Trakhak

Some interesting assertions. I can't square them with what I see here, with riders on bikes with zero-reach stems, etc.

Trakhak

One more.

Ironfish653

I wrote three paragraphs, but I guess since I didn’t directly address the magical thinking of the effect of from reflector brackets on self-steering, none of it counts. I’m also not going to go out to the garage and tip my bikes over to see which side the handle bars flop to.

Here’s a data point for you:
I have two similar bikes: a Cannondale F-1000 and a Klein Pinnacle, both aluminum frame, 26” wheel MTBs with ~700mm wide bars.
The Cannondale has a 140mm stem and is nearly impossible to ride no-hands; only if you’re going fast, straight, and you hold really still.
The Klein, OTOH, will go for blocks; you can pedal, get a drink, take pictures, go around curves; I’ve never had a bike that stable.
It has a 50mm BMX stem.

It’s not the stem length.

veganbikes

I was talking to you and directing my comment at yours. Re-read my post and then make a comment don't just reply without reading and understanding. You frequently post useless stuff that goes nowhere yet you are complaining about a similar thing here even though you are guilty of it yourself.

There is no butthurt, My butt is quite unhurt, I am in one of those AeroChairs quite comfortable and has lasted a really long time and still looks kinda new. People are giving good advice and you and the OP are taking it like we are just attacking him and we are just a holes because we aren't just being an echo chamber for the OP.

SkinGriz

^ This.

Have a bike with just a coaster brake? You can even ride with the whole front end spun around.

It’s awkward, but no it’s not going to be incredibly unstable and make you magically fall over.

john m flores 

I read what you wrote again and now I think I understand what you are trying to say. Let me try to explain it another way and let me know if it is the same...

​​​​​In motorcycle class, you are taught that if you want to turn right, you push the right handlebar forward. That's counter steering, which precipitates a shift of the tire's contact patch from the centerline of the tire towards the edge and the familiar lean. In a way, it's kind of a controlled fall to the right counteracted by the forward momentum of the motorcycle. That's precession.

The same thing happens on a bicycle. When you push the right bar forward (you may not think of steering in those terms but that is what is happening) the bicycle begins to lean, countersteer, and precess. The force required to initiate the turn and the sensitivity and stability whilst turning depends upon a number of things, including rake, trail, tire circumference, etc...

Now imagine riding no hands and the bike starts to lean to the right. Without touching the handlebar (imagine flat bars for easier visualization), the right handlebar has pivoted forward (with the steering axis as the point of rotation). Since the head tube is not vertical but rather raked, the tip of the right handlebar is now vertically higher than the neutral position. Not a lot - millimeters perhaps - but is is higher. And the because of gravity, the tip of the right handlebar wants to return to it's lower position thanks to gravity, so it exerts a "corrective" force that helps bring the bike back to vertical.

To make this idea clearer, imagine a really relaxed head tube angle - say 45 degrees - and a comically long stem - say 1 foot. As the bike starts leaning and falling to the right, the tip of the right handlebar will rise considerably and gravity will pull it back towards center. Now imagine the same head tube ange but a 0 extension stem; the tip of the bar will rise but not nearly as high.

(to model it more precisely, you really need to be looking at the center of gravity of the handlebar plus stem and how that CoG relates to the steering axis. The CoG is likely near the juncture of the stem and bar, and it rises if the bike falls to the right.)

This kind of makes sense. A longer stem will push the CoG further away from the steering axis thus creating a greater "corrective" moment force upon that axis. Imagine, for example, 2 lb weights at the end of the handlebars. A longer stem will exert a stronger "corrective" moment upon the steering axis vs a smaller or 0 extension stem.

With all of this said, whether a bike with 0 stem extension can be ridden no hands or not likely depends upon front end geometry and tire profile as much as anything. Also note that a rearward facing stem will exhibit the same behavior as a forward facing stem in this no hands example.

Is this what you were suggesting?

Wildwood 

I still maintain the type of bike and the type of fork and the type of handlebars and the use of the bicycle = best determine optimal placement of hands for a given handlebar/stem combo. Can it be ridden in any other configuration? = absolutely.. Is it worth trying? = why not for people so inclined?

Consider the differences: commuting within Amsterdam, maybe loaded. As opposed to motorpaced Stayer bike riding.

Love the paint with coordinated rims and the lock not my style of riding

nice patina, bit 'o history, not my style of riding

urbanknight

I believe those bikes have different geometry as well, and trail is probably a key factor in the handling of the bike. But the more I read these responses, the more I realize that I was indeed (as someone here put it) only thinking of drop bar road bikes and not one of the many other types of bikes, some of which are designed to have shorter stems.

phughes

No it won't.

Trakhak

Post 82, just above your post, shows a stayer bike - drop bars, fork turned around to ensure that the bike can get maximum draft from a motorcycle. Motorpacing is fast. It's obvious from a glance at that bike that trail was not a "key factor" in its design.

The bikes used for artistic cycling violate all the rules that people in this thread have put forth. In fact, over many years of attempts to design an unrideable bike, the only version that seems to qualify is one where the wheel and handle bar move in opposite directions. Do a search for "unrideable bicycle," and you'll see a bike with sprockets between the handlebar and the headset to accomplish that.

Bicycles are astonishingly forgiving of variations in stem length, fork geometry, handlebar configuration, etc. If nothing else, people can learn from this thread that some of their fundamental beliefs concerning bike design were mistaken.

Trakhak

One thing I've learned from reading Bike Forums threads over the years - every bicycle rider who has taken motorcycle classes believes fervently that bicycles cannot be ridden without counter-steering, whereas most bicycle riders who haven't taken motorcycle classes find that hard to believe.

The simple fact that a bicycle can be steered easily from the saddle while riding no hands, both in a straight line and around corners, would seem to obviate the assertion that bikes can't be steered without counter-steering as described in the quote above, and yet . . .

Yes, bicycles can be counter-steered, but doing so is not essential.

Pop N Wood

And all the OP wanted was some links to zero length stems, LOL

Not a chance

PeteHski

Well there was this experiment showing what happens when you deliberately prevent any counter-steering.


When you ride no handed I think counter steering happens automatically. Try riding a bike with a very stiff headset no-handed. It makes it almost impossible.

The above video also addresses some of the other common misconceptions about bike stability and their interesting research into it.

john m flores 

Motorcycles can be ridden without counter-steering too, at parking lot speeds or when navigating slowly through technical terrain. I once tested a three-wheeled leaning scooter. One of the features was a lockout of the leaning function at traffic lights so that you did not have to put your foot down when stopped. When the light turned green, if you accelerated very slowly, the scooter would crawl forward perfectly vertical, and if your wheel was pointed slightly to the right, the scooter would move in that direction. In other words, not countersteering. Once you hit 5mph or so, the lockout stopped and the bike was free to lean again and from that point on it was countersteering.

Bicycles behave similarly. When you're on a mountain bike picking the best line through a field of softball sized rocks, you're not countersteering. When you've taken that first half pedal stroke, you're not countersteering. When you're slowing to a stop and aiming the bike towards a bike rack, you're not countersteering. But once you've achieved a speed above walking pace, whether you realize it not, you're countersteering.

urbanknight

That would increase trail, increasing the stability of the bike.

Ah yes, I found that video a year or two ago and was amused and amazed. I would have thought one could train themselves to make their movements opposite, but that did not seem to be the case.

urbanknight

A little late to the party, but thanks for your thorough input.

phughes

Yes, well I have been traveling out of the country, and Ave been at sea so I just saw the thread, and your horrible hyperbole deserved another response.

urbanknight

I acknowledge that I’m not always right, and I don’t mind being corrected. However, disagreeing without providing some sort of information or support is weak and pointless. Then when you consider that multiple people have already corrected me with said information days before you joined in? Silly.

wheelreason

Ya'll right, I'm wrong. (for the young guys that need that sort of thing, I may even have some trophies here somewhere).
With all the talking over each other, pseudo science v. pixie dust arguments, we're missing the point. Length of stem does not change the steering characteristics of a bike, but it certainly appears to, because it magnifies or diminishes the lever, making an equal input (deliberate or inadvertent) have a different magnitude. And yes, one certainly counter steers when steering with one's butt, it;s a lean and pivot of the hips.

phughes

I'm so sorry you are so bothered that I read a thread, without seeing the date of your post, then replied in a manner that is displeasing to you. Had I realized the thread was old, I would not have responded. Yeah, I responded to you before I read the entire thread. It happens.

SkinGriz

IOW, a trike that was forced to steer as a car, steered as a car.
As soon as it was allowed to steer with lean, it did.

You know… bikes with training wheels don’t need to be counter steered. Bikes with training wheels don’t steer like bikes.

”I can make a 3 wheel vehicle steer like a car.”

Not applicable to bikes.

john m flores 

May you did not understand. This was no normal trike. A trike or a bicycle with training wheels does not lean or countersteer in order to turn.

urbanknight

I can’t tell if that apology is sarcastic or genuine, but I’ll take it either way, and I admit I chuckled that you responded to me simply because of my sarcasm. The only thing that really bothers me is when someone says “you’re wrong” without backing it up with supporting facts or evidence. I’ve been guilty of not reading a whole thread before.

SkinGriz

It doesn’t matter.

A bike or motorcycle has one gyro in front and one in back. The one in front is roughly in line with the steering axis. These gyroscopes are also the wheels and tires that contact the ground.

Any machine that matches the above description for wheel arrangement will steer the same way, initiating a turn with counter steering.

The machine you posted has three three contact patches. In geometry how many points make a plane? How many points make a line? The machine you posted is irrelevant to bicycles.




^ The above motorcycle probably also does not lean or counter steer to turn at very low speeds. I’ll let you think about why.

john m flores 

I'm no longer sure what your argument is - that motorcycle and bicycles don't use the same physics? Or that they do? Or that the only way that two wheeled vehicles steer is via counter steering?
​​​​​​
To be clear, I'll restate my position - at slow speeds, two wheeled vehicles can sometimes steer by turning in the direction of travel but beyond walking speeds steering is accomplished via counter steering.

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