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Road Cycling “It is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle.” -- Ernest Hemingway

02-28-11, 05:15 PM
#1
Phantoj
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https://www.amazon.com/Mastering-Esse...8934376&sr=1-8

OK, I know this is a troll/parody thread, but seriously, the key to figuring out "Should I get a compact crank?" "Can I go from a triple to a compact?" "Is it worth \$100 to go from a 12-27 to a 12-28", etc., is to take the ratios in your current setup, and figure out how the ratios (that's fractions) would be different in the potential setup. Do you spend any time climbing in your lowest gear? Do you wish it was X% higher or lower? Do the math!

Here's the relevant equation for you math majors:

Your personal experience + a little common sense > opinions of riders unlike you X 1000

If you're not so handy with the fractions, you can even make use of a number of online gear calculators...
02-28-11, 06:20 PM
#2
merlinextraligh
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Add in a power calculator, such as this: https://www.noping.net/english/, and a mapping program such as this https://ridewithgps.com/, and for those too lazy to do math, https://www.sheldonbrown.com/gears/ and you've got all you need.

Figure out the grades you're riding with the mapping progam.

Figure out the speed you can maintain on that grade with your power/ weight ratio.

Select geat that allows you to maintain desired cadence.
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02-28-11, 06:35 PM
#3
Seattle Forrest
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So I'm thinking of going from an 18-45 cassette to an 11-23. That'll make it harder to climb hills, right? I looked up the grade, and it said pass.
02-28-11, 07:06 PM
#4
Randochap
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It's not just about formulas. The jumps between front rings--and what a rider will tolerate on wide range gearing--play an important part of the decision.
02-28-11, 07:12 PM
#5
merlinextraligh
pan y agua

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Originally Posted by Randochap
It's not just about formulas. The jumps between front rings--and what a rider will tolerate on wide range gearing--play an important part of the decision.
but again, if you know the power you're capable of, the terrain you ride and the cadence you like, you can figure that stuff out. For example, you can figure out that the speed you usually cruise at on the flats and the cadence you like puts you right in the 53/16, which means you might want to buy the 12/27 which has a 16, and not the 11-28 which doesn't.
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03-01-11, 10:18 AM
#6
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Originally Posted by Randochap
It's not just about formulas. The jumps between front rings--and what a rider will tolerate on wide range gearing--play an important part of the decision.
Because shifting down 3 rcogs in the back before shifting to the 34t chainring is soooo much harder than shifting 2 down when shifting to the 39t chainring .
03-01-11, 10:26 AM
#7
RT
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Quite frankly, I do not notice a significant enough difference between my 8 speed 12-25 and my 10 speed 12-25 on the same double crank. My 9 speed 11-26 is about the same. It's not like you only have a handful of ratios to choose from. I don't know how I ever did my paper route 35 years ago on only five speeds

IMHO, when you start talking about increasing cassette capacity, unless you're going from something like 12-23 to 11-34, it's all about the middle being more compact. I prefer not having to switch gears three times to get to where I am comfortable (10 speed). Would rather have an 8 speed and one, maybe two shifts. As for climbing as it relates to ratios, take what you have and pedal harder/more efficiently. It may seem harder, but your body will get stronger to compensate. You'll never get stronger by making it easier to go up hills.
03-01-11, 10:28 AM
#8
Bob Ross

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Originally Posted by merlinextraligh
if you know the power you're capable of, the terrain you ride and the cadence you like, you can figure that stuff out.
I would contend that most folks who start these ubiquitous "What Gearing...?" threads probably don't know what cadence they're most comfortable at in any objective sense, and definitely don't know what power they're capable of.

imho the answer is not more math, but rather more remedial explanations of how gears work and how to use them in a practical situation.
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