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Gear ratios 42/16 vs. 32/16 - First ride on my new bike today (9 speed)

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Gear ratios 42/16 vs. 32/16 - First ride on my new bike today (9 speed)

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Old 12-26-04, 10:49 PM
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prestoncrawford
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Gear ratios 42/16 vs. 32/16 - First ride on my new bike today (9 speed)

So I took out my new winter/commuter bike today for the first time. For
reference, this is the bike. Bianchi Castro Valley 9-speed.

http://www.bianchiusa.com/607.html

Took it on the "big" hill I have to ride every day (usually in the lowest
gear on my Trek 1000). I did fine personally, but it was mashing, to be
sure. I'm a bit concerned that mashing like that, I may do some damage to
my legs/knees and that I might be better off with 32/16 ratio. Can any of
you who single-speeds or commuter bikes give me an idea of what kind of
ratio you ride? If I go to a 32/16, will I find myself needing more gears?
If I stay with the 42/16 will I find myself building up muscles I don't
need (I already have big thighs) or unnecessarily beating up my joints? My
sense from the first ride is that I need to gear down. But I was curious
what others had to say on the issue.

One more thing. If I switch to 32/16, will I find myself seeing much of a
difference between gears 1-8, do you think? By that I mean, since this
isn't a single-speed and does have gears, do you think that gives me a
better shot at getting away with a smaller chainring in the front?

Also, for reference, I live in Portland, Oregon. Quite hilly here. No San
Francisco, but still pretty hilly.

Thanks,

Preston
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Old 12-26-04, 11:01 PM
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prestoncrawford
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One more thing...

The reason I chose this ratio (32/16) even though this bike is a single in
front, is because I did a lot of Googling and this turned up as a common
hill-climbing ratio for single-speeds. So I thought that may be the place
to start. Maybe something bigger would work as well.

Preston
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Old 12-26-04, 11:21 PM
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prestoncrawford
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Obviously I meant to discuss the ratio with *my* big back chainring, a 26, not a 16. That was a typo prompted by my fixie research into optimum ratios, etc. Obviously my choice is between 42/26 and X/26. Sorry for the confusion.

Preston
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Old 12-27-04, 01:22 AM
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Do you see yourself realistically using the top gear that you currently have on a regular basis? If you don't then get a smaller chainring (try a 38 or so) if yes, then well, you're stuck.
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Old 12-27-04, 01:34 AM
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prestoncrawford
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I don't see myself using it on a regular basis and I do think the bike is currently very close to being good enough to do hills. So yeah, maybe a 38. Is a 38/11 a good enough ratio for riding on the flats?
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Old 12-27-04, 01:42 AM
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I'd say 38/11 is pretty decent. You know I plugged in some numbers at Sheldon Brown's gear calc, http://www.sheldonbrown.com/gear/. I put in your tire size, 700x28c. I guessed at 170mm cranks. Asked it to show gear inches. Put in sizes of 36, 38, 42, so the differences could be seen. Here's how it came out:

42 38 36
Low: 26 43.2 39.1 37.1 gear inches

High: 11 102.2 92.4 87.6 gear inches

With a high of 87 gear inches, it looks like a 36 might be right for you. Most single speed and fixed gear bikes are around 70 gear inches, and you'd have that, and then some, as well as a plenty of low with that low 26 on there. You could probably go down to even a 34 if you don't mind losing the top end speed on the downhills.

Really though its just up to you. Play with the gear calculator and see what the real differences are, that's what I usually do.

[EDIT: That chart didn't come out like I had hoped. See the attached one instead]
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Old 12-27-04, 11:32 AM
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prestoncrawford
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Thanks for the analysis. That's helpful. Do you think that's the way to go, then? Someone else suggested replacing the rear cassette with something with more range.
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Old 12-27-04, 11:50 AM
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Well you have a pretty good range already with an 11-26 cassette. You can go bigger though, up to a 34 for a low. That would be a good change without having to change your chainring at all. Plus, you'd keep your top end. Just make sure you have a rear derailer that can handle the larger cogs in the back.
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Old 12-27-04, 11:51 AM
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Forgot to mention the URL to see a bunch of available (and custom!) shimano cassettes.
http://sheldonbrown.com/harris/k7.html#9
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Old 12-27-04, 12:03 PM
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I don't have a single speed, but it's so flat around here that I usually don't shift. On my old commuter I would ride 38x13 unless going over something bigger than a freeway overpass. That bike has 26" tires.

My new bike I shift all the time, I think i just like pushing the STI levers all over the place.
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