53-11 alltheway

EDIT: I posted a poll that went along with this thread. It is separate so you will have to scroll down the forum to find it.

Due to the increased questions about the compact double I though I would dispel a few misconceptions (and misunderstandings )about it.

First of all most people here are interested in it (the 110 bcd compact) because they want lower gearing, but want to keep their doubles.....

Wrong reason to get it! (Unless you swap out short cage rear derailleur for long cage...)

Merely switching to a compact double such as a 50/33 combo will give you smaller rings, but will force you to use a "tighter cassette" like the 11/23 (because rear derailleur wrap capacity is at it's limit: 29T)

Side note to all you mechanics: I know rear derailleur capacity can be exceeded, but I kept it this way for the sake of discussion (and to keep it even)

See the below comparison (both using short cage)

Gear range of 50/33 combo with 11/23: 37.7 inches to 119.5 inches
Gear range of 53/39 combo with 12/27: 38.0 inches to 116.1 inches

As you can see there is no lower gearing to be achieved by the compact double (even with 33T chainring!). Although you will get a much tighter progression....the range is the same. (actually compact has more top end power than 53/12 double, but not by much.)

Now if you swap out the shortcage for a long cage (ie, triple rear derailleur) you can truly have a very wide range of gearing if that is what you want with your compact double.

Gear range of 52/42/30 triple with 12/27: 29.2 inches to 113.9 inches
Gear range of 50/33 double with (custom)11/28: 31.0 inches to 119.5 inches (using long cage rear)
Gear range of 50/33 double and (custom)11/30: 28.9 inches to 119.5 inches. (using long cage rear)

So the only way you guys switching to compact are going to get the lower gearing you want is to run a 12/27 cassette (possible with shortcage is you watch out for the Big-big combo) and lose your top end gearing (because of weak 50/12 combo)

or.......

swap in a long cage rear derailleur and run a semi-custom cassette like the Sheldon Brown "High and Wide" 11-28 or use a pure custom cassette like a 11-30.

The Upshot of all this is...............


The beauty of the compact crankset is not lower gearing (which it doesn't give you if you still have short cage), but rather tighter progressions than the 53/39-12-27 is able to give you with less overlapping gears.

53-11 alltheway

I think I am going to start a poll......53/39 with 12/27 vs. 50/33 with 11/23.

galen_52657

Every post of yours provides prima-fascia evidence of your noobness.

You just don't have a clue!

First: Compact cranks are designed for those riders who wish to ride a double chainring instead of a triple (to brag that they 'don't ride a triple' or for what ever sad reason, or to keep a top gear that they can't really use) but who are (pick a number) - 1) to weak 2) to fat 3) to old 4) to slow to climb a hill with a standard 39 tooth inner ring and a 29 (Campy) or 27 (Shimano) largest cog on the cassette.

Your comparison of a 53/39 to a 50/33 is stupid. A 50/33 chainring setup exceeds the front derailleur capacity of every double front derailleur made.

If one wants to use a compact crank, one is not 'forced to use a tighter cassette'. One can match the low gear of a 39/29 or 39/27 with a tighter cassette, but that defeats the purpose of having a lower first gear! One just has to use a mid or long cage rear derailleur.

This is how to figure out what gearing to use on your bike: Go for a long ride in the hills. Can you climb all the hills in your area with the lowest gear you have? If so, than you are OK. If you are really struggling (standing, barely able to turn the cranks) on the steepest hills, you need a lower first gear. If your current low gear is a 39/29 (Campy) or 39/27 (Shimano) than you need a triple or a compact double. It’s nice to have closely spaced gears, but people made do with 5, 6, 7 & 8 cogs in the back for a long time so be thankful for 9 or 10.

IMHO if you cannot climb the hills with a standard 39 tooth chain ring and cassette with a 29 or 27 tooth low gear, having a high top gear of 53/11 or 12 or 50/11 is useless. If your condition and fitness is such that you can't climb, than why do you need a high top gear? You can't turn it on flat ground anyway. One goes with the other. If you can’t climb the hills, you are not miraculously going to turn into Lance Armstrong when your reach the top. 53/12 or 52/13 is all the top gear you need. You coast down hill anyway.

So, this winter instead of obsessing about chainrings and cassettes, may I suggest six days a week of weight lifting and trainer intervals (alternating days) and as much road riding as time and weather allow. Then, come Spring you will say to your self ‘compact double or triple…. who cares!!!!!

audiojan

... and normal compacts are 50/34 or 50/36.... No such things as a 50/33.

53-11 alltheway

Have you ever tried a 50/33 combo? No, of course you haven't. It works perfectly (flawlessly!).

Did you know that Shimano's front derailleur capacity is 15T, but even a 50/34 exceeds that with a 16T difference!

53-11 alltheway

Well, I am running a 50/33 combo on one of my bikes right now. So it does exist.

53-11 alltheway

the 50/33 and 11/23 has the same range as a 53/39 and 12/27 (but with tighter progressions and less gear overlap). There is no benefit in lower gearing with a compact! How can you fail to understand this?

A compact can not give you triple gearing unless you use a long cage rear derailleur.

Galen_52657 I thought you knew about this kind of stuff. WTH?

audiojan

.. in that case... I stand corrected.... I'll leave the two of you alone to argue.

HunterBee

A wider gear range is easier (and cheaper) to acheive by swapping out your cassette & rear derailleur. For example, an MTB cassette (12-34) gives plenty of usable gears even if you keep that rediculous 53/39 crankset.

What I would really like to have is a 13-36 cassette with matching derailleur but no one makes such an animal.

53-11 alltheway

We are not talking about wider range here....though it is possible to do with any crankset by swapping rear derailleurs and using mtn cassettes.

We are only discussing gear options within the confines of a short cage rear derailleur (which is 29T for shimano.)

galen_52657

Thanks for testing it out for me. If I loose a leg in an untimely misshap... I will get one.....unless I turn 80 first...

53-11 alltheway

I thought you were not a n00b. Galen, go get a gear chart and tell me if a 34-23 is lower than a 39-27?

I'll admit that a 33-23 is a fraction of a gear inch shorter than a 39-27....but they are essentially the same gear!!

53-11 alltheway

33-23: 37.7 gear inches
39-27: 38.0 gear inches

How come it's so much easier to climb hills with the compact double? Their lowest gears are the same. What gives?

DogBoy

I fall into the: 2) too fat category, and I thought about putting a compact crank on my tri-bike (coming in January). I run a triple on the road bike and occasionally need to bail from 42-25 to 30-23. I figure that running a 50/34 would get me bailout gearing without giving up much on the top. I rarely spin out, but I only race tris, so there is no need to sprint. A 50:12 is more than enough big gear for me. The only reason I haven't done it is because I'm a little concerned about chainline issues since the stays on my tri-bike are very short. I decided to stick with the standard 53/39 and go with a 12/27 cassette for now. If I can't handle the hills with that, I will think again about the compact crank with a triple front derailleur and a midcage rear derailleur, or whatever combination it takes to get it to work properly.

But before I do any of that, I will just super-inflate my rear tire. I hear that negates the effect of gravity

53-11 alltheway

your 53/39 double with 12/27 will be slightly easier to pedal up hills than a compact crank(50/34) and 11/23 cassette.



34/23: 38.8 gear inches
39/27: 38.0 gear inches

So Galen, what's this about a compact being easier than a 39/27 double. It's not! That's the reason I wrote this thread........to dispel the BS out there!

A 50/33 compact is essentially equal to a 53/39 double with 12/27 as far as hill climbing goes, but with much tighter progressions.

DogBoy

Maybe I wasn't clear, but I would run a 12-25 cassette, hence the potential need to change rear derailleur. 34:25 is less gear than 39:27. Heck, with a 10 sp cassette, I might even go 34:27 since the low is still pretty tight and I'd have to change the derailleur anyway.

sydney

You don't have to change the friggin RD to run a 27 anyway.

53-11 alltheway

Then we are comparing apples to oranges.

While that may be be the best option for you.....it would not be fair to compare a compact with long cage to a regular double with shortcage.

Most serious compact doubles come with the shortcage and the tight 11-23 casette and are meant to operate in the same range as a conventional double.

53-11 alltheway

He didn't read my initial post. You can run a 12-27 with short cage.....you just have to avoid the big-big combo I think....or run the chain a little long and not worry about a loose chain in the small-small combos.

Personally I have no experience with 12-27 and compact so I'm just guessing. Anyway a 50/34 with 12-27 comes out to 31T so I don't think it would be a problem (only exceeds capacity by 2T)

galen_52657

OK ******,

rider A rides a 53/39 with a 12/27 10 speed cassette
rider B rides a 50/34 with a 11/23 10 speed cassette

rider A's high gear is 119.2 gear inches
rider B's high gear is 122.7 gear inches

rider A's low gear is 39 gear inches
rider B's low gear is 39.9 gear inches

rider A will have a 12,13,14,15,16,17,19,21,24,27 cassette
rider B will have a 11,12,13,14,15,16,17,19,21,23 cassette

rider B will have one tooth less jump 2 gear changes.
rider A will have not have to shift as far across the cassette when shifting from the big ring to the small or the small to the big and the front will shift much faster.

Hardly enough difference to make it worthwhile. I will take the quicker front shifts, thanks.

53-11 alltheway

Hahahahaha......so you finally agree with me that the compact isn't any easier to pedal up hills.....Good.


Front shifts are pretty damn fast with 50/33! You would be very suprised, In fact I would say there is no difference between my 53/39 and my 50/33! Seriously.

53-11 alltheway

There is no difference on my bikes.....just to re-emphasize. In fact I expected the compact to have slower front shifting, but in practice I am suprised to see the 50/33 shift incredibly fast!

I think it is easier for the front derailleur to handle the smaller rings believe it or not....sure the difference is 17T, but the actual distance the front derailleur has to move is a lot closer than you think.

Anyway on a nine speed bike.....I think I rember seeing that a conventional double has 12 non- overlapping gears while a compact with 11-23 has 14 non-overlapping gears. (I haven't actually calculated this out yet though)

53-11 alltheway

Unfortunately I can only imagine what will happen when Ziggurat gets a hold of this.......

If I'm not cruising around with at least 130 gear inches...........

sydney

Not real sure what your point to this is anyway. You can get lower gearing with a compact, doesn't require a LC to run a 27 cog,and the average person that needs a 27 doesn't need an 11 or often even a 12.

HunterBee

I thought the point of this thread was that installing a compact crank will not give you wide range gearing unless you also swap the rear derailleur. My point was- if you have to swap the rear derailleur anyway, why not forget the compact crank and just install an MTB cassette? Same results, less money.