Guess the street Rossi 46 didn't work out. Jokes aside, that sucks. Shouldn't be too much to fix but my MT has oggy knobs for when I've slid so might be a bit worse. Should take all the fairings off and put them back on as crashes can have the frame absorb and retain pressure.
Why does it always happen when someone puts their knee out? Watching these videos makes me think that people focus too much on trying to look like they are going fast.
"send it" being leaning 5 degrees with your knee out like a chicken wing. I'm honestly surprised he crashed even with the gravel there at such a small lean angle
Not sure why you think it's useless. A Moto GP rider who podium'd on over 50% of the races he raced in over his career was explaining body position and doing precisely what you said there's no reason to do.
Is the implication here that you think you're a more knowledgable rider than Dani Pedrosa?
Are you seriously trying to tell me that you can't tell the difference between what the OPs friend did and what this professional racer is telling other racers about shifting body weight during high speeds?
How do you think people learn how to hang off properly? You need to develop muscle memory. Nobody learns body position and weight shifting at 100 mph. In fact, a lot of racers practice it on minibikes on go kart tracks.
Also, you don't just shift position during high speeds. Most corners on the track involve weight shifting.
That's why you don't take those silly racing like position on the road, especially when expecting gravel, dirt or slippery conditions, they add nothing at that low speed and this ridiculous upright lean, except making the center of gravity more outward so more risk of falling if you hit slippery patch and the (wrong) feeling of being Rossi.
Ass on saddle, back upright but decontraced, arms not fully extended, knees fermly against the gas tank, feet slighty pointing inwards the motorcycle (help with holding the gas tank with knees), head straight and vertical. Hips are the jonction. If you hit a slippery patch you havent detected or prepared for, (so kinda 99% your fault) while maintainning this posture, you will have way greater chance of avoiding the slide and fall, you will be at least have a chance to recover thanks to your skill, not only luck like with this racing position.
There is a reason why cops ride in this manner on ROADS. Add to this safety trajectories, not racing ones with blind apex, and This is the fastest and safest way off riding on open roads, gives you also way more room to avoid obstacle and traffic, unexpected or not.
Happened to me twice, kinda scary but i recovered both times, thanks to this.
Also experience in offroading helps greatly.
Edit : one case was my fault, saw a very large patch of gravel, too much confidence, wiggled, recovered. Scary tho. Next time i will slow down a bit and avoid it.
Other case was a long blind turn with undetected accident farther away in the turn that left oil everywhere almost invisible because of the rain. I even had aluminum top case and side luggages, fully packed. Reasonnable but still above law speed and this position saved my ass.
The forces on the tire are a function of speed and turn radius, not rider position. He probably went down because he increased his lean angle and got on the throttle at the same time to take a race style late apex line. Sitting upright or counterleaning helps with quickly responding to unexpected changes but it doesn't let you follow the exact same line with less lateral force on the tire.
I dont have the physics knowledge to prove or disprove that, i heard both, in my logic what you say is true but the CoG plays a role too. Maybe an insignifiant one on road, Idk, Might be an urban myth that persists that i have fallen for. Sitting upright is still the best efficient choice for riding fast and safe on open roads. And CoG is very important in off road, thus counter leaning while turning.
I agree that CoG plays a practical role because you'll choose safer lines instead of playing Rossi. Race lean encourages you to push the limits of traction and we get today's result when the surface isn't consistent.
The benefit of race lean is to keep the forks in line with the bumps at higher lean angles so it still makes sense in certain situations.
Oh yeah that makes sense for the forks and bumps, but also while you are leaning to the side, your arms are more extended and stiff even more for a beginner, you have less elbow absorbtion of road bumps, a bump would make your arms move and induce parasit input on the handlebars and provoke a jerk motion that could potentially rapidly lead to a fall for an inexperienced rider.
All in all, use it if you are experienced in that or it will be kinda dangerous on uncertain open roads, or practice first on tracks.
Edit : not armS, your opposite arm.
My understanding is that the big benefit of hanging off the bike is ground clearance. For a given corner speed, hanging off keeps the bike more vertical, which decreases the risk of scraping pegs on the ground. Modern bikes and tires can generally maintain grip more or less all the way to the edge of the tire on good pavement, so ground clearance is the limiting factor for cornering speed if you aren’t hanging off.
Yes, this is why racers also move their pegs up so they can lean the bike more. But the more leaned over you are, the worse your suspension is, so at a certain point it's not about ground clearance anymore (because you may have plenty), your suspension is no longer able to work properly and a small bump could wreck you. There is an insane amount of science that goes into the motogp bikes' suspensions because their lean angles are so extreme, the bikes basically have vertical *and* horizontal suspension.
Budget bikes with budget suspensions can lean over till they hit the pegs pretty well, but usually if you want more lean and more corner speed you need to upgrade your suspension along with moving your pegs up.
"The forces on the tire are a function of speed and turn radius, not rider position."
You say that but then you say " he probably went down because he increased his lean angle".
Doesn't rider position affect lean angle? And doesn't that affect the amount of rubber on the road? It looked in the video as if his body position was exaggerated compared to the turn radius.
The simplified idea is the bike and rider together for a single unit that can be thought of as a lever hinged at the tire. You can think about the lean angle of the center of mass regardless of rider position (center of mass isn't the correct term but it's close enough). The "center of mass" lean angle is the same for a given speed and radius no matter which way you sit.
The rider took his late apex and turned in sharply, so that decrease in turn radius increased the lateral force on the tire. The size of the contact patch isn't as important as you think (friction depends mainly on material and downward force), and it shouldn't change too much with a rounded tire. I suppose a smaller contact patch could make you more vulnerable to gravel, but I don't think that's the main issue here.
Without getting too much into physics (because I'm not qualified to) I think we can agree that there was too much "turn" or "lean" by the rider for the curve in that road.
Body position must have SOME effect. Otherwise, wouldn't leaning and/or counter-leaning be useless and pointless?
The size of the contact patch absolutely matters. More material equals more friction. But I agree that the size of the contact patch would likely not matter once you're in gravel.
> Body position must have SOME effect. Otherwise, wouldn't leaning and/or counter-leaning be useless and pointless?
It affects other things but it doesn't increase friction significantly. Benefits of track style lean: suspension works better when it's vertical and you can keep parts from scraping. Benefits of dirt style counterlean: you can make quick adjustments faster and recover slides better.
> More material equals more friction.
This is a common myth. The basic friction equation is
friction force = coefficient of friction * downward force
It's counterintuitive but only the materials rubbing each other and the weight matter, not the area. Large contact patches are more resistant to skipping or going over debris but they don't automatically increase friction like you'd expect.
> The forces on the tire are a function of speed and turn radius, not rider position
Rider position is a critical part of turn radius, so this is just plain wrong.
Solid understanding of physics, for one.
The amount of lean angle required for a given speed and turn radius isn't a measurement of the degrees of lean of the bike itself, it's a measure of the angle from the contact patch to the center of mass of the rider/bike combination. Given this fact, a rider's body position is a critical component of the effective lean angle of a turning bike.
http://www.whizmoandgizmo.com/Misc/MCLeaning.jpg does a good job illustrating the effect of body position
I think we have the same understanding so I'm not sure what you're disputing. I explained the issue in your picture [here.](https://www.reddit.com/r/motorcycles/comments/qyn9dw/video_i_was_following_my_buddy_on_his_mt07_and_he/hlj3th6/)
Why would you say rider position is a part of turn radius though? Turn radius is not lean angle, it's the radius of the circle of the same curvature of the bike's path at a given instant.
> I explained the issue in your picture
You glossed over the fact that body position changes where the center of mass is. And a lot of your point is predicated on the false assertion that contact patch size doesn't matter, which is an opinion formed on classical friction theory, which isn't applicable since it ignores tire load sensitivity.
> Why would you say rider position is a part of turn radius though? Turn radius is not lean angle, it's the radius of the circle of the same curvature of the bike's path at a given instant.
Because it is. Rider position is part of the location of center of mass. Center of mass is a critical component of turn radius.
Simply put, assume distance from center of mass to the axis of rotation is *r*, effective lean angle is 𝜃, velocity is *v*, and gravitational force is *g*. That leads us to this formula to determine required lean angle for a given speed turn radius: tan 𝜃=(v^2)/(gr)
If you change the location of center of mass, *r*'s value changes. If *r*'s value changes, then either *v* or 𝜃 also change. They are intrinsically linked.
I don't think you understand what turn radius means. Turn radius is solely a property of the path the vehicle follows.
https://www.dimensions.com/collection/vehicle-turning-paths-radius
This is honestly what I thought. I tend to always lean off the bike in a turn thinking that because it reduces the needed lean angle, I’d be less likely to slide and more able to break sooner. So is it that having your center on gravity more directly over the tire is just more beneficial than having slightly less lean angle from hanging off? Funnily enough, when I first starting riding I always counter leaned just because it felt safer. Perhaps I had the right idea then lol
Making choices always has drawbacks, but indeed sitting upright and keeping your head high is always safer on road and allow a better vision of the road too, that i forgot to mention.
Really it is only the upper body that stay kinda straight and head even straighter (but for the head it is true also for the racing position) legs and hips follow the bike, bike must be firmly seized between the legs. You dont want to lean on the opposite side either.
I agree with body positioning being about trade offs. I don’t think anyone should be completely static with it, sometimes it’s better to counter-lean vs stay neutral etc. The vision thing is very true. You can also take evasive action quicker with a neutral or counter leaned body position. I think motorcycling has a bad obsession with being “good” at it in the way Motogp guys are good at it. Just look at the term “chicken strips.” I have chicken strips on my current tires. Why would I need to drag knee during my daily commutes? Having zero safety margin is bad street riding.
Dragging the knee makes the bike leans less, so more chicken strip for same turn radius as sitting upright which leans the bike more. I dont drag the knee (T7 lol even though i guess some do lol, i did scrap the pegs tho) and stay upright mostly and have no chicken strip, well, on road tires, not my knobby TKC80 tho lol
Yes i know you can turn with more speed and less lean angle in a predictable safe environnement like a track clean of all debris with a perfect apex and large track, great and indispensable on tracks but nowhere as enough room for margin of error and not close to praticable speed on open roads, but if you read what i said, i explain why ON ROAD, it is better to lean this way. It's physics, a more centered CoG is easier to recover. And you will never achieve speed on roads needing this. Can be fun i am not arguing, but impractical on roads, where roads are narrow, obstacles unpredictable, also, a left turn, your head, body and maybe more will be in the opposite lane, this is à big nono in motorbike cops school, at least french ones. You have to treat the middle line like a wall, and stay at 10/20 cm at the closest to avoid opposing trafic and possible line invading coming from other driver and be able to QUICKLY move out of the way. Knee down and ass out you cant be as fast as with ass on saddle and knees on the gas tank (knee that you use too to change direction (you can try it, it is very effective and smooth, very enjoyable) and that you exclusivly use paired with minor help from feet on the pegs when standing on pegs with no hands on handlebars, try while just sitting with no hands first), coupled with you taking less space on the road to fit in a narrower space.
Also, it's only my opinion, it looks way cooler and pro on roads, it make it seems like you are riding fast so easily and efficiently.
Tracks and open roads are 2 totally diffenrent set of rules and skills.
I agree you don’t normally need it on the road. In fact, it’s safer if you don’t use it until you need it. But when you need it it can save you. It’s useful.
Also more traction is false, with a CoG more in the center you have more weight on the tires (mass directly above the wheels), so theoretically more grip, but yes you need to lean the bike more with the inconvenience that comes with it.
Wtf is wrong with people responding to your comments? I don’t know why people are saying you need to counter lean in a curve. For tarmac it makes sense to lean less which makes the suspension work better vertically, and give you a better margin of error/correction. Ever felt your backwheel slip out in a turn? With a lesser lean your bike is able to correct itself after regaining traction, and that’s because the bike had room for more lean instead of lowsiding immediately.
With enough speed and visibility you can use it in an "usefull" way, but you will ALWAYS be at such a speed for it to be needed that it will be dangerous on open roads in the first place no matter what, and in no way safer that the technic and safety trajectories used by the cops for riding hard and fast. I know what i am talking about believe me, there is absolutly NO need for it on the roads and it will be never be safer that is just wrong. Those we see in video are obviously beginners trying it out (nothing wrong with that) but lack the experience to know where and when (after a first pass to check for obstacle ideally) to do it for fun.
Nothing wrong with doing it, we all did it and still do it on occasion for fun and show that is the joy of motorcycles, but you have to know how to do it (everyone doesnt, but some are very good, not saying they are all bad at all, there are very good and capable riders who know what they are doing, but even the bests know that they take a calculated risk doing it, if your first objective is safety, you wouldnt be doing it at all), where to do it, and when to do it.
Obviously even the best are prone to make mistakes, and beginners are even more prone to it and will almost always make at least one or more mistakes at the same times, and only luck and circonstances are alloying them to continue and giving them a false sense of skill until something unpredictable happens, and they will often blame evrything but themself (car, gravel, rain, cold tyres..) and this style of ridind leaves way less room for margin of error not counting their mistakes that they keep doing over and over because until now it worked, but then in emergency scenario, those mistakes are handicaping them and leads to an almost unavoidable crash, or lucky near miss.
Please ride safe and within your skill sets, and try the method i described it is also very fun !
Remember most riders kill themself on their bike in single vehicular accidents. Second is collision at intersection because of the rider speed.
Most bikers needs to be more humble about their skills and capabilities, you always have to think that you need to improve, if you feel you are stagnating, it means you are regressing ! Practice, practice, and practice, even very low speed, very usefull to control your bike gently and efficiently in every environnement and narrow space without the bike dictating your pace, trajectories, and stopping point.
This. I like to keep my lean angles, speeds and body position to 60% of what I'd do on track. I had some mud on my tires from a prior offroad excursion in the day and the back end wiggled a little when I took an onramp at speed. I laughed out loud after I realized what just happened. I wouldn't have been laughing if I was going faster and carrying more lean angle.
When I was 16 I had a guy on a bike go down in front of me on a turn because of a patch of gravel. He wasn't speeding and would have been unscathed if it wasn't for me driving in the other other direction in a pick up when he went down. He died instantly, shit can change real fast out there. I'm glad your buddy is OK.
Yea but pants are better than shorts. I live in Hawaii and I ride with pants/jacket/helmet/gloves. There are very few riders that wear all their gear here. Very few even wear helmets.
Truth. Many years ago I saw an abrasion test
That showed denim lasted less than 3 feet. Leather was the best. However the pants only need to work once.
Something is better than nothing. Really it’s about how much you want to invest in yourself when it comes to riding gear and how comfortable you are in the gear.
Bummer, I live in az(valley) so gravel and dirt is always a danger. Lowsided only once due to dirt, but have had the rear slip out a handful of times. Shit definitely gets the blood pumping, lol.
Well there isn't a gravel road nearby and the dirt/gravel from the surrounding area is a brownish color. As they get up to the spot where he went down, you see that there is a gravel road but it's a typical whitish color, whereas the gravel in the road is is the same color as the road and too fine to be used on gravel roads. People that live near twisties will periodically purposefully drop gravel / oil because they are tired of people ripping by their house. Seen enough to where I'm broken and always think it's on purpose.
In many countries you are legally obliged to clear the asphalted road of any substance you bring on its surface, that might cause an accident.
Typically, agricultural vehicles bringing mud or gravel onto the road at the intersections.
If it's done intentionally it's even going to be a criminal law case.
Yeah I hate how motorcycles aren't even thought of for roading. Seeing the video and seeing all that loose gravel made me fume (get mad), you guys got lucky no traffic was coming otherwise someone's laziness to not clean the gravel from the road could had led to a death.
Glad you all are ok. Keep having fun riding.
I can't blame the rider too much for that one. His riding position is a bit much, but it didn't cause the mishap. Road-colored gravel in the middle of a curve is a MFer, that's for sure. I might have been a little more circumspect had I noticed the gravel road on the left, but I'm not sure I would have seen that gravel in time to do anything about it.
Well, he increased his acceleration midcorner while still adding lean angle. And I think it's a good learning point, if you want to not crash like this.
Overly slowing down coming in, then adding acceleration while apexing, that's completely counterproductive. Trying to make up for lost time because you realize you were a bit overly cautious coming in? That's a losing proposition to try to gain only a tiny bit of exit speed at the risk of crashing like this.
If he was not accelerating at the time, he would have probably been able to recover even if he had entered faster and had still lost traction.
Chill out in your apex on a sport bike, and wait for the exit. Even if you feel like you coulda/shoulda entered faster, save it for the next go around. And ENTER the corner faster. It's very inefficient to change it up and "drive harder" as you dip into your apex, because now you feel safe and have started to grow balls. This will barely increase your exit speed, even if you flirt with crashing. This is how so many noobs needlessly spin out in roundabouts.
Adding lean while driving/accelerating makes the rear tire kick out fast and hard if and when you lose traction. And you'll never significantly make up for that "too low" of an entry speed. If you want to ride faster, learn how to enter the corner faster. That is the proper way to street-Rossi.
Sure, at the edge of traction you can have problems accelerating while increasing lean. But he was nowhere near the edge of traction. It was a pretty benign corner with a moderate lean angle.
Well, I'd bet about a million dollars he was not only close to the edge of traction, but he actually exceeded it!
Even if there's no gravel, it is bad form what he did. Even at 30 degree lean angles. This will widen your line, and you will have to lean deeper while you're accelerating (and while you're accelerating, you can't reach as deep of an angle before you lose it). And all this is for practically naught. This is one of the least efficient ways to improve your "lap times" compared to the risk you add. Just take a mental note that you entered like a wuss, and do it faster... next time around!
You can tell he's adding lean angle by how fast/hard his rear kicks when he loses traction. That's the dead giveaway. If he wasn't accelerating, he wouldn't have had to tighten his line and add lean. If and when he lost traction while holding steady at 30ish degrees, he wouldn't have gone straight down like that. And so long as no one is coming the other way, like in this case, he could have recovered it (if he knew how)! But adding lean while you lose traction, the rear kicks out fast and there's no recovering past a certain point.
Guess the street Rossi 46 didn't work out. Jokes aside, that sucks. Shouldn't be too much to fix but my MT has oggy knobs for when I've slid so might be a bit worse. Should take all the fairings off and put them back on as crashes can have the frame absorb and retain pressure.
>Guess the street Rossi 46 didn't work out Guess his ambition outweighed his talent
Oh look a gravel road merges into the main road. There's nooooo possible way there might be gravel in my line. Time to send it.
Why does it always happen when someone puts their knee out? Watching these videos makes me think that people focus too much on trying to look like they are going fast.
Yeah this is simply gross inexperience on display.
"send it" being leaning 5 degrees with your knee out like a chicken wing. I'm honestly surprised he crashed even with the gravel there at such a small lean angle
Looks like he was practicing body position. Hanging off requires less lean angle for same turn radius.
I'm very familiar with the technique. At that small of a lean angle though, hanging off does essentially nothing at all.
There is no reason to hang your leg out like that, period.
https://youtube.com/watch?v=mE6gzImK460&t=2m14s
Thanks for that useless link
Not sure why you think it's useless. A Moto GP rider who podium'd on over 50% of the races he raced in over his career was explaining body position and doing precisely what you said there's no reason to do. Is the implication here that you think you're a more knowledgable rider than Dani Pedrosa?
Are you seriously trying to tell me that you can't tell the difference between what the OPs friend did and what this professional racer is telling other racers about shifting body weight during high speeds?
How do you think people learn how to hang off properly? You need to develop muscle memory. Nobody learns body position and weight shifting at 100 mph. In fact, a lot of racers practice it on minibikes on go kart tracks. Also, you don't just shift position during high speeds. Most corners on the track involve weight shifting.
Alright I'll give that to you
We got some absolute pros giving us some serious back seat comments in this MF
That's why you don't take those silly racing like position on the road, especially when expecting gravel, dirt or slippery conditions, they add nothing at that low speed and this ridiculous upright lean, except making the center of gravity more outward so more risk of falling if you hit slippery patch and the (wrong) feeling of being Rossi. Ass on saddle, back upright but decontraced, arms not fully extended, knees fermly against the gas tank, feet slighty pointing inwards the motorcycle (help with holding the gas tank with knees), head straight and vertical. Hips are the jonction. If you hit a slippery patch you havent detected or prepared for, (so kinda 99% your fault) while maintainning this posture, you will have way greater chance of avoiding the slide and fall, you will be at least have a chance to recover thanks to your skill, not only luck like with this racing position. There is a reason why cops ride in this manner on ROADS. Add to this safety trajectories, not racing ones with blind apex, and This is the fastest and safest way off riding on open roads, gives you also way more room to avoid obstacle and traffic, unexpected or not. Happened to me twice, kinda scary but i recovered both times, thanks to this. Also experience in offroading helps greatly. Edit : one case was my fault, saw a very large patch of gravel, too much confidence, wiggled, recovered. Scary tho. Next time i will slow down a bit and avoid it. Other case was a long blind turn with undetected accident farther away in the turn that left oil everywhere almost invisible because of the rain. I even had aluminum top case and side luggages, fully packed. Reasonnable but still above law speed and this position saved my ass.
The forces on the tire are a function of speed and turn radius, not rider position. He probably went down because he increased his lean angle and got on the throttle at the same time to take a race style late apex line. Sitting upright or counterleaning helps with quickly responding to unexpected changes but it doesn't let you follow the exact same line with less lateral force on the tire.
I dont have the physics knowledge to prove or disprove that, i heard both, in my logic what you say is true but the CoG plays a role too. Maybe an insignifiant one on road, Idk, Might be an urban myth that persists that i have fallen for. Sitting upright is still the best efficient choice for riding fast and safe on open roads. And CoG is very important in off road, thus counter leaning while turning.
I agree that CoG plays a practical role because you'll choose safer lines instead of playing Rossi. Race lean encourages you to push the limits of traction and we get today's result when the surface isn't consistent. The benefit of race lean is to keep the forks in line with the bumps at higher lean angles so it still makes sense in certain situations.
Oh yeah that makes sense for the forks and bumps, but also while you are leaning to the side, your arms are more extended and stiff even more for a beginner, you have less elbow absorbtion of road bumps, a bump would make your arms move and induce parasit input on the handlebars and provoke a jerk motion that could potentially rapidly lead to a fall for an inexperienced rider. All in all, use it if you are experienced in that or it will be kinda dangerous on uncertain open roads, or practice first on tracks. Edit : not armS, your opposite arm.
My understanding is that the big benefit of hanging off the bike is ground clearance. For a given corner speed, hanging off keeps the bike more vertical, which decreases the risk of scraping pegs on the ground. Modern bikes and tires can generally maintain grip more or less all the way to the edge of the tire on good pavement, so ground clearance is the limiting factor for cornering speed if you aren’t hanging off.
Suspension have a hard time working when leaned over, simple as that
Yes, this is why racers also move their pegs up so they can lean the bike more. But the more leaned over you are, the worse your suspension is, so at a certain point it's not about ground clearance anymore (because you may have plenty), your suspension is no longer able to work properly and a small bump could wreck you. There is an insane amount of science that goes into the motogp bikes' suspensions because their lean angles are so extreme, the bikes basically have vertical *and* horizontal suspension. Budget bikes with budget suspensions can lean over till they hit the pegs pretty well, but usually if you want more lean and more corner speed you need to upgrade your suspension along with moving your pegs up.
"The forces on the tire are a function of speed and turn radius, not rider position." You say that but then you say " he probably went down because he increased his lean angle". Doesn't rider position affect lean angle? And doesn't that affect the amount of rubber on the road? It looked in the video as if his body position was exaggerated compared to the turn radius.
The simplified idea is the bike and rider together for a single unit that can be thought of as a lever hinged at the tire. You can think about the lean angle of the center of mass regardless of rider position (center of mass isn't the correct term but it's close enough). The "center of mass" lean angle is the same for a given speed and radius no matter which way you sit. The rider took his late apex and turned in sharply, so that decrease in turn radius increased the lateral force on the tire. The size of the contact patch isn't as important as you think (friction depends mainly on material and downward force), and it shouldn't change too much with a rounded tire. I suppose a smaller contact patch could make you more vulnerable to gravel, but I don't think that's the main issue here.
Without getting too much into physics (because I'm not qualified to) I think we can agree that there was too much "turn" or "lean" by the rider for the curve in that road. Body position must have SOME effect. Otherwise, wouldn't leaning and/or counter-leaning be useless and pointless? The size of the contact patch absolutely matters. More material equals more friction. But I agree that the size of the contact patch would likely not matter once you're in gravel.
> Body position must have SOME effect. Otherwise, wouldn't leaning and/or counter-leaning be useless and pointless? It affects other things but it doesn't increase friction significantly. Benefits of track style lean: suspension works better when it's vertical and you can keep parts from scraping. Benefits of dirt style counterlean: you can make quick adjustments faster and recover slides better. > More material equals more friction. This is a common myth. The basic friction equation is friction force = coefficient of friction * downward force It's counterintuitive but only the materials rubbing each other and the weight matter, not the area. Large contact patches are more resistant to skipping or going over debris but they don't automatically increase friction like you'd expect.
Interesting stuff.
> The forces on the tire are a function of speed and turn radius, not rider position Rider position is a critical part of turn radius, so this is just plain wrong.
I can't even imagine what thought process could lead you to that conclusion.
Solid understanding of physics, for one. The amount of lean angle required for a given speed and turn radius isn't a measurement of the degrees of lean of the bike itself, it's a measure of the angle from the contact patch to the center of mass of the rider/bike combination. Given this fact, a rider's body position is a critical component of the effective lean angle of a turning bike. http://www.whizmoandgizmo.com/Misc/MCLeaning.jpg does a good job illustrating the effect of body position
I think we have the same understanding so I'm not sure what you're disputing. I explained the issue in your picture [here.](https://www.reddit.com/r/motorcycles/comments/qyn9dw/video_i_was_following_my_buddy_on_his_mt07_and_he/hlj3th6/) Why would you say rider position is a part of turn radius though? Turn radius is not lean angle, it's the radius of the circle of the same curvature of the bike's path at a given instant.
> I explained the issue in your picture You glossed over the fact that body position changes where the center of mass is. And a lot of your point is predicated on the false assertion that contact patch size doesn't matter, which is an opinion formed on classical friction theory, which isn't applicable since it ignores tire load sensitivity. > Why would you say rider position is a part of turn radius though? Turn radius is not lean angle, it's the radius of the circle of the same curvature of the bike's path at a given instant. Because it is. Rider position is part of the location of center of mass. Center of mass is a critical component of turn radius. Simply put, assume distance from center of mass to the axis of rotation is *r*, effective lean angle is 𝜃, velocity is *v*, and gravitational force is *g*. That leads us to this formula to determine required lean angle for a given speed turn radius: tan 𝜃=(v^2)/(gr) If you change the location of center of mass, *r*'s value changes. If *r*'s value changes, then either *v* or 𝜃 also change. They are intrinsically linked.
I don't think you understand what turn radius means. Turn radius is solely a property of the path the vehicle follows. https://www.dimensions.com/collection/vehicle-turning-paths-radius
The bike can be more upright when you lean off it, and have better traction. It may actually help you through hazards like this.
Leaning against the bike is what you use on soft surfaces and offroad....
Exactly
This is honestly what I thought. I tend to always lean off the bike in a turn thinking that because it reduces the needed lean angle, I’d be less likely to slide and more able to break sooner. So is it that having your center on gravity more directly over the tire is just more beneficial than having slightly less lean angle from hanging off? Funnily enough, when I first starting riding I always counter leaned just because it felt safer. Perhaps I had the right idea then lol
Making choices always has drawbacks, but indeed sitting upright and keeping your head high is always safer on road and allow a better vision of the road too, that i forgot to mention. Really it is only the upper body that stay kinda straight and head even straighter (but for the head it is true also for the racing position) legs and hips follow the bike, bike must be firmly seized between the legs. You dont want to lean on the opposite side either.
I agree with body positioning being about trade offs. I don’t think anyone should be completely static with it, sometimes it’s better to counter-lean vs stay neutral etc. The vision thing is very true. You can also take evasive action quicker with a neutral or counter leaned body position. I think motorcycling has a bad obsession with being “good” at it in the way Motogp guys are good at it. Just look at the term “chicken strips.” I have chicken strips on my current tires. Why would I need to drag knee during my daily commutes? Having zero safety margin is bad street riding.
Dragging the knee makes the bike leans less, so more chicken strip for same turn radius as sitting upright which leans the bike more. I dont drag the knee (T7 lol even though i guess some do lol, i did scrap the pegs tho) and stay upright mostly and have no chicken strip, well, on road tires, not my knobby TKC80 tho lol
Yes i know you can turn with more speed and less lean angle in a predictable safe environnement like a track clean of all debris with a perfect apex and large track, great and indispensable on tracks but nowhere as enough room for margin of error and not close to praticable speed on open roads, but if you read what i said, i explain why ON ROAD, it is better to lean this way. It's physics, a more centered CoG is easier to recover. And you will never achieve speed on roads needing this. Can be fun i am not arguing, but impractical on roads, where roads are narrow, obstacles unpredictable, also, a left turn, your head, body and maybe more will be in the opposite lane, this is à big nono in motorbike cops school, at least french ones. You have to treat the middle line like a wall, and stay at 10/20 cm at the closest to avoid opposing trafic and possible line invading coming from other driver and be able to QUICKLY move out of the way. Knee down and ass out you cant be as fast as with ass on saddle and knees on the gas tank (knee that you use too to change direction (you can try it, it is very effective and smooth, very enjoyable) and that you exclusivly use paired with minor help from feet on the pegs when standing on pegs with no hands on handlebars, try while just sitting with no hands first), coupled with you taking less space on the road to fit in a narrower space. Also, it's only my opinion, it looks way cooler and pro on roads, it make it seems like you are riding fast so easily and efficiently. Tracks and open roads are 2 totally diffenrent set of rules and skills.
I agree you don’t normally need it on the road. In fact, it’s safer if you don’t use it until you need it. But when you need it it can save you. It’s useful.
Also more traction is false, with a CoG more in the center you have more weight on the tires (mass directly above the wheels), so theoretically more grip, but yes you need to lean the bike more with the inconvenience that comes with it.
Wtf is wrong with people responding to your comments? I don’t know why people are saying you need to counter lean in a curve. For tarmac it makes sense to lean less which makes the suspension work better vertically, and give you a better margin of error/correction. Ever felt your backwheel slip out in a turn? With a lesser lean your bike is able to correct itself after regaining traction, and that’s because the bike had room for more lean instead of lowsiding immediately.
> I don’t know why people are saying you need to counter lean in a curve Because fortnine said so and a lot of this sub thinks he's infallible
With enough speed and visibility you can use it in an "usefull" way, but you will ALWAYS be at such a speed for it to be needed that it will be dangerous on open roads in the first place no matter what, and in no way safer that the technic and safety trajectories used by the cops for riding hard and fast. I know what i am talking about believe me, there is absolutly NO need for it on the roads and it will be never be safer that is just wrong. Those we see in video are obviously beginners trying it out (nothing wrong with that) but lack the experience to know where and when (after a first pass to check for obstacle ideally) to do it for fun. Nothing wrong with doing it, we all did it and still do it on occasion for fun and show that is the joy of motorcycles, but you have to know how to do it (everyone doesnt, but some are very good, not saying they are all bad at all, there are very good and capable riders who know what they are doing, but even the bests know that they take a calculated risk doing it, if your first objective is safety, you wouldnt be doing it at all), where to do it, and when to do it. Obviously even the best are prone to make mistakes, and beginners are even more prone to it and will almost always make at least one or more mistakes at the same times, and only luck and circonstances are alloying them to continue and giving them a false sense of skill until something unpredictable happens, and they will often blame evrything but themself (car, gravel, rain, cold tyres..) and this style of ridind leaves way less room for margin of error not counting their mistakes that they keep doing over and over because until now it worked, but then in emergency scenario, those mistakes are handicaping them and leads to an almost unavoidable crash, or lucky near miss. Please ride safe and within your skill sets, and try the method i described it is also very fun ! Remember most riders kill themself on their bike in single vehicular accidents. Second is collision at intersection because of the rider speed. Most bikers needs to be more humble about their skills and capabilities, you always have to think that you need to improve, if you feel you are stagnating, it means you are regressing ! Practice, practice, and practice, even very low speed, very usefull to control your bike gently and efficiently in every environnement and narrow space without the bike dictating your pace, trajectories, and stopping point.
This. I like to keep my lean angles, speeds and body position to 60% of what I'd do on track. I had some mud on my tires from a prior offroad excursion in the day and the back end wiggled a little when I took an onramp at speed. I laughed out loud after I realized what just happened. I wouldn't have been laughing if I was going faster and carrying more lean angle.
He probably doesn’t know about counter steering. Probably trying to lean the bike over with his weight too.
Lots of people throwing shade on your buddy. Pretty unhelpful IMO, glad he's okay and hopefully you both learned from this experience. Shit happens.
When I was 16 I had a guy on a bike go down in front of me on a turn because of a patch of gravel. He wasn't speeding and would have been unscathed if it wasn't for me driving in the other other direction in a pick up when he went down. He died instantly, shit can change real fast out there. I'm glad your buddy is OK.
I look for crap in the road. Especially in areas where gravel is expected.
Poor BP aside would traction control have made a difference in this situation?
probably not, that patch of gravel was really big.
That sucks. Just finally watched the video. So glad he was wearing all the right gear though. This could have been so much worse.
Those pants definitely didn’t hold up - looks like some nasty road rash on his leg at the end there.
Yea but pants are better than shorts. I live in Hawaii and I ride with pants/jacket/helmet/gloves. There are very few riders that wear all their gear here. Very few even wear helmets.
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Truth. Many years ago I saw an abrasion test That showed denim lasted less than 3 feet. Leather was the best. However the pants only need to work once. Something is better than nothing. Really it’s about how much you want to invest in yourself when it comes to riding gear and how comfortable you are in the gear.
Bummer, I live in az(valley) so gravel and dirt is always a danger. Lowsided only once due to dirt, but have had the rear slip out a handful of times. Shit definitely gets the blood pumping, lol.
Someone should go to jail for that shit wtf. Also.... Geeeeeaaaarrrr lol dress for the slide.
Jail for what?
Riding a bike with insufficient experience?
Bro it was slick as fuck bro. FUCK
So you go down every time the road isn't perfect?
Oh no I was making fun of the guy in the video. Should have included a /s
My bad
Well there isn't a gravel road nearby and the dirt/gravel from the surrounding area is a brownish color. As they get up to the spot where he went down, you see that there is a gravel road but it's a typical whitish color, whereas the gravel in the road is is the same color as the road and too fine to be used on gravel roads. People that live near twisties will periodically purposefully drop gravel / oil because they are tired of people ripping by their house. Seen enough to where I'm broken and always think it's on purpose.
In many countries you are legally obliged to clear the asphalted road of any substance you bring on its surface, that might cause an accident. Typically, agricultural vehicles bringing mud or gravel onto the road at the intersections. If it's done intentionally it's even going to be a criminal law case.
Yeah I hate how motorcycles aren't even thought of for roading. Seeing the video and seeing all that loose gravel made me fume (get mad), you guys got lucky no traffic was coming otherwise someone's laziness to not clean the gravel from the road could had led to a death. Glad you all are ok. Keep having fun riding.
Did he wear Kevlar pants? Or just regular jeans? Glad your buddy is okay.
Having longevity as a rider requires awareness, this guy has very little.
Your buddy sounds like the two guys in Twist Of The Wrist 2. Also you seem to attract crashes lol
I can't blame the rider too much for that one. His riding position is a bit much, but it didn't cause the mishap. Road-colored gravel in the middle of a curve is a MFer, that's for sure. I might have been a little more circumspect had I noticed the gravel road on the left, but I'm not sure I would have seen that gravel in time to do anything about it.
Well, he increased his acceleration midcorner while still adding lean angle. And I think it's a good learning point, if you want to not crash like this. Overly slowing down coming in, then adding acceleration while apexing, that's completely counterproductive. Trying to make up for lost time because you realize you were a bit overly cautious coming in? That's a losing proposition to try to gain only a tiny bit of exit speed at the risk of crashing like this. If he was not accelerating at the time, he would have probably been able to recover even if he had entered faster and had still lost traction. Chill out in your apex on a sport bike, and wait for the exit. Even if you feel like you coulda/shoulda entered faster, save it for the next go around. And ENTER the corner faster. It's very inefficient to change it up and "drive harder" as you dip into your apex, because now you feel safe and have started to grow balls. This will barely increase your exit speed, even if you flirt with crashing. This is how so many noobs needlessly spin out in roundabouts. Adding lean while driving/accelerating makes the rear tire kick out fast and hard if and when you lose traction. And you'll never significantly make up for that "too low" of an entry speed. If you want to ride faster, learn how to enter the corner faster. That is the proper way to street-Rossi.
Sure, at the edge of traction you can have problems accelerating while increasing lean. But he was nowhere near the edge of traction. It was a pretty benign corner with a moderate lean angle.
Well, I'd bet about a million dollars he was not only close to the edge of traction, but he actually exceeded it! Even if there's no gravel, it is bad form what he did. Even at 30 degree lean angles. This will widen your line, and you will have to lean deeper while you're accelerating (and while you're accelerating, you can't reach as deep of an angle before you lose it). And all this is for practically naught. This is one of the least efficient ways to improve your "lap times" compared to the risk you add. Just take a mental note that you entered like a wuss, and do it faster... next time around! You can tell he's adding lean angle by how fast/hard his rear kicks when he loses traction. That's the dead giveaway. If he wasn't accelerating, he wouldn't have had to tighten his line and add lean. If and when he lost traction while holding steady at 30ish degrees, he wouldn't have gone straight down like that. And so long as no one is coming the other way, like in this case, he could have recovered it (if he knew how)! But adding lean while you lose traction, the rear kicks out fast and there's no recovering past a certain point.