Tuesday, April 19, 2011

Are you man enough... to use a compact?


"You ride a compact? Why aren't you using a standard crank?"

We've all heard this comment. Many of us have made it. The subtext of that statement is clear.

"You are weak. HTFU and ride a real big ring, you wheel sucking little man."

It's the cycling version of a pissing contest. The "standard vs compact" argument. Many egos out there think that a "real cyclist" should be riding a 53/39 crankset and that a 50/34 is only for "weak" cyclists. Except that's not really true. In fact, a standard crank probably doesn't make sense for most cyclists, except for those who are fairly advanced amateurs and/or racers. And even then.... Garzelli rode a 34x28 when he won the mountain time trial stage up Plan de Corones in last year's Giro. And I vaguely remember reading somewhere that some of the riders even used mountain bike cassettes with 32 teeth on that stage!

When it comes to the standard vs compact debate, most of the machismo-fest focuses on the higher gears (because nobody really brags about how low their gears go). So let's take a look at some of the numbers from a straight-up gearing perspective.

Using a standard crank with a 700/23 wheel and calculating meters of development:
53x11 gives you 10.1 meters of development
53x12 gives you 9.3 meters of development

In comparison, a compact crank with the same setup:
50x11 gives you 9.5 meters of development
50x12 gives you 8.7 meters of development

Another way to digest this would be to calculate how fast you'd go at each gear ratio.

Standard crank with a 700/23 wheel at a cadence of 90rpm:
53x11 equates to a speed of 33.9mph
53x12 equates to a speed of 31.1mph

Same variables with a compact crank:
50x11 equates to a speed of 32.0mph
50x12 equates to a speed of 29.3mph

Therefore: 53x11 (standard) is faster than 50x11 (compact) is faster than 53x12 (standard and common). 

If you're strong enough to turn over a 53x11 at 90rpm for any reasonable amount of time, then you obviously should be riding a standard crank. (And by reasonable time, I mean longer than 2.3 seconds on a -7% downhill.) But most people aren't strong enough to turn over that gear except during a sprint finish. And in fact, I'd argue that most people can't even turn over a 50x11 at 90rpm (or higher) for any significant duration.

On the other hand, I think a lot of people can use the help that compact gearing provides on steeper or longer climbs. These are the people who grind up a hill on a 39x25 at 40rpm and look like they're either going to give birth or bust a hernia while they're doing it. Not a good look. Trust me, nobody's going to remember how "pro" you looked on your big 53 ring going downhill when you looked like you were about to leave the world's greatest skid mark on that last climb.

Remember, virtually all stock "standard" drivetrains come with a high gear of 53x12 and most compacts come with a 50x12. If you wanted to increase the higher gears on a compact, you could swap in an 11-23 cassette and you'd only be missing out on the 53x11 gearing. But you'd still have the benefit of a compact's ability to access much lower gears if needed for climbing. In fact, a reasonable setup might be to have two cassettes: 11-23 for flat courses and a 12-25 or 12-27 for climbing routes.

There are some who argue that using a compact makes you "weaker" because you psychologically have an "out" to spin up a climb on a lower gear. They also argue that, because you've gotten used to spinning, you've somehow forgotten how to mash the pedals when it comes to a sprint. I don't really buy that argument. It's a question of gearing... not castration.

Use standard cranks if:
  • You truly are strong enough to turn the higher gears over at a reasonable cadence. 
  • You're a racer and you do need the 53x11 for sprint finishes, even if it's only for a few seconds. Yes, winning does matter.
  • You live in an area where the climbs don't force you into the really low gears.
Use compact cranks if:
  • You realistically can't turn over the standard cranks like some of the strongest riders. (That said, if you can use a 50x11 at 90rpm to go 32mph, you'll probably be fine for most group rides.) 
  • There's significant terrain variability in the rides you participate in... because it is far easier to swap cassettes (e.g. from an 11-23 to a 12-27) than to swap cranksets. 
  • You do a lot of climbing. Like you live on the summit of Mt Ventoux. At which point, you should probably just buy a damned car.
Of course, if you big ring it like this dude, I will lick your brake pads clean after you come to a stop from a 100mph sprint.

6 comments:

  1. i think the guy is using the big ring so he can motor pace with that porsche on the autobane

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  2. I've an old bike with a 50/39 non-compact. It raises a few eyebrows when I tell them. "You sure you don't mean 53/39?"
    It's odd because I live in very hilly terrain, and my "new" bike with a 53/39 hardly ever sees use in the big ring.

    Nobody's laughing (except me), when I spin by most riders up the hills. Then again, I manage that on my old bike with a 39/23

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  3. I've gat that same 52/42 campy crank on my bike... I love the 42 but hate going up hill.

    Sauf que le pédalier est tellement beau que j'ai pas le goût de la changer!

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  4. 55/42t for me. I like to take full advantage of the steep downhills instead of gliding.

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  5. I'm 61 years and use a 44/32/22 with an 8-speed 12-25 rear on my road bike. Live in a mountainous area.

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  6. Great article! In fact I laughed so hard reading some lines that I left "the greatest skid mark" on my chair. Thanks for the article.

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