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Changing gear ratios

Old 06-10-24, 02:38 AM
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Originally Posted by Duragrouch
Cross-chaining: If you mean constant switching of chainrings, I think it depends on where the border gears sit in the range. Right now, the 2X conversion on my folder, 21-85 gear inches, is about the lower 2/3 of a MTB range, as I am limited in my high gears without a monster chainring or IGH overdrive. With a normal gear range, and wider 2X spacing, I'd be on the small ring 98% of the time. If you mean bad chainline angle... that's the definition of modern 1X system, so I can't see how a wide 2X would be much worse, in fact I think that is still an advantage of a wide 2X, inner ring for the low half of the cassette and outer ring for the high half of the cassette.

Yeah, 39:23 would be too tall for my hills with my **20" wheels**, much less 700c. Calculating now for my old 700c road bike, eesh, with original 52/42x25 in flatland, low was 44 gear inches, and when I put a triple on it (I think 30T road triple), that still gives 32 gear inches, about what I started with on my 7 speed folder, which wasn't low enough.
I mean extreme chainline angle yes, on a 2x, if they were all unique ratios, youíd have to go through every cog which would mean probably spending a load of time in the worst combinations, and then also somehow get from cog 8 to somewhere near cog 1 when you switch chainrings.

I spend 84% of my time in the 52 according to the Di2 stats
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Old 06-10-24, 03:09 AM
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Originally Posted by choddo
I mean extreme chainline angle yes, on a 2x, if they were all unique ratios, youíd have to go through every cog which would mean probably spending a load of time in the worst combinations, and then also somehow get from cog 8 to somewhere near cog 1 when you switch chainrings.

I spend 84% of my time in the 52 according to the Di2 stats
Seems a bit incongruous to have a system of electronic shift controls AND automatic statistics, for a system that essentially throws the chain from one sprocket to another, like a late nineteenth century machine shop with ceiling mounted common power shafts driven by a waterwheel or steam engine, and the machine operator reaches up with a pole and hook to move the long leather belt onto or off a flat pulley. Same thing.
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Old 06-10-24, 03:46 AM
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Originally Posted by Duragrouch
Seems a bit incongruous to have a system of electronic shift controls AND automatic statistics, for a system that essentially throws the chain from one sprocket to another, like a late nineteenth century machine shop with ceiling mounted common power shafts driven by a waterwheel or steam engine, and the machine operator reaches up with a pole and hook to move the long leather belt onto or off a flat pulley. Same thing.
I understood most of the words contained in that. But not sure why having a record of which gear ratios youíve been using, which is only possible with electronic shifting, is surprising when using electronic shifting
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Old 06-10-24, 05:58 AM
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Originally Posted by choddo
I understood most of the words contained in that. But not sure why having a record of which gear ratios youíve been using, which is only possible with electronic shifting, is surprising when using electronic shifting
Oh I agree, electronic does mesh with having a record of things. It's just... a very digital system controlling and tracking a very analog one. It's like having a joystick and electric servos to move the stern paddle for a canoe running the rapids. It's an electric knife at a sushi bar. It's an electric guitar at the 1965 Newport Folk Festival.
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Old 06-10-24, 06:35 AM
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Originally Posted by choddo
On a normal RD/cassette though, youíre looking at a life of cross-chaining which Iíve always assumed is why the two ranges overlap by as much as maybe 3-4 cogs?

OP Iím amazed you can even get up any hills with a 39:23 low gear. Kudos.
Are you kidding? 39 x 23 is not a "high gear" by any means, and will get you up most any paved road in North America if you are out of the saddle.

The fact that there are 3-4 overlap gear combinations is the thing that prevents you from needing to shift chainrings all the time.
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Old 06-11-24, 12:57 AM
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Originally Posted by Kontact
Are you kidding? 39 x 23 is not a "high gear" by any means, and will get you up most any paved road in North America if you are out of the saddle.

The fact that there are 3-4 overlap gear combinations is the thing that prevents you from needing to shift chainrings all the time.
I'd be really happy with 3-4 overlaps. On my old road race bike with 52/42, it was 6 overlaps of 7 cogs. On my current 50/34, it's 5 out of 7. If I can do a 50/30 (which others have done, but would require a new crank for me), it's only 4 overlaps of 7, and very nicely matched, not half-steps off, the ratios look nice, I could do 98% of my riding on the 50, and have a touch lower-low on the 30 (which I could use loaded touring), without widening the cog jumps which I don't want to do. Others have done 20 tooth jumps, even back in the day of flat chainrings. I just need a 110/74mm BCD crank, with hollow spindle. I don't expect to find cheap new, but with everyone going 1X, I might find a deal in the used bin at the LBS.
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Old 06-12-24, 06:12 AM
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Originally Posted by Kontact
Are you kidding? 39 x 23 is not a "high gear" by any means, and will get you up most any paved road in North America if you are out of the saddle.

The fact that there are 3-4 overlap gear combinations is the thing that prevents you from needing to shift chainrings all the time.
I donít kid about these things.

Without my 36:34 I would be gasping like a recently landed salmon on some of the hills around here. Even with it some of them are out of the saddle (I donít regard that as sustainable for a 2km+ climb which is what a ratio like 39:23 would demand of me, as I am not Contador but itís fine for 100m).

And I am not unfit.

Would love to know what a high gear (considering weíre talking about the lowest available on the bike) is in your world old bean?

Last edited by choddo; 06-12-24 at 06:16 AM.
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Old 06-12-24, 06:44 AM
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Originally Posted by choddo
I donít kid about these things.

Without my 36:34 I would be gasping like a recently landed salmon on some of the hills around here. Even with it some of them are out of the saddle (I donít regard that as sustainable for a 2km+ climb which is what a ratio like 39:23 would demand of me, as I am not Contador but itís fine for 100m).

And I am not unfit.

Would love to know what a high gear (considering weíre talking about the lowest available on the bike) is in your world old bean?
I live at the high point of Seattle and usually use 39x26 as my lowest gear, but two bikes have a 42x26. And that was the same gearing I was using in the Blue Mounds area of Wisconsin - some of the greatest elevation change in the US.

When I was young I used a 42x24 in the same terrain. And that was considered low-ish for road bikes at the time.


As gearing gets lower and lower we shouldn't forget what was considered perfectly normal and useful just a few years ago. I frankly don't understand sometimes how anyone can stand riding a 34x34 on a road bike - might as well walk.
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Old 06-12-24, 08:26 AM
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Originally Posted by Kontact
I live at the high point of Seattle and usually use 39x26 as my lowest gear, but two bikes have a 42x26. And that was the same gearing I was using in the Blue Mounds area of Wisconsin - some of the greatest elevation change in the US.

When I was young I used a 42x24 in the same terrain. And that was considered low-ish for road bikes at the time.


As gearing gets lower and lower we shouldn't forget what was considered perfectly normal and useful just a few years ago. I frankly don't understand sometimes how anyone can stand riding a 34x34 on a road bike - might as well walk.
Beast

Cadence of 90 on a 10% incline with a 36:34 is fine. Plenty of torque still needed but can stay in the saddle at 300W.

Only ever really used a 34:34 once, to get over Hardknott at over 30% gradient. A lot of people were walking that one.
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Old 06-13-24, 03:03 AM
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Originally Posted by Kontact
I live at the high point of Seattle and usually use 39x26 as my lowest gear, but two bikes have a 42x26. And that was the same gearing I was using in the Blue Mounds area of Wisconsin - some of the greatest elevation change in the US.

When I was young I used a 42x24 in the same terrain. And that was considered low-ish for road bikes at the time.


As gearing gets lower and lower we shouldn't forget what was considered perfectly normal and useful just a few years ago. I frankly don't understand sometimes how anyone can stand riding a 34x34 on a road bike - might as well walk.
Queene Anne?

Back when I lived in flatland, yeah, 42x24 was the low on my 700c road race bike (and 24 was considered wimpy low on a race bike, but I wasn't a racer), but I can't recall anything steep enough that I could not spin up in that. It was FLAT.

In steeps, I want the option to climb standing, or spin, or walk. That climb up from Discovery Park beach is not huge, I think 220 feet vertical, but for us lesser souls in the latter third of our life, it's a challenge, even when I geared the bike down to 34x30 on **20" wheels**. Yes, it's barely above walking. I often walk part of it to stretch my calves. But the bike weighs 55 lbs, townied. And I'm a good 40 lbs overweight, trying to work on that, easier to get in shape aerobically. I wonder what it would feel like on my old race bike, around 20 lbs, me 40 lbs lighter, in 42x24?
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Old 06-13-24, 04:35 PM
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Originally Posted by Duragrouch
Cross-chaining: If you mean constant switching of chainrings, I think it depends on where the border gears sit in the range.
Cross-chaining is running big/big or small/small and similar gears, where the chain is running at a significant angle to the chainring/sprocket - this is inefficient and/or increases wear and/or marks you as a noob. I've never been overly concerned about it, and with 1X systems you get no choice anyway.
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Old 06-14-24, 01:39 AM
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Originally Posted by grumpus
Cross-chaining is running big/big or small/small and similar gears, where the chain is running at a significant angle to the chainring/sprocket - this is inefficient and/or increases wear and/or marks you as a noob. I've never been overly concerned about it, and with 1X systems you get no choice anyway.
Oh, yes, that's one of the things I like about my folder conversion from 1X to 2X, I have better choices in chainline. I normally don't sweat it either, except when climbing out of the saddle, I try to use whatever combo has the least cross-chaining. I have noticed more wear on the cogs from standing climbing versus spinning up, and I have to think that higher chain tension is even worse in all regards when cross-chained.
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