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Weight.

2% of the weight off the unsprung bits, or shaved from places far from the center of mass might be pretty noticeable.

Left/right transitions don't happen pivoting from the contact patch, but pivoting around the center of mass.

The ELF team found that out when they tried slinging the gas tank under the bike, left/right transitions got harder, not easier.
 
psykown said:
So this is the opposite of what most of you all have mentioned but maybe food for thought, When I had the rotopax on the tail of my DRZ thta little bit of weight mayde for a huuuuuge handling difference whereas the one time I had the same rotopax full and in my backpack it was hardly noticeable. Weight is important, but where that weight is place(or removed) is even more important
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Being able to decouple some of the mass from the bike can make a huge difference, if you are going left and right putting some of the mass on you and letting the bike move around under you makes the bike-rider system more nimble even though the mass is the same.
 
AwDang said:
Thats the thinking that OEM’s went on a binge of mass centralization.
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Sort of, that came about when they realized that a low CG doesn't necessarily make for a good handling bike, having the mass a localised on the CG longitudinal axis makes for a better handling bike ( See XR650L_Dave reply)
 
Anders- said:
It also comes down to rideability, all that spinning stuff keeps the motor running well (not too erratic or "hot"), plus it provides a nice gyroscopic effect when riding.
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All depends on perspective. Yeah, flywheel effect is good. Hell, two stroke guys buy flywheel weights on purpose. Do we call engine gyroscopic good while complaining that gyroscopic forces from heavy wheels make a bike heavier to turn? Muddy waters.
 
XR650L_Dave said:
2% of the weight off the unsprung bits, or shaved from places far from the center of mass might be pretty noticeable.

Left/right transitions don't happen pivoting from the contact patch, but pivoting around the center of mass.

The ELF team found that out when they tried slinging the gas tank under the bike, left/right transitions got harder, not easier.
Click to expand...
Interesting. With the tank that low I guess they were actually having to lift the weight of the tank like a pendulum. Makes perfect sense.
 
Shinyribs said:
All depends on perspective. Yeah, flywheel effect is good. Hell, two stroke guys buy flywheel weights on purpose. Do we call engine gyroscopic good while complaining that gyroscopic forces from heavy wheels make a bike heavier to turn? Muddy waters.
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Sprung vs unsprung weight
 
for fun mostly, I took some weight out of the alum RPAX mount

1662413105379.png



also figure it might make a decent mount for a tow strap

1662413141687.png
 
MVI said:
for fun mostly, I took some weight out of the alum RPAX mount

1662413105379.png



also figure it might make a decent mount for a tow strap

1662413141687.png
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Those triple clamps look awfully heavy... :lol3

Edit: by the looks of that tank mount, it could just as well have been made of some tough plastic.
 
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Shinyribs said:
All depends on perspective. Yeah, flywheel effect is good. Hell, two stroke guys buy flywheel weights on purpose. Do we call engine gyroscopic good while complaining that gyroscopic forces from heavy wheels make a bike heavier to turn? Muddy waters.
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Its not muddy waters.

Everything is a compromise, and if you MUST have weight, the flywheels which is normally going to be right on top of your CG is literally the best place to have it. In that case its not gyroscopic force that you are generating (the wheel isn't large enough) its momentum to resist changes in RPM i.e. makes it harder to stall.

This is why dealer bikes and race bikes have different weight flywheels, or in the case of the 1290 KTMs the street version of the engines in the Super Dukes have lighter flywheels than the Super Adventure lines.

Wheels are another matter, that is unsprung weight which EVERY once you can get off of the bike is a good thing.
 
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Anders- said:
Makes your wallet lighter too, no? :dunno
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Yep, the last ex-wife got pregnant without agreement despite my wanting us to wait until the following year because I knew the relationship was on shaky ground... which of course, ended with 14 years of child support. So, $96k later, lots lighter
 
Tripped1 said:
Its not muddy waters.

Everything is a compromise, and if you MUST have weight, the flywheels which is normally going to be right on top of your CG is literally the best place to have it. In that case its not gyroscopic force that you are generating (the wheel isn't large enough) its momentum to resist changes in RPM i.e. makes it harder to stall.

This is why dealer bikes and race bikes have different weight flywheels, or in the case of the 1290 KTMs the street version of the engines in the Super Dukes have lighter flywheels than the Super Adventure lines.

Wheels are another matter, that is unsprung weightm which EVERY once you can get off of the bike is a good thing.
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You say it's not muddy water, followed by everything is a compromise.

There's no one secret recipe that suits everyone. Sport bike guys want quick turning, touring guys want stability. MX guys want fast building revs, enduro guys want heavy flywheels. There is no "right" answer.
 
Amos Malone said:
Just to clarify. I don't dislike when people put lot of work or money into making their bikes lighter. It's a nice hobby and as long as you are adding bling it might as well be somewhat useful. I just think it's more beneficial to concentrate on other areas.
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What other areas ?
 
Tripped1 said:
Its not muddy waters.

Everything is a compromise, and if you MUST have weight, the flywheels which is normally going to be right on top of your CG is literally the best place to have it. In that case its not gyroscopic force that you are generating (the wheel isn't large enough) its momentum to resist changes in RPM i.e. makes it harder to stall.

This is why dealer bikes and race bikes have different weight flywheels, or in the case of the 1290 KTMs the street version of the engines in the Super Dukes have lighter flywheels than the Super Adventure lines.

Wheels are another matter, that is unsprung weightm which EVERY once you can get off of the bike is a good thing.
Click to expand...
There is a fair amount gyroscopic forces generated from an engine (talking about large 4-strokes here).
This can easily be observed when going through a chicane, do a regular lap (for reference) and the next time you arrive at the entrace make sure it's 2-3 gears lower (whatever fits) but keep the original speed.
 
Shinyribs said:
That's true, but some areas are particularly useful to shed weight from. I bought a shinko tire once that was quite heavy adding right at a full pound on one tire. You feel that pretty easy.

A new exhaust on my Yamaha took 10lbs off the bike. You can't feel that whatsoever.
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A very good example of unsprung weight versus weight being carried by the suspension. The one pound in tire weight is huge.
 
Anders- said:
There is a fair amount gyroscopic forces generated from an engine (talking about large 4-strokes here).
This can easily be observed when going through a chicane, do a regular lap (for reference) and the next time you arrive at the entrace make sure it's 2-3 gears lower (whatever fits) but keep the original speed.
Click to expand...

Traditionally I feel the amount of fuel more than the engine speed, my last true track bitch was a Daytona 675 though.
 
Tripped1 said:
Traditionally I feel the amount of fuel more than the engine speed, my last true track bitch was a Daytona 675 though.
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That's a sweet engine. The large capacity fuel cell likely make a good candidate for being stuffed full of gas tank foam, just a guess though...
 
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