azza_333

Is there that much of a noticeable difference between 19.6 & 22.1 gear inches, as I am looking at a 3x10 or 2x22 speed setups.

Jim Kukula

That's about 13%. You'll definitely notice it! It's pretty close to the difference between a 30 tooth sprocket and a 34 tooth sprocket. About one gear change for a moderate spacing.

GeoKrpan

2.5 gear inches, not very much. Go with the 3x10.

azza_333

the 2x11 is 22.1 GI if its not that much I would probably go with that.

Jim Kukula

A nice question, whether subtracting or dividing is the appropriate operation.

Is e.g. 19 vs 21 inches about as noticeable as 89 vs 91 inches?

I think dividing will correspond to experienced difference more than subtracting... hmmm....

OK, here is some logic. Let's say you are pushing at whatever steady power level at a comfortable cadence but then conditions change e.g. it gets more uphill or a headwind kicks in, whatever. To keep that cadence you'd have to increase the power. If you keep the same power, the cadence drops. You want to change to a lower gear to keep the same cadence and same power.

To increase one's cadence from say 80 to 90 is going to mean a fixed ratio change in gear inches, not a fixed difference.

saddlesores

given certain variables -- road inclination, your physical conditioning,
weight of gear carried, wind speed velocity of unladen swallow, etc...

it could be the difference between pedaling or pushing uphill.

bradtx

azza_333, While it can be a noticeable difference in cadence, if maintaining a desired speed, it can be insignificant with a light load. The closest I came to your numbers is with my mountain bike.

Mountain bike

[TABLE]
[TR]
[TD][/TD]
[TH="bgcolor: yellow"]22[/TH]
[/TR]
[TR]
[TH="bgcolor: yellow"]30[/TH]
[TH="bgcolor: white"]19.1[/TH]
[/TR]
[TR]
[TD="align: center"]7.1 %[/TD]
[/TR]
[TR]
[TH="bgcolor: yellow"]28[/TH]
[TH="bgcolor: white"]20.4[/TH]
[/TR]
[TR]
[TD="align: center"]3.7 %[/TD]
[/TR]
[TR]
[TH="bgcolor: yellow"]27[/TH]
[TH="bgcolor: white"]21.2[/TH]
[/TR]
[TR]
[TD="align: center"]3.8 %[/TD]
[/TR]
[TR]
[TH="bgcolor: yellow"]26[/TH]
[TH="bgcolor: white"]22.0[/TH]
[/TR]
[/TABLE]

Brad

Tourist in MSN

When you are in that gear, almost all of your energy is fighting gravity as you climb up a hill. Because of your slow speed, mechanical friction is nil, aerodynamic loss is also nil. It is like asking the question, is there a difference between climbing up a hill that is 9.7 percent grade instead of 9 percent grade?

If there are other benefits to the system that has the higher gearing, that outweigh the loss of low gear, consider that,

From past comments you have made, I assume you are a highly athletic cyclist. And it is very clear that you do not carry significant weight on your bike. So, I would say that the difference between those two gears is pretty small.

Furthermore, how much time will you actually spend in that lowest gear? That all depends on where you go. You might be in that gear for hours each week, or maybe you never need that gear. Only you can answer that.

chasm54

I'd say don't. Not because of the low gear, because I don't think that matters much. But the 2x11 will have bigger jumps between ratios on the cassette, and you'll be shifting a lot more often at the front. With the 3x10 you can spend most of your time in the middle ring going up and down a tighter cassette, it's a much more pleasing riding experience.

acantor

I would opt for the lower gear. I don't use my "granniest" gear often, but when I do, I'm glad I have it.

While in the Alps, carrying 10 kg/20 lbs., I spent almost two entire days in my lowest gear.

DeadGrandpa

I agree with acantor. When you need that lowest gear, you are really going to hate not having it. You can get away with the "almost as low" gear on short hills, or when you're not really loaded, or when they're not all that steep. Personally I don't care much about how close each gear is to the next one, but not having one low enough to allow me to keep pedaling, instead of walking, is really important. My limited experience tells me that, if I am loaded and / or the grade is steep and long, the number I want is 17 gear inches. YMMV.

LeeG

It's noticeable but whether that difference matters is more an issue of whether you ever needed a lower gear than 22"

chasm54

Indeed. I'm pretty amazed by the gearing some here seem to think is desirable, 19 gear inches is as low as I've ever gone, and at that I feel like a hamster, I've almost never used it. 2nd gear on my rohloff-equipped bike is 21.6 gear inches, and that's about as low as I think I need. In that gear I'm only going 4 mph at 60 rpm.

Walter S

+1. I recently climbed a long 15% grade loaded and used my low 16.8 and maintained a comfortable 3.5 mph.

LeeG

I think the wide range of power to weight ratios different people operate under is reflected in these low gears.

When I was young, light and carried a light load a 31" gear was perfectly adequate for all day climbing at high altitudes but I'd have a heart attack if I tried replicating that effort now. Comparing discrete numbers for what's desirable gearing is kinda useless if one person is perfectly happy cranking out 225 watts and another calls it quits at 200.

chasm54

Yes, I agree. But I'm old and fat: that's why I find some of these numbers so surprising. Still, each to their own.

alan s 

If I was planning to climb all day on a fully-loaded touring bike in the Alps, 16-17 g.i. would be my choice. 21-22 would not be low enough for that terrain. One of my touring bikes has a mountain triple that will get me up just about anything (22/32/44 and 11/34), which gives the range of 17-105 g.i. or 618%. That provides two extra gears lower than 22 g.i.

Jim Kukula

That's about 250 watts, hauling 225 pounds. It'd still be 200 watts at 170 pounds, and that's as light as I could reasonably get (in my dreams!)

yeah I think the range of rider capabilities is quite broad! No way I could sustain 200 watts any significant length of time... nevermind 250!

djb

this is so true, both for triples in general, and if you are able to use a tighter cassette-for me a tighter cassette is very much a much more pleasing riding experience--but, you do have to be realistic of what sort of low you need for your specific situation--rider power, weight and terrain that you will be riding in.

and that can only be figured out by getting out in the real world yourself and seeing how x weight on y gradient works for you.

djb

I've mentioned this before, but while I've done lots of touring with about 21 gear inches and 40lbs of stuff, bike + load about 70lbs give or take, and this low has been generally fine in the Pyrenees and mountains here in the east of Canada US, so maybe 15% max?

that said, I have travelled on my bike with 19.5 g.i with about 25lbs of stuff that bike, so about 55lbs bike+load, in Latin America where even with less load, the sometimes really steep hills made me realize right away that if I were to add in my tent and all that stuff (which I didnt have at about 25lbs of load) plus some extra water etc etc, I would very much need a gear lower than that 19.5 gear, and maybe a smidge lower than just the equivelant of one shift lower, especially if you've are feeling rotten one day and have had the runs all day or something.

dont forget alititude. So add on a full load, steep rough roads, altitude (and it does make a difference in taking energy from you) and potential blahness from various potential possibilities, and hell ya I'll take lower gearing.

again, this is my experience and actually being in those situations, but can only speak for myself.

*feeling like a hamster, at nearly 22 gear inches, riding from Montreal to Boston a few summers ago, there were a few pitches that with 40odd lbs of load had me in low gear and putting out all my force. I'm not particularly strong, nor weak, but when you've got to go to nearly 100 % for a stretch, that tells me lower gearing is needed.
Same thing with the 25lb load and 19.5 g.i in Latin America, going down into short sharp river valleys and going up had me in low gear putting out close to max output, slow but putting out all the watts I could.
Again, that tells me I need lower, and my knees tell me at the end of the day too.

heck, there were some roads I couldnt ride up in Costa Rica with only one pannier on while out for a short ride, paved no less. I was not feeling well those days and was getting accustomed to the heat and altitude (not that high) but that short bit must have been easily 25 if not 30%. In the moutainy areas my friends live in, I've seen stuff like that a lot.
This is why everyone uses torquey diesels and low gearing in their cars, you just plain need it.