Why is it recommended to hang your butt off the seat when in aggressive cornering

[vtbob]

I've never under stood why it is standard practice to hang your butt off the seat when cornering hard!

The only reason I can understand if for serious racers who's lean angles either go beyond the edges of the side tread on the tires or lean angle puts the pegs in the pavement.

But I see riders, even racers doing it well before reaching the above limits. Why?

 

[brownie0486]

https://www.visordown.com/features/advanced-riding/advanced-motorcycle-riding-course-hanging

Weight shifting or hanging off can be anything from the smallest movement of your upper body to the full-blown, backside-off-the-seat, letting-it-all-hang-out style of the top racers. There are a number of well-documented reasons why it’s useful. The laws of physics obviously have something to do with it and, while I’m no expert in physics, I do know that if bodyweight is moved to the inside of the corner then the angle of lean required to get round at a given speed will be usefully reduced.

The obvious knock-on advantage here is improved ground clearance

Positioning your body to the inside of your motorcycle when cornering means that the motorcycle does not have to lean as far for a given speed and turn radius. Hanging off makes this so by shifting the combined weight of body and machine to move the center of gravity lower and to the inside.

Taught this in motor school, it saved my butt last summer when I hit a direct crosswind blowing 50-55mph. Running 70mph, when I ran into it, it threw the bike into the other lane, and kept pushing me toward the edge of the tar. Bike was leaned hard just trying to stay upright and not be blown over, but I was still being pushed further to the edge of the tarmac. Then I remembered the training and hung off the bike, that kept me from losing anymore more ground, and over the next several hundred yards I was able to get the bike back into my lane. Without hanging off the bike, I'd been slowly pushed off the road.

I'd slowed considerably through all this but had to keep the bike moving fairly fast or the wind would have high sided the bike and myself into the ditch. It was a very unpleasant experience that could have resulted in a major crash. Saw that wind whipping across the plain as I was nearing it, but it was so forceful, slowing too much would have high sided the bike. IOW, the only way to keep the bike tracking straight and not wandering further to the edge of the tar was hang off the seat. There wasn't even time to think about much at the time, it was keep balance, lean, lean harder in the gusts, keep the bike moving and in the end, hang off the bike to maintain line and regain control.

 

[exgman]

Cornering Body Position

I took a non-sportsbike track day in Palmer, MA in July 2018. As the day progressed many, if not all of us on our non-sportbikes learned to get more of our body weight toward the inside of curves. With a Russell Day-Long seat, getting my butt up and on the outer edge of that seat was difficult. In my case, I got my head and some of my upper body toward the inside the curve.

The important part of the exercise is using your arm strength to tilt the bike upward to insure that the pegs don't drag. In my case, that was very helpful because I have Ilium Sport Boards (which lower the foot position some...bad knees being the issue with me) installed on my RT.

I'm sure others will have other experiences.

 

[nickrides]

Lee Parks book Total Control explains this with photos and text.
One of the major causes of MC accidents is running wide on a corner and leaving the road.
In a nutshell you want your body to be inside of the vertical line running through the bike before you enter a corner.
1 Inch or 1 foot take your choice but you should be to the inside of the vertical line.
When you set up corners like this the bike wants to turn in.
The bike is slightly more upright too, lees chance to drag the pegs or something on the ground, tire contact patch is larger too.

Parks explains it something like this:
Before the corner move your body to the inside of the bike of the next corner.
Hold the bike straight with the bars.
Enter the corner and counter steer as necessary.
Finish the corner and center up everything.
He warns the first few times you do this method you may Over steer, and he's correct!
This has helped me hundreds of times when I've encountered a corner that tightened up on me unexpectedly, or I came into a corner too hot.
Good book that Total Control by Lee Parks.

 

[Paul_F]

Hanging off the bike while maneuvering curves, keeps the bike more upright, which results in keeping the tires' contact patches larger on road surfaces, resulting in greater stability. This practice is worth doing in the rain. It also permits smoother and faster right hand turns on city streets (although I worry that local law enforcement might view it as stunt riding).

I believe that it facilitate a quicker lane change when necessary to. move away from external dangers.

I use this technique on many curves where it really isn't necessary, just to reinforce muscle memory in order to keep comfortable and smooth for where and when it does matter.

 

[vtbob]

Thanks for your thoughtful experiences and examples of professionals who train this technique.

However I'm not convinced that it really does any good (from the hard physics perspective) for other than those who are running hard in corners 10/10s or very close!

I mentioned the 2 conditions of where I do agree it helps, running our of tread on the side of the tire due to lean angle and keeping a foot peg out of the pavement.

Moving your butt to the side, moves the center of mass of the motorcycle off (not a good thing) the vertical center line of the motorcycle. This put side loads on the wheels (wheel flex effects) and side loads on the front forks and rear suspension ( more flex effects which could lead oscillations, source of tank slappers, etc). In most cases this movement also causes the center of mass to Raise (move higher from the ground) as it is the riders mass on top of the bike that is moving. This also is not a good thing (think high side).

I do agree it gives the sensation of falling into the corner, inadvertently or more easily counter steering so for most if "feels" good.

I do not believe that the feel good benefits out weigh the negative effect of side loads and higher center of mass.

Am I missing something?

 

[ncpbmw1953]

Moving your butt to the side, moves the center of mass of the motorcycle off (not a good thing) the vertical center line of the motorcycle. This put side loads on the wheels (wheel flex effects) and side loads on the front forks and rear suspension ( more flex effects which could lead oscillations, source of tank slappers, etc). In most cases this movement also causes the center of mass to Raise (move higher from the ground) as it is the riders mass on top of the bike that is moving. This also is not a good thing (think high side).

I do agree it gives the sensation of falling into the corner, inadvertently or more easily counter steering so for most if "feels" good.

I do not believe that the feel good benefits out weigh the negative effect of side loads and higher center of mass.

Am I missing something?

The 'moves the center of mass off the moto' is a fine thing if you're turning because it allows you to lean the bike less for the same turn radius. 'In most cases this causes the center of mass to raise' doesn't happen I'm actually moving the center of mass lower as my thigh, lower leg, butt, and even upper body are slightly lower to the ground than if I was centered. I don't get any 'feel good' it's simply a matter of requiring less lean which means when you hit areas of less traction due to road debris you're less likely to slide out of the turn. The most aggressive riders of all (track racing) do this which should make it eminently clear it's a good thing for aggressive cornering. Is it necessary for street riding? Only to the extent it may get you a little closer to saving you from a slide out but in general if you're respecting the street environment--hardly necessary.

 

[BC1100S]

Is it necessary for street riding? Only to the extent it may get you a little closer to saving you from a slide out but in general if you're respecting the street environment--hardly necessary.

Well put.

 

[rhodetrip]

Try a track day

Thanks for your thoughtful experiences and examples of professionals who train this technique.

However I'm not convinced that it really does any good (from the hard physics perspective) for other than those who are running hard in corners 10/10s or very close!

I mentioned the 2 conditions of where I do agree it helps, running our of tread on the side of the tire due to lean angle and keeping a foot peg out of the pavement.

Moving your butt to the side, moves the center of mass of the motorcycle off (not a good thing) the vertical center line of the motorcycle. This put side loads on the wheels (wheel flex effects) and side loads on the front forks and rear suspension ( more flex effects which could lead oscillations, source of tank slappers, etc). In most cases this movement also causes the center of mass to Raise (move higher from the ground) as it is the riders mass on top of the bike that is moving. This also is not a good thing (think high side).

I do agree it gives the sensation of falling into the corner, inadvertently or more easily counter steering so for most if "feels" good.

I do not believe that the feel good benefits out weigh the negative effect of side loads and higher center of mass.

Am I missing something?

Try a track day and see if you still feel the same.

 

[redc650gt]

Cornering Confidence, too.

The techniques being discussed have been some of the most beneficial and empowering tools I have developed. The neat thing about it is, once I started the practice exercises was able to see, gradually, the benefit of using and developing these skills.


https://www.amazon.com/Cornering-Confidence-Formula-Control-Curves/dp/069208732X

 

[akbeemer]

If you do not believe that moving ones weight to the inside of a corner and as low as possible is effective in increasing apex speed and directional control, then study the riding styles of F1/MotoGP riders over the last 60 years. Compare Hailwood’s riding style to Roberts, Rossi and Marquez. Marquez does not drag his elbow in corners because it looks cool.

What we should be asking is, why do the top riders in the world stick their inside leg out when setting up for a corner?

 

[20774]

What we should be asking is, why do the top riders in the world stick their inside leg out when setting up for a corner?

I had heard that Valentino Rossi started doing it and others figured that if Rossi was doing it, it must help. In reality, I suspect that it doesn't really help all that much but it gives the rider some sense of where the pavement is...it just felt right. The Rossi leg wave or dangle.

 

[nickrides]

I don't know about the rest of you guys; I'm no GP racer.
My feet stay on the pegs, I like my legs the way they are now, attached.

 

[akbeemer]

In an interview Rossi said the first time he stuck his leg out was on the last lap of the first F1,500cc race he won. He was racing for the lead and fighting for position going into a corner and said he stuck his leg out to break the concentration of his opponent. He said years later Team Yamaha asked him to stop lowering his leg. He resisted so they had him do several laps in a practice session keeping his leg on the peg and then the same number of laps while lowering his leg. The lap times were essentially identical.

 

[mlytle]

Moving your butt to the side, moves the center of mass of the motorcycle off (not a good thing) the vertical center line of the motorcycle. This put side loads on the wheels (wheel flex effects) and side loads on the front forks and rear suspension ( more flex effects which could lead oscillations, source of tank slappers, etc). In most cases this movement also causes the center of mass to Raise (move higher from the ground) as it is the riders mass on top of the bike that is moving. This also is not a good thing (think high side).


Am I missing something?

I am sorry, but none of your assumptions in the paragraph above are correct.

you really should spend some time reading the better riding books and taking a track day to understand the physics involved here. a rider's weight is a huge percentage of the total bike weight and positioning that weight correctly has significant positive effects on the handling of a motorcycle....including street riding.

yes, you are missing something....a lot of something.

 

[Omega Man]

Counteracting forces-

om

 

[vtbob]

Counteracting forces-

om

Very interesting analogy!! Made me think. Thanks

But! note the center mass of the belt is HIGHER on this clever hook than it would be if it was just on the finger directly. While clever and thought provoking the picture seems to prove my contention.

 

[Omega Man]

Very interesting analogy!! Made me think. Thanks

But! note the center mass of the belt is HIGHER on this clever hook than it would be if it was just on the finger directly. While clever and thought provoking the picture seems to prove my contention.

I couldn’t find a picture of the ones we made in the now eliminated “wood shop program” but there are many variations that could be fun, safe and interesting projects for the youngsters.
OM

 

[vtbob]

I am sorry, but none of your assumptions in the paragraph above are correct.

Could please explain why my assumptions are incorrect. That is the wisdom that will help me understand the benefit of normal street riders doing this at 5/10s 7/10s riding in the twisties.
I do not dispute the benefit riding at 10/10s in racing, as they do most often move off the seat to the side low enough to really lower the center of mass .

 

[mlytle]

Could please explain why my assumptions are incorrect. That is the wisdom that will help me understand the benefit of normal street riders doing this at 5/10s 7/10s riding in the twisties.
I do not dispute the benefit riding at 10/10s in racing, as they do most often move off the seat to the side low enough to really lower the center of mass .

do some reading of the recommended books. take a class.