cyccommute 

Not only is it possible, I find it highly useful. My touring bike has a 15.2” low and my mountain bikes have 14.6” lows. I have 20 tooth inner chainring and 36 tooth large cog. A 40 tooth cog would be relatively simple to bring the gear down to 13.2”.

My range is 105” to 14.6” on my mountain bikes and can be from 119” to 15.2” on my touring bike, although I have downgraded my high to 110” recently. Still gives me a 720% range. I’ve used the low gear a lot and, a times, for hours on end.





A cadence of 90 is 4 mph. A cadence of 60 is around 3 mph, which is brisk walking speed.

And, when the road looks like this (25% grade)



at 12,000 feet, even a 14.6” gear isn’t low enough.

cyccommute 

Depends on what you mean by “modern”. With a 1x system, it wouldn’t even take that much work to get to less than 20”. A 36/52 (chainwheel/cassette cog) is right at 20”. A 29/52 gives the 15” low I have. The high gear is crap (72”) but it does allow for a really good low.

If by “modern” you mean from the era of triples, it’s not all that hard to get the components to work well. I have ISIS cranks that have 98/54 BCD and they are simple since they take a 20 tooth inner ring (they will take an 18 but those are extremely hard to find). A 104/64 BCD crank can be modified with relative ease to accept a 20 tooth inner. It takes a little filing but it does work.

Getting a 9 speed derailer to work with a 36 tooth cog isn’t that hard either. Adding a Wolf Tooth Road Link makes it easier but it is possible to push the limits of a mountain 9 speed to 36 tooth cog.

For my mountain bikes where I use intermediate “modern” components, it’s even easier. A 10 speed rear derailer (which isn’t all that modern) can easily handle a 36 tooth cog.

livedarklions

Thanks for the reminder that what is or isn't practical really depends on context--I've never ridden in a state like Colorado and sure have never done anything that steep on dirt.

Honest question though, just as a matter of efficiency/conservation of your energy, wouldn't it be better to walk the bike in gravel contexts calling for gearing that low? I'm asking this as someone who tries to stay off of hilly gravel because I'm quite sure I don't know what I'm doing on it.

ofajen

Right. The difference can be too small to really adjust for, in which case there is really no need.

Effective wheel diameter reflects the outer dimension with the tire, and that is always the relevant factor in calculating gear inches. The example you mention has effective wheel diameters of roughly 691 mm and 698 mm. That’s just 1% so not really enough to bother trying to make an adjustment, since even one chainring tooth will change things by 2-3%.

Otto

indyfabz

No idea, but pushing a loaded bike uphill for another distance really sucks. Ask me how I know.

livedarklions

Yeah, I'd have no real basis for comparison between the lesser of two evils. Totally deferring to you and cyccommute on all questions mountain range oriented.

Badger6

Within the last couple of generations of components. Not being modern doesn't mean obsolete, plenty of triples and plenty of 8 and 9 and most certainly 10 speeds out there that work just fine. 1x is easier to get below 20gi, but 23-25 is more common for most of those systems unless the rider wants to run a tiny chainring, which is appropriate in certain situations, they just aren't situations I ever find myself within...even on gravel, and never on the road. I'm not really a MTB guy, I own one, and I often ask myself why.

indyfabz

I messed u[p a foot pushing last month. There is this climb in the Delaware Water Gap National Recreation Area that maxes out at 13% and is 8% or greater for nearly .62 miles. A lot of that is in double digit territory.

Badger6

I think the only case to be made for changing the gearing with the swapping of wheel sets would be if there was a major difference of tire tread diameter. Say 5% or more? I don't know, I don't notice a difference when swapping between 700c and 650b. And my power output as measured by a PM looks the same.

ofajen

Sorry, I’m coming at this from a single gear point of view, where the change in wheel diameter changes the one gear you have by that percentage. When you have a wide range multi gear setup, it’s probably not that useful to worry about changes in wheel size or tire dimension.

Otto

Badger6

Don't apologize, I didn't realize that was your perspective. Yes, I can see where it really does matter, in that case. In the case of the genesis of this back and forth, the other poster posts frequently about minute and insignificant changes, or wildly specific measurements, without any consideration for the rest fo the system at work...hence my initial reply that "I wouldn't" (and I do not) consider changing my gearing when swapping wheel sets on the one of my bikes that I do from time to time.

HTupolev

Not very. Pushing a bicycle up the sorts of hills where gearing that low would actually be used, "walking speed" is usually very slow. It's very different from moving about unencumbered on flat ground.

Walking and pushing takes considerably more bodily motion than turning a crank and rolling on wheels. There are some conditions where you just don't really have a choice, but whenever riding is reasonably practicable and you've got the gearing, it's just about always the better option.

Walking and pushing up a gravel road can also get uncomfortable if it's sustained for extended periods, as it can put abnormal side loads on the core and back.

Yes. There are tons of ways to go sub-20 GI. With most typical gravel wheel/tire sizes, you cross that line with a ratio somewhere in the .7 to .75 ballpark.

On a 1x setup, for example, a 38T chainring paired to a cassette with a 52T big cog would get you to .73. Lots of wide-range 1x rear derailleurs are designed to tolerate such large cassettes no problem.

On a 46-30 double, a cassette with an 42T big cog will usually do it. Not a lot of standard options will handle this, but there are lots of ways to make it work on various systems.
On SRAM 11-speed mechanical, the straightforward solution is to use a SRAM 10-speed long-cage MTB derailleur.
Shimano mechanical is a bit weirder, since the current Shimano 10/11-speed road derailleur actuation isn't directly compatible with any of their MTB stuff. But a Wolf Tooth Tanpan can allow a long-cage 11-speed Shimano MTB derailleur to be used. Alternately, the GRX RD-RX400 and RD-RX810 rear derailleurs can tolerate substantially more cog size and wrap than they're rated for: they can usually be made to work pretty reasonably with 11-40 and 11-42 cassettes with some b-screw manipulation and/or a hanger extender, and a number of my friends ride setups of this sort.

On my gravel bike, I have a 48-38-24 triple paired with an 8-speed 11-13-15-18-21-24-28-32 cassette, resulting in a slightly sub-20" gear when paired to my 2.1" 26er tires. That's a 581% gearing range and quite a bit of wrap, but my Alivio RD-T4000 has no trouble with it. What I really like about this setup is that there's some 1.5-step gear interleaving between the two larger chainrings that isn't clumsy to tap into, so it basically forms a road-drivetrain-plus-bailout. The drivetrain feels just as at home cruising in a road paceline at 25mph as climbing steep double-track at 4mph.

Kapusta

Looking at your ride pics really make me miss living out west.

livedarklions

Low gears are an undiscovered country for me.

cyccommute 

Generally, if you can ride your efficiency and energy use is lower. Bicycles are the most efficient mode of transportation there is. We are about 5 times more efficient on a bicycle than walking and even more efficient than running. 98% of the energy we input into cycling goes to propelling us forward. If you can pedal, you are better off then walking. There are limits of course and trying to do aerobic exercise at over about 10,000 feet is difficult even for those of us who have lived our entire lives above 4000 feet.

PeteHski

I ride a lot of steep climbs in UK Sportive events (well over 20%) and invariably when someone has to get off and walk I ride past them (slowly). I have never once had someone pass me while pushing their bike up a hill. I've had runners pass me on very steep pitches, but they don't have a bike to move and they have running shoes. Basically if you have to get off and walk your bike it is invariably slower than if you can ride it, however slowly.

PeteHski

That gear set would drive me nuts!

PeteHski

I'm curious as to what actually happens when/if you try riding in a lower gear than your favoured 53/11? I don't think I've ever come across anyone else with a preferred cadence as low as yours.

ehcoplex 

I've got 26/38/48 and 11-34 and where I live I pretty much use all of it. It's rare that I have to go to 26x34, but there are a few steep climbs on regular routes where I might drop to it if I'm especially tired/bonking. And I don't use 48x11 too often- I mostly coast down the hills because I've just completed a big climb and there's gonna be another climb right after the descent. Thinking about building myself a 'custom' cassette and ditching the 11 in favor of something to cover what feels like a big jump between the second and third largest cogs.

(I kind of love that the terrain where I live requires wide gearing and that I use it....)

livedarklions

I ride in lower gears, especially in a headwind, and I'll actually spin a low gear going uphill. I'm just fastest in the 53x11 on the flat. Mostly, though, I just find spinning a lower gear tedious. There's a certain sense of power I experience pushing a high gear that I just can't duplicate in lower gears. The great distance covered with a single turn almost feels like a super power. Also, I can accelerate like crazy a few gears below and shift up rapidly.

I've measured it a lot, I'm 1 mph or better faster in the highest gear than I am in any other.

Moisture

No.

mstateglfr 

This tracks.

tomato coupe

Yep, that was standard gearing 4 decades ago.

wolfchild

For pavement riding on flat and rolling terrain I use fixed gear with 44 x 16 gear ratio and 700 x 32 mm tires
For gravel riding I use singlespeed with 42 x 18 gear ratio and 700 x 45 mm tires
For mountain biking on technical and hilly singletrack I use a singlespeed MTB with 36 x 18 gear ratio and 26 x 2.35 tires.

livedarklions

Yes. I've measured it several times over the years. I have no reason to respect your opinion on this.