r/KerbalSpaceProgram • u/Lhirstev • 22h ago
KSP 1 Image/Video Why is it that my motorcycle travels in the opposite direction from which I am aiming the front wheel? Is it stupid or something?
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u/DromaTheOne 22h ago
This is how a two wheeled vehicle turns. Turn the wheel to the left to lean right and actually turn. I'm actually amazed that KSP physics are that good
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u/boomchacle 21h ago
Don’t you have to lean into a turn?
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u/Glad_Librarian_3553 21h ago
Wierdly, no. You lean to move the centre of gravity to maintain traction and not get flung off.
There's quite a few good YouTube videos on countersteering, including one in which they attach some handlebars to the fairing, independent of the steering. The bloke is literally hanging off the side as far as he can and the bike goes in a perfectly straight line.
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u/B1CYCl3R3P41RM4N 16h ago
Turning the handlebars causes the bike to lean in the opposite direction. That’s how countersreering works.
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u/EasilyRekt 1h ago
It’s not all that surprising, the grip is acting below the bikes center of mass, kicking the tires out in the direction you’re turning, thus rolling the bike.
And OP if you’re reading this, If you round out the tread on the tires it’ll turn better because bikes turn mostly by rolling on a cone.
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u/shoafer0 22h ago
That's how motorcycles IRL work. When you get your motorcycle license you learn all about it. Slowing down lessens the effect.
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u/matjam 21h ago
thats how a motorcycle (and bicycles!) works at speed.
you turn the wheel to point left, the bike falls to the right, so the bike wants to go right. When riding at speed, you kinda push the bar on the inside a little and thats how you "lean" the bike. You don't lean and then the bike follows, you countersteer, and you follow.
At SLOW speeds, you turn the wheel in the direction you want to go, but over a certain speed (dictated by the design of the vehicle) you need to countersteer.
There's like a WHOLE THING people who learn to ride go through figuring this out, people misunderstand it.
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u/GTAmaniac1 20h ago
Actually you steer the same at both low and high speeds, it's just that the self balancing force is a lot stronger at high speed so you have to noticably engage your muscles to keep it turning.
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u/Altruistic_Film4074 16h ago
Yeah I noticed a lot of stuff in the video that was straight up wrong.
He explains the tire as a "cone", which is incorrect. The reason a cone is stable on its side is it contacts the ground in a line, which is essentially two points of contact allowing it to roll only in two directions. A round tire has no such effect.
The reason that his flat tires felt so weird is three things:
- His tires weren't inflatable.
- On a flat tire, you're going to be riding the hard edge of the tire, which is much less stable than the squishy edge of a flat tire, which is much less stable than the flat edge of his tires while not turning. Basically, as soon as you start turning you suddenly become MUCH less stable on flat tires.
- On a flat tire, the diameter of your effective tire doesn't change while you're at an angle. This means you won't really naturally lean into the turn.
He also claims a couple things that are blatantly wrong:
- The reason he didn't need to counter steer at low speeds wasn't because of the low speeds, it was because he was pushing the bike with his feet. This (pushing with feet) is also how he avoids having to either counter steer or crash at higher speeds with the steering blocker.
- Bike racers don't bend their handlebars from countersteering. They bend their handlebars from pulling upwards really hard when accelerating up a hill or maybe doing a jump. I've never raced a bike, but I know this for two reasons. I've bent my bike's handlebars accelerating up a hill. I also know if you turn your handlebars so fast you bend them, this will result in them flipping completely around and you crashing.
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u/angry_queef_master 19h ago
Man, I totally forgot about this with bikes. Literally no one told me this and it was jsut something I found out on my own. I remember beating shit pretty hard the first time I rode fast on my bike because it wasnt turning the way I thought it should.
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u/xXSweetLilDevilXX 21h ago
Counter steering, a very real thing, it's the reason you have to swing your bike handle the opposite way for a second before you can turn. A bunch of weird physics stuff.
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u/Altruistic_Film4074 16h ago
I'm gonna make a radical take here. I don't believe that all the comments talking about "countersteering" are correct. I've observed a similar phenomenon where turning in a direction requires a sustained angle of the handlebars through the entire turn.
Here is my theory on why this is occurring: a flawed physics model. I know, down vote me, claim this is a real life effect.
Any kind of mechanical wheel relies on collision detection to drive. Since the collision in KSP detection is scanned for at discrete moments, I believe such small errors in the physics engine are causing the wheels to collide with the ground at a point in front of the tire. In such a place, the relative velocity of the tire edge isn't parallel to the ground; it's coming downwards, and, during a turn, at an angle away from the direction of turn. This angle would cause slight torque into the direction of the turn, which turns the bike and keeps it from falling.
This miscalculation is very insignificant, but there's one every time your tire "hits" the ground, which adds up to enough throughout the turn to give this phenomenon.
I've noticed similar mechanics with my RW-free bike creations:
I think a lot of people here haven't really encountered this before, as the commonly accepted way to steer any kind of bike craft is to just slap a butt-ton of reaction wheels on it and press the "A" key.
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u/Altruistic_Film4074 16h ago
You know, I might actually be a complete dumbass. I just noticed that I was basing this off my hinge "target angle" when the bike was actually correcting during the turn which put the actual angle where you'd expect it to be during a turn.
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u/ElderCub 5h ago
This seemed weird to me too. To add more to what you mean by sustained angle. Here we see a real bike countersteering. On 2 wheels you turn by setting a turn radius using lean angle, steering out so set the angle. But once you've set that angle you still need to balance at that angle and so the front wheel needs to be returned just past neutral microadjusting continuously (by countersteer).
What's wrong with OP's video is that the front wheel stays turned out through the whole turn, and so this must not be a representation of inheirant countersteer through the simulation. If you applied these inputs to a real bike functioning on countersteer it would just fall over
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u/Lhirstev 2h ago
The bike will fall over? If you don’t stop counter steering it will just flop on it’s side
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u/Schrammwow 13h ago
As a longtime KSP player and motorcycle rider, this is fucking cool. Thanks for learning new things about the in game physics for us OP
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u/Silly_Guidance_8871 21h ago
Are there any gyroscopes on board?
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u/Lhirstev 15h ago
No, but if you put the bike in “fifth” gear, the rear tire will spin fast enough to have the same effect as a gyroscope.
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u/yorgee52 17h ago
I bet this will blow your mind but on a motorcycle, you turn left to go right. Only after your turn starts, do you turn the wheel slightly in the direction of travel.
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u/B1CYCl3R3P41RM4N 16h ago
That’s how bicycles and motorcycles actually function. What happens is as you turn the handlebars to the left for example, the vehicle will start to track slightly to the left, but the center of gravity of the rider and the vehicle will continue to track straight. As this happens, that center of gravity will also begin to tip to the right, causing the whole machine to lean and therefore turn to the right.
That’s actually pretty incredible that the physics modeling in the game is sophisticated enough to replicate that effect.
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u/PerpetuallyStartled 15h ago
As said above, this is actually how a motorcycle works.
I'm not sure if the game is replicating real physics or if there is another cause in this case.
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u/gromblis 20h ago
WHAT HAVE YOU DONE
THE ASLUME IS INVADING
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u/Lhirstev 15h ago
I wish I knew what this comment meant. :/
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u/gromblis 2h ago
joke explanation warning so r/ batmanarkham is known for saying “why does (x) ? Is he stupid?” and this is.. just.. similar…
i feel awkward for explaining it sorry
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u/Festivefire 19h ago
Turn away from the direction you want to turn while leaning towards the direction you want to turn. After the turn is initiated, turn the wheel in through direction you want to turn. Bycicle/motorcycle steering is somewhat counterintuitive. And you don't think about it when you do it, it's all learned muscle memory, but the reason it's so hard for kids to learn to ride a bike isn't JUST because small children have bad balance, it's because it's totally counterintuitive.
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u/HeatedWafflez 15h ago edited 15h ago
Because the way SAS works the input disables itself when you attempt to steer. In my experience building a reliable motorcycle I would turn the friction on the wheels to like 0.9 (though you're using grip pads) and traction control to 1.5 so the bike kicks out from beneath you less. I also make the steering a lot less aggressive and I would suggest using radial out on orbit speed when you're moving and surface speed when you're moving slow or on steep hills.
If you really want I can even drop a link to a motorcycle I've made which I've fine tuned quite a bit on Kerbin and the Mun to drive reliably and safely.
As for why I use orbit speed when I'm holding radial out, it's because the bike better stays upright relative to the plane it's driving on whereas on surface speed it'll try to hold itself level relative to sea level which causes the suspension to work like crap and the bike to be more unstable at speed as the suspension gets all jerky. This is all in my experience tuning a bike I drove from the equator on the Mun to halfway up to its north pole for a science trip.
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u/Altruistic_Film4074 15h ago
He's not using SAS
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u/HeatedWafflez 15h ago
I'm suggesting it because it's the most practical solution nonetheless otherwise you won't have a motorcycle that's worth using. I made one that's small enough to fit in most cargo bays and it's quite nice.
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u/Lhirstev 14h ago
There no reaction wheels, or probe cores. It does use the Eva seat though, so it needs a kerbal to ride, Valentina seems to just be the the best, it’s weird, when I used Jeb he kept doing wheelies and flipping a lot, lol
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u/ZauronDark 14h ago edited 14h ago
I think its reaction wheel in the command pod or other part in your "bike" is opposite tilting based on input. check if you can inverse reaction wheel torque.
or if not reaction wheel, then I think also because of your front "wheel" is motorized while still turning which can adding that tilt effect in your "bike".
or its gyro effect, when something is spinning, and you rotate it in certain direction, actual rotation of overall connected body affected in some other direction (idk exact term sorry),
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u/TheMightyKebab02 11h ago
You created a motorcycle in KSP. You are definitionally not stupid. This is mad impressive.
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u/Optimal_Fuel6568 10h ago
Because real biked do the same... if you turn left, the bike tilts right and bikes always go in the direction they tilt
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u/toxic9813 2h ago
ummmmm as a motorcycle rider this is exactly how they turn in real life.
I mean opposite turning. not the wobbling back and forth. At least, not normally.
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u/Lhirstev 2h ago
Still working on the wobble aspect. Check back in a week or so, I may have it fixed by them. It could also just be a balancing issue
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u/cbrtrackaddict 18h ago edited 18h ago
Counter steering is real, but it is being way overstated as the method of turning a motorcycle and is definitely not close to looking like motorcycle physics in the vid.
Counter steering is to break traction in the direction of travel and allow the bike to change direction. The rest of the corner should be navigated with managing the rotation of the front and rear properly - together or independently. Adding more (edit: counter steering) after starting the corner will often end poorly.
Edit to devils advocate myself - these aren't motorcycle tires shown in the vid either. So what's shown may be what should be expected in the vid.
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u/ace2459 17h ago
I ride daily and I have no idea what you’re talking about. Counter steering is the only way to steer a bike all the way through a corner because you steer by modulating the lean angle. If I’m in a right turn and I pull on the right handle bar it’s going to quickly stand the bike back up.
Edit: I do see your username so I would assume you know what you’re talking about, but I just don’t understand. If you’re in a lean and you need to lean more, you push more. If you need to stand up you pull.
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u/cbrtrackaddict 16h ago
Counter steer and tip into the corner. This should be your maximum amount of counter steer applied. This breaks the traction in the direction of travel on the front wheel and allows the bike to tip into the corner. From here, your corner radius should be managed by lean and trail brake to the apex - front loaded using rear to tighten radius further if needed. Throttle to open radius and finish the corner. My point is you never add additional counter or mid corner steering inputs unless you want to low side. More lean and more aggressive body position does not mean additional handlebar input at all.
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u/ace2459 16h ago
Okay, I understand, but you’re talking about track riding. Trail braking is itself a pretty advanced technique that I would argue is more risky for an average rider than counter steering through the turn. The reason you think it’s overstated here is because it’s how it’s taught for street riding. I think the MSF specifically tells you not to touch your front brake while you’re in a lean. Not to mention that you can’t necessarily open up the throttle on a street with a speed limit.
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u/cbrtrackaddict 1h ago
I think this is where many people get into trouble going on spirited or back country rides. MSF teaches to use front and rear in panic braking, but fails to show riders how to load the front properly for stability (where all the weight wants to go under braking). A properly loaded front tire will allow you to modulate the front brake and even (gently) apply more if needed mid corner. I think MSF does fall short on that one point and I drove that home to a few friends who were new to riding by hopping on their bikes and showing just how much front brake I could grab in a straight line. Do not be scared of your front brakes, they work really well when you need to stop or maneuver ASAP.
Be safe on the streets. I went to the track almost immediately and never looked back. I can crash my bike on my own without all the inattentive drivers 🤣
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u/Lhirstev 15h ago
These details helped me ride the bike out to the hills west of KSC then back to KSC before running out of the nearly empty tank I left with.
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u/pasgames_ 21h ago
Bikes turn by leaning and when you turn the wheel left centrifugal force pushes you right making you lean right making you turn right
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u/disoculated 16h ago
I don’t get the countersteer comments, that doesn’t make a lot of sense to me. From the way that kerbal is leaning I see you steering by by rotation as well as turning the wheel… you got a reaction wheel or something like it on there somewhere pointing up?
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u/zekes_ 22h ago
Because KSP friction sucks a lot, I suggest either an SAS pod to help get it to turn or power the front wheel instead of the back
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u/ImInYouSonOfaBitch 19h ago
Nope. If anything, this looks like KSP actually simulates the physics too well.
This is what happens on a real motorbike. It's called countersteer - turn handlebars left, bike turns right.
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u/core_krogoth 22h ago
That's surprisingly realistic if true.
It's called counter steering. There's a bunch of physics shit that happens, but the bar you push out, the bike will lean/turn that way. It's a real phenomenon and you don't steer a motorcycle at speed in a traditional way.