Vetter streamliner body kit

[sendler]

[QUOTE=3-Wheeler;377822]I don't see any inherent advantage of a bike with a high CG offering a reduction in lean angle.

QUOTE]

Raising the cg of a motorcycle/ rider reduces the lean angle that is needed for any given lateral acceleration by increasing the radius that the cg moves through as it leans. The higher cg is now displaced laterally more to the inside of the contact patch than the lower cg would be for the same angle.
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Wide tires also corner less for any given angle because the mass is moving in as you lean but the contact patch is also following it to the inside as well so there is less net offset than with a narrower tire and wheel.

[sendler]

A higher cg is also better in crosswinds given the same height of the side center of pressure because it mass anchors the higher part of the bike against blowing over with the wind to lean the wrong way while it also allows the less massive lower part of the bike and wheels to swing over WITH the wind which automatically leans the bike into the side wind giving it lateral force to resist being blown off line. The nose of my bike goes straight down the road even as the wheels blow back and forth under me as if by magic. This works with a well balanced sport bike even if you take your hands off of the bars while laying on the tank. See the link to the Aero thread where we were discussing this earlier and Ken Fry gave us a great explanation of how the trail in the front steering geometry works to make this self correction happen.
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http://ecomodder.com/forum/showthrea...tml#post279874
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[3-Wheeler]

[QUOTE=sendler;377883]

Originally Posted by 3-Wheeler

I don't see any inherent advantage of a bike with a high CG offering a reduction in lean angle.

QUOTE]

Raising the cg of a motorcycle/ rider reduces the lean angle that is needed for any given lateral acceleration by increasing the radius that the cg moves through as it leans. The higher cg is now displaced laterally more to the inside of the contact patch than the lower cg would be for the same angle.
.
Wide tires also corner less for any given angle because the mass is moving in as you lean but the contact patch is also following it to the inside as well so there is less net offset than with a narrower tire and wheel.

Hi,

OK, I think I see your point about a higher CG causing less lean angle to negotiate a turn on a typical motorcycle.

This phenomena is strictly based on the tire width of the front/rear tires.

When I initially made my comments that lean angle is NOT affected by CG, my intent was that the acting forces are limited to A-B.

However, tire width of any motorcycle tire changes the acting forces to A-C. With the forces acting in this plane, CG does indeed affect the resulting lean angle.

I had to include a graphic that would clearly show the force path that we are talking about. A graphic would have helped me from making a wrong assumption.

The force path A-C needs to be modified in location at C based on the amount of lean of the bike. The more lean, the wider the C location moves from the bike centerline.

Jim.

[PeterS]

Originally Posted by sendler

A higher cg is also better in crosswinds given the same height of the side center of pressure because it mass anchors the higher part of the bike against blowing over with the wind to lean the wrong way while it also allows the less massive lower part of the bike and wheels to swing over WITH the wind which automatically leans the bike into the side wind giving it lateral force to resist being blown off line. The nose of my bike goes straight down the road even as the wheels blow back and forth under me as if by magic. This works with a well balanced sport bike even if you take your hands off of the bars while laying on the tank. See the link to the Aero thread where we were discussing this earlier and Ken Fry gave us a great explanation of how the trail in the front steering geometry works to make this self correction happen.
.
http://ecomodder.com/forum/showthrea...tml#post279874
.
.

Thanks fellas, a lot of good explanation and i finally get it !

[sendler]

Originally Posted by 3-Wheeler

The more lean, the wider the C location moves from the bike centerline.

The displacement of the tire contact from B TO C is just a side note to the discussion which is more relevant to comparing different tire/ wheel widths.
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Your drawing shows how as the CoG A moves lower in the bike towards B, the distance that it is displaced to the left for any given lean angle is less. Which gives the mass less lateral offset to create a force vector to counter being thrown to the outside of the turn.

[stiletto2]

I've made a little more progress on my project in spite of delays of one sort or another. Here it is as it is now. Nose and tail sitting on the bike but needs more cuts/trimming to fit better and to allow for movement of the swing-arm/muffler. Plus, it needs a slight angle change to the main rear bulkhead. Still have a lot to do yet. At this rate, I'm not so sure it is going to be completed in time for VMD in Ohio. But, done or not, I'll haul it down there anyway.

[renault_megane_dci]

Nice work !

[mikeyjd]

cool thread.

[Grant-53]

The tail looks like it is dragging. I know that there adequate clearance but I am used to a different line from the sailplanes around here.

[stiletto2]

Originally Posted by Grant-53

The tail looks like it is dragging. I know that there adequate clearance but I am used to a different line from the sailplanes around here.

Yeah for sure it needs to be adjusted. It is just sitting up on the bike for now so I could take pictures. A plastic chair I had there would have made it sit up way too high so I just used a gas can that was handy to prop up the tail end some.