"The 33"-Road Bike Racing - 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. :thumb:

And... a 53x11 is bigger still.

What the hell is a skid patch?

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.

Haha, not too sure! I've got gear calculation software and that's one of the pieces of data. Anyone else know?

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?

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. :thumb:

It's all about torque.

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.

What the hell is a skid patch?

I've always heard it called a 'mark'. YMMV.



:D

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.

Is the reverse true? Is a 39x27 smaller a gear than 34x25 for instance? If so, what's the benefit of compact gearing?

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.

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?

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.

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.

http://www.photoscene.com/kimandsteve/images/5038.jpg

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.

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.

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.

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.

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. :thumb:

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.

55t big ring.

;)

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.

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.

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:

http://www.photoscene.com/kimandsteve/images/5090.png

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

Can depend on your musculature. More of a spinner? Go smaller big ring.
I'm not a spinner. As such, for crits (flat and/or power hills), I run 53/44 and 11/21. Road races, same up front but 12/25 out back.

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. Moving from a 12 to an 11 is 9.1% jump vs 8.3% for 13 to 12. Hardly a significant difference. Just for reference if you are pedalling at 100 RPM in a 13 and shift to the 12 you will be at 92.3 RPM vs 91.7 RPM for a 12 to 11 shift.

I typically run an 11-23. Not because I need the 11, but because I don't need anything bigger than a 23 where I ride most of the time.

You can put way too much effort in all this however if you obsess. I did 2 flat crits this season with a 12-27, just because I was too lazy to change the cassette. It did not affect my performance.

I don't know how you fast guys are running compacts, I had a 50/36 and was always at one end of the cassette or the other.

I run 53/44


Love me a 44.
In fact I used to always run a 44, 45, or 46 on the inner.
That coupled with a 12-19, 7spd straight block.

Look at all the old photos.
52/44 was the norm.

I typically run an 11-23. Not because I need the 11, but because I don't need anything bigger than a 23 where I ride most of the time.

You can put way too much effort in all this however if you obsess. I did 2 flat crits this season with a 12-27, just because I was too lazy to change the cassette. It did not affect my performance.

Bingo. This isn't rocket science.

I do very flat races at home and some big climbing events in CO - last year I just went with 12-27 (on a 53-39) on both wheelsets to simplify things, and it worked fine in each location. My newer bike has a 50-34 and I'm gonna run 11-26 cassettes, and I'm sure that'll be fine, too.

Bingo. This isn't rocket science.

I do very flat races at home and some big climbing events in CO - last year I just went with 12-27 (on a 53-39) on both wheelsets to simplify things, and it worked fine in each location. My newer bike has a 50-34 and I'm gonna run 11-26 cassettes, and I'm sure that'll be fine, too.


yes, a 12x27 will cover you on all bases, but there are gaps that would drive me nuts!

How do you get on without a 16t, or even an 18t?

Switching between the 15 and 17, or the 17 and 19 all day is like my daughter never being able to get every hair in place.

I've still never understood why people make such a big deal specifically about the 16T, and why it's absence would be any more or less annoying than the 17T.

Is the reverse true? Is a 39x27 smaller a gear than 34x25 for instance? If so, what's the benefit of compact gearing?

39/27 and 172.5mm cranks--
Gear Ratio: 1.44
Gain Ratio: 2.81
Skid Patches: 9
Gear inches: 38.1 in.
Development: 3.040m (119.7 in.)

34/25 and 172.5mm cranks--
Gear Ratio: 1.36
Gain Ratio: 2.65
Skid Patches: 25
Gear inches: 35.9 in.
Development: 2.863m (112.7 in.)

I have used 53/11 in races. I have never wished for anything lower than a 39/25...

I have used 53/11 in races. I have never wished for anything lower than a 39/25...

Then you are too strong. :D

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.

And for a visual reference:

http://www.optionnz.com/users/afs/i1/FixedRatio.jpg

53x11 is advantageous on a long descent or in a TT with downhill portions, it's like a secret weapon that can be used to spin at a self-selected cadence and maintain a consistent power output.

that being said, I simply use a 53x39 and 12x25, I ride crosschained big to big all the time. I have yet to be in a sprint that I was spun out on, but have been overgeared due to operator error on occaision. Only time I wished I had a rear dinner plate bigger than a 25 or an inner chain wheel smaller than a 39 was going up brasstown bald after unicoi and hogpen gap, that thing was too steep for 39x25, at least for me, and I was glad for the pushes I got from the crowd awaiting the T o GA peloton arrival. although I'm sure I looked pathetic.

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:

http://www.photoscene.com/kimandsteve/images/5090.png

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

Harsh! I think I would get shelled pretty hard on a climb like that, though I'm working on my threshold this year. Sheesh, at least I'm more aero than most of the 140 lb guys that climb better than me. :rolleyes:

Moving from a 12 to an 11 is 9.1% jump vs 8.3% for 13 to 12. Hardly a significant difference. Just for reference if you are pedalling at 100 RPM in a 13 and shift to the 12 you will be at 92.3 RPM vs 91.7 RPM for a 12 to 11 shift.

The math doesn't change the fact that the gap from a 12 to an 11 is uncomfortably large. 13 to 12 could be smaller, too.

The math doesn't change the fact that the gap from a 12 to an 11 is uncomfortably large. 13 to 12 could be smaller, too.

ummm..... what?

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 see above that it's not true.

FYI, a 36x27 is equivalent to a 34x25, so obviously you'd need a slightly larger cog to get the same gear inches with a 39T ring. A 39x29 is about as close as you can get.

Compact gearing gets you more on the low end without moving to a triple. It only gets you more on the top end as well if you would run a 50/11 or a 53/12 (not a 53/11).

seems like a useful thread, at least on the discussion aspect.

There is a local climb that I did the other day, and for the life of me I couldn't stay seated the whole way up in my 39x25. I wanted to, I know it's better, but I just couldn't turn over the gear.

Data I found:
1.3 miles, 650 ft up, average grade 10%, max grade 15%
and
200 meters climb in 2.3 km distance. Steepest section (top of straightaway) over 15% grade

I feel like I could have knocked off a reasonable chunk of time with a 36x27 or something of that sort that allowed me to put power down more efficiently w/o hopping out of the saddle and muscling the bike around.

The GT GTR Team Carbon bike I plan to order soon comes with a DA7900 50/34. I guess I'll just have to try it out on local training rides and hopefully racing season won't be over before I get it. I'm currently running 53/39 up front and 12/25 rear for racing (12/27 for training).

ummm..... what?

Just what I said: the gap between a 12 and 11 tooth cog feels uncomfortably large when upshifting, probably because of the amount of effort I'm already putting out to turn over the 12. The 13 to 12 upshift, while not as bad, is still somewhat unpleasant. The fact that's only an 8% to a 9% gap doesn't mean that it's small enough not be unpleasant. If I'm pedaling at high effort at 100 RPM, dropping to 93 RPM doesn't feel good. An 8% gap is great closer to the middle of the cassette. I don't think this is unusual - don't most of us prefer to do most of our riding in the middle part of the cassette if it is possible?

Just what I said: the gap between a 12 and 11 tooth cog feels uncomfortably large when upshifting, probably because of the amount of effort I'm already putting out to turn over the 12. The 13 to 12 upshift, while not as bad, is still somewhat unpleasant. The fact that's only an 8% to a 9% gap doesn't mean that it's small enough not be unpleasant. If I'm pedaling at high effort at 100 RPM, dropping to 93 RPM doesn't feel good. An 8% gap is great closer to the middle of the cassette. I don't think this is unusual - don't most of us prefer to do most of our riding in the middle part of the cassette if it is possible?

As mentioned; it depends on your musclature - amount and predominant type (I vs. II). For me (to use your example), I'd rather drop from 100rpm to 93. I presume your a relatively small guy, so your example makes more sense for someone of your stature. I'm over 190lbs and push bigger gears more efficiently (than spinning smaller gears) as I'm predominantly type II...

From my usual morning route... spinning the 53x11 before slowing for a stop sign.

http://www.photoscene.com/kimandsteve/images/5091.png

From my usual morning route... spinning the 53x11 before slowing for a stop sign.

[IMG ]http://www.photoscene.com/kimandsteve/images/5091.png[/IMG ]

That's how much elevation change is on my entire 28 mile commute.

:twitchy:

That's how much elevation change is on my entire 28 mile commute.

:twitchy:

That's why I love the 53x11. I was only doing a tempo ride so I could stay in my zone. Honestly I can barely keep in my SST zone down that descent.

I like how your heart rate drifts upward on the descent.