Lean angle in turns

[SuperG]

So after 30 some years on motorcycles, I wanted to try something.

 

When I ride my dirt bike off-road or on trails, even at semi fast speeds I tend to lean the bike into the turn but keep the body upright. In street riding it seems to be the opposite. Lean the body with the bike or even slide off the seat and lean the body more into the turn.

 

SO today I was experimenting with different techniques.

At speeds 50-55MPH, in some twisties, I tried the off-road maneuver of leaning the bike way in but keeping the body in a more upright position or should I say not leaning with the bike.

It felt really good and secure, bike angle was less than 45 degrees form vertical.

 

Shroud I stop doing it, is there any danger in it?

[tallman]

OIl, tires, saddles, modulators, and cross controlling vs countersteering...

it ain't winter yet.

 

Maybe.

[Huzband]

 

Shroud I stop doing it, is there any danger in it?

 

Yes & yes.

[SuperG]

With all the wisdom (<-oil and tires and winter topics)...and wasted keystrokes typed away...

The question remains the same. WHY? I am all ears...

[Huzband]

To be more specific, counter leaning on the street decreases your available traction. You're leaning the bike more than you're leaning your body, & thus the tires can be at maximum grip when not necessary. If you find a need to lean more mid-corner because of an obstacle, you're SOL.

 

Tell me, does this look right to you?

 

 

Bottom line...keep dirt riding techniques in the dirt.

[Huzband]

Let me try this. The reason for leaning the bike under you in the dirt is to push on the outside peg to maximize traction.

 

 

The reason for leaning inside the bike on the street is to maximize traction & available lean angle.

 

 

Make sense?

[TEWKS]

Not as bad as Danny's picture of bad body english. But, he's on a boxer, this good visual shows a not so smart lean angle.

 

 

Because, with a little more force this will lever and unconnect your front tire from the pavement.

 

Pat

 

 

 

 

[Huzband]

Russell has a pic of himself on his 11RT doing it wrong. He's posted it several times for educational purposes. Hope he will again.

 

Thing is, a lot of riders get away with it for a very long time. So they think it's okay. We never hear from the ones that get bit, because they don't know what went wrong.

[russell_bynum]

Russell has a pic of himself on his 11RT doing it wrong. He's posted it several times for educational purposes. Hope he will again.

 

Thing is, a lot of riders get away with it for a very long time. So they think it's okay. We never hear from the ones that get bit, because they don't know what went wrong.

 

Yup.

 

 

I don't undestand the difference between dirt and street. The whole "weight the outside peg for more traction" thing never made sense to me.

 

I have a fuzzy idea in my head that the dirt style is more about balance than traction. I'll try to articulate that thought...bear with me. (Also, note that it is entirely possible that I'm full of crap.)

 

In the dirt, you're sliding much of the time, so you need to do things that let you handle the slides.

 

Think of it this way...go ride in slow, tight circles. Lean your body off to the inside of the turn. Gradually come to a stop while still having the bike leaned and your body leaned in. You fall over. Now do it again, but counter-balance the bike by pushing it down under you and keeping your body upright. If you get the balance right, you can stop with the bike still leaned over and you will not fall down.

 

In other words...the bike is balanced when it is leaned because you are counter-balancing it with your body weight.

 

In a turn at speed, you have traction from the tires and the bike's inertia is trying to go straight...which means that inertia is the counter-balancing force that is keeping the bike from falling over. When you take traction away (slide), you lose that counter-balancing force and the bike wants to fall down (towards the inside of the turn.)

 

Otherwise...if all things were equal....when the bike is more upright you have more traction. The suspension works better when it is upright and you are on the meaty part of the tire. And if you're leaned far enough over, the contact patch actually starts to go past the edge of the tire, so your contact patch is getting smaller.

 

 

So...if you're in a situation where slides are more likely, you want to counter-balance the bike with your body so you can handle those slides. If you're in a situation where slides aren't likely, you minimize lean angle to maximize traction and to give yourself the option of increasing lean angle if you need to tighten the turn or take evasive action.

 

One exception...if you're going slow (parking lot stuff), you don't have all that inertia holding the bike up in a turn, so you counter-balance with your body. (Watch police rodeo videos...if those guys leaned into the turns, they wouldn't make it past the first set of cones...they all counter-balance because at that low speed, they have to.

 

That's my thought, anyway.

[Joe Frickin' Friday]

Not as bad as Danny's picture of bad body english. But, he's on a boxer, this good visual shows a not so smart lean angle.

 

 

Because, with a little more force this will lever and unconnect your front tire from the pavement.

 

Pat

 

 

 

 

Yeah, that looks familiar:

 

 

For street riding, leaning your body inward on turns does several things:

 

1. It increases ground clearance. This is especially important on big bikes, which may have the traction to make high-g turns but will hit hard parts on the road and lever the tires off of the ground if you lean them over too far. See pics above, demonstratng this principle; people have levered these bikes into a lowside before, especially on really twisty roads.

 

2. It improves suspension performance. The closer to vertical you can keep the bike, the better the suspension will be able to absorb the bumps and dips in the road, minimizing chassis upset and reducing the likelihood of losing static traction. Think about this: if you're in a turn, and you ride over a speed bump, would you rather have the bike leaned over 30 degrees, or standing up vertical (or as close to vertical as you can get it)?

 

3. It makes the bike want to turn. The steering geometry is self-correcting. If you center yourself in the saddle like a sack of potatoes, and then put the bike into a turn, the bike will want to go back to being upright and traveling in a straight line. If you're truckin' through a sweeper, you'll be fighting the bike's self-correcting tendency the whole time. Lean to the inside instead, and the bike will want to stay leaned over (and turning), too. You'll be able to relax your death grip on the handlebars (especially if you're gripping the chassis with your feet and legs), and the bars will be more free to jiggle a bit and get you through the bumps and dips without incident.

[russell_bynum]

3. It makes the bike want to turn. The steering geometry is self-correcting. If you center yourself in the saddle like a sack of potatoes, and then put the bike into a turn, the bike will want to go back to being upright and traveling in a straight line. If you're truckin' through a sweeper, you'll be fighting the bike's self-correcting tendency the whole time. Lean to the inside instead, and the bike will want to stay leaned over (and turning), too. You'll be able to relax your death grip on the handlebars (especially if you're gripping the chassis with your feet and legs), and the bars will be more free to jiggle a bit and get you through the bumps and dips without incident.

 

This is absolutely correct. Using a throttle lock (and a professional rider on a closed course, of course), get the bike into a high-speed turn. Pay attention to what your hands are doing...what kind of pressure are you having to maintain. Let go with one hand to make sure you're not fighting yourself. Now adjust your body position and feel the difference. When you get the speed/lean/throttle/body position all balanced, you can take your hands off the bars and the bike will maintain the same lean angle.

 

In a perfect world, you're only using the bars to countersteer...which gets the bike leaned. Once you have the lean angle you need, you should be able to release pressure and let the bike track through the turn.

[Bernie]

Time for RideSmart classes

[Glenn Reed]

Time for RideSmart classes

 

That helped me immensely.

[TestPilot]

To be more specific, counter leaning on the street decreases your available traction. You're leaning the bike more than you're leaning your body, & thus the tires can be at maximum grip when not necessary.

 

Not quite true. If two motorcycles take the same line around the same corner at the same speed, and one ride leans in while the other leans out, both sets of tires are generating the same amount of lateral (centripetal) force (physics 101). The only difference is the mechanism by which the forces are generated. Lateral forces can be generated by camber thrust and by slip angle. Leaning in results in less camber thrust and requires more slip angle, but the total forces are the same for both bikes.

[greiffster]

To be more specific, counter leaning on the street decreases your available traction. You're leaning the bike more than you're leaning your body, & thus the tires can be at maximum grip when not necessary.

 

Not quite true. If two motorcycles take the same line around the same corner at the same speed, and one ride leans in while the other leans out, both sets of tires are generating the same amount of lateral (centripetal) force (physics 101). The only difference is the mechanism by which the forces are generated. Lateral forces can be generated by camber thrust and by slip angle. Leaning in results in less camber thrust and requires more slip angle, but the total forces are the same for both bikes.

 

Both bikes on the same line at the same speed will generate the same lateral force that the tires need to oppose. But what force (or traction) is AVAILABLE is different based on the lean angle.

[Jake]

To be more specific, counter leaning on the street decreases your available traction. You're leaning the bike more than you're leaning your body, & thus the tires can be at maximum grip when not necessary.

 

Not quite true. If two motorcycles take the same line around the same corner at the same speed, and one ride leans in while the other leans out

 

I believe Danny's point of "available traction" is better understood when you think of it as the remaining lean angle you have available for a given turn. So, in that sense, more available lean angle = more traction. If the same motorcycle goes through the same turn on the same line at the same speed, by default the bike itself is at the exact same lean angle whether or not the rider's body is inside the plane or outside the plane. That said, the question of technique is important because pushing the bike down (riding outside the plane) leaves the rider with less available lean angle - and less time - to take corrective measures in a surprise decreasing radius turn.

 

When that surprise happens, you want to be inside the plane.

[TestPilot]

If the same motorcycle goes through the same turn on the same line at the same speed, by default the bike itself is at the exact same lean angle whether or not the rider's body is inside the plane or outside the plane. That said, the question of technique is important because pushing the bike down (riding outside the plane) leaves the rider with less available lean angle - and less time - to take corrective measures in a surprise decreasing radius turn.

 

These two statements contradict each other. The second is true; the first is not. It's the combined CG of the bike plus rider that's at the same lean angle.

 

[Jake]

In retrospect, at worst they are unrelated. And I grant that the first statement is not technically correct in a physics class, but isn't offensive in reality. Combined CG has a role, but not a particularly big one per my readings. But hey, I went to a state school and will happily do pennance with a dusty copy of Motorcycle Dynamics to clear my thinking. Getting inside of the plane and keeping one's bike upright for a given curve is the takeaway for the reasons Mitch outlined, and being ready-quickly, which is my point (though not well made). There certainly are complicated physics going on beyond the scope of the average rider's willingness to study, and the below is just a start of me grabbing a bottle of Advil.

 

 

Ouch!

 

 

[SuperG]

interesting....

 

SO far some of the scientific explanations and pictures are intriguing, however pretty much none apply to my situation.

 

My current ride is a transverse V-twin, so scraping cylinder heads is not possible. No side bags, only a center top mounted trunk.

Also as much I lean... I will not run out of available lean angle anytime soon. Even in panic situation, also I can just lean inward more if needed.

I am not a GP racer wanna be and don't ride a sportbike. I only lean in far enough and go fast enough, to scare myself just enough

 

TO me the GP rider in the picture is leaning in so far for two or more reasons.

1: he ran out of the available tire sidewall surface, leaning further more would take away from tire to road surface contact (traction).

2: he wants to be further in and lower to reduce center of gravity combined with centrifugal forces- at that speed it matters. Standing upright would create much more centrifugal force higher center of gravity and even more air resistance.

 

I am not trying to argue the reasons, I am sure there is a good one just need to coax it out.

 

[greiffster]

 

I am not trying to argue the reasons, I am sure there is a good one just need to coax it out.

 

It's "possible" we may be over-thinking this. I think Mitch has the best reason for us normal riders.....With the rider's weight to the inside of the bike and curve, the bike itself will need less lean to go through the same curve at the same speed. This is a good thing.

 

 

[Jake]

Well, your questions were should you stop doing it, and is there any danger in it. Very practical questions, and we're chiming in that there is risk.

 

I think of riding inside the plane as beneficial as it keeps my arms largely centered on my body and torso centered between my legs. If there is a surprise moment I can use everything. They will be bent and loose rather than extended and stiff - giving me more margin for reaction. Perhaps I need to quickly countersteer to avoid an unforeseen pothole, fuel spill, or gravel. Your body will be better positioned to ride out surprises if your weight is between the verticle plane of the bike, and the horizontal plane of the road.

[SuperG]

so it seem that leaning the bike in more, not the body,

would increase the roll angle

decrease steering angle

increase caster angle

 

leaning the body in more and keeping the bike up would be the opposite of all angles mentioned.

 

 

[Jake]

Yes, no and it depends! Going back to your original post, you wrote that you felt secure (while cross controlling your bike). I can see where you are coming from - but I would view it as time when you were giving yourself a comfy break, rather than using good technique.

 

I think people unconsciously ride in a cross controlled manner because their eyes are most comfortable level with the horizon, and their bodies naturally follow (or stay). We like to remain upright - we spend all day doing it. It is comfortable to sit up and remain perpendicular to the road, and at lower speeds somewhat fun to push your bike around you. Lollygagging type stuff - we all do it.

 

For safety and traction-use maximization, particularly at higher speeds, one should switch to the Ride Smart Kiss-The-Inside-Mirror orientation. It's fun, and you can boogie doing it.

[Dave_zoom_zoom]

 

For safety and traction-use maximization, particularly at higher speeds, one should switch to the Ride Smart Kiss-The-Inside-Mirror orientation. It's fun, and you can boogie doing it.

 

 

"YES!"

 

Dave

[russell_bynum]

 

For safety and traction-use maximization, particularly at higher speeds, one should switch to the Ride Smart Kiss-The-Inside-Mirror orientation. It's fun, and you can boogie doing it.

 

 

"YES!"

 

Dave

 

Yup.

 

And racers do it for the same reason...more available traction means they can USE more traction to go faster.

 

For mortals on the street, we use that extra traction to save our asses if we've misjudged a turn or meet an oncoming Prius in our lane around a blind corner.

[TestPilot]

And racers do it for the same reason...more available traction means they can USE more traction to go faster.

 

I still disagree. Either technique, lean in or lean out, uses up the same amount of traction at the same speed on the same line. Unless you claim that there is more traction available from slip than from camber thrust, it's a wash.

 

[tallman]

LIke I said.

Maybe.

 

Given ideal road conditions with no traffic or potential intrusions, maybe ok bu tprobably not the quickest way.

 

Given real world conditions, definitely no because the world is full of stuff htat wants to make the bike fall down and or run you over.

 

Best wishes.

[russell_bynum]

And racers do it for the same reason...more available traction means they can USE more traction to go faster.

 

I still disagree. Either technique, lean in or lean out, uses up the same amount of traction at the same speed on the same line. Unless you claim that there is more traction available from slip than from camber thrust, it's a wash.

 

If nothing else, less lean means the suspension is more upright, which means is works better. Since the purpose of the suspension is to maximize traction...less lean = suspension works better = more traction.

[SuperG]

Russel,

 

look at this guy, if he hits a pebble (or a turtle) the suspension wouldn't be too effective.... just some humor that is all.

[Stan Walker]

look at this guy

 

At least he doesn't have far to fall!!!!

 

 

Stan

[Dave_zoom_zoom]

Russel,

 

look at this guy, if he hits a pebble (or a turtle) the suspension wouldn't be too effective.... just some humor that is all.

 

Great photo! Just think, what the attitude (lean angle) of this motorcycle would be if under the same circumstances this rider were to move his body weight to the high side of the motorcycle. Oh my!

 

Dave

[Jake]

Just think, what the attitude (lean angle) of this motorcycle would be if under the same circumstances this rider were to move his body weight to the high side of the motorcycle. Oh my!

 

Dave

 

Ah, you would be referring to Ruben Xaus then!

 

[russell_bynum]

Russel,

 

look at this guy, if he hits a pebble (or a turtle) the suspension wouldn't be too effective.... just some humor that is all.

 

That's a great shot. I was having a blast that day and really putting down some quick laps. It does get expensive wearing out the elbows of my leathers all the time, though.

[SuperG]

Looking at the picture above it almost seems that just about all of the weight it removed from the tires.

 

With this GP rider above ..I am trying to visualize... in dirt riding having the weight directly above the tire by rider standing in an upright position in a turn/weigh on the outside footpeg would benefit traction.

[Dave_zoom_zoom]

Just think, what the attitude (lean angle) of this motorcycle would be if under the same circumstances this rider were to move his body weight to the high side of the motorcycle. Oh my!

 

Dave

 

Ah, you would be referring to Ruben Xaus then!

 

 

 

EXACTLY! Thanks Jake!

 

Dave

[Dave_zoom_zoom]

Looking at the picture above it almost seems that just about all of the weight it removed from the tires.

 

With this GP rider above ..I am trying to visualize... in dirt riding having the weight directly above the tire by rider standing in an upright position in a turn/weigh on the outside footpeg would benefit traction.

 

Hi Super

 

I think I can see your vision. In your vision the motorcycle would maintain the same lean angle we see in the photo (it won't) and the additional weight of the rider (Russell ) moving up and over the saddle would add more weight to the tires.

 

The fly in the ointment is when he moves up, the motorcycle must lean down to compensate. For every action there is an equal and opposite reaction.

 

I do enjoy your vision (hope I see it as you do) however, physics says it won't work.

 

Dave

[greiffster]

Looking at the picture above it almost seems that just about all of the weight it removed from the tires.

 

Seems maybe, but absolutely not. Assuming the bike and rider weigh 600 lbs, the track is "pushing back" 600 lbs opposite the direction of gravity. That weight on the tires and coefficient of friction between the tires and road surface is what is providing the centripetal force required to hold the line.

 

No weight on the tires and there is no friction....Dude slides.

 

Things get a bit more complicated if you factor in a superelevation of the track.

[Selden]

The first photo is a little misleading, as it appears to be rotated about 30° counterclockwise, vs the Reuben Xaus photo, which is rotated about 5°clockwise. This doesn't take away anything from the skill and courage of the Honda rider, but his front wheel isn't horizontal, unless he's on a 30° banked at Daytona or Monza.

[Dave_zoom_zoom]

"his front wheel isn't horizontal"

 

 

Yea, You are right!

 

But it would sure be neat if we could do it.

 

Dave

[Huzband]

 

...it would sure be neat if we could do it.

 

 

But we can. Provided

we

are on a track, &

we've

grown up racing without fear.

[lkraus]

The first photo is a little misleading, as it appears to be rotated about 30° counterclockwise, vs the Reuben Xaus photo, which is rotated about 5°clockwise. This doesn't take away anything from the skill and courage of the Honda rider, but his front wheel isn't horizontal, unless he's on a 30° banked at Daytona or Monza.

 

That Honda rider is the current MotoGP champion, who regularly exceeds a 60 degree lean angle. No, not horizontal, but the pictured bike-to-pavement angle is typical of his riding position on any turn, banked or not. His elbow is basically his lean limiter. (Except in this instance, when he attempted to ride horizontally, scraped his axle end, and then continued riding.)

 

 

 

 

[Dave_zoom_zoom]

 

...it would sure be neat if we could do it.

 

 

But we can. Provided

we

are on a track, &

we've

grown up racing without fear.

 

 

Hi Huzband

 

If we could do all the above, we may be able to ride as well as the racer in the photo but----- Selden said "his front wheel isn't horizontal".

 

I was trying to say, wouldn't be neat if we could lean over so far that our front were horizontal.

 

Hell, I'd be extremely pleased if I could get down even close to where he is under any circumstances. Even if I did rotate the photo.

 

Dave

 

 

 

[Warhorse]

There are lots of information that has been researched (mostly in military aviation) regarding head lean angles, body lean angles, the effects of force on the brain (and brain chemistry). One of the bike mags did a great article, think it was in the 90s about what can happen when the head matches the lean angle of the body.

 

To put it short, the brain tries to correct itself because it thinks it's falling over. This creates a response in the FASTER moving neurotransmitters (250ms vs. 450ms) that engage the survival instinct. It's the same thing that makes you flinch when you walk around a corner, not expecting to see someone cause you're in your own house, and your wife / girlfriend is there. You flinch, then about a 1/4 second later, you smile, or duck as indicated because you're executive process overrides the survival process.

 

When you brain thinks it's falling over as in the force applied during a leaning angle curve, it MAY force a flinch response to stand itself up straight. That article nailed it perfectly. Their suggestion was to NOT lean with the body, but to leave the head vertical relative to the lean angle.

 

Helicopter and fighter pilots, or blackbird pilots all have to deal with this force disorientation and they're trained to keep their head as vertical as possible.

 

Be careful testing this one out. The part of the neuro chemistry that forces this reaction is FASTER than your executive process that makes Smart decisions.

 

Respectfully,

[SuperG]

Warhorse,

Interesting write up, thanks

I am half way into the book Deep Survival - Who lives Who dies and Why - by Laurance Gonzales. It talks about similar things why and how our brain control risk and our behavior, survival and instinct. The book so far has not been about survival,but about the brain.

 

I am sure all of us would love to know and being able to lean over like the GP rider-without fear.

 

However the GP rider have several things going for him...that I/We may not have:

Perfect track

matching tire to the track.

knee and elbow pads + full leather suit.

he does not have to pay for the suit if it rips.

His insurance rate does not go up when thing don't go too well.

He does not have to pay for bike parts at dealer prices.

He likely get paid very well to do what he does with his bike.

 

On my tires, there is still about an 1/8" strip on the edge that still looks new/ not worn. I think in motorcycle circles it is called the "Chicken strip".

 

 

 

 

[Warhorse]

Hello, Deep Survival has a good mental link to Col. David Grossman's "On Killing" 800+ page read. While this stuff is a little off subject, it talks a lot about human mentality, and points out a lot of contradictions in conventional medicine / psychology regarding the daily brain and what I call the war fighting brain. The common term is fight and / or flight. Between those two ends of the spectrum is posturing and submitting. All mammals do it. Intra species, it occurs daily. It is also at the core of why we flinch. GP riders, being in the top 1% of the world, or even tighter than that, have long since disposed of the flinch response, and I believe what we call super quick reflexes aren't reflexes completely. But a series of superfast identifying of changing events and a super fast neuro / muscular system of response to those inputs.

 

I also believe, sorry about off topic, but it's not really, that current societies definition of "anger", PTS(D), the Disorder part of the PTS issue has been dropped by some astute mental health professionals. PTS is a NORMAL part of reaction to a traumatic situation, it's not a disorder at all.... sorry, I've rambled into an area of intense interest.

[Matts_12GS]

Mitch, Russell, and Jake nailed it...

 

when you stay inside the bike, you are giving yourself more room for error.

 

I can't explain the physics of it, because I ain't that smart, however I can give you the anecdotal of it, and can show you in a few weeks when I get back to ATX.

 

With your body, even just your helmet/upper torso inside the corner in a Kiss the Mirrors position, you are lessening the lean angle and keeping the bike incrementally more upright giving your suspension better opportunity to control your tires and thus your traction. To move you inside the bike, the bike has to at a different attitude than if you are outside/on top of it.

 

When you have reserve lean angle you have room to pull the bike down into that decreasing radius turn you misjudged or you can more easily stand it up to change your line for stuff in the road. Taking Marky Marquez out of the equation and getting back to mortals at street speeds, that is the fat part of the Bell Curve where more safe riding happens. Your bike is not fighting your inputs and you are in a position that is less physically fatiguing so you can stay sharper longer.

 

Riding dirt style means you have to make a more complex and less easily controlled rapid motion to adjust your line in a corner instead of just moving your head to the other side of the bike. That's the net effect of the physics the smart guys are impressing us with. So, if you have cat like reflexes and squirrel like quickness to move and change your motorcycle's position under your body, then you'll be fine.

 

One thing though, you mention your transverse twin with no hope of hitting your cylinder head, how about your foot, or footpegs, or centerstand/kickstand, exhaust? Any of those things lower on the bike than the heads? I thought that might be the case...

[Bernie]

If you just slow down enough, you can corner perfectly upright. You guys just always are riding way to fast.

[Dave_zoom_zoom]

Hey Bernie, there's an idea.

 

I've never tried that! (maybe you haven't either)

 

Dave

[Bernie]

Well, I been told that if you have to lean too much or shift your weight to be able to lean, that you are going way to fast for riding on public roads. These folks are very experienced and full of opinions.

 

[SuperG]

Mitch, Russell, and Jake nailed it...

 

One thing though, you mention your transverse twin with no hope of hitting your cylinder head, how about your foot, or footpegs, or centerstand/kickstand, exhaust? Any of those things lower on the bike than the heads? I thought that might be the case...

 

NO Sir, None of those parts will ever touch the road; not the way I lean in the turns.

I like to take turns semi fast, but I know my limit. A few years ago coming back from Big Bend Nat. park in Texas heat, on a road infested with tar-snakes...the tar-snakes HAVE put the fear in me.

I was on my Rt1200 and almost lost it, just barely being able to make the turn. I leaned but the bike kept sliding little by little on melted tar toward the edge of the road. It was a very close call.

I am not getting any younger, and it seems thing hurt a lot more nowdays than when I was younger. I want to be able to enjoy motorcycling a for a little wile longer.

This is my story and I am sticking to it!