Bike width(From left to right when viewing as a rider) ?
paddle height from ground?
overall height?
Bike length (from back wheel to front wheel)?
Tire width?
Tire radius?
Suspension?
Longer chain shorter chain?
The different connecting metal pipes between front and back wheels?
In: Physics
Probably the MOST important factor is caster. This is the angle of the axis that the front tire pivots on. Tilt it back, the bike is more stable, but harder to turn. Tilt forward, quick turning and less stability.
Think of motorcycles. Those old choppers with the front wheel stretched waaaaayyyy out in front? They’re super stable, but you need a ton of room to turn around.
I’m no expert at bike stability, But I would imagine tire mass effects it. the more mass you have, the more mass can produce a gyroscopic effect. So more tire mass means more stability. (The mass would have to spin with the tires)
I’m not an expert and this is just my assumption.
Bikes are fun because there is so much that affects it’s stability. The easiest way to start thinking about it is that anything making it more stable makes it harder to maneuver.
Speed- speed adds the gyroscopic effect of tires which makes both your lean angle and your handle bars more stable. In motorcycle classes they make you practice at low speed, but always say it gets easier when you speed up.
Height- as balance usually tends to go, the higher you are the less stable you are. This is one of the reasons you see motocross bikes which are relatively high. Besides adding clearance, it adds maneuverability.
Weight- so this affects a lot of things but among those it adds inertia, so going straight with more weight will add stability.
I may have gone too basic, but I encourage you to take this same train of thought for how to determine if something adds stability.
Edit: formatting
Gyroscopic effects play a big role. When you have a spinny thing, it’s hard to get it to change direction (kinda like how it’s hard to move a heavy object). It also doesn’t change direction the way you’d expect. The bike doesn’t actually want to tip over, the wheels want to turn left or right.
Here’s what affects this. Wheel weight, heavier wheels have more momentum (although this has drawbacks). Larger wheels, wheels with a larger radius have more angular momentum even if they weigh the same. The shape of the wheel matters as well. If you have the weight distributed further out from the center, you increase the angular momentum. Finally the speed plays a big role. The faster the wheel spins, the more angular momentum there is. You notice how you’re more unsteady when you’re going really slow?
Unfortunately, the answer is “yes.”
Larger, heavier wheels are more stable. Longer wheelbases and lower seating position-which translates to lower center of gravity- will also increase stability. In the steering, flatter rake angle (another poster called it caster, both are correct), increased trail, and wider handlebars add stability as well – the last one because it allows the rider to steer more easily (increased leverage.)
Chain length won’t make any difference. It’s just a power delivery system. Suspension may affect you a bit in that it changes the geometry as it moves, but not past that. Frame tube length is determined by your desired geometry, and by other factors such as wheel size and the size of the intended rider.
Keep in mind that there’s diminishing returns, though, and that every gain in stability has a loss in some other area.
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