Closely-spaced ratios = quicker shift?
Couple questions for you guys. First, what exactly are the benefits (if any) of having closely-spaced ratios? I've heard that there's a wider space in between the cogs for something like the 11/34T than there is with the 11/25T or 28T, correct? If so, does that translate to a noticeably quicker (or perhaps "snappier") shift?
The other thing is, I've heard people mention that you should stay away from gears that you don't need. I ride on flats like 98% of the time, so does it make "sense" for me to have a 50/34 crank with an 11/32 cassette? Or is there a "better" configuration? I mean I know this is super subjective, but I wonder if anyone could at least guide me in the right direction. Perhaps a 28T is better suited for someone mainly on flats? Or is there more to it than that? |
Originally Posted by Ataylor
(Post 21954514)
First, what exactly are the benefits (if any) of having closely-spaced ratios?
Power is, more or less, your pedaling torque multiplied by your cadence. Shifting allows you to balance how much torque your legs are having to put out versus how fast you're having to spin your legs in circles. Having more closely-spaced ratios means that you have finer control over this. I've heard that there's a wider space in between the cogs for something like the 11/34T than there is with the 11/25T or 28T, correct? If so, does that translate to a noticeably quicker (or perhaps "snappier") shift? Not really. Theoretically there's probably a small difference, but it doesn't really show up in practice. Wider ratios primarily make for a more disruptive shift, i.e. they'll create a larger change in the pedaling force you're having to push with, and the rate at which your legs are spinning. The other thing is, I've heard people mention that you should stay away from gears that you don't need. I ride on flats like 98% of the time, so does it make "sense" for me to have a 50/34 crank with an 11/32 cassette? Or is there a "better" configuration? I mean I know this is super subjective, but I wonder if anyone could at least guide me in the right direction. Perhaps a 28T is better suited for someone mainly on flats? Or is there more to it than that? This really depends on the particulars, because it depends on the terrain and the rider and the riding, and variation in all these things is huge. What's the context? Do you have a bicycle and you have some issue with it? Are you contemplating a bicycle purchase, and you're wondering what to look for? How strong of a rider are you, and what sorts of rides are you doing? What parts of your gearing range are you spending a lot of time in? |
HTupolev explains it really well, but I'll elaborate a little based on my experience.
Personally, I didn't really care too much about close ratios until I started training and riding in fast-paced group rides. In situations where you're at the very limit of your capabilities, hanging on by your fingernails, I find that having closer ratios helps a lot to keep you in a pocket of cadence *and* torque that's manageable. It really sucks to be just hanging on and then find that you're straddling a gap where the cadence is a little too high with one cog and the torque a little too high with the other. This is, obviously, just my experience and can't speak to the sensitivity of others with regard to this. In terms of largest cog, I'd take a look at both the length and steepness of your climbs. I live in a relatively flat area, but there are some steep pitches. That said, I can usually power my way up and over the vast majority of them within a handful of minutes. Because of my terrain and riding habits, both with solo and with the group, I prefer tightly spaced cogs and have been riding with a 50/34 and 12-25t for the last few years. |
Percentage difference between the sprockets is what matters. Shimano has a horrible 11-34 with large 11-13-15 jumps from the start, where it should be 11-12-13-14. Campy does it right, with as many small changes as possible, and larger changes only in the largest 3-4 sprockets.
My sram axs 10-36 cassette is OK, but not perfect. It doesn't have a 14. It should be like Campy's 9-36 13 speed, without the 9. 10-11-12-13-14-16-18-20-23-27-31-36. |
Originally Posted by HTupolev
(Post 21954516)
The main benefit of having closely-spaced ratios is that you have closely-spaced ratios.
Power is, more or less, your pedaling torque multiplied by your cadence. Shifting allows you to balance how much torque your legs are having to put out versus how fast you're having to spin your legs in circles. Having more closely-spaced ratios means that you have finer control over this. Wider ratios primarily make for a more disruptive shift, i.e. they'll create a larger change in the pedaling force you're having to push with, and the rate at which your legs are spinning.
Originally Posted by HTupolev
(Post 21954516)
This really depends on the particulars, because it depends on the terrain and the rider and the riding, and variation in all these things is huge. What's the context? Do you have a bicycle and you have some issue with it? Are you contemplating a bicycle purchase, and you're wondering what to look for? How strong of a rider are you, and what sorts of rides are you doing? What parts of your gearing range are you spending a lot of time in?
I honestly don't know how to describe my riding style. I wouldn't say that I'm a "strong" rider. I like longer rides. 6+ hours. I'm never really riding at a consistently fast pace. I don't ride in groups. The majority of my rides are usually pretty casual (I'm averaging about 17 mph), though I do speed about 20-30% of the time? And during those times, I'd like to experience shifts that are not disruptive - at least less so than other cassette's. I'm mainly in the top sprocket of a 50/34 chain wheel, but with regard to the cassette, though I honestly never paid super close attention to any of this, I believe I lingered in the 14 to 25 range most of the time and, as mentioned, took advantage of the 32 cog from time to time. I just don't know how big a difference there would be on a 20% incline between the 32 and, say, a 28 or a 30T cassette and whether or not that difference is worth it to me.
Originally Posted by WhyFi
(Post 21954631)
HTupolev explains it really well, but I'll elaborate a little based on my experience.
Personally, I didn't really care too much about close ratios until I started training and riding in fast-paced group rides. In situations where you're at the very limit of your capabilities, hanging on by your fingernails, I find that having closer ratios helps a lot to keep you in a pocket of cadence *and* torque that's manageable. It really sucks to be just hanging on and then find that you're straddling a gap where the cadence is a little too high with one cog and the torque a little too high with the other. This is, obviously, just my experience and can't speak to the sensitivity of others with regard to this.
Originally Posted by WhyFi
(Post 21954631)
That said, I can usually power my way up and over the vast majority of them within a handful of minutes.
Originally Posted by WhyFi
(Post 21954631)
Because of my terrain and riding habits, both with solo and with the group, I prefer tightly spaced cogs and have been riding with a 50/34 and 12-25t for the last few years.
Originally Posted by DaveSSS
(Post 21954689)
Percentage difference between the sprockets is what matters. Shimano has a horrible 11-34 with large 11-13-15 jumps from the start, where it should be 11-12-13-14. Campy does it right, with as many small changes as possible, and larger changes only in the largest 3-4 sprockets.
My sram axs 10-36 cassette is OK, but not perfect. It doesn't have a 14. It should be like Campy's 9-36 13 speed, without the 9. 10-11-12-13-14-16-18-20-23-27-31-36. 28: 11, 12, 13, 14, 15, 17, (1) 19, (1) 21, (1) 23, (1) 25, (2) 28 30: 11, 12, 13, 14, 15, 17, (1) 19, (1) 21, (2) 24, (2) 27, (2) 30 32: 11, 12, 13, 14, 16, (1) 18, (1) 20, (1) 22, (2) 25, (2) 28, (3) 32 I guess there might be a slightly less noticeable (slightly less disruptive) shift with the 30T than there would be with the 32 (and maybe even ore so with the 28 vs the 32), since there's up to three spaces on the 32 (in between 28 to 32) and from one to two with the 30. And with the 28 there's only one space starting from 15 to 25 and then finally two spaces that happens once right at the very end, where it jumps twice from 25 to 28. I guess this is all boils down to preference and what I'm willing to sacrifice for the sake of potential gain in smoother (or less disruptive) shifting. Might just have to test ride a 28 when I get a chance. Probably not too many hills around my LBS's, but it's the only thing I can think of that might giving me a better, experiential understanding of the differences. |
Couple more questions for anyone willing to answer:
1) If I went down to a 28T cassette, could a different crank size make up for the "loss" of the cassette (i.e. going from 32T to 28T)? 2) If I did decide to go to a lower-sized cassette (it'll definitely be either 28 or 30), is there any advantage to using the shorter (SS) derailleur vs the longer one (GS)? I was told I could just use the long version, but I wonder if there's any benefit at all to using the shorter cage? |
I run 14-28 on my Domane and ALR as I am in Florida and have no hills. I do have plenty of wind. I like the close spacing due to the wind, so some days, a 16, 18, or 20 tooth cog, might be more comfortable than a 15, 17, or 19. I rarely if ever ride in the 11,12, or 13 tooth cogs, so they are wasted on me, and I have no worries of running of out gears going downhill on a bridge that is at max, 110 ft.
If you are 95% flat, you might look into the 14-28. |
Originally Posted by jaxgtr
(Post 21954946)
I run 14-28 on my Domane and ALR as I am in Florida and have no hills. I do have plenty of wind. I like the close spacing due to the wind, so some days, a 16, 18, or 20 tooth cog, might be more comfortable than a 15, 17, or 19. I rarely if ever ride in the 11,12, or 13 tooth cogs, so they are wasted on me, and I have no worries of running of out gears going downhill on a bridge that is at max, 110 ft.
If you are 95% flat, you might look into the 14-28. |
Google for bicycle gear ratio calculators. Look at the ratios, speed at cadence and other stuff. They'll help you see where you might get some benefits. But know what your own current bike does for you and what gears you normally use on it to climb or cruise. Then you can makes some assumptions about what changing things up might do for you.
I go to this site quite often, https://www.bikecalc.com/gear_ratios but it shows you gears that you don't have when it calculates. I've used a lot of others too, but keep coming back to this one. You want your 1 tooth splits to be in the gears you use the most. For the extreme low range that is for those hills you seldom encounter, you can do with many more teeth between cogs. |
Originally Posted by Ataylor
(Post 21954940)
Couple more questions for anyone willing to answer:
1) If I went down to a 28T cassette, could a different crank size make up for the "loss" of the cassette (i.e. going from 32T to 28T)? 2) If I did decide to go to a lower-sized cassette (it'll definitely be either 28 or 30), is there any advantage to using the shorter (SS) derailleur vs the longer one (GS)? I was told I could just use the long version, but I wonder if there's any benefit at all to using the shorter cage? The difference between a longer crank and a short one is similar to one lower gear, but crank length choice is more relevant to riding position, leg length, etc., or mainly what happens to be on the bike. A 28t cassette can use a short cage RD for slightly snappier shifts and a few grams lighter, but the GS one preserves the option to put a larger cassette on if you want. For the overall question, IMO the need for tighter ratios only shows up when riding fast with a group. On your own or with cadences < 85 or so it doesn't matter. |
Originally Posted by Ataylor
(Post 21954975)
Whoa. That's interesting. Never heard of the 14/28. Judging by what I read on a forum or two just now, that sounds like a dream, but I wonder: how much of the speed aspect do you think you've sacrificed for the smoother shift? Is it a noticeable difference? Or negligible? Or has it been so long that you don't remember?
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Originally Posted by woodcraft
(Post 21955033)
A 28t cassette can use a short cage RD for slightly snappier shifts and a few grams lighter, but the GS one preserves the option to put a larger cassette on if you want.
|
Originally Posted by Ataylor
(Post 21954975)
Whoa. That's interesting. Never heard of the 14/28. Judging by what I read on a forum or two just now, that sounds like a dream, but I wonder: how much of the speed aspect do you think you've sacrificed for the smoother shift? Is it a noticeable difference? Or negligible? Or has it been so long that you don't remember?
With a 14-xx cassette, your usable top speed will likely be in the 15 cog while in the small chainring. That same 90rpm means topping out at 16mph where a shift to the large chainring becomes necessary. |
Originally Posted by Sy Reene
(Post 21955089)
Not to add to your list of considerations, but while people say they never use the 11, 12, 13 - and this could be true, also realize that with a 14-28 you'd also be losing the 12 and 13 which might well have been usable when you're adding speed while still in the small front chainring, At a cadence of 90rpm that's in the neighborhood of 18-20mph speeds. (The 11 probably would have been off limits anyway due to too excessive cross-chaining).
With a 14-xx cassette, your usable top speed will likely be in the 15 cog while in the small chainring. That same 90rpm means topping out at 16mph where a shift to the large chainring becomes necessary. |
I went from an 11-34 cassette to 11-28 with no real "science" behind the switch--just experience. I wasn't using the big cogs on my cassette so my 11-speed cassette was effectively an 8-speed or so the way I was using it. So, I got rid of the cogs I wasn't using and in exchange got closer spacing for the ones I was using. It's definitely an improvement having more closely-spaced gears, and now I'm using all 11 of them.
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Best advice would be to go out for a ride. Find an area where there’s a gradual descent or a decent tailwind, shift into the gear you like, and see what cog you’re in. Then find the biggest hill you’ll ever take on, shift into the gear you like, and see which one it is. Practically, that will likely be the extent of your range -maybe add one more on either end for a bit of extra range?
I have a bike with a 52/44/32 triple in the front and a 12-27 nine speed in the back, and I have a bike with a 50/34 11-34 eleven speed. The gaps created by the 11-34 are very noticeable to me coming from the 12-27, to the extent that I am likely to switch to an 11-30 to have smaller gaps in cadence. The biggest hill around here is less than 7%, and I think I’ve only ever used the 32 and 34 cogs by accident. Conversely, I’ve taken the other bike up a 13% grade and could have used more than my 32-27 gearing allowed for. |
Originally Posted by Ataylor
(Post 21954514)
Couple questions for you guys. First, what exactly are the benefits (if any) of having closely-spaced ratios?
The other thing is, I've heard people mention that you should stay away from gears that you don't need. I ride on flats like 98% of the time, so does it make "sense" for me to have a 50/34 crank with an 11/32 cassette? Or is there a "better" configuration? In the 8 speed era I paired a 50-40-30 triple crank with a 13-14-15-16-17-18-19-21 cassette providing a 13-19 straight block for plains rides east of Boulder, CO and low like 42x28 mountains west. Eddy Merckx dominated the pro peloton with a 52x13 and I didn't need a gear bigger than he used. |
Originally Posted by Sy Reene
(Post 21955089)
Not to add to your list of considerations, but while people say they never use the 11, 12, 13 - and this could be true, also realize that with a 14-28 you'd also be losing the 12 and 13 which might well have been usable when you're adding speed while still in the small front chainring, At a cadence of 90rpm that's in the neighborhood of 18-20mph speeds. (The 11 probably would have been off limits anyway due to too excessive cross-chaining).
With a 14-xx cassette, your usable top speed will likely be in the 15 cog while in the small chainring. That same 90rpm means topping out at 16mph where a shift to the large chainring becomes necessary. |
Originally Posted by Iride01
(Post 21954987)
Google for bicycle gear ratio calculators...
Originally Posted by Iride01
(Post 21954987)
You want your 1 tooth splits to be in the gears you use the most.
Originally Posted by Iride01
(Post 21954987)
For the extreme low range that is for those hills you seldom encounter, you can do with many more teeth between cogs.
Originally Posted by woodcraft
(Post 21955033)
The difference between a longer crank and a short one is similar to one lower gear, but crank length choice is more relevant to riding position, leg length, etc., or mainly what happens to be on the bike.
Originally Posted by jaxgtr
(Post 21955037)
I don't give up that much in speed on the flats....
Originally Posted by Sy Reene
(Post 21955089)
Not to add to your list of considerations...
Originally Posted by Random11
(Post 21955601)
I went from an 11-34 cassette to 11-28 with no real "science" behind the switch--just experience....
Originally Posted by aliasfox
(Post 21956766)
Best advice would be to go out for a ride. Find an area where there’s a gradual descent or a decent tailwind, shift into the gear you like, and see what cog you’re in. Then find the biggest hill you’ll ever take on, shift into the gear you like, and see which one it is. Practically, that will likely be the extent of your range -maybe add one more on either end for a bit of extra range?
Originally Posted by aliasfox
(Post 21956766)
I have a bike with a 52/44/32 triple in the front and a 12-27 nine speed in the back, and I have a bike with a 50/34 11-34 eleven speed. The gaps created by the 11-34 are very noticeable to me coming from the 12-27, to the extent that I am likely to switch to an 11-30 to have smaller gaps in cadence. The biggest hill around here is less than 7%, and I think I’ve only ever used the 32 and 34 cogs by accident. Conversely, I’ve taken the other bike up a 13% grade and could have used more than my 32-27 gearing allowed for.
Originally Posted by Drew Eckhardt
(Post 21957021)
There are fewer situations where one cog offers a bit less resistance than you like and the next a bit more.
Originally Posted by Drew Eckhardt
(Post 21957021)
I think cassettes with more than a two tooth jump before the 19 cog are unsuitable for road riding. With 10 cogs I ride 13-14-15-16-17-18-19-21-23-26 and with 11 it would be 12-25 switching to a 46T big ring.
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Originally Posted by Ataylor
(Post 21957135)
Originally Posted by Iride01 For the extreme low range that is for those hills you seldom encounter, you can do with many more teeth between cogs. Unless of course you have say maybe a 32 speed rear. (I pulled 32 out of my ...... so don't dwell on that specifically) |
Originally Posted by Iride01
(Post 21957387)
... you can't just have one tooth gaps from 11th to 1st gear. At some point you have to accept more than one tooth gaps and the potential of ever so slightly worse shifting or drastic change in gear ratios.
|
Originally Posted by SoSmellyAir
(Post 21957757)
It is simply math. On the small end of the cassette, a single tooth makes a big difference, e.g., 12/11 = 1.0909. This means you have to increase your cadence by about 9 percent to maintain the same speed after shifting from the 11T to the 12T cog. This differential decreases as you move toward the big end of the cassette, e.g., 13/12 = 1.0833, 14/13 = 1.0769, etc. At some point it becomes pretty small, e.g., 19/18 = 1.0556, so it makes sense to have a two teeth jump. At the big end of the cassette, where one is generally climbing and thus going slower, one can tolerate a bigger, multiple teeth jump in order to have a bigger mechanical advantage to climb steeper slopes, i.e., a bail out gear. For example, the 7 speed cassette on my wife's cruiser bike has two teeth jumps throughout except the largest cog is 10 teeth larger than the next largest cog. But she never uses it.
I already knew what you are trying to express, but I didn't think it quite material to what I was attempting to convey to the OP. However the OP does need to realize that. |
Originally Posted by Iride01
(Post 21958132)
Is that for my benefit or the OP's?
I already knew what you are trying to express, but I didn't think it quite material to what I was attempting to convey to the OP. However the OP does need to realize that. |
If you want to do the deeper dive you can use the Sheldon grown gear calculator and you can see where the overlaps are from big to small ring. If I have a very flat ride - I will put on a 12-23 cassette which gives me a super tight shifting ratio. If I am climbing then I opt for a 12-27 or even 13-29 cassette - depending on how many climbs are over 10% grade. If you are using Shimano or Sram - you do not need to buy Dura Ace / opt for Ultegra or even 105 cassettes to save you money. The other thing is that many do not really need an 11 cog - start your cassettes with a 12 or even 13 if you are climbing a lot those days.
https://www.sheldonbrown.com/gear-calc.html |
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