Standing while riding

brownie0486 said:

That's not what I've found when moving from seated to standing on the Dalton Hwy. 45mph tops seated and barely able to maintain balance due to road surface. Standing, immediately moved to 55mph with more stability and balance of the bike.

The weight is on the pegs. It was offered that the best riders become a neutral force on the bike standing. It takes a lot of practice to get there [ I'm not there yet and may never get to that level ] but I have much better control of the bike standing for the same reasons others have posted here.

Moving the weight of the rider from the seat at about 32-33 inches off the ground to the weight on the pegs which are 12" or so off the ground lowers the COG. This guy explains it in simple terms.

https://youtu.be/1pwOB5I1m7Q

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The CG of a human is located near their navel/waist. The CG of a GS is a bit above the cylinder heads. You can sum the product of weight and distance (i.e., M = weight x distance) to either a vertical or horizontal plane. The location of the reacting forces (foot-pegs or seat) doesn't matter. If it did, we would all be hovering (i.e., like a lady using a dirty toilet) to lower the CG.

Standing allows you to alter the fore-aft and lateral location CG, use your legs as shock absorbers (decoupling the two primary masses at the expense of the knee and hip joints) and provides a longer line of sight.

The center of mass of the human body depends on the gender and the position of the limbs. In a standing posture, it is typically about 10 cm lower than the navel, near the top of the hip bones.

In sitting, the true center of gravity is not at the center of the body, but actually slightly higher with more weight on the top half of the body than the lower half.

brownie0486 said:

Moving the weight of the rider from the seat at about 32-33 inches off the ground to the weight on the pegs which are 12" or so off the ground lowers the COG. This guy explains it in simple terms.

https://youtu.be/1pwOB5I1m7Q

Click to expand...

Alas, "the guy explains it in simple terms" but he's dead wrong. The mass is where the molecules are. If one stands up and raises many molecules, one raises the center of gravity.

The fact that one can more easily move more of one's mass side-to-side and for-and-aft while standing is why standing can be beneficial.

Ride safe, be happy.

stooie said:

Alas, "the guy explains it in simple terms" but he's dead wrong. The mass is where the molecules are. If one stands up and raises many molecules, one raises the center of gravity.

The fact that one can more easily move more of one's mass side-to-side and for-and-aft while standing is why standing can be beneficial.

Ride safe, be happy.

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All the professional off road course trainers, many world class title holders at one time, must all be wrong as well. Just amazes me how all the pros can be so wrong

Nearly 30% of the new wave of food delivery drivers admitted to sampling the food.
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brownie0486 said:

All the professional off road course trainers, many world class title holders at one time, must all be wrong as well. Just amazes me how all the pros can be so wrong

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They are right that it works; that's why they all do it. Those who think that standing up lowers the center of gravity are still wrong.

- When one stands up one raises one's center of gravity.
- When one climbs a ladder one raises one's center of gravity.
- When one ascends in an elevator one raises one's center of gravity.

Apparently when his high school physics class was in session the guy in the video skipped out to go riding. Those who paid attention in the high school physics class, went on to engineering school, then spent forty-year careers in aerospace engineering just might have a little bit better handle on the why of it. Alas, we also probably ended up with lesser riding skills than he did.

Ride long and prosper.

I will bet.... Marc Marquez cannot explain the physics of turning a bike, but he seems to be able do it fairly well. Perhaps the fellow in the video should stick to riding and like Marquez leave explaining the physics to others.

akbeemer said:

I will bet.... Marc Marquez cannot explain the physics of turning a bike, but he seems to be able do it fairly well. Perhaps the fellow in the video should stick to riding and like Marquez leave explaining the physics to others.

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I know lots of highly educated people who can not find their way out of a closet with the door open and the light on.

Friedle

Pretty sure they are trying to say that standing moves the weight from the seat to the foot pegs. Sure the actual mass is higher, but what the motorcycle "feels" is much lower. You can "steer" the motorcycle by putting more weight on one foot or the other. Anyone that has spent any time riding in the dirt understands how this works very well.

PoorUB said:

Pretty sure they are trying to say that standing moves the weight from the seat to the foot pegs. Sure the actual mass is higher, but what the motorcycle "feels" is much lower. You can "steer" the motorcycle by putting more weight on one foot or the other. Anyone that has spent any time riding in the dirt understands how this works very well.

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Steer or lean?

stooie said:

They are right that it works; that's why they all do it. Those who think that standing up lowers the center of gravity are still wrong.

- When one stands up one raises one's center of gravity.
- When one climbs a ladder one raises one's center of gravity.
- When one ascends in an elevator one raises one's center of gravity.

Apparently when his high school physics class was in session the guy in the video skipped out to go riding. Those who paid attention in the high school physics class, went on to engineering school, then spent forty-year careers in aerospace engineering just might have a little bit better handle on the why of it. Alas, we also probably ended up with lesser riding skills than he did.

Ride long and prosper.

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But, you don't have a YouTube video.

BTW - an aerospace engineer, a marine engineer and a YouTube spokesman offer comments on CG. The peanut gallery responds with comments about educated people not knowing how to do things. Isn't the web a wonderful place

36654 said:

Steer or lean?

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Well, if you lean the motorcycle one direction, it should turn in that direction, so, both!

PoorUB said:

Well, if you lean the motorcycle one direction, it should turn in that direction, so, both!

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Only if the lateral axis of the tire contact patches intersect. If they remain parallel, the bike just leans. For example, when you're leaning into a prevailing crosswind.

This

Loving this discussion btw. If my bike weighs 650 lbs and I weigh 230 kitted up and we are tied together as a unit then the speed at which the entire 880 lbs moves around is limited by physics in that the entire mass needs to be accelerated to acheive a specific outcome. The exageration of this is both bike and rider hit a bump that fully compresses suspension. Bike has to go up or bend. It runs into rider and rider has to go up or bend and in extreme cases rider gets acclerated vertically and decouples from bike and supermans to wherever. Road racers decouple by transferring force to the inside peg and making their mass as low as possible and centered between both tire contact patches. Their mass is also loading upmthe lowest part of the bike the inside low foot peg. It looks like they are sitting but they are standing on one leg and pulling the bike down with the bars as its trying to stand up. This also allows them the act as a shock absorber so they can go to the very edge of adhesion with some wiggle room for surface imperfections.

The cg of the system of rider and bike goes up when standing but it becomes a totally different system when 880 lbs becomes 650 lbs not limited by the rider in how it reacts to riding surface inputs and control inputs with 230 lbs acting as a damper above it. The same bump that launches the rider off the seat into space now is controlled with the tires more evenly loaded on the riding surface which is safer than totally unloaded with 880 lbs of mass accelerated and vectored wherever.

A good skier will have the majority of their mass very still with their hips and legs moving side to side underneath their center of mass. Direction of the system can change quickly because the upper body is not committed by angulation and is not a pendulum. On very tight roads the same is achieved on the bike by angling the bike and not the rider. I seem to be rambling. Good night fellow lovers of motos!

Forums are the best place to watch fun topics get totally beaten to death

chrisinsc said:

On very tight roads the same is achieved on the bike by angling the bike and not the rider.

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That's called being ...... "crossed-up". Your bike will have more ground clearance if you minimize bike lean by moving the rider CG to the inside of the turn.

skibum69 said:

Forums are the best place to watch fun topics get totally beaten to death

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It kind of got derailed onto a completely different topic. LOL

This recent image taken at a well known off-road riding training center illustrates an emerging technique designed to lower the center of gravity of a bike/rider combination. You can expect to see it in common use in your neighborhood soon

akbeemer said:

This recent image taken at a well known off-road riding training center illustrates an emerging technique designed to lower the center of gravity of a bike/rider combination. You can expect to see it in common use in your neighborhood soon

View attachment 75537

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Biker wallet, helmet and Converse All-stars................ Some days, the eclectic approach to fashion, just doesn't work.