It feels natural. But this is usually the result of considerable practice. Very few kids - or adults - hop on a bicycle the first time and pedal off with natural balance and control.
Machine Elf’s video is very interesting. TLDW: Guy teaches himself to ride an “inverse-steering” bike - takes him 8 months. His 6-year-old son also masters this - takes 2 weeks.
Personally, I never did much counter-steering. I mostly rode a very light bike, that weighed a bit less than I did, and I steered it mostly by body weight and by directing the front wheel towards where I wanted to go. I would lean left, and turn the handles, the bike wouldn’t lean much at all (because it was pitching up), but that would’t matter, because the bike didn’t weigh that much anyway. Precesion would help turn the handle bars, and the bike tracked with the wheels.
Yes, it was difficult to turn sharply like that. but that was only rarely a problem.
Well, yeah, you have to lean. But that doesn’t demonstrate that you have to countersteer to lean.
Newton says you have to countersteer (or let the bike countersteer) to lean. If you just shove your body to the left, you also shove the bike to the right; the combined center of mass (you + bike) will stay planted directly on the straight line it was traveling on in the first place, directly above the contact patch line; gravity will not be able to exert any moment to roll you into a left lean.
Since you can’t move your combined center of mass off of its line of travel, the only option is to steer the contact patches out from under you. Either you do it, or you let the bike do it. Either way, the countersteer must happen.
My son did. When he was three years old. But he had been riding one of those Razor scooter things for six or eight weeks first. I saw him balancing on that thing, and I took the wheels off his tiny bike (it couldn’t even freewheel, so the pedals would be turning if it was moving because it wasn’t designed to be ridden without training wheels), and he was off with no problems.
Chronos, you’re a smart guy - how the hell can you lean without countersteering? You can’t just throw your weight to one side if the wheels maintain a straight line path.
That there is the main difference between riding a bicycle and riding a motorbike (note that counter balance/ counterweight steering is a quite different thing from countersteering, and that casdave knows exactly what he’s talking about). Both bicycles and motorbikes need to countersteer to initiate a turn, but after that the techniques are quite different. A motorcyclist doing more than 25 mph or so will hang low towards the inside of the corner, whereas a cyclist should keep the body upright, keep the outside pedal low, and lean the bike towards the inside of the corner. Counterweight steering can also be used by motorcyclists at low speeds, and is the dominant technique for dirt bikes.
I’m a keen mountain biker, me, and I’ve experimented with both counterweight steering and hanging low on fast turns with low grip. Both these techniques are better than no technique at all, but counterweight steering gets me round a corner faster, that’s for sure. Hanging low is fun and feels stable even when the bike starts to drift, but is definitely slower. That’s why you don’t see cyclists using the hanging low technique. That said, despite having a pretty good grasp of basic Newtonian physics, I still can’t work out why counterweight steering gives better grip than hanging low (on a bicycle).
As for countersteering, it’s so subtle on a bicycle that you don’t even know you’re doing it. Motorbikes, being much heavier, require more tangible effort.
The question’s been answered so I’m going to speculate/question on Fridgemagnet’s post.
The difference I see in these techniques is that the counterweight gives me just that, more weight on the bike/wheels. Hanging-off allows more lean (with a sacrifice of weight). The motorcycle, with its big, wide, sticky tires can make up for the variations in traction using these attributes of the tire, along with a road-optimized suspension (I can lean more w/o adding more weight). But the small, thin tires on a bicycle won’t allow for a lot of traction variation anyway, so we maximize our traction potential at all times by putting more weight on them.
In riding dirtbikes, we corner just as you’ve mentioned; we put the corner of the seat in the crack of our butt and sit as high as possible. That pushes down and helps the tires bite better *. This situation is similar to the bicycle because I don’t have the excellent traction offered by rubber on asphalt.
When roadracing, we’re hanging off and low to the inside to keep the bike more upright. This is a relative term `cause it’s still leaning like mad, but now I get more arc out of the same lean, letting me cut a sharper corner.
Just in general terms of similarities between the two, if you’re a good off-road motorcyclist then you’ll automatically be a good mountain biker, IME, for downhill, enduro, any of the technically demanding stuff. It seems the skills translate extremely well. Also the physicality of handling the bike, which is quite different from the outright aerobic power you associate with fit cyclists, is a shared attribute.
No idea if it goes the other way, good mountain biker picking up a motorcrosser, but I guess it should.
On average, the weight on the wheels can only be equal to your weight plus that of the bike. This is true regardless of lean angle, and regardless of where you put your body’s weight relative to that of the bike.
Hanging your body to the inside of the turn on a road bike does three things:
[ul][li]It increases ground clearance for the hard parts of the bike. Most sport bikes don’t have an issue with ground clearance (if they do, it’s because you’re riding them dangerously hard for public roads), but many sport-touring and touring bikes do; getting your body weight to the inside can make the difference between a graceful turn and levering the tires off of the pavement with the centerstand.[/li]
[li]It keeps the bike’s suspension closer to vertical; all the better for coping with the bumps and dips in the pavement. If the bike is closer to horizontal, the bumps/dips will have a greater tendency to upset the whole chassis, when your goal is to arc smoothly through the turn.[/li]
[li]It makes the self-correcting steering geometry want to turn. If you don’t lean your body to the inside, you’ll be fighting to keep the bike turning; with your weight moved to the inside, the handlebars will want to stay turned.[/ul][/li]
For street motorcycles, cross-controlling (leaning your body to the outside of the turn) is useful for extreme low speed tight maneuvering, when you are limited by how far you can turn the handlebars before they hit the stop. In theory, the shortest turning radius would be had when the bike is perfectly horizontal; the radius will then be the distance between the front and rear contact patches. In reality, the shortest turning radius is had with the bars turned full-lock and the bike leaning as far as it possibly can; the only way to achieve high lean angles without high lateral acceleration is to lean your body to the outside of the turn.
Look upthread for my police rodeo link; cross-controlling is how those guys are able to wiggle those big motorcycles through insanely tight obstacle courses.
I also found this very good video on countersteering a bicycle:
I haven't ridden a bike in a good while, but seeing this did remind me of how it works. Yes, you do have to countersteer a bit, but you get so used to it that you don't think about it.Great post, Mr. Elf.
So, then am i changing a vector or something?
Upon re-reading, that sounded snarky. I agree that weight=weight, didn’t want to sound like i was discounting or disagreeing w/ what i quoted from you.
And now I am remembering riding a bike as a kid and doing big countersteers/leans to make a sharp, swooping turn. I also kind of thought of the countersteer part almost as a kind of trick, something special to make turning easier in such a case. But I probably didn’t think of it as necessary for little turns. Memories coming back…
I’m not an experienced off-road motorcyclist, so take my speculation here with a grain of salt - but I think cross-controlling a dirt bike allows the bike more freedom to wiggle and squiggle beneath you, which it’s going to want to do since it’s got sliding traction. It also puts you in a better position to dab a foot down on tight slow turns if the bike starts to fall down to the inside (which is a no-no for a heavy bike on the street; that’s how my buddy broke his tibial plateau…).
you gotta get off road, MachineElf… it’s a blast ! 
And it will greatly enhance your riding skills and understanding/feel for machine behavior close/at/over the edge of control/traction. With much less risk. You can approach these limits with much less (accumulated) energy than where those conditions are experienced on asphalt.
Anyway, so when I’m hanging off, I’ve moved my center of mass *way *off the bike, relative to the wheels. When I’m up on the bike, my center of mass is closer to being right above the contact patches. This would -in my somewhat clouded, fun-loving mind- seem to put more (effective) weight/pressure in a downward direction than if I were hanging off. Am I missing or oversimplifying something?
The first year of classes for an engineering student typically includes courses on statics and dynamics, in which we learn to analyze the forces involved in keeping an object stationary (or at fixed speed) or making it accelerate. One of the basic tenets is that if an object isn’t accelerating in some direction, then the sum of all forces applied to the object in that direction must be zero (F=m*a, a=0, therefore F = 0).
So with that in mind, consider a bike moving through a turn. Constant lean angle, nothing is accelerating in a vertical direction. This means that the sum of all forces acting on you and the bike in a vertical direction must be zero. What are the vertical forces acting on you and the bike?
-Gravity is pulling you down. 180 pounds for you, 220 pounds for the bike, so 400 pounds total.
-The ground is pushing up on the tires. (there’s a traction force too, but that’s horizontal, not vertical, so irrelevant to our present analysis.)
That’s it. There are no other vertical forces pushing or pulling on the bike. The upward force on the tires from the ground must therefore be 400 pounds. Period. If it was ever something other than your total weight, you’d be accelerating upward or downward.
If you lean your body to the outside of the turn, the bike leans farther to the inside of the turn. The lean angle from the contact patches to your combined center of mass will remain constant, dictated by your turning radius and your forward speed. But the magnitude of the tire loading won’t change.
I think you have to specify level ground for this to be true. If you continuously circle a banked track, the average weight on the wheels will be greater than the sum of you + bike.
When I speak of weight, I’m referring to force in a vertical direction (and when I say vertical, I mean in a direction parallel to the gravity vector).
Lateral acceleration will confer an additional load on the tires and suspension which will add, in vector fashion, with the weight of the bike. A turning bike + rider leaned over 45 degrees (relative to gravity) is subjected to 1g of lateral acceleration, and the total load on the tires (400 pounds vertical + 400 pounds lateral) is 566 pounds. This is true regardless of whether the ground under the bike is banked or not.
That would be true if the tires were not in contact with the road. But when I ride, the tires are generally in contact with the road, and thus are capable of exerting a sideways force, and thus I am able to lean without countersteering.
For what it’s worth, I tested again on my commute home, just to be sure I wasn’t misremembering. When I made a left turn, I kept my left hand off of the handlebars, and my right hand open, so the only way I could rotate the handlebars was counterclockwise. I nonetheless had no difficulty making the turn.
Between my last post and now I have been out mountain biking, and decided to test the hypothesis that a pre-leaned bike doesn’t need to counter-steer to turn. On a bit of level ground that was reasonably flat I leaned the bike over to the right (necessitating a slight lean of my body to the left to compensate) and happily rode along in a stable straight line. Then I attempted to turn right by taking my left hand off the handlebar entirely and pulling gently with my right hand, being very very mindful not to slip a left-twitch counter-steer in there. The result was the same as a right-twitch counter-steer, and the bike tried to swing over to the left. I repeated this several times with no difference in results.
tl:dr - pre-leaning the bike is not the same as counter-steering. I’m not sure why this is - I’ll have to have a bit of a think on that one. I think there may be clues in some of the responses to this thread.
While I was out I was having a think about the forces involved in hanging low compared to counterweight steering (i.e. body upright, bike leaned - not the same as counter-steering). I have been ruminating on the following points:
Counterweight Steering
[ol]
[li]Wheels are at an angle and naturally want to plough into the ground. While this would give an advantage on soft ground, what about hard ground with hard tyres?[/li][li]The rider’s centre of gravity is pretty much in line with the tyres’ contact patches.[/li][li]Given the point above, any small bumps that would perturb the grip will have to fight the whole weight of the rider (and some of the weight of the bike).[/li][li]What effect is the centripetal force having? If you’re not losing grip then that force is either going into potential energy in keeping something upright, and/or it’s creating additional pressure on the tyres’ contact patches.[/li][li]Additional downforce on the tyres will create a larger contact patch.[/li][li]It’s possible to do very quick corrections using this technique; conversely the bike handling can be twitchy (and thus the natural balance of the universe is restored).[/li][li]Many MTB tyres have aggressive side knobs for extra grip when leaning. I could discount that effect today as I’m still on my summer tyres, which have a rounded profile and low, uniform knobs.[/li][/ol]
For my hanging low technique, note that it’s not quite the same as for a motorbike. I have the bike much more upright, and I can move my centre of gravity much lower relative to the seat.
Hanging Low (Fridgemagnet on a Bicycle Style)
[ol]
[li]The bike is fairly upright, and if it starts to lose grip it’s much more of a slow, gentle drift. Conversely, the effect of corrections is quite slow.[/li][li]It’s not a stable position if you’re static, so some of the centripetal force must be acting to keep the rider from falling to the ground.[/li][li]Any bumps that could perturb the tyres’ grip will be pushing against most of the weight of the relatively light bike, but little of the weight of the rider. Some of the force from a bump will go into rotating the bike/rider around their common centre of gravity, not into extra downforce on the tyres.[/li][li]With an upright bike the tyres won’t try to plough into the ground.[/li][/ol]
All these observations are for a bicycle. I am 5X the weight of my MTB; if I rode a sports (motor)bike I’d be about half the weight of the machine. These ratios make a difference.
I think you’ve hit the nail on the head there, thank-you. There may be other factors at play, but I reckon that one’s overwhelmingly dominant. With counterweight steering, most of the centripetal force will be adding downforce on the tyres, thus increasing grip. Hanging low on a bike that’s almost upright means that most of the centripetal force will be going into holding the rider off the ground.
Your body is a few feet above the contact patches. When you move left, you apply a force toward the right on the bike. The tire grip prevents the whole bike from simply translating to the right; the bike leans (rotates around its roll axis) to the right. The countersteer then happens as I described upthread.
Then you’re doing something wrong. are you:
A) giving the right handlebar a quick, sharp forward shove with your right palm to show that countersteering works to commence a turn? Or
B) trying to use your right palm to prevent the handlebars from automatically countersteering while you move your body to the left, in an attempt to demonstrate that countersteering does not happen when controlling the bike with body english?
If the latter, the automatic countersteer is going to be pretty subtle, and you can’t count on your body to clearly prevent the bars from moving like that. If you installed a hard mechanical stop that absolutely prevented the bars from deviating to the right, you would definitely not be able to use body english to transition from straight travel to left turn.