Why do professional Supermoto racers, such as Jeff Ward above, and even road racers Kevin Swantz and Aaron Yates below, attack most tarmac corners at race speed by dipping the bike to the inside and shifting their weight to the outside? Isn’t it always preferable to shift your weight to the inside while cornering … like a MotoGP racer (see Jorge Lorenzo at the top of yesterday’s article)?
This subject has come up before on MD, and there is certainly no consensus as to why it sometimes may be faster to weight the outside of the bike, rather than the inside, when attacking a corner. Here are a few things to consider:
- When ground clearance is not an issue, can you control the bike better from a body position above the center of the machine?
- Can you control a slide better from this position?
- If you are above the bike as it is dipped into the corner, as opposed to hanging off the inside, is there less centrifugal force transferred to the tire contact patches?
- Does this position simply work better on slower road courses (Supermoto vs. MotoGP, for instance)?
- Are these riders just lazy, and they don’t want to expend the effort hanging off the inside (some Supermoto riders do hang off the inside on some corners)?
Feel free to weigh in with your own thoughts below. Stay tuned for some riding tips and instruction from MD.
Camber thrust. Every tire has an optimal camber angle for a given corner radius (and slip angle, and bike and some other variables). Supermoto corners have a tight radius and ‘like’ big camber angles. MotoGP corners tend to be large radius, which combined with the high bike/rider combination lean angle, can overstress the tires and give too much slip/scrub. Getting under the bike minimizes the camber scrub effect and allows the tires to work more optimally. It’s about using the tires more optimally.
Most of the above comments are valid and correct, but if you’re not thinking about how the tires work you haven’t answered the headline question.
I can tell you why Wardy does it because that’s the way he learned from racing MX. And it has to do with transferring your weight to maintain traction and keeping your body centered over the bike to maintain control over rough terrain. Typically just weighting the outside peg by pushing down will provide all the weight transfer necessary.
I don’t know why those road racers do it but I can tell you Wardy does because that’s the way he learned racing MX. And it has to do with keeping your body centered over the bike to maintain control regardless of
I’d like to address point 5 as all the experts seemed to have skipped that one.
Having done a few motard endurance events (tarmac only kart tracks) I can say without doubt that it’s far more energy efficient to ride “road race” style and keep those feet on the pegs. Hanging the foot off (more like up against the handlebar out of the way) becomes pretty tiring after about 20 minutes of 45 second laps, especially with the relatively high corner loads one can generate with slicks. Maybe I shouldn’t skip leg day so often?
I have no clue why. It’s like pushing the wrong way on the handlebar in a corner. Seems wrong but works. So who am I to try to figure it out?
Racers go with what works, don’t need to know why.
Riding a dirt bike the bike is higher and longer so you need to keep weight centered.
As a road bike is shorter and lower the center of gravity changes
Before traction control, bikes slid and lost traction lots, especially with their unruly 2 stroke engines. Therefore, riding a 200+ horsepower, 2 stroke GP bike was like riding a dirt track, and needed riders with dirt track skills who were less likely to lose control when the rear end lost traction. Clearly, this is a skill set not needed in racing today, where computers do all the work of keeping the bike in line. It’s not bad, just evolution of the sport.
this threads gonna be long…lotta experts here 🙂
Motorcycle gymkhana riders seem to use the same technique, so I assume it has to do with how tight the track is. I have noticed myself doing the same thing to manage slides on tight trail rides. I am new to dirt and have much more experience hanging off on the inside, but I am more comfortable in the dirt with a more upright body position and can put a foot down to catch myself much easier.
I started mountain biking after riding sportbikes for several years. I used to “hang off” on the corners… and fall off. Fellow riders I met on the trail pointed out the errors of my ways and told me to push the bike under me and to steer into the corner.
It took a while to get used to it, but the singletrack fear left me and I stopped crashing.
In his Dirt Wise riding schools, Shane Watts teaches this technique for cornering a dirt bike on sweeping flat (non-bermed) surfaces. I’m only an intermediate rider on my best days, and even I can feel the added control being “above” the bike provides.
Depends on the bike. My 955 Tiger would slide out from under me if I leaned my body inside. I counter its top heaviness by staying on top. Same it likely to be true for a tall SM, though I’ve never ri
den one. Lorenzo, et al, ride low cg, mass centralized bikes that want/need to pushed down to make them turn.
Q: Shifting Your Weight to the Outside in a Corner … Why?
A: equilibrium.
he’s not so much as shifting his weight to the outside…? as he’s shifting SOME of his weight to the outside. the nature of Physics and Natural Law itself is balance and those tires only offer but so much grip.
Weight to the outside if:
1) You are steering with the rear wheel, or
2) Your speed is slow enough that you aren’t countersteering to make the turn, i.e. your front wheel is pointing in the direction of the run.
Otherwise, lean into the turn to keep the bike as close to vertical as possible.
Your front wheel always points in the direction of the turn.
Only if you ride a trike.
? Tell me how a wheel pointing one direction will roll another. I think you are misunderstanding countersteering. When you countersteer, you are applying pressure to the bars in the opposite direction to counteract gyroscopic precession but the wheel is still turned in the direction of travel. Your pressing on the bars makes the wheel lean over and steer against the force you are providing – but it’s still pointing in the direction of travel.
Counter-steering is a very short-lived action placed upon the front-end of a bike. It almost happens in a nano-second, but it initiates the “roll” onto the side (just slightly) of the tire causing lean. Take a typical styrofoam coffee cup and lay it on it’s side and push it. It will be pointed in one direction but will roll in a tight circle. Which is the same effect we get when we initial a turn with counter-steering input. The bike rolls onto the a portion of the tire some distance from the center of the tire which is a smaller circumference than the center which gives the tighter roll hence a turn.
Haha. Yes you are right. I am a douche.
It’s simple- Anyone that has ever ridden a dirtbike on a dry lakebed and tried tries to make fast turns will come to the conclusion that weighting the outside of the peg is a natural way to ride. If you weight the inside peg while ripping around a turn on this loose surface, you will soon be on the lakebed sans bike.
That’s true of riding on loose surfaces and low traction, but does it also apply to the scenarios shown in the photos above?
On the street or track, your angular velocity (w) is much greater. Angular velocity is how fast your go around a corner; imagine a ball tied to a rope and spinning it fast. The spinning speed is angular velocity. Centripetal force is a function of angular velocity: F = mrw^2. M = mass of rider and machine, r = radius of the turn, and w is the angular velocity (notice it’s a square term, so at higher angular velocities, the centripetal force gets much larger! Since in a corner, rider and machine must stay upright, so now it becomes a force balance, or moment balance to be more exact. Imagine the rider leaned over on a bike, the centripetal force trying to high side him, and his weight of him and bike trying to low side him. There must be a balance or he’ll fall. The rotation point is where the tires make contact with the ground. If you do a free body diagram, summing the moments about the tire contact patch, you get:
h*m*r*w^2 = x*m*g
m = mass of rider and machine
r = radius of curve
w = angular velocity (notice it’s a square term!)
h = height of center of mass of rider and machine from the tire contact patch
g = acceleration of gravity
x = horizontal distance of the center of mass of rider and machine from the tire contact patch
Notice the mass terms cancel out and you get;
h*r*w^2 = x*g
Since the angular velocity term (w^2) is huge on the street or track, you want both h to be small and x to be large. This is essentially what a street bike rider is doing, he is dropping his weight off to the inside of the bike, making both h small, and x large to counteract the angular velocity term.
Well, thanks for taking all the fun out of motorcycle riding…
What, I don’t understand…math and physics are fun! Riding a motorcycle is applied physics = more fun! Well, for me anyways…
don’t sweat it, Scott probably didn’t like to do homework, either.
Weighting the outside peg only matters when the rear is sliding/going to slide.
When the rear slides with more rider weight on the outside peg this applies a righting moment to the chassis that helps regain traction.
If you are not sliding the rear then varying weight across the pegs can be done for other reasons like accommodating upper body position and a flat-spotted rear tire.
More rider weight on the inside peg helps slide the rear going into the turn (learn this in the dirt first!)
+1
LTJ,
NIce approach ! Good to see the right solution here, math is still the way to elude it.
Along with preference I believe it has to do with distributing weight to the footpegs and the way you want the bike to slide or prepare for which way it might slide. Dirtbikes/trials bikes have to have the pegs weighted to keep the bikes from falling into the turn or falling too far into the turn. As I ride a bit of trials, trails, street, they all require a different style depending on the speed, camber of the turn, available traction, ascend/descinding. Think berms, slide in and pivot – top of bike, rail the berm – inside weight the body, weight the outside peg. I don’t ride the street fast enough to do knee down, but a slight weight shift down and inside peg and lower CG to weight tire
I do this on my mountain bike on corners. The additional downforce weights the tire and enables it to stick better.
I think you are onto it. I don’t have the mountain bike chops to confirm, but have seen it described as you say. Additionally, this is how off-road/motocross motorcycle pilots increase traction: weight the outside peg, lift the inside handlebar (and push down on the other). It’s how good riders leave the rest of us in the dust in low traction situations. My guess is that it carries over to supermoto because of the commonalities in bike ergos and terrain. The higher speeds, higher traction, and different chassis/ergonomic situation with sportbikes must result in a lack of need/advantage of this body position, and other goals take precedence (the need to reduce lean angle to allow a higher speed, etc). Horses for courses, as they say.
I dunno.
Maybe we should ask this guy : https://www.youtube.com/watch?v=yn01WoTJrEg
There’s two separate issues involved here. One relates to rider technique and the difference in lines and style between dirt, flat track or supermoto on the one hand, compared to higher speed road courses. Weighting the outer leg is just one of those techniques needed for the tighter turns and more radical sliding. But the other issue is pure physics. Riders hangs their bodies off to shift the combined center of gravity of the bike + rider inward, which allows the bike itself to lean less for a given corner speed, or, to put it another way, to corner faster for a given bike lean angle. This allows faster cornering without dragging things (pegs, pipes, frame, feet) since the lean angle is always the limiting factor. In addition, hanging off and keeping the bike more upright on corner exit allows better traction for accelerationout of the turn. For the fairly smooth arcs and large radii of road course corners, this provides far more advantage than the possible advantages of maneuverability and control at turn-in or while sliding, of other riding styles and positions. Less skilled riders, like me, may really feel more confident on a road course or paved twisties on an upright or supermoto style bike, but that’s just because it’s more comfortable getting close to our limits. But it’s not faster in the hands of a good rider.
dman,
Nice answer. Seems logical and i totally agree as my experiences in both situations given me the same impression!
It’s all peer pressure and keeping up with the joneses.
What all about what the cool kids are doing I hear
I always shift my weight at the dinner table.
I believe it’s the nature of the bike and the seating position along with the corner and track tightness. Put a GP bike on those little Super moto tracks and not only would they not work… but I bet you might ride them different… let’s ask Marquez.
I think if you put a supermoto on the GP track, you would probably ride it more like a GP bike to keep corner speed and momentum going based on the length / speed / shape of the track.
Perfect example of this is Nicky Hayden. If anyone is comfortable with leg-out dirt-track riding, it’s him. Yet, when he gets on a supermoto bike, he’s hanging off and dragging his knees!
A lot of it is just rider preference when it comes to Supermoto. Road racing clearly favors hanging off, and dirt riding is better suited to the opposite. Supermoto is where you see a healthy variety of riding styles…
I am not a physics professor, but in my view the force diagram is simple. The Center Of Mass of the bike and rider is probably somewhere just above the seat on the inside of the turn. The bike wants to rotate around the COM. By weighting the outside peg, the weight of the rider causes the back tire to be pushed into the ground as it rotates about the COM, giving more traction. The opposite is true by weighting the inside peg.
My informal “experiments” with my dirt bike on a figure 8 practice loop confirmed this.
“Dirt tracking” the bike (as it was referred to me by Reg Pridmore one day at his school C.L.A.S.S. at Texas World Speedway when he caught me doing it)….. is the act of pushing the bike down into the corner, leaving the rider more or less upright. He took considerable time (because he felt it important) to explain to me why my subconsciousness was telling me to do this and why I should NOT do this on a road bike.
It does primarily appear in the habits of those of us who grew up on dirt bikes. Particularly those who liked to slide around ovals. Pushing the bike does increase the downforce (vector) on the contact patches which in turn will eventually, sometimes suddenly, give up their purchase on the surface and with a little throttle combined with pushing the bike over, we get the back end to break loose and drift out, which enables rear-end turning. Those who haven’t ever turned a bike using the rear end, may find that to be a little non-intuitive. Those of us who’ve used it, find it perfectly natural.
BUT……on tarmac…. not such a good idea UNLESS you ARE Kevin Schwantz or someone with extraordinary skills AND a need (because you are racing for a living) to risk putting both the rear and front end into a slide (hopefully a controlled slide no doubt). Forcing a rear end to break loose in a corner (road) can and will change the “line” you are currently on. Which is why racers sometimes elect to make a drastic decision to break the bike loose….say to dive under another bike/rider’s line.
Doing this while back road bombing is gonna eventually put you in a bind on a corner. I always say (w/regard to road riding) lead with your inside shoulder, shift your weight (head/torso) slightly to the inside, weight the inside peg, get your “outside” of corner butt cheek on the saddle (i.e. hang half the butt off), nothing too drastic….. this will allow some shifting to keep the bike MORE upright and in the fat of the tire for a given lean angle. IOW, it keeps the bike slightly more upright. If you are too hot going in, or something else in the corner forces you to tighten the turn drastically….you will still have tire left to adjust lean angle (increase lean, tighten radius). Otherwise, if you are “pushing” the bike over, you are gonna low side it one day, or if it catches…highside it (even worse).
I would keep this “pushing” the bike over to a slow speed (parking lot) maneuvering technique and generally stay away from it on a street bike at speed. But on dirt…….totally push it !!!! And get the rear end power sliding….it’s the only way to ride on the dirt !!!
Corollary to above……you can do whatever you want riding position, lean, etc. etc. etc. within a margin of safety that’s actually pretty wide. So many folks will get away with this habit with no consequences. But for those interested is riding faster, smoother and simultaneously increasing their safety margin while doing so, some habits need to change.
IMO
I think its an answer for the physics team. But your ability to make adjustments for tire slippage and standing the bike back up on its tires is easier when you are keeping your body in its own plain and only tipping the bike in. First you have less mass being moved when adjustments are needed. Your body mass is not part of the equation in the recovery. It’s just the bike moving. Also you have more range of motion to adjust the bike as your arms and legs can easily handle absorbing the bike back up to the default position.
If you watch flat track riders you see that hundreds of minor adjustments they make in a turn while using this tip the bike in style. The ability to turn and recover slip quickly by moving only the bike is what it’s all about. It’s about leveraging Newton’s second law.
Try an American Supercamp school and they will explain and demonstrate it. It is indeed a CoG issue and the flat track guys have the key.
“When ground clearance is not an issue” In road racing it usually is, thus the hanging. If it isn’t the riders don’t hang (see 125 racers, very different style). Also, in road racing the ground clearence issue is with the bike. In motocross its almost always with the leg, especially tall riders have trouble with fitting their legs somewhere in deep ruts. MX bikes are designed with this in mind and that’s how they must be ridden even in smooth corners. Since supermoto bikes are modified MX bikes that translates over.
I would say you are using your weight to leverage the bike back up on the tire, while the inside leg is acting as an outrigger and sometimes a feeler.
Sometimes I would think your body would also be considered part of the outrigger, but I always have my weight on the outside peg.
As a very modestly skilled rider of dirt bikes, supermoto, and street bikes… Weighing the outside foot leaves the inside foot free to act as a skid, counter balance, etc. The inside foot with a heavy boot on it can be positioned to provide the aforementioned body english. My 2¢
Leaning the bike more (than yourself) means you don’t need to turn the bars as much to turn. I think it’s called “Giving the bike English.” The farther a bike is leaned over the less you need to turn the bars to turn. When the handle bars are turned, the front and rear wheels are out of alignment and take two different tracks. This also makes the bars succeptible to wobble and being knocked around. Leaning the bike more to turn gives it more traction. A good way to demonstrate this is to ride a bike with rock-hard knobbies on the street. If you don’t give it some English, the bike will feel like the front tire wants to slide out from under you in the turns.
Right off the top of my head, it looks like hanging off the outside may have something to do with keeping the center of mass over the contact patches, and increasing the downward force vector on the patch – hanging off the inside of the bike seems like it would increase the horizontal force on the patch, increasing the risk of a lowside on a flat (non-banked) corner. That may explain the difference in style between a roadracer and flat-tracker.
But that’s a total guess – I KNOW I’m not a great rider – I defer to the wisdom of my betters. I’m looking forward to the next segment (Stay tuned for some riding tips and instruction from MD).
+1!
…may have something to do with keeping the center of mass over the contact patches, and increasing the downward force vector on the patch …
This is what Shane Watts teaches in his Dirt Wise school…
I think the traction provided by the tires and the type of surface determine the optimal technique. All of the styles to ride to ride different types of motorcycles have evolved over a lot of time. I think we’ve got it figured. It’s not a one style fits all kind of thing.
…its not weighting the outside peg, its simply leaning the bike over. I ride my street bike this way.
One has to wonder how much is just the ergonomic difference between a MX bike and a road race bike.
One of the two methods is superior from a tire contact perspective (road style), but as others have pointed out, it’s more limiting in low speed, fast transition situations.
Having ridden all types of motorcycles as well as mountain bikes, dual sports and supermotos just ride that way. I think it has to do with the ride height and suspension angles. I’ve always cornered like that naturally on DS bikes and mountain bikes alike, and it just seems to work. Having the weight on the top edge of the seat seems to help push the bike down into the corner, rather than trying to pull it down. Dunno…
It’s simple. You’re looking at the wrong pictures:
https://www.2wheeltuesday.com/wp-content/uploads/2010/12/Jorge-Lorenzo-Supermoto.jpg
Also, tires, tires, and tires.
It’s a balance between centripetal and centrifugal forces.
twas the #1 answer. (Ex-pat Richard Dawson voice)
It’s more effective in controlling a slide and avoiding a low-side when traction is less than optimal. If you have a berm, then it feels natural to lean into the turn with the bike.
Faster left/right transitions.
When leaning off, only the mass of the bike needs to be transitioned left to right with the rider remaning relatively static above the bike. If the rider leans into the turn, a transition into the opposite turn direction requires both the position of the bike AND the rider to be changed which requires more effort on the riders behalf. As the riders ultimate strength is a limited factor, then the transition motion of the combined masses must occur more slowly.
Simple high scholl math. F=m.a where F = force m = mass and a = acceleration. If you increase the mass (bike plus rider) but apply the same force, then the acceleration must be slower. Reduce the mass (bike only) and for the same force the acceleration is quicker.
We have a winner!!
For any single corner, hanging off on the inside is preferable. Even on an unlimited clearance sumo with 180 degree contact patches. If for no other reason than to allow the suspension to deal with bumps more properly instead of being loaded from the side.
But, in Sumo, quick transitions is where it’s at. Few corners are long enough that you could hope to get fully cranked over while hanging off before you have to go the other way. So, whatever little gain you get from hanging off in any one corner, is more than lost back by the extra time it takes to go from one to the next.
The corners are the trees. The line through the entire circuit, is the forest.
Off road it just feels right to sit up straight and weight the outside peg. It helps with traction and allows a fast reaction to front end push or rear end slides.
Staying on top of the bike allows much quicker left-right transitions in consecutive tight corners. Getting from one side of the bike to the opposite side with the bike swinging in the same direction requires a lot more rider movement and takes too much time in quick transitions.
It gives you leverage to vary the lean of the bike…raise it up if needed. With your weight only on the inside you’ll have little leverage to raise the bike.
Racing motocross we use to plow a furrow in the dirt with the inside peg. if you were leaning off, you would be plowing a furrow with your head
Shift weight to the outside to help with rear wheel traction. Leaning to the out side transfers weight but the outside foot keeps the bike planted.
Gotta be a reason for it, and I doubt it’s laziness. I think at the slower speeds of SM, weighting the “top” of the bike may change the tire/ground dynamic and allow faster cornering speeds. Just a theory! I’ve never tried it (always hang off on the inside) but if I ever get a supermoto/motard, I’m gonna give it a go.