cyclezen

no luv for the 16 & 18....
for many decades the 16 & 18 have served me well...
to me the 16 is essential - easily 10 fold more important than an 11 would be...
and the 18 - well, when it's constant "up and down" rollers that 16-17-18 is Da Kine
and when it's 15 mph of wind in the face, That one tooth shift helps keep the momentum rollin...

it's been easier to just add the 30 to my 52/42 or 52/39
50/34, even with a single tooth jump up to 19, is just so much swiss cheeeeezzzz.

all the 'weight' you save by not having a triple (std w/ that little badboy 30), but gearing the compact up for reasonable climbing is handed back by the 22,25,28, and you lose the 16 and of course, the 18...

my guess is if you were to weigh for the total weight difference between a 53/39/30 crank + 12-25 cassette, and 50/34 crank + 11/28 cassette - same models - there would be NO weight difference.

so lotsa gearing choices, mostly single shifts, smallest possible steps in the mid gearing range, lowest possible gears on the low end, yadda - yadda - yadda
VS
less of all of the above with compact...

easy choice for me...

Campag4life

So what is your choice front and back Zen?

ThermionicScott 

I think a discussion of chain ring size is meaningless without considering the cassette. If my bike had a 52/42 crankset, I'd be hating life with an 11-23 cassette, loving it with a 14-28 or so.

cyclezen

going to U-rup in a few days, takin the sworks tarmac
put on a 52/39/30 (I'm tooo old and slow for a 53...) and compromising the 18 - so 12-26 rear

should get me through the Tirol and cruise nicely up Bavaria...
bored of the rings...

buffalowings

I run a 50-34 with 12-30 on the back, some hills can be real killers..

tanguy frame

I ride 50/34 and 11-25 or 12-25. I like it fine, but I work hard on mountain rides. Based on this post, I'll order 12-27 and see how I like it on mountain rides. Thanks Banerjek!

gregf83 

I prefer a tighter cassette and use 12-23. I have a 53-39 on my winter bike and 50-34 on my summer bike. The compact works well for me with a mix of solo, group and crit races. 90+% of the time I am on the big ring. The 39 is tougher to use on some longer hills but I don't usually do those in the winter. I can sprint OK up to 56-60kph and at the age of 53 have accepted that I'm not going to win many full field sprints so the 12 in the back doesn't hold me back.

The longer hills 40+min in our area aren't that steep but with the 34 I can use a little higher cadence. Short hills (<5min) I can use the 34, 39 or 50 depending on how hard I want to work.

Dunbar

Agreed, in SoCal I just leave it on the 50 unless the road points upwards. I have no problem staying off the lowest three cogs of the cassette (so no worries about cross-chaining.) As far as headwinds, the 50 is fine down to about 14mph IME and it takes one heck of a headwind to slow me down to that pace. I was climbing this weekend and definitely felt like I would miss my 34/28 on some of the steeper sections. I do think many of the complaints about having to do a lot of front shifting on a 50/34 are solved by riding more and improving your conditioning.

I have a secondary bike that I purchased coming this weekend with a triple 50/39/30 crank so I'll get to play with the 39T and see how it compares to the 34.

Erwin8r

My compact-equipped bike sports a 48/34, with a 12/26 out back. 48 really makes a lot of sense to me, as it shortens the gap down to the bail-out 34, and it provides plenty of thrust--I am almost never in 48/12, save for nice long descents, and I never feel like I run out of gear.

mprelaw

52/40 was pretty much the standard touring crank when I started riding. I still have an 80s tourer with that crank, and a six speed 13-28 freewheel. You want to talk about gaps?

Drew Eckhardt 

They're great for bike companies because they let them get away with making, stocking, and selling fewer SKUs for bigger profits.

Some people like them because in their minds compact cranks are more "pro" looking than triple; although once you put big pie-plate cogs on back that train has left the station.

Beyond that they're not so good. There are four things people don't consider:

1. Using the same cassette a 34 ring only provides one gear lower than a 39 ring - 34x23 is like 39x26. While the stock 30 ring on a 74mm BCD road triple only provides one more gear lower than a 34, you can run as small as a 24 ring for two gears versus a compact and three a 39.

2. The biggest usable gear with the 39 ring on a triple is three gears larger and 42 ring four compared to a 34. Looking at the ratios, 34x12 is like 39x14 or 42x15. You can also use the smallest cog on the middle ring of a triple crank with an acceptable chain angle since it splits the chain lines of the big and small rings on a compact double. This is _HUGE_ on flattish ground where most of your power is going into aerodynamic drag with the force of drag increasing with the square of speed and power to overcome cube. At the same cadence you can put out nearly 100% more power on the triple before you need to shift to the big ring although that still understates the effect since a pleasant cadence increases with power and as intervals get shorter.

3. With a tight cassette the big ring can end not much beyond a slightly up hill false flat and small ring dead flat.

Between #2 and #3 there can be a _lot_ more double shifting with the compact versus a triple with the same or wider range. I was shifting several times a mile on "flat" ground when I made the mistake of running a compact (50-34 x 13-23 had the same range and gear spacing as the 50-40-30 x 13-21 I ran in the 8-cog era, and two rings were supposedly better than 3) versus rarely with the triple. If I wasn't riding Campagnolo where the double shift to the small ring and five cogs away was accomplished with simultaneous thumb shoves I'd have switched back immediately.

4. The lower top speed on the 34 ring than the 39/40/42 on a triple leads to cross-chaining with more drive-train noise. Instead of running 39/40x16 or 39/40x17 in the middle of the cassette I spent a lot of time in 50x21 or 34x14 (out of 13-14-15-16-17-18-19-21-23 in the 9 cog era).

At 3.5W/kg threshold power (I'm extrapolating from my measured output now that we have affordable power meters and weight as a much younger cyclist) a 39 small ring and 23-26 big cog works great on the majority of paved roads (grades up to 6%) and is usable up double digit segments so you can do fine with a full-sized double for classic looks, no negligible risk of accidentally shifting to the small ring, and a couple ounces less. In sufficiently flat places that works well too even with middle aged spread and/or stopping structured training.
Otherwise you want a triple.

Assuming you're still running 10 cogs officially the short cage is for doubles with all cogs except 13-29, medium for doubles with all cogs and triples all cogs except 13-29, and the long cage is approved for everything.

Unofficially people have had success with 53-39 x 13-29 and there's some wiggle room.

ricohman

My 12-27, 50-34 compact drove me nuts. Still does. I live on the flats and its cross chain city.
I swapped the compact for a standard road to gain all my sweet spots back. And the 39-27 was great for hills.

My new CAAD10 has an SL-K carbon compact. I would like to swap the rings, but I cannot find any FSA rings for sale individually.
I'd like to try the mid-compact.

Drew Eckhardt 

They're standard 110mm BCD rings. Apart from cosmetics there's nothing stopping you other branded rings.

ricohman

My worry is the fitment to the crankarm, not the BCD. I guess I could grind away or have gaps.

Fox Farm

Put an 11-25 or something like that on as a cassette with your 50/34 and you will have nearly the same big gear in the 50 / 11 as you would with a 52 / 12

Drew Eckhardt 

Eddy dominated the spring classics with a 52x13.

50x13 is only half a gear easier than Eddy used and plenty for the rest of us, being pleasant for cruising speeds up to 30 MPH and sprints 40. Going down steeper hills tucking works well enough.

People did fine with 52x14 as the common top gear during the bike boom. I've run 50x13 for the last 16 years including a decade in the Colorado Rockies. The advantage over a smaller starting cog is that you get more in between for a given range, and cogs running 16-17-18-19 feel great on flat ground.

This ignores the applications of smaller cogs with smaller rings, where eschewing the fully-cross-chained combinations a 34 ring with an 11 starting cog is like having a double with a 39 ring and 13 starting cog or triple with a 39 and 14.

Noting that I've been playing with 50-39-30 and a 14-23 10 cog straight block. Having one cog jumps to the 21 cog is a little better than stopping at the 19, but the 22 is superfluous unless you're Lance time trialing up l'Alpe d'Huez and 13-26 or 12-23 is probably a better choice.

Scorer75

I've been running a 50/34 for a while.

I usually like it, but sometimes have a hard time finding that sweet spot without changing the rings a billion times on a ride.

I use a 12-23 locally, and a 12-27 when I go to the hills, I've also used a 12-25 with good results. My buddy recently gave me a bike for a ride I have coming up, and it has a standard crank. I'm really nervous about going with a 39 tooth small ring on some of the climbs on that ride Let's see how that 39 ring works for me in training...

BoSoxYacht

I use a 50/39 standard crankset with a 12-23 cassette. Nearly all of my riding is in the big ring, and I love having the 18t cog that you get with a 12-23 cassette.

My next crankset will be a 50-36 compact. 34x23 is useless here in Phoenix.

Bah Humbug

It's a good thing you're here to make these decisions for us. Amazing you know all our riding conditions, fitness levels, and goals to know what's best for everyone.

chasm54

Dislike a 50/34, but that doesn't mean I dislike compacts. I currently run a 50/36, with a 12-25 cassette. That is a big improvement over the 50/34 I used to have, somehow the smaller drop between front rings means that I find it much easier to be in the right gear.

Having said that, I think the much-touted advantages of a compact over a triple are illusory. Put on a road triple - 50/39/30 - and an 11-21 or 23 cassette and one can have the range of a compact with the advantage of really nice tight ratios at the back. And a shimano 105 or Ultegra triple shifts as cleanly as a compact.

Drew Eckhardt 

Presenting different views grounded in fact and historic frames of reference amongst calls to use gears more like genetic mutants with 2-3 times the power to weight ratio seems very reasonable to me.

Jakedatc

50/36 with 11-28 here in RI... most of the rides i do i can stay in the 50 ring for most of the ride.. 50-25t gets me up most short hills. If the hill is extended, i'm tired on a longer ride or i go further west to CT then the 36 gets more use. for me, here the jump to 34 is too much but i did put it in the middle of my rain/MUP bike's triple

Bah Humbug

And, yet, your constant preaching doesn't change what I like best, for my fitness, on my terrain. Do you have any idea the level of ass you sound like telling everyone you know better than they do what gearing to run? Especially when you paste the same rant in every thread?

Bandera

I was building a new "Rando-style" bike up a few months ago and thought I'd give compact a try.
So far I like it, quite appropriate for that bike and it's intended use.

Running 50/34 w/ 12-25 allows me to remain seated all the way up my local Hill Country grind w/ a nasty 34/25 pitch at the top into the next valley. Beats standing and doing a bad Ocana impression in 39/25, Wheez...

50/12 is plenty tall enough, so is 53/13 my Vitus's top gearing. I gave up trying to scare myself a long time ago.


-Bandera

Drew Eckhardt 

I said that full-sized doubles with a 23-26 big cog work great for guys making 3.5W/kg living in the Colorado Rockies (been there, done that) and the rest of us living in sufficiently flat places (been there, done that too). There's a lot of wiggle room there.

I'd like to be able to buy new equipment which suits my tastes and that was looking less likely as lemmings leapt on the compact band wagon. Keeping the triple crank dream alive on-line reduces the chances of that happening. Campagnolo has seen the market demand and is now shipping 3x11 combinations, and Shimano hasn't joined SRAM's move to a compact only lineup. OTOH 13 starting cogs are going away and SRAM is double-only with no 18 tooth cogs.

I'll stop posting the same rant when other people stop asking the same gearing questions over and over, people stop suggesting everyone needs an 11 cog, "compact" isn't the most common response to "my gears aren't low enough," or I get tired of it.

The same gearing questions have been recurring for decades on the internet, people aren't going to stop the push for 11 tooth starting cogs until 10 tooth ones come from the big manufacturers, and I've grown a lot more patient with age.