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Understanding gearing ratios for least cadence differences

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Understanding gearing ratios for least cadence differences

Old 06-21-21, 11:46 AM
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Awesomeguy
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Understanding gearing ratios for least cadence differences

I have a 46/30 X 11-36 9 speed.
I'm mostly riding in the 46 ring, but i want understand , how do i learn\figuire out the gearing, to shift in a way, so there is list difference in the gears and cadence.
I feel like i have to go in the small ring sometimes up front, and shift down to smaller cog in the back, for lesser difference in cadence, so i want to know , to shift in way, with least difference in cadence.

Is their some sort of reference chart i can look at ?
.
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Old 06-21-21, 12:22 PM
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You can pop your chainring/cassette info in to a number of gearing calculators online (like this one here - https://mike-sherman.github.io/shift/) to show your speed in a given gear combination and cadence range - it should give you a good idea of how your gearing overlaps between the two chainrings with your cassette.

I don't know how practical this is when you're actually out riding, though. Are you really going to have the presence of mind to remember that (for instance) when you're in your 46/21 that the next step up is the 30/12? I wouldn't. Hell, most of the time, I don't even know what gear I'm in, let alone which would be next highest in terms of gear ratio.

If the gaps in your gearing are bothering you, I think that the more practical thing to do would be to use the above chart to look at new cassettes, with tighter spacing, while ensuring that you still have the necessary gearing covered for your terrain (if you don't have any hills steep/long enough to warrant the 30/36, go with a cassette that tops out at 28 or 30, for instance).
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Old 06-21-21, 12:33 PM
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Sheldon Brown's Bicycle Gear Calculator

Set up the chart in whatever format is instructive for you. I prefer gear-inches, because that's the way I was taught way back when.

I've run a simple representation of yours, and it looks like 2 clicks on the right will correct for one change for the left (in the same direction, meaning larger left, then two larger right gives the next available gear).
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Old 06-21-21, 01:18 PM
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Originally Posted by WhyFi View Post
You can pop your chainring/cassette info in to a number of gearing calculators online (like this one here - https://mike-sherman.github.io/shift/) to show your speed in a given gear combination and cadence range - it should give you a good idea of how your gearing overlaps between the two chainrings with your cassette.

I don't know how practical this is when you're actually out riding, though. Are you really going to have the presence of mind to remember that (for instance) when you're in your 46/21 that the next step up is the 30/12? I wouldn't. Hell, most of the time, I don't even know what gear I'm in, let alone which would be next highest in terms of gear ratio.

If the gaps in your gearing are bothering you, I think that the more practical thing to do would be to use the above chart to look at new cassettes, with tighter spacing, while ensuring that you still have the necessary gearing covered for your terrain (if you don't have any hills steep/long enough to warrant the 30/36, go with a cassette that tops out at 28 or 30, for instance).
same same.
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Old 06-21-21, 01:22 PM
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I like this one: Bicycle Gear Calculator.

I like the way that I can visualize what's available for different combinations of chainring and cassette gearing. Very nice for comparing, for example, two different cassettes with everything else staying the same.

One can also compare two completely different setups (including tire size). As an example, here's a comparison of my 3x7 hybrid to a 2x9 road bike that I'm working on:


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Old 06-21-21, 02:42 PM
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I agree. If you don't need the 36t, go for a tighter range. Some obsessive who rides the same 20 mile loop every day, alone, might switch front rings back and forth while watching his cadence read out. Nobody else would, even with Di2 to facilitate.
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Old 06-21-21, 03:01 PM
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11-36 is crazy wide for a road bike. I have used a 12-26 with 36/46 for years. I put an 11-32 on for loaded touring, but swap it back as soon as I get home. Don't overthink this. Use big ring for flats and downhill, the small ring for extended climbs and headwinds.
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Old 06-21-21, 03:59 PM
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Originally Posted by Awesomeguy View Post
I have a 46/30 X 11-36 9 speed.
I'm mostly riding in the 46 ring, but i want understand , how do i learn\figuire out the gearing, to shift in a way, so there is list difference in the gears and cadence.
I feel like i have to go in the small ring sometimes up front, and shift down to smaller cog in the back, for lesser difference in cadence, so i want to know , to shift in way, with least difference in cadence.

Is their some sort of reference chart i can look at ?
.
I also like the Dirk Feeken’s calculator. It’s fairly easy to see how the gears work together. Here’s your gearing with the MPH over the gear combinations. At a given cadence, match the speed and you’ll see which gear you should shift to to maintain speed and cadence. Remember that when you shift, you are usually changing speed anyway. So, for example, if you were riding in the 40/21 gear at 90 rpm and downshifted to the 24 on the back, you’d lose about 2 MPH. If you downshift on the front, you’ll lose 4 MPH which will feel a more jarring than the 2MPH transition. If you upshift one gear, the transition is similar to the 40/24 gear that you would end up with on just a rear cassette shift. This, of course, necessitates a double shift if you go that route. It’s a bit more fiddly because of the large difference between the outer and inner ring. You can play with the gearing to see if there is a better combination that doesn’t result in quite as large a transition.
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Old 06-21-21, 04:07 PM
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Originally Posted by c_m_shooter View Post
11-36 is crazy wide for a road bike. I have used a 12-26 with 36/46 for years. I put an 11-32 on for loaded touring, but swap it back as soon as I get home. Don't overthink this. Use big ring for flats and downhill, the small ring for extended climbs and headwinds.
What works for you may not work for others. A 46/36 12-26 can be crazy narrow for a road bike depending on the rider, terrain, and preferences. In Kansas, it might work. Colorado, not so much. Climbing would be much more difficult with that gearing.
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Old 06-21-21, 06:47 PM
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Don't break your brain. You should be able to ride in the big ring for general riding, and shift your rear gears to the most comfortable ratio. There is no rule. For myself, I tend to use a gear which allows me to use a quicker cadence, this is easier on the knees. I shift down as I come to a stop, then shift up as I accelerate, just as I would on a motorcycle or when driving a car. Use your gears, that is what they are there for. When I worked as a bike mechanic, I was always surprised how many people bought multi-speed bikes, but only used one gear.
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Old 06-22-21, 06:42 AM
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IMHO, the simplest way to “visualize” what the OP wants to know is using the Sheldon Brown Gear Calculator. I use the “gear inch” mode. After inputting specific wheel size and crank length, enter the number of chainring teeth (small to large) and the number of cog teeth (large to small) in the provided “boxes” and then click “calculate”. The result will be columns of numbers that can be used to compare the relationships of the gear (chainring to cog) combinations to one another. In the OP’s situation, the left column will go from 22 to ~72 and the right column from ~34 to ~110. When looking at these columns of numbers, one will see that several of the gear combinations are very similar in value. (The OP’s bike doesn’t have 18 different gears!) These numbers DO have meaning but to me, the difference between them is the most meaningful. While maintaining a given cadence, going between gear combinations with the smallest “number” difference will be the smoothest transition. Unfortunately, doing so may require “double shifting” and more than one cog decrease or increase. I’ve been mocked for this before but I’ve printed out the “gear inch” chart and taped it to the stem on several of my bikes. At a glance, I can see the gear combination that has the smallest difference (without being nearly identical) when shifting to a higher or lower gear. I suppose a person could memorize the “progression” but that’s too much work for me!
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Old 06-22-21, 06:51 AM
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Originally Posted by WhyFi View Post

I don't know how practical this is when you're actually out riding, though. Are you really going to have the presence of mind to remember that (for instance) when you're in your 46/21 that the next step up is the 30/12? I wouldn't.
This, exactly.

Once I am on the large chainring, I stay there until circumstances require me to switch to the small one. Such as, if I have to stop and then dart across a busy street, for example. Or stop and navigate a curb or something. Once I get moving enough that I can switch into the large chainring, I shift into it and I don't go back-and-forth large-small at all.
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Old 06-22-21, 07:05 AM
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Originally Posted by sovende View Post
I’ve been mocked for this before but I’ve printed out the “gear inch” chart and taped it to the stem on several of my bikes. At a glance, I can see the gear combination that has the smallest difference (without being nearly identical) when shifting to a higher or lower gear.
I can understand why - this is madness, IMO. I can't imagine a gearing gap intrusive enough that referencing a chart mid-ride world be a lesser evil. If I felt that strongly about gaps, and I couldn't narrow them satisfactorily with a new cassette and/or chain rings, I'd pony up for electronic shifting with a sequential mode.
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Old 06-22-21, 07:17 AM
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A triple half-step plus granny is my solution. I don't use the half step for progressive shifting but use it for fine tuning cadence. The challenging part is that the best half stepping comes with a 3 tooth difference between the middle and outer ring if one is using rings in the 40's and finding odd tooth count rings can be a real challenge these days. A 4 tooth difference may be better than nothing but 3 is ideal.
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Old 06-22-21, 11:46 AM
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Originally Posted by WhyFi View Post
I can understand why - this is madness, IMO. I can't imagine a gearing gap intrusive enough that referencing a chart mid-ride world be a lesser evil. If I felt that strongly about gaps, and I couldn't narrow them satisfactorily with a new cassette and/or chain rings, I'd pony up for electronic shifting with a sequential mode.
Well, it’s hardly “madness” but I’ll acknowledge that it’s your opinion. I was providing an answer to the OP’s query on how to figure out a way to understand/use the gears available on the bike that he has. The fact that the Sheldon Brown Gear Calculator actually provides a printable chart to “reference mid-ride” (actually while riding), tells me it’s not madness at all!
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Old 06-22-21, 01:09 PM
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a chart seems rather academic at best. i can't see using it while riding. after a while you just figure out what gear you need to be in based on feel. i've been told once or twice that there are things i don't know that i don't know. i think this is one of those times where that is a good thing.
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Old 06-22-21, 01:39 PM
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What the "Bicycle gear calculator" showed me is that 8 of the the 21 gears on my 3 x 7 speed comfort bike are pretty much redundant. More importantly it showed me the best progression to utilize it without spending endless hours experimenting. I suspect this is what the op is looking for. When I'm on the 48t chainring and in 2'nd gear @52 gear inches If I switch to the 38t ring and move 2 cogs up, I'm in between gears.

This tool is very useful when comparing a new bike or proposed gearing changes. For a bike we already have we needn't over think this. Just plug in the numbers to find a progression that works best. All I need to know is 2 shift points. The 28t to 38t shift and the 38 to 48t shift.
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Old 06-22-21, 01:40 PM
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I reckon part of "getting to know" a particular bike is coming to grips with its gears and your favourite cadences. A lot of the fun of riding a geared bike is the feeling that you're becoming more efficient at moving through space, and that boils down to your fitness and your understanding of your machine. For me, that understanding comes down to feel rather than number-crunching.
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Old 06-22-21, 01:49 PM
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Originally Posted by sovende View Post
.... a printable chart to “reference mid-ride” (actually while riding)
I wonder if he meant that tongue-in-cheek.
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Old 06-22-21, 02:43 PM
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Originally Posted by sovende View Post
Well, it’s hardly “madness” but I’ll acknowledge that it’s your opinion. I was providing an answer to the OP’s query on how to figure out a way to understand/use the gears available on the bike that he has. The fact that the Sheldon Brown Gear Calculator actually provides a printable chart to “reference mid-ride” (actually while riding), tells me it’s not madness at all!
Then we must ride bikes in an entirely different manner - either my effort is too hard for me to faff about with charts or my effort is light enough that it's not necessary.
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Old 06-22-21, 02:44 PM
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Originally Posted by sovende View Post
I suppose a person could memorize the “progression” but that’s too much work for me!
Interesting. I sometimes make charts, but mostly to plan builds or explain gearing to others. Referencing a chart mid-ride has always sounded very cumbersome to me.

Even if I was going to tape something to my stem, it would probably not be this...



...but instead something along the lines of this:



But I mostly have the latter in my head anyway.
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Old 06-22-21, 03:30 PM
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I use sram axs 12 speed with the widest range 10-36 cassette with a 48/31 crank. I don't have to remember much. If I shift to the little ring, I will have waited to become a little bogged down in my 48/32, make the chain ring shift and immediately follow with a shift two sprockets smaller. Another trick is to pedal standing in the big ring, then sit and shift to the little ring with no compensating shifts between sprockets. In the little ring I'll shift up if my speed gets much over 15 mph. Shift to the big ring, then 2 sprockets larger. With axs, I can set a 2 sprocket limit if a shift lever is held for a multishift.

I ride a 52 mile loop with 3000 feet of climbing in the first 20 miles. I can ride that twenty miles in the big ring, by pedaling standing in several of the steeper sections. After that, there's 2 miles with grades in the 6-12% range where the little ring is a must. After 22 miles, it's mostly down hill and big ring only.
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Old 06-22-21, 03:51 PM
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You're going to drive yourself bonkers trying to remember...

Single step upshift is usually Up in the front, down two in the rear, or down in the front, up three in the rear. Plus, that may not be uniform across the cassette. And, you'll be cross-chaining.

I generally use the front derailleur to select "high range" (flat, descents), or "low range", hill climbing. Then step up or down with the rear as needed.

So, to do tighter single-step gearing, either pick a smaller rear cassette. Say 11/23 or 11/25.

Or try a half-step chairing setup. So, for example use a 46/44 chainring setup. That way each shift will involve moving the front either up or down, and half the time moving the rear in one direction.
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Old 06-22-21, 05:43 PM
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Originally Posted by HTupolev View Post
Interesting. I sometimes make charts, but mostly to plan builds or explain gearing to others. Referencing a chart mid-ride has always sounded very cumbersome to me.

Even if I was going to tape something to my stem, it would probably not be this...



...but instead something along the lines of this:



But I mostly have the latter in my head anyway.

Of course you are joking with the crazy decimal fractions . I like the “dot” diagram but I’d have to put it on the top tube! My “chart” is much simpler:
41 (50)
47 59
54 67
63 78
71 88
(81)100

left side small chainring, right side large chainring
top of column large cog, bottom of column small cog
Parentheses indicate cross-chain combinations

Individuals can ride their bikes however they please BUT that wasn’t what the OP asked. The OP wanted a way to quantify his set up. My reply did so. A good share of the others did not!
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