Heavy rider vs Lighter rider.

Here's what I'm curious about... When running in the twisties does a heavier rider need to lean into the curve more than a light rider to maintain zero effect and balance at the same speed taking into consideration the static weight of the bike?? Hey it's raining...whadija expect...

I always tell the passenger to simply look over my sholder in the direction of turn. That way, if I lean more or less they stay in the same plane with me. I do notice less lean needed when loaded 'heavy'.

I know I have to pull harder when the bike is heavier. lol

'Specially in the really tight low speed twisties. One of the sisters has a truly nice set!!!! The crown is opposite too.

Here's what I'm curious about... When running in the twisties does a heavier rider need to lean into the curve more than a light rider to maintain zero effect and balance at the same speed taking into consideration the static weight of the bike?? Hey it's raining...whadija expect...

Nope.

This is Friday... that's too complicated for my brain today. Ask me again on Monday (not next Monday, one of the one's 10 years from now)

hey, you asked....

Learn to counter steer. Then there is no "pulling" the bike over. One becomes much faster and smoother when you learn to let the bike do the work. Counter steering is the key to fast cornering.

Learn to counter steer. Then there is no "pulling" the bike over. One becomes much faster and smoother when you learn to let the bike do the work. Counter steering is the key to fast cornering.

Me countersteering.

To be honest I dont notice too much difference if I am riding alone or 2 up in the twisties.

:whistling:although with that said I do hafta qualify that by telling you all that here in saskatchewan my tires do have an issue with wearing in the middle beacause of all the straight roads.

Brian

I suppose you do have to turn in and out of the driveway

If the suspension geometry does not change due to the increased mass, no, the bike will not have to be leaned more or less, but if it does change, then the answer is maybe.... it might have to be leaned more or less to make the same radius turn at the same speed.

Simple physics. If you change the center of gravity, the angle of the lean must also change accordingly when going into a curve at the same speed. Though it may be such a slight difference that you might not even notice.

Simple physics. If you change the center of gravity, the angle of the lean must also change accordingly when going into a curve at the same speed. Though it may be such a slight difference that you might not even notice.

There are 3 axes going through the center of gravity.

There is for aft COG, vertical COG and side to side COG.

It is the side to side COG that determines the lean angle.

As long as the side to side COG does not change, the lean angle does not change. Watch a cycle racer, they hang way off to the side to change the side to side COG so that the bike does not have to lean as far, they are also usually sitting straight up entering a corner because the vertical COG does not matter to the corner but they are after the aerodynamic breaking.

Due to the geometry of everything involved, adding a passenger will cause a very slight decrease in the lean angle. Slight as in it may not even be measurable.

Then there is the real world where having a passenger may have a profound effect on the lean angle of the next turn while you work the busing out of your back from going into the last turn so hard.....

The only thing that I have seen change is if I add more weight to the bike, passenger/stuff in bags, I need to air up the suspension some or I will drag easier. There is not any difference than I am aware of about obvious lean angle, but simply that the bike is riding lower to the ground. A little added rear shock air corrects that for me.

RandyA

Here's what I'm driving at. Think about gravational pull wanting to make the bike fall toward the pivot axis, and centrifical force wanting to throw you away from the pivot axis. Without changing the speed between a light rider (125#) and a heavier rider (350#) will the heavier rider tend to be overcome by gravation at the same speed? The reason I'm curious is I seem to take curves with a greater lean angle when riding in a group or with another rider and our speeds are equal. Maybe it's more noticable when riding with a 2ndGen with a lower center of gravity. When comparing two up with solo do you take the curves at a different speed to compensate for the gravational effect?? I donno. Any physics majors around??

You do realize that a 125 pound rider would have a heck of a time holding up an 800 pound bike. Right?

Here's what I'm driving at. Think about gravational pull wanting to make the bike fall toward the pivot axis, and centrifical force wanting to throw you away from the pivot axis. Without changing the speed between a light rider (125#) and a heavier rider (350#) will the heavier rider tend to be overcome by gravation at the same speed? The reason I'm curious is I seem to take curves with a greater lean angle when riding in a group or with another rider and our speeds are equal. Maybe it's more noticable when riding with a 2ndGen with a lower center of gravity. When comparing two up with solo do you take the curves at a different speed to compensate for the gravational effect?? I donno. Any physics majors around??

Don't forget about the equation f=ma, force = mass x acceleration. There will definitely be more forces in the system with the lateral acceleration x the rider's mass. That's why those skinny sport bike riders can flick through the twisties much easier than us old fat guys (speaking of myself) on 850 lb bikes. I notice a real difference when riding 2-up with a bag on the trunk rack. I would also think the height of the rider and load would make a difference because it raises the COG.

Dennis

You do realize that a 125 pound rider would have a heck of a time holding up an 800 pound bike. Right?

Ok, so make 'm 150#'s... I think you get the picture.....

Any physics majors around??

I'm not a "Physics Major", but I have had a couple semesters of it. Which is why I know that a heavier person will have to lean farther than a lighter person.

And to burst another bubble... there's no such thing as centrifugal force.

You do realize that a 125 pound rider would have a heck of a time holding up an 800 pound bike. Right?

That might be a problem at the standstill, but once moving the 'holding up' part is in the control of the right hand and the gyro effect of the turning wheels.

Now that's all that I'll inject into this conversation, mainly because I limit my output of info directly to the amount of input at any one time, and seeing as there was no real input at any one time on this issue, it would not look good on me to go spouting off more than I already don't know. (or something like that)

Don't forget about the equation f=ma, force = mass x acceleration. There will definitely be more forces in the system with the lateral acceleration x the rider's mass. That's why those skinny sport bike riders can flick through the twisties much easier than us old fat guys (speaking of myself) on 850 lb bikes. I notice a real difference when riding 2-up with a bag on the trunk rack. I would also think the height of the rider and load would make a difference because it raises the COG.

 

Dennis

f=ma is correct. By basic algebra you get to f/m=a. There are two accelerations, gravity and the turning acceleration. The torque they apply around the motorcycle axis needs to be balanced or the motorcycle falls over. That balance is achieved by the lean angle.

As you turn tighter the turning acceleration increases (gravity is pretty much constant). The torque is balanced by increasing the lean angle.

Without going through all the equations let me assure you that the mass (rider, passenger and motorcycle weight) cancel out so that all that matters is the lean angle. Ergo, it's the same regardless of weight.

The reason sport bikers can flick through the twisties is because they have a short wheelbase and low trail suspension geometry that lets them change the attitude (lean) much quicker than a touring bike.

All other factors being equal, a heavier rider( or adding a passenger) (normally) causes the center of gravity (CoG of the combined rider and bike) to be higher, and for any given speed and arc, the lean angle away from vertical must be increased to track thru a given turn. Also, the width, inflation, and wear patterns of the tires on the bike will affect lean angle, as the riders weight is varied. Newer tires, inflated properly, will affect the lean angle less. But as the tires are worn down in the center and begin to have a 'squared off' shape, the lean angle must be increased as the riders weight is increased. This is assuming that the heavier ( or added) rider will be carrying the added mass up in the torso, and not all in the legs.

All other factors being equal, a heavier rider( or adding a passenger) (normally) causes the center of gravity (COG of the combined rider and bike) to be higher, and for any given speed and arc, the lean angle away from vertical must be increased to track thru a given turn. Also, the width, inflation, and wear patterns of the tires on the bike will affect lean angle, as the riders weight is varied. Newer tires, inflated properly, will affect the lean angle less. But as the tires are worn down in the center and begin to have a 'squared off' shape, the lean angle must be increased as the riders weight is increased. This is assuming that the heavier ( or added) rider will be carrying the added mass up in the torso, and not all in the legs.

Just to be complete on this subject, adding a child or smaller female as a passenger probably doesnt affect lean angle at all( since the CoG is not affected much)...and even with a heavier passenger, the CoG and lean angle is not GREATLY affected, only slightly...also, in the real world, most riders will slow down in a turn when carrying a heavier passenger. We can 'feel' the handling change, and will instinctively slow to compensate, so that the lean angle is about the same as what we are used to feeling in that type of turn. Many of us can feel the slight drop in the ride height, and know that hard parts may scrape sooner in a deep lean angle, so we slow down so this wont happen.

SO...of all the answers in this thread...most of them are right, even though they seem to disagree!

My initial thought was COG too, then I realized that doesn't matter either. As the COG moves up there is more outward leverage in the turn but there is also more downward leverage.

You can see it for yourself if you draw a triangle and slide your COG up and down the hypotenuse. It's exactly proportional so everything stays in balance.

Good thing too. Be a shame if the handling changed every time you loaded a, er, well endowed chick on that high back seat.

What the ....? HUH? Heck if I know! I just ride until I fall over!!!