David Bierbaum

Since I'm snowed in, I've been gathering wool, and I remembered climbing Rock Hill, which I still can't quite do in one go, and I have a question.

In climbing a steep hill, why does swerving back and forth seem to make climbing easier? One doesn't have to swerve much, but it feels as if the very act of leaning in one direction or the other makes pedaling easier. Why is that?

fietsbob

Taking the whole width of the road you can make your own switchbacks, so the run* is extended.

* from Stairway layouts .. Run , the horizontal , Rise the height ..

Monoborracho

Going back and forth (swerving) the roadway can significantly decrease the angle of the climb. As an extreme example, if you go perpendicular (straight across) the roadway you have zero climb angle.

BigAura

I've always thought of it like the physics of a screw. Spiraling all the way around doesn't work so a switchback breaks it into pieces.

Zinger

A bit like squirming under the weights during a military or bench press I guess. It cheats the resistance effect a bit.

Bill Kapaun

You are trading additional distance for less slope.

cplager

Pretty much all the answers here are correct. This one is how I think of it.

TejanoTrackie 

I prefer to shift down to a sufficiently low gear so that I can ride in a straight line. All that turning back and forth actually wastes energy as the tires create more frictional resistance with the turns.

Zinger

^^^
I've been riding on a low 39x26 for decades and personally I find that hopping on it out of the saddle, and using my body weight, relieves the other muscles better than sitting and drifting into a swerve. I'm getting older though and about to test out a low 36x28 as soon as the weather breaks.

Bikey Mikey

...and puts you in the path of cars(unless it's a road that doesn't allow vehicles.

JimF22003

I very rarely do the "serpentine" thing on the roads. Usually the grade is 16% and above by that point and I'm barely moving. Watch out for toe overlap however!

Bill Kapaun

IF you have sufficiently low gears.

rdtompki

I've found the same thing. On a narrow, climbing road that change of direction at low speed can be very tricky in my experience. I'd rather alternate standing/sitting if necessary. I suppose on a wide, smooth road the serpentine thing would work.

cccorlew

It may make it easier for you, but anyone coming up behind you will hate you. A lot.

jyl

Don't zig zag up a steep hill. Either go straight up, or walk. Zig zagging asserts that you have sole right to the road, and is at the same time a shameful groveling manner of climbing. The contradiction is untenable. One willing to grovel uphill like a belly-winding worm cannot deserve mastery of the road, bike path, trail or sidewalk. The only time zig zagging up a steep climb is acceptable is when you are pedaling a cargo bike heavily laden with precious medicine desperately needed to prevent a deadly outbreak of disease in a remote town in the north. Even then, when you come in sight of the grateful townsfolk, you must force your screaming legs to turn and drill directly up the fall line. Lest you save the little childrens' lives but irreparably besmirch their moral sense, begetting a town of ignoble zig zaggers.

StanSeven

Post this on AS&S and everyone will tell you that you do have sole right to roads

woodcraft

However, if you're talking about rocking the bike while climbing,

letting the tires follow a serpentine path is more work, from increased friction, loss of momentum and longer path of travel.

David Bierbaum

I kind of figured about the slope thing, but it seemed easier out of proportion to the amount I swerved, just so long as I was leaning one direction or the other. I thought it might be some sort of skater's effect, where the side-to-side motion conveys some propulsion effect.

I agree about swerving on roads in general. Rock Hill is a bit special, since you can see all cars on it from 50 zillion miles away, and my swerves are not more than 2 feet in either direction, and the traffic on that road is about one car per minute on a busy day. When it gets warm again, and I get myself back in riding shape, I want to train myself to get up that hill straight, with minimal granny-gear grinding, and maximal standing-stomp storming!

DiabloScott

Your average road isn't wide enough that tacking will significantly increase the distance over which you change elevation - especially if you limit yourself to a single lane.

I do find that allowing the bike to find it's own path on a steep section is a little easier than forcing it into a straight line; maybe that's what OP is sensing.

Gonzo Bob

Hey, I remember doing that when I was a kid. We would swerve back and forth quickly and be able to keep going on a flat road without pedaling - but not real fast, though.

Gyro

Like this?

groth

Several years ago on the FANY ride (a week long 500 mile ride across NY), I got into camp and saw these two guys that I knew were riding together. I went up to talk to them and noticed that one of them had tire tracks on his jersey. I asked how he got the tire tracks. There was some hemming and hawing and some sheepish looks. Finally they fessed up. Tire track guy was zig zagging up a hill and fell over right in front of the other guy who ran over him. Then in trying to stop, he went backwards and rolled over him again! As far as I could tell, only pride was damaged.

- Ed

phoebeisis

And-maybe you can actually use your torso and arms to provide a tiny bit of propulsion-
Of course you are effectively covering more distance for the same altitude gain-as everyone has said
I just tried it-I can get propulsion by just wiggling the handlebar back and forth
sorta wiggling it-leaning a bit
But it is tiring-wears your arms out
so safe bet it is more run for same rise-increasing your mechanical advantage

David Bierbaum

HAHA! That's less of a swerve, and more of a classic switchback! Reading the comments on Youtube, it sounds like you need something like a Surly Big Dummy or XtraCycle, just to keep from flipping over backwards, if you try to go straight up that hill...

Groth, that does sound like a danger to the swerving, since one is basically pushing the front tire sideways, so the turn converts the sideways acceleration into forward motion. Hit a loose patch, and you'll push the tire right out from under yourself... Poor guy, getting run over twice, by the same bicycle...

BlazingPedals

I'm pretty much in agreement that there are good reasons NOT to do it. Some of my bents have such limited turning capabilities that they pretty much rule out any zig-zagging that would be sharp enough to do any good.