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Old 02-10-09, 04:26 PM   #1
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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.
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Old 02-10-09, 04:35 PM   #2
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And... a 53x11 is bigger still.

What the hell is a skid patch?
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Old 02-10-09, 04:37 PM   #3
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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.
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Old 02-10-09, 04:37 PM   #4
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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?
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Old 02-10-09, 04:38 PM   #5
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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.
How does the gearing affect that?
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Old 02-10-09, 04:40 PM   #6
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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.
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Old 02-10-09, 04:41 PM   #7
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It's all about torque.
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Old 02-10-09, 04:42 PM   #8
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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.
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Old 02-10-09, 04:46 PM   #9
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What the hell is a skid patch?
I've always heard it called a 'mark'. YMMV.



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Old 02-10-09, 05:19 PM   #10
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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.
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Old 02-10-09, 05:41 PM   #11
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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?
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Old 02-10-09, 05:46 PM   #12
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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?
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.
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Old 02-10-09, 05:51 PM   #13
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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?
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Old 02-10-09, 05:55 PM   #14
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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.
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Old 02-10-09, 05:59 PM   #15
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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.

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Old 02-10-09, 06:02 PM   #16
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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.
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Old 02-10-09, 06:11 PM   #17
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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.
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Old 02-10-09, 06:24 PM   #18
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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.
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.
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Old 02-10-09, 06:27 PM   #19
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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.
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Old 02-10-09, 06:33 PM   #20
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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.
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Old 02-10-09, 06:38 PM   #21
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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.
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Old 02-10-09, 06:54 PM   #22
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55t big ring.

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Old 02-10-09, 07:05 PM   #23
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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.
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Old 02-10-09, 07:07 PM   #24
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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.
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Old 02-10-09, 07:18 PM   #25
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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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