It all depends on what your terrain is like where you live.

cyclezen

you've gotten your answer,
but I think you'll like this gear calculator - don't know where or from whom I first found it, but It's AB FAB my favorite.
not only shows gear ratio chart, but also Log graph, speeds graphic over an rpm range, gain ratio, rollout AND specific speed at a specific rpm...
https://home.earthlink.net/~mike.sherman/shift.html
easy to spot where you're well covered and where the holes might be for gears you need/like
you can plug in your cassettes and then different chainring combos (and use the 'triple' to compare other ring sizes - like 36 to 34...)

it is da kine

SanDiegoSteve

I really like the 11-28 on my Ultegra 10-spd.

As noted the 39/28 is 36.7". The next one is a 39/24 @ 42.9" which is about the same as the 39/25. I don't think I can tell a difference between the 24 and the 25, but I sure can tell on the 28! SRAM has their WiFli or something like that which goes to a 32 or something.

I almost got the compact (two knee surgeries later), but I am happy with the regular and the 11-28. Those uphills are really fun downhills in my neighborhood where I can use the 53 up front.

s4one

I ended up changing my setup to 53/39 and 12-28, it made a really noticeable difference.

DannoXYZ 

Heh, heh.. me too. I started racing on 52x14t junior gearing. I hardly ever used the tallest gear anyway. Even later in 1-2-pro races with 45-47mph finishing sprints, I'd be using 50x15t or 50x14t max on a 13-21t corncob. And having closely-space cogs with 50/34t 13-24t gearing for road-races makes finding the exact climbing gear to get into a steady rhythm easy.

Bah Humbug

Oh good, I was starting to think I was alone in thinking that was clearly the ideal "easier" chainring combo. Going to be making it for myself this spring; I don't think anyone actually offers it officially on a bike.