# Gearing Explained?



## bolt30 (Sep 4, 2006)

Alright, I am about to replace the worn out cassette (already did the chain which is how I know the cassette is shot) that came on the used road bike I bought (first one). Therefore, I am faced with the choice of cassettes to replace it with. Unfortunately, I don't really grasp all the aspects of gearing. Anyone no of a good site to read about it? Or can someone here explain it to me? The bike currently has 11-23 cassette and 53-39 chain rings. I live in Norhtern VA where most of the riding is flat with rolling hills. However I would occassionally like to go to the Shenandoah Mountains to do some climbing. Is the current setup good for this or should I consider changing? I've done about 200 miles on the current setup and found it OK. But I don't know any better either. I should mention that I am in good shape as I am a runner. I know that cycling is different, but my cardio is at least at a good point. Anyway, hope someone can help me out here and thanks in advance.


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## ARP (Mar 7, 2002)

*9 speed? Shimano?*

Go with a 12-25, I would go with a 105 group cassette and a new chain with a quick link connector. Without getting too technical, the 25 lowest gear will give you a lower gear for climbing and the 12 is plenty tall enough for fast downhill descents. 105 group because it is cheaper, quick link because you need a new chain if the cassette is worn out (so is the chain) and quick link because they make removing the chain for cleaning really easy.


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## bolt30 (Sep 4, 2006)

*10 Speed Campy*

Thanks Lone Gunman. I should have mentioned that. Thanks for the feedback.


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## dekindy (Jul 7, 2006)

I think I would go for a 12-27 and/or think about a 53/39/30 triple in front. If you have not trained for hills, they will zap you. A lot of riders in Indiana that ride the Hilly Hundred will go to a 30 front and 30 rear to get a 1:1 ratio to combat the hills.


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## John Nelson (Mar 10, 2006)

Assuming that all you are planning to change is the cassette, the only thing you need to know about gearing is that difficulty will be inversely proportional to the number of teeth. So if you get a 12-27, pedaling in the the 27-tooth cog will be 23/27 as hard (and 23/27 slower) than the 23-tooth cog. Doing the division says that the 27-tooth cog will be 15% easier (85% as hard) than the 23-tooth cog. A 25 tooth cog will be 8% easier than the 23 tooth, and 7.5% harder than the 27 tooth.

I don't know anything about the Shenandoah Mountains, but I suppose that it's safe to say that they have climbs of all sorts of different difficulty. And I don't know anything about how strong you are either. So it's really hard to say what gearing you need. But assuming you have a fair amount of training under your belt, and aren't 70 years old, the 25 or 27 tooth cog will get you up most hills.The more difficult the hill, the more you'll be out of the saddle.


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## golzy (Dec 18, 2005)

This doesn't exactly address your question but can still be handy to figure out what you're looking for in a cassette (and it's fun to play with too):

http://www.sheldonbrown.com/gears/


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## tgiboney (Jan 11, 2006)

bolt30 said:


> Alright, I am about to replace the worn out cassette (already did the chain which is how I know the cassette is shot) that came on the used road bike I bought (first one). Therefore, I am faced with the choice of cassettes to replace it with. Unfortunately, I don't really grasp all the aspects of gearing. Anyone no of a good site to read about it? Or can someone here explain it to me? The bike currently has 11-23 cassette and 53-39 chain rings. I live in Norhtern VA where most of the riding is flat with rolling hills. However I would occassionally like to go to the Shenandoah Mountains to do some climbing. Is the current setup good for this or should I consider changing? I've done about 200 miles on the current setup and found it OK. But I don't know any better either. I should mention that I am in good shape as I am a runner. I know that cycling is different, but my cardio is at least at a good point. Anyway, hope someone can help me out here and thanks in advance.



You state “already did the chain” so I’m assuming that you have swapped out he chain. If so when you change the cassette to a different ratio you may have to change the length of your chain.


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## bolt30 (Sep 4, 2006)

*Thanks*

Thanks for the replies. Good point tgiboney. I'm leaning toward getting the 12-25. Unfortunately, I have already cut and installed the chain for the 11-23. I'll get the 12-25 and see if it will work. Hopefully the chain won't be to short! I'd hate to have to toss a brand new chain! But it sounds like the 12-25 is better than the 11-23 for the terrain I want to ride. I guess the 11-23 is more for an area that is basically flat. Thanks again.


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## Cory (Jan 29, 2004)

*Personally, I couldn't ride an 11-23 down my driveway*

Full disclosure: I'm an old guy who's taken about six weeks off for various lame reasons, so I'm suffering even more than usual on climbs these days.. Even so, I think 11-23 is unrealistic gearing for nearly everybody, especially in hills, and 11-25 is only marginally better. When Greg Lemond used to conduct clinics in the Sierra foothills near here (he started riding in Reno), even HE ran a 26-tooth large cog (I'm thinking 13-26, but a little voice is saying, "THAT can't be right!"). The students would show up with their 11-19s, and they'd all go ride on the first day, and that night everybody was scrambling for lower gears.


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## brianmcg (Oct 12, 2002)

Cory, that's a funny story.

I would think, especially in the beginner forum, that everyone should have at least a 12-27. A 13-30 Century Special (www.sheldonbrown.com) would be even better.


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## Argentius (Aug 26, 2004)

12-25 is a good all-'rounder cassette but beginners on bigger mountains could appreciate easier gears. Depends upon your style and fitness.

Took me a while not to need my 26. Now I ride an 11-23 and don't use the 23 more than once a week...


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## Zwane (Jun 30, 2006)

I'm 26, in pretty good shape, but there are lots of hills here ranging from 10-19% for over 1km and i still need to get out of the saddle with my 12-27, my daily ride has a 1.3km 8-15% hill, i'm sure i could do it in the 12-25 but with a lot of suffering out of the saddle and perhaps not after doing 100km+... Of course my idea of 'pretty good shape' may also be wrong.


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## funknuggets (Feb 4, 2004)

In my opinion...

Cassettes are cheap enough that why doesnt he just buy two. I have a climby one (12x27) for when I go to the hills... then I typically around here run 11x21 or normally a 11x23... I live in MO, and the hills here are a lot less long, and often more severe than when I go to the mtns. I dont really know why "chain length" is even an issue. Anyone of decent enough knowledge knows not to hit the "big-big" where the limits of the DR would be severely tested. If they stay off of that combo.... staying between 12x25 would really not really matter vs the 12x23. Ive run them both with the same chain without any negative consequences. But... I would estimate at load that big big combo could probably rip the DR off. Just gotta be smart.

I vote for getting one of each. Cant have enough bike parts...


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## Argentius (Aug 26, 2004)

I hear ya. I live on the side of a canyon that's about 500' deep, there are several roads up the thing ranging from the gentle 5% side to the brutal 12% avg, 21% max. But with only 400' of gain, I just power over it... if it were 5 km at 10% I would certainly use a 23 or 25.

Funk's pretty right on though, as long as you don't get silly Ti ones cassettes are cheap enough and changing them is a 5-minute affair...


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## bolt30 (Sep 4, 2006)

*Thanks*

Thanks for all the replies. I ordered a 12-25. I'll see how that works out. Going with two cassettes is a pretty good idea as well. I was wondering though, lets say I mainly rode the flats with a 11-23 and then decided to hit steeper terrain and wanted to switch cassettes. If the chain primarily runs on a 11-23 and has broken in a stretched some with that cassette can you just switch to say a 12-27 and be OK? Just curious.


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## funknuggets (Feb 4, 2004)

*I think you will be fine.*



bolt30 said:


> Thanks for all the replies. I ordered a 12-25. I'll see how that works out. Going with two cassettes is a pretty good idea as well. I was wondering though, lets say I mainly rode the flats with a 11-23 and then decided to hit steeper terrain and wanted to switch cassettes. If the chain primarily runs on a 11-23 and has broken in a stretched some with that cassette can you just switch to say a 12-27 and be OK? Just curious.


Just follow the standard ... stay off the small small and big big and you will be fine within the limits of your DR. 

As far as the 'chain stretch" and wearing in... I think if you keep a new enough chain on, you will not notice much difference between the two. If you let them get really worn, you might notice some clatter in certain gears, but overall you will be fine.


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