I learned something today

[faffi]

But I do not know what

Went for a 200 mile ride over winding hills, and all of a sudden I realised my struggles to keep the bike on line when getting on the throttle through left hand corners were gone. Why? Not sure. Perhaps I slightly changed my line of sight, or was more relaxed on the handlebars, or used different inputs. Or a combination of those, likely, together with just riding like I've been used to: Trail brake towards the apex, then the instant maximum lean is achieved, gently and gradually roll on the throttle while smoothly and gradually releasing the brake. This gives a short overlapping period.  For whatever reason, I could not make it work with this bike before, but now all is well. Whatever the cause and solution, it was an operator error and not a fault with the bike.

[radguzzi]

Line of sight that you mentioned is Everything when dancing in the twistes...

When you look Through the curve, your movements become very  fluid and graceful. 
The idea being, you are going where you're looking is huge.

Keep up the good work.

Ride on,
Rob

[Ncdan]

Line of sight that you mentioned is Everything when dancing in the twistes...

When you look Through the curve, your movements become very  fluid and graceful. 
The idea being, you are going where you're looking is huge.

Keep up the good work.

Ride on,
Rob

Agreed and one of the hardest techniques to train new riders. They feel like they are going to hit some invisible object in the roadway if they are not looking directly in front of where they are at in the curve.

[faffi]

I have been riding since 1980, and how you look is very important, as you describe. I did not think I changed anything when going to the Guzzi, but chances are I did, for whatever reason. Anyway, glad that the bike is reacting the way I am used to have bike reacting now 

[nc43bsa]

Over 30 years ago, I traded my 900SS for a hour or so with a friend who had a CB900F Super Sport.  The first thing he mentioned when we stopped was how the Ducati "stood up" in the corners under braking. 

I had never noticed that tendency, so when we switched back to our own bikes, I experimented with trail braking up to right before the apex and releasing the brakes;  I was surprised to find how much the bike fell into the turn.  The Duc did it equally right and left.

[faffi]

The worst bike I've had in that respect was the CX500. Hit the brakes when leaned over, and the bike would just instantly go vertical and straight on. It was the worst handling motorcycle I have owned.

[Moparnut72]

I think this trait has more to do with tires than the bikes themselves. Back when I rode Airheads the standing up in a turn when braking happened all the time. Magazines talked about it all the time and cautioned new about braking in corners with the possibility of winding up in the oncoming lane. I didn't ride for a number of years and when I got back into bikes I haven't experienced this at all, didn't matter whether it was the Harleys, the Triumph or my Guzzis I have owned. Back in my Airhead days I did a lot of riding on the slabs and found that Dunlop K70's were a great tire for that kind of riding, lasting for many miles. They were kind of a square tire and wore that way even more as the miles piled on. Current tires are so much better and manufacturers are designing tires with cornering as a main priority. So I think tires are or were the main contributor to this issue. What do you guys think?
kk

[Bulldog9]

Line of sight that you mentioned is Everything when dancing in the twistes...

When you look Through the curve, your movements become very  fluid and graceful. 
The idea being, you are going where you're looking is huge.

Keep up the good work.

Ride on,
Rob

It's absolutely true that you go where you look.

I think the "standing up in a curve" phenomenon is a combination of many things. The rider, speed, conditions and of course the motorcycle itself including the tires.

Some bikes like my Kawasaki ZG1000 Concours didn't care what I did or what the conditions were low air in the tires the eggs loaded with a passenger etc The bike just responded the same every single curve and time.

My old faithful XS1100 was always a bear in the twisties as the frame would bend flex load up and then spring back into shape as you transitioned through the turns, and being shaft drive always wanted to stand up. That thing wouldn't stand up it would sometimes pop up. Caught a lot of bad press for poor handling, but a custom forced and some welded frame supports helped settle down.

I think it takes time to adjust to any new motorcycle to learn its limits and how to interpret the bikes responses into your muscle memory.

That said, I found over the years that body position, load (bags, passenger) and running my rear tires at slightly higher pressure and more compression damping help to keep the bike consistent.

[Moparnut72]

Body English figures in differently on different bikes. My Audace cornered well with just counter steering. My Triumph T120 had to have quite a bit of leaning to turn well. My Mandello likes some of each. I have no idea what my V7lll likes and probably won't until I put some decent tires on it. Of course your experiences will probably be different, just what I found.
kk

[Huzo]

I’m sometimes amused to a degree that people can say how one bike needs to lean more or less than another for the same corner radius at the same speed.
It won’t matter if you are on an RD 350 Yamaha or a Honda CBX, the angle of lean required is that where the horizontal force vector (centrifugal) = the downward force vector (mass x gravity)…If it were not so, the bike would fall over one way or the other.
It is not something we can choose to vary or that which alters with design, Isaac Newton said so….
Now of course there will be those that espouse…
“My buddy hangs off his R1 Yamaha but my V85 likes to lean in more motocross style…”
The fact was, is and always will be, the the centre of mass is acted upon by those two forces previously mentioned and the resultant of the two must act down through the line of the rider and into the tyre contact patch.
You only have to remind yourself that the bike is a single track vehicle and the balance of the vertical and horizontal vectors are a function of speed and corner radius.


Note that the C of M is “outside” the riders butt and “inside” that of the bike, but the “resultant” of the two is straight through the contact patch.

[Moparnut72]

Of course the angle will be roughly the same but what it takes to get there won't necessarily the same. My Audace had very wide handlebars so it didn't take much pressure to initiate and maintain a turn. My Triumph not so much it took some leaning off to help it along. When I rode it from the dealership I was surprised how much more effort it took to get around a turn than the big heavy Audace.
kk

[Dr. Enzo Toma]

Center of gravity heavily impacts lean angle all other factors the same. Take the same corner on a Triump Tiger 1200 as a Daytona 660 and you'll find the lower cog sport bike requires more lean angle, same curve same speed.

[faffi]

I’m sometimes amused to a degree that people can say how one bike needs to lean more or less than another for the same corner radius at the same speed.
It won’t matter if you are on an RD 350 Yamaha or a Honda CBX, the angle of lean required is that where the horizontal force vector (centrifugal) = the downward force vector (mass x gravity)…If it were not so, the bike would fall over one way or the other.

Not quite true, since tires have width. So the wider the tires, the more lean is required. And also, CoG will hence influence the amount of lean requiered for any given cornering speed; raise the CoG, and less lean is requiered.

And here is an observation that I do not have a rational answer to. My NT650V Deauville required massive lean for any given cornering speed. You can see a picture of the rear and front tires below - there are no chicken strips, and that is unusual for street bikes. Also, they are worn equally from center to edge, which is something I have never experienced before - the edges wear less on road bikes in my experience.

But despite that, and despite throwing sparks around basically every corner, my cornering speed was slow. As in 55 mph with everything decked around a corner where I did not even put down a peg feeler on my CB400 doing 65. People riding behind me would giggle at the silly lean angles I carried compared to them.

[faffi]

If you want to google-translate from German, or read German, you can read it all here https://www.motorradonline.de/ratgeber/alles-ueber-schraeglage-schraeg-schraeger-am-schraegsten/

 For those who will not do that, here are a few facts:

Slowest and fastest:

Ducati Diavel, rider pushing bike down, bike lean 41 degrees, combined lean 38, corner speed 47 kph

Marq Marques on his MotoGP bike, hanging off, bike lean 62 , combined lean 66, speed 78 kph

 

Honda Fireblade, rider sitting straight, bike and combined lean 45, speed 55 kph

Honda Fireblade, rider pushing bike down, bike lean 46, combined lean 43, speed 53 kph

Honda Fireblade, rider hanging off, bike lean 48, combined 51, speed 61 kph

Honda FIreblade, Pirelli SBK Qualifier, hanging off, bike 51, combined 53, speed 65 kph

 

Husqvarna 701 Supermoto, rider pushing bike down, bike lean 57, combined 51, speed 62 kph

Husqvarna 701 Supermoto, rider sitting straight, bike and combined lean 47, speed 57 kph

Husqvarna 701 Supermoto, rider hanging off, bike lean 46, combined 51, speed 62 kph

 

[faffi]

One more to bore you

[Huzo]

Yes, the lower the CofG then the moment arm of the downward vector is shorter, but so is the moment arm of the centrifugal component.
The forces will be of a different magnitude than the high C of G case, but they will still be the same as each other.

[faffi]

Yes, the lower the CofG then the moment arm of the downward vector is shorter, but so is the moment arm of the centrifugal component.
The forces will be of a different magnitude than the high C of G case, but they will still be the same as each other.

Only if tires have zero width.

[faffi]

I have updated the link to the German article above, which also have a lot of illustrations, and repeat it here https://www.motorradonline.de/ratgeber/alles-ueber-schraeglage-schraeg-schraeger-am-schraegsten/

[chuck peterson]

I humbly submit my 1000-10,000 words.. 

Jerry Wood, race instructor

[Huzo]

Only if tires have zero width.

Sorry but no..
The width of the tyre is only as important as how much is contacting the road. It could be 12” wide and it wouldn’t matter, as long as only 1” is on the ground. It is the CONTACT PATCH that the forces are acting through, all the rest is just mud in the water.
Just consider the pure physics of it, but look. You’ll never believe me I know, we would need to go right back to force and vector analysis and no one wants to do that.

[Huzo]

I humbly submit my 1000-10,000 words.. 

Jerry Wood, race instructor

Was there a point somewhere in there ?

[faffi]

Huzo, the issue with tire width is that it moves the contact patch away from the center line, so the forces act through a point outside of the like of the CoG. This is a vector. Hence the wider the tire, the more you must lean a bike for any given corner speed.

[chuck peterson]

Was there a point somewhere in there ?

“A picture is worth a thousand words..”

Just a visual for comparison..

[Huzo]

Huzo, the issue with tire width is that it moves the contact patch away from the center line, so the forces act through a point outside of the like of the CoG. This is a vector. Hence the wider the tire, the more you must lean a bike for any given corner speed.

Based on what you say, I’m going to align my thoughts closer to yours. I don’t say that your reasoning is rock solid in it’s basic principles, but I’m not as convinced as I was that my stance is totally correct…

[faffi]

Just to add further confusion, I forgot to mention that wheelbase also have an impact on how much a bike must lean for any given cornering speed. The longer the wheelbase, the more lean is required. Fun, isn't it 

[Huzo]

Just to add further confusion, I forgot to mention that wheelbase also have an impact on how much a bike must lean for any given cornering speed. The longer the wheelbase, the more lean is required. Fun, isn't it 

Okaaayyyyy.
Why…?

[faffi]

I have just accepted that this is the way things are, after it was explained to me in laymen terms many years ago, as I could never wrap my head around the mathematics. But if you want to learn all(?) about two wheel physics, starting out with Wikipedia will give you more insight. And hopefully you are brighter than me and can really understand the various forces involved, not just accept it as I have done https://en.wikipedia.org/wiki/Bicycle_and_motorcycle_dynamics

[Dr. Enzo Toma]

Some interesting demonstrations and visualizations in this video:
https://www.youtube.com/watch?v=vSZiKrtJ7Y0

The 3D printed wheels used to demonstrate that motorcycle tires are (usually) conical reminded me of train wheels which permit turning in the same way.