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  1. #1
    Knowing's half the battle SushiJoe's Avatar
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    50/11 Compact vs. 53/12 Standard.

    I posted this in another thread but I see it come up quite often: "Which gearing is bigger?"
    50/11 is a bigger gear than 53/12. Here's some data.

    53/12 and 172.5mm cranks--
    Gear Ratio: 4.42
    Gain Ratio: 8.60
    Skid Patches: 12
    Gear inches: 116.5 in.
    Development: 9.296m (366.0 in.)

    50/11 and 172.5mm cranks--
    Gear Ratio: 4.55
    Gain Ratio: 8.85
    Skid Patches: 11
    Gear inches: 119.9 in.
    Development: 9.568m (376.7 in.)

    For what it's worth.

  2. #2
    umd
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    And... a 53x11 is bigger still.

    What the hell is a skid patch?

  3. #3
    Edificating dmotoguy's Avatar
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    haha.. its for fixed gears, they want the most skid patches so they dont get one or a couple flat spots when they skip or skid.

  4. #4
    Knowing's half the battle SushiJoe's Avatar
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    Haha, not too sure! I've got gear calculation software and that's one of the pieces of data. Anyone else know?

  5. #5
    umd
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    Quote Originally Posted by dmotoguy View Post
    haha.. its for fixed gears, they want the most skid patches so they dont get one or a couple flat spots when they skip or skid.
    How does the gearing affect that?

  6. #6
    Knowing's half the battle SushiJoe's Avatar
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    Quote Originally Posted by umd View Post
    And... a 53x11 is bigger still.

    What the hell is a skid patch?
    That's actually what I'm running on my Wilier: a DA 7800 53/39 crank with a SRAM Red 11-26 cassette.

  7. #7
    Sensible shoes. CastIron's Avatar
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    It's all about torque.
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    Quote Originally Posted by cedricbosch View Post
    It looks silly when you have quotes from other forum members in your signature. Nobody on this forum is that funny.
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    Why am I in your signature.

  8. #8
    nom nom nom Frunkin's Avatar
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    Quote Originally Posted by umd View Post
    How does the gearing affect that?
    You generally skid with your feet in roughly the same position and if there are only a few skid patches you will wear the tire unevenly in those spots.

  9. #9
    Senior Member rankin116's Avatar
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    Quote Originally Posted by umd View Post

    What the hell is a skid patch?
    I've always heard it called a 'mark'. YMMV.




  10. #10
    Senior Member grolby's Avatar
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    50x11 is a bigger gear than 53x12, but so what? The jump from 50x12 to 50x11 is much worse than the jump from 53x13 to 53x12. I prefer to avoid using the little cogs for that reason, among other. Not that the difference between a 50 and 53 tooth ring is enough to make a whole lot of difference, but I don't think that top-end gearing is one of the more important objections to compact gearing. And like umd says, you can just slap on an 11T cog, and the "biggest gear" prize goes to the standard double.

  11. #11
    bf is my facebook. ljrichar's Avatar
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    Is the reverse true? Is a 39x27 smaller a gear than 34x25 for instance? If so, what's the benefit of compact gearing?

  12. #12
    umd
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    Quote Originally Posted by ljrichar View Post
    Is the reverse true? Is a 39x27 smaller a gear than 34x25 for instance? If so, what's the benefit of compact gearing?
    You can always calculate the relative ratios. 39/27 is 1.44 and 34/25 is 1.36, so it is still a smaller gear. Of course whatever cassette you can put on a 39 you can also put on a 34 so you will always be able to get a lower gear with a compact just like you will always be able to get a higher gear with a standard.

  13. #13
    bf is my facebook. ljrichar's Avatar
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    Quote Originally Posted by umd View Post
    You can always calculate the relative ratios. 39/27 is 1.44 and 34/25 is 1.36, so it is still a smaller gear. Of course whatever cassette you can put on a 39 you can also put on a 34 so you will always be able to get a lower gear with a compact just like you will always be able to get a higher gear with a standard.
    Just curious, for someone like you who climbs a lot but also races crits, what do you run?

  14. #14
    starting pistol means war YMCA's Avatar
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    I am a cat1.
    I run 50x12 top gear and rarely need it.

    It's not the size, it's how you use it.
    At least that's what my wife says.

  15. #15
    umd
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    Quote Originally Posted by ljrichar View Post
    Just curious, for someone like you who climbs a lot but also raced crits, what do you run?
    I used a 53/39 with an 11-26 almost exclusively last year, and am switching between an 11-23 and 11-26 as appropriate this year. I have the 11-23 on my race wheels currently and the 11-26 on my "regular" wheels. I used it last weekend for a road race with a short [1km] 8% climb (with 10% pitches) without any issues and Sunday for a crit with an 8% power climb. Actually looking at the pictures you can see I'm in the middle of the cassette.


  16. #16
    umd
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    Quote Originally Posted by YMCA View Post
    I am a cat1.
    I run 50x12 top gear and rarely need it.
    I agree, I rarely use the 53x11 but it does come in handy on ocassion. I can spin a smaller gear for short periods of time but if I am on a long descent I tire quickly at a high cadence and currently need the taller gear to keep up with people.

  17. #17
    Glorified Blender mikearena's Avatar
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    Quote Originally Posted by umd View Post
    I agree, I rarely use the 53x11 but it does come in handy on ocassion. I can spin a smaller gear for short periods of time but if I am on a long descent I tire quickly at a high cadence and currently need the taller gear to keep up with people.
    Racing in California vs. racing in Florida.

  18. #18
    Senior Member Duke of Kent's Avatar
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    Quote Originally Posted by YMCA View Post
    I am a cat1.
    I run 50x12 top gear and rarely need it.

    It's not the size, it's how you use it.
    At least that's what my wife says.
    I use the 53x11-23.

    Not because I NEED it, but because:

    a) is lighter than a 12-23 or 12-25,
    b) is the same price
    c) most importantly, keeps me closer to the middle of the cassette. I'm seriously considering blocking off the 11 and 23 this season; no matter how well you adjust your RD, you can throw a chain into the spokes if you have a perfect storm of chain/RD/dirt/stick/whatever/23t combinations. Particularly if you're doing an 88mi RR over gravel, dirt, and cobbled roads.
    "If a non personal post makes you feel as if you've been attacked, maybe the problem IS you."

  19. #19
    Senior Member
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    Quote Originally Posted by umd View Post
    How does the gearing affect that?
    If you think about revolutions of the crank relative to revolutions of the rear cog, which is directly proportional to the # of revolutions of the rear wheel then for one revolution of the crank you will end up at a particular point on the cog/rear wheel. The goal is to maximize the number of unique points that your tire or cog will end up at after one revolution of the crank assuming a fixed starting and finishing position of the crank. If you can divide the rear cog into the front chainring, # teeth on the front chainring/# of teeth on the rear cog, and you have no remainder then you will only have one place where the tire will land after a revolution of the crank. You can probably see why this is bad for a fixed gear. Since I have this idea that you , UMD, are a programmer you can easily calculate the # of skid patches using the modulus of the front chainring and rear cog. You can also choose your gearing on relative primes. I dont know if this made sense as I remember thinking about it for a while about a year ago before it clicked for me.

  20. #20
    umd
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    Quote Originally Posted by jonestr View Post
    If you think about revolutions of the crank relative to revolutions of the rear cog, which is directly proportional to the # of revolutions of the rear wheel then for one revolution of the crank you will end up at a particular point on the cog/rear wheel. The goal is to maximize the number of unique points that your tire or cog will end up at after one revolution of the crank assuming a fixed starting and finishing position of the crank. If you can divide the rear cog into the front chainring, # teeth on the front chainring/# of teeth on the rear cog, and you have no remainder then you will only have one place where the tire will land after a revolution of the crank. You can probably see why this is bad for a fixed gear. Since I have this idea that you , UMD, are a programmer you can easily calculate the # of skid patches using the modulus of the front chainring and rear cog. You can also choose your gearing on relative primes. I dont know if this made sense as I remember thinking about it for a while about a year ago before it clicked for me.
    Thanks, it made sense after Frunkin's response.

  21. #21
    cmh
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    Quote Originally Posted by dmotoguy View Post
    haha.. its for brakeless fixed gears, they want the most skid patches so they dont get one or a couple flat spots when they skip or skid.
    Fixed that for you.

  22. #22
    Young and unconcerned Treefox's Avatar
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    55t big ring.

    Die schokoladenseite des radfahrens.

  23. #23
    Senior Member grolby's Avatar
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    Quote Originally Posted by ljrichar View Post
    Just curious, for someone like you who climbs a lot but also races crits, what do you run?
    There are more real mountains in CA, but we do have similar mix of short, steep "wall" climbs, gradual rollers and moderately long climbs that make it into races here in southern/central New England. I don't know about southern California, but really insane long grades that take more than 5 minutes to climb are rare in races, and most of those top out at 10-15 minutes. I've been successful riding and racing with a 53/39, 13-26 cassette in the past, and am currently using a 12-25 cassette. Honestly, in most of the races I do, a 12-23 and even a 12-21 would do the trick. A 12-23 is good enough for 90% of the climbs around here. I like the gearing of a standard double because it's low enough, the jump between chainrings isn't too great and I'm in the middle range of the cassette for typical racing speeds. I did find myself a bit fatigued from spinning the 53x13 on a few descents last year, so the jump to a 53x12 is a welcome change, even if I rarely use it.

  24. #24
    Whateverthehell Chucklehead's Avatar
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    I'm regarded as a sprinter and I use a 50-34/11-23. Never once have I felt under-geared. What I have found, though, is that with a compact I'm able to make better use of a larger portion of the cassette than I could with a standard 53-39.
    "When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return." - Leonardo daVinci

  25. #25
    umd
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    Quote Originally Posted by grolby View Post
    There are more real mountains in CA, but we do have similar mix of short, steep "wall" climbs, gradual rollers and moderately long climbs that make it into races here in southern/central New England. I don't know about southern California, but really insane long grades that take more than 5 minutes to climb are rare in races, and most of those top out at 10-15 minutes. I've been successful riding and racing with a 53/39, 13-26 cassette in the past, and am currently using a 12-25 cassette. Honestly, in most of the races I do, a 12-23 and even a 12-21 would do the trick. A 12-23 is good enough for 90% of the climbs around here. I like the gearing of a standard double because it's low enough, the jump between chainrings isn't too great and I'm in the middle range of the cassette for typical racing speeds. I did find myself a bit fatigued from spinning the 53x13 on a few descents last year, so the jump to a 53x12 is a welcome change, even if I rarely use it.
    In California long climbs in races are much more common. Many races are comprised mainly of long threshold climbs. For example, this is the race from this weekend that I unfortunately flatted out of, so this isn't my data:



    The data shows it took the rider about 40 minutes to do the main climb.

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