# HELP! Understanding Sprocket Sizes?!



## Canuckophile (May 23, 2011)

Hello group,

The Shimano Ultegra CS-6700 rear cassette comes in the following ratios:

Option 1 11-23
Sprocket Sizes 11-12-13-14-15-16-17-19-21-23

Option 2 11-25
Sprocket Sizes 11-12-13-14-15-17-19-21-23-25

Option 3 11-28
Sprocket Sizes 11-12-13-14-15-17-19-21-24-28

Option 4 12-23
Sprocket Sizes 12-13-14-15-16-17-18-19-21-23

Option 5 12-25
Sprocket Sizes 12-13-14-15-16-17-19-21-23-25

Would you please explain to me how these sprocket sizes work?

More specifically, which one would allow me to have the most power in the flats?

Which one would have the easiest granny gear for the hills?

Thank you,

Canuckophile


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## brucew (Jun 3, 2006)

It's not the gears that give you power, it's the legs.


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## brucew (Jun 3, 2006)

brucew said:


> It's not the gears that give you power, it's the legs.


Let me flesh that out a bit. You're near Ottawa, right? I ride in the Rideau Lakes region every July. Been visiting there since 1962, riding it since 2006.

When I started on '06, II needed a triple (52/39/30) with a 12-28. These days I run a standard double (53/39) with a 12-27, and then only because of one hill. (The climb out of Westport towards Perth.)

Back in '06, I couldn't imagine riding anywhere around there without a granny gear. These days I'm feeling pretty chuffed that I can do it--and easily--without one. It wasn't the gears that made the difference over these years, it was the legs.

My point is, the question you're asking depends on a whole lot more than just one part of the bike. It depends on the gears in the front too, but mainly, it depends on your legs. And that's the part you left out of the question.

Yes, bigger gears in the back will help on the climbs. But smaller gears in the back don't translate into speed and power. Only kms under your wheels--and thousands of them--will do that.

On the flats, your pedaling style also influences the choice of cassette. Many guys who have been riding for years and years, started out with a limited number of gears and have developed a pedaling style based on that. They seem to find a gear they like, stick with it and adjust their cadence and power output to the terrain.

Newer guys like me, tend to find a cadence and power output we like, then change our gears to adjust to terrain.

Which way you lean informs the choice of cassette. I strongly prefer "close-ratio" cassettes. I ordinarily run a 12-23 on three of my bikes, an 11-21 on the fourth. The gaps between the gears on a 11-28 are a total frustration for me. 

Hell, I'm thinking this year of taking my 12-23 along with me for the days I don't ride that hill out of Westport. I miss my 18 in the headwinds on the flats, and find myself hunting between the 17 and 19.

See what I mean? It's the legs that that should choose the cassette, not a bunch of strangers on an internet forum.


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## brucew (Jun 3, 2006)

Canuckophile said:


> Would you please explain to me how these sprocket sizes work?
> 
> Which one would have the easiest granny gear for the hills?


And through all that, I didn't answer two of your questions.

The numbers are how many teeth are on each of the gears that make up the cassette. To find out what's on your current bike's cassette, simply count them.

The granny isn't on the cassette. It's the smallest ring on a triple crankset. The 30 on a 52/39/30.


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## ericm979 (Jun 26, 2005)

Larger sprockets on the rear wheel mean lower gears. Smaller chainrings on the crank mean lower gears.

You can use http://www.sheldonbrown.com/gears/
to plot the gearing you have now and the gearing you'd get from different cassettes. Most people use "gear inches" instead of gain ratios.

A higher gear won't make you faster on the flat. You'll be turning the cranks too slowly to make sufficient power.


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## Canuckophile (May 23, 2011)

brucew said:


> It's not the gears that give you power, it's the legs.


Is this guy really this big of a dip ****?


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## Kontact (Apr 1, 2011)

Canuckophile said:


> Is this guy really this big of a dip ****?


Nope. He's actually one of the most respected guys on the forum. Consider your next post carefully.



For you, who can't figure out how rear cassette gearing works, despite the Google:

Little number is the high gear - for downhills and flats. 11 is higher than 12.

Big number is a low gear for climbing and going slow: 27 is lower than 25.

Bikes tend to come with somewhat reasonable gearing, so pay attention to that and modify accordingly. If the gear ratios are too high, you won't use them. If the gear ratios are low, you won't use those. Pick a cassette with gearing that is useful and you'll have more choices to keep the right cadence.


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## tihsepa (Nov 27, 2008)

Canuckophile said:


> Is this guy really this big of a dip ****?


No but he is right and you just labled yourself. Nice. 
Negative rep for you.
Ride more and you will have more power. Thats it.


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## cxwrench (Nov 9, 2004)

Canuckophile said:


> Is this guy really this big of a dip ****?


wow...10 whole posts and you're slamming people. nice. :nono:
considering you're the one w/ no clue about gearing, you might want to watch the attitude for a while.


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## johnlh (Sep 12, 2008)

Canuckophile said:


> Is this guy really this big of a dip ****?


The initial post would suggest yes, but notice that he followed it up with a very helpful second post.


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## Canuckophile (May 23, 2011)

Kontact said:


> Little number is the high gear - for downhills and flats. 11 is higher than 12. Big number is a low gear for climbing and going slow: 27 is lower than 25.


Hi, that is what I was looking for...thank you!

I would say OPTION 3 would be the best for me with 11 - 28.

Option 3 11-28
Sprocket Sizes 11-12-13-14-15-17-19-21-24-28

Cordially,

Canuckophile


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## danl1 (Jul 23, 2005)

Canuckophile said:


> Hi, that is what I was looking for...thank you!
> 
> I would say OPTION 3 would be the best for me with 11 - 28.
> 
> ...



There are a fair number that would argue that if you 'need' the 28, you won't have much use for the 11. 

There are some exceptions, but it's a fair analysis in most situations. 

Also, you didn't mention if you have a standard or compact crankset. Can't really answer meaningfully without taking that into consideration.

Generally, closer-ratio cassettes are more comfortable in overall use - the ratios being closer-together makes it easier to find a 'just right' gear. In particular, stretching the ratios puts uncomfortably long gaps in the middle of the cassette where you spend most of the time.

Bear in mind that you don't need to get Ultegra - anything from Shimano or SRAM will work (within limits.) Miche, IRD, and others also make compatible cassettes. That provides a lot of extra options.

I like a 12-25 as a good compromise, but SRAM has a 12-28 that is sensible enough to include the 16.


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## DrSmile (Jul 22, 2006)

The vast majority of "recreational" riders are best served with a 12-27 on a standard crankset and a 11-25 on a compact. If you're riding no hills then the 11-23 or 12-23 provide more intermediate gears, as there are some people that complain that a 16 or 18 tooth sprocket tends to be in their sweet spot.


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## Kerry Irons (Feb 25, 2002)

*The vast majority*



DrSmile said:


> The vast majority of "recreational" riders are best served with a 12-27 on a standard crankset and a 11-25 on a compact. If you're riding no hills then the 11-23 or 12-23 provide more intermediate gears, as there are some people that complain that a 16 or 18 tooth sprocket tends to be in their sweet spot.


Actually, I would argue that the "vast majority" of recreational riders have very little use for a 12 (standard) or 11 (compact) and would be much better served with closer spaced gears in their normal riding range. What the vast majority of recreational riders need to do is work on their spin. Somehow a lot of people think that cycling doesn't require skills, but only power. A 53/12 at 100 rpm is 34+ mph and a 50/11 is 35+ mph, which very few people can hit on anything but a downhill, and at that speed you are better off in a tight tuck.


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## DrSmile (Jul 22, 2006)

I agree in concept but unless you're riding Campy cassettes that start with 13 aren't standard and with 11 speed Campy the only thing you're losing going from the 12 to the 11 is the 19.


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