weight the outside peg?

[stormer94]

I keep seeing guys mention 'Weighting the outside peg". What exactly does this get you, and why would you do it. In theory, all I can see it doing is adding weight to the front of the bike, because the peg is likely further forward than your butt would be. What's the reasoning, when do you do it?

Thanks,
Bob

 

[Jake T]

I think what they mean by that is when you're coming through a corner
you have an inside peg and an outside peg. The inside peg being the peg
on the left in a left turn and so on. If you weight the outside peg on a corner I think
theres less chance of falling over or washing out. I could be wrong though...

 

[dirt bike dave]

This is how I see it:
The more weight you put on the pegs, the lower your center of gravity is, which will help cornering. Think about it; if you are standing, all your weight is on the pegs, so as far as the tires are concerned your center of gravity is lower when standing than when sitting with all your weight on the seat.

You often can't stand or weight both pegs when cornering because you might have your inner leg off the peg or very little weight on the inner leg. The more you weight the outer peg when sitting, the less weight you have on the seat, lowering the center of gravity.

 

[OoM_WoC]

The reason for weighting the outside peg is so you get better traction in turns.... the simple truth. It presses the tires into the ground more, helping prevent washouts.

 

[yzguy15]

Yea, better traction. That's what the Gary Semics book says. Theoretically, if you're leaning the bike underneath you, keeping your body perpendicular to the ground, you have the potential for a wash out and weighting the outside peg gives you more traction and less chance to wash out. If you'll watch most of the pros in pictures and such, this is the way they turn.

 

[stormer94]

Is it the rule, or the exception, to weight the peg. Should I be practicing that way, always trying and weight the outside peg? Or is it a 'feel' thing, and to be done when you need it.

The rest of the time, it's your butt putting the weight down?

Thanks for the input,
Bob

 

[RM_guy]

Here’s my theory

I agree with DirtBikeDave, it’s a center of gravity issue. Anytime that you weight the pegs, whether when you’re turning or standing up, you effectively change the CG for the bike/rider. When you weight one peg or the other you are shifting the CG to the side of the bike that you are weighting.

When the bike is straight up and down, the CG is centered over the tires and the bike remains upright. When the bike is leaning in a turn (with no foot peg weighting) the CG moves off center and tends to make the bike lean further.

Try putting your bike on a stand. It stays there by it’s self with out tipping over because the CG is directly over the center of the bike. Now push the bike to the side and it starts to fall over. This is because the CG is now shifted to the side and starts to pull the bike over. If you are on the bike when it begins to tip, you would instinctively move you body to the opposite side (moving the CG in the other direction) to balance the bike and keep it from falling over.

The same thing happens when you lean into a turn except centrifugal force is acting on the CG to pull it back up. The combination of gravity pulling the CG down and centrifugal force pulling the CG to the outside of the turn, keeps the bike from falling over and it maximizes the downward force on the tire to maximize traction. So the right combination of speed (to control centrifugal force) and lean will get you around the turn without falling or sliding out.

Now we move into real life. In reality is very difficult to get your speed and lean optimized since the conditions in a turn are so variable. Friction through out the turn can change from loose to tacky dirt. This is where weighting the outside peg comes in. By weighting the outside peg you are shifting the CG to the weighted peg side. Since leaning the bike shifts the BIKE’s CG to the inside, weighting the outside peg counteracts that force and moves the bike/rider CG back over the tires which optimizes traction. You weight the peg more or less depending on your speed in the turn and the amount of bike lean.

So the idea is to maintain the bike/rider CG over the point where the tire meets the ground. Saying to weight the outside peg or to keep your body perpendicular to the ground are simpler ways of saying to move the CG over where the tire meets the ground.

When negotiating flat (no berms) or off camber turns it is more important to weight the outside peg since there is nothing to keep the tires from sliding out. Turns with big berms that are taken at high speed require less peg weighting.

I hope this helps.

 

[yzguy15]

Nice way of explaining it RM Guy. You pretty much said what I said, except explained it a little more in depth.

Might I ask what centrifugal force is? I was wondering if you meant centrifical force and just typed it wrong, or if that is actually a kind of force.

 

[RM_guy]

Originally posted by yzguy15
Might I ask what centrifugal force is? I was wondering if you meant centrifical force and just typed it wrong, or if that is actually a kind of force.

Oops:confused:
I spelled it so wrong that the spell checker couldn't even find it.

You're right. I meant centrifical force like the kind that holds you in the rollercoaster car when doing a big loop de loop.

 

[High Lord Gomer]

Poor, poor, YT_Guy...even when he's right he doesn't know it. :p

Centrifugal force is the force directed outward during an arcing motion, centripetal force is the force directed inward.

 

[RM_guy]

Sorry Gomer. I'm right so often that I loose track:p :p

Actually I thought I made a mistake onetime but I was mistaken:p

 

[stormer94]

tried it.

Okay, I went riding today for about 5 hours with the kids and some buddies. It seems to me that when you get forward and weight the outside peg you accelerate quicker, which is what it sounded like was gonna happen from those that posted. What I really noticed though was that I could get sideways in the corners and it felt more in control than when I'm not weighting the peg. Still slides out the same distance and angle, but just feels more in control, less likely to slide out all the way and spin out and lay it down.

Does that sound about right?

 

[yzguy15]

Sounds like you got it to me.

 

[will pattison]

now i know dave is an engineer, too!! :p

it's cool when someone see's the physics, then goes out and turns it into greater enjoyment. whether it's faster lap times or fewer crashes, that's one of the true joys of riding motorcycles.

now that you've got the concept, try fine tuning it with a few additional things: one of the keys to the technique is getting your butt crack over the outside corner of the seat. the other is to drive your outside knee into the radiator shroud, which causes you to also push back on the outside peg a bit. that not only aids in keeping the back end from coming around, but it also helps you keep the upper body as far forward as possible. THAT in turn helps keep the front tire weighted and less likely to low-side. isn't it cool how it's a knee-bone-connected-to-the-thigh-bone kind of thing? when you get it all put together and can roll on steady throttle all the way around an off-camber, it's a truly sweet thing.

good luck and enjoy!!

 

[KawieKX125]

Try an experiment, go through a fast flat sweeper corner. Try it without the weight on he peg, then with. Go as fast as you possiblt can with each untill the tires begin to slide. You will go faster with your weigt on the peg.

On the centrifugal force issue;
My brother took physics this year. The way he explained it to me is that centrifugal force is actually the force that holds you in the turn and that your straight line momentum wants to yank you out. I don't know if this is correct, it is just what I have heard.

 

[stormer94]

Will,

I thought we were supposed to keep the weight centered on the seat? So sliding the butt crack over onto the edge is the ticket 'eh? I had been thinking the more inline with the bike your body was, the more it drove the tire square into the ground.

 

[yzguy15]

Well the idea is to keep perpendicular to the ground. So, if you're leaning the bike underneath you, which I think was mentioned as the way to go, you're butt crack will be on the edge of the seat. Always try to lean the bike underneath you if possible, because if you lean with it, the more of a chance you have to wash out.

Kinda like if you were going to do a donut. You wouldn't lean into the inside of the donut, you'd keep your weight on the outside so you don't fall.

 

[BillyWho]

RMG explained it very well .
The only difference of opinion I have is I think it is inertia of the combined weight of the rider/bike and the CG, not so much centrifugal force.
The way I understand centrifugal is it has an "attached" center point of rotation that is fixed. Inertia of weight has no "guide" to where it goes other than it wants to keep going in the same direction it is already traveling.
When you are coming into a corner all the "mass" is headed in one direction, then you steer/lean the bike to turn , and what makes you turn is the bite the tires have on the ground verses or overcoming the inertia of the weight wanting to continue straight.

RMG explained perfectly about how shifting the CG to as low and in line with the center line of the contact point of the tires as possible is key, and the only thing to add to help understand better is when you have all your weight on the seat and the bike is leaned over, the angle from your butt (your CG) to the centerline of the tires, let's say 15 degrees, is the angle that the weight of your body is pushing on the tires, which means your helping keep an outward (straight) force on the inertia of you and the bike. When you weight the outside peg, you are putting all the force directly straight down on the center of contact ( at least as close as your going to get) of the tires which gives you as much "down force" as possible to get more traction to over come the "mass" wanting to continue straight.

Kind of the same theory as Indy cars. They try and create as much straight down force as possible to keep the tires glued to the track, other wise as you know when they loose traction going into a corner at 200mph that incredible amount of inertia continues straight till they hit the wall:( !

Everything evolves around gaining traction with the contact of ground/tires to get the bike to go where YOU want it to go. Just my 2 cents:)

If there is a berm or rut, it's not near as important , but it still keeps the bike more stable and controllable.

stormer, the reason it feels more controllable is the increased traction your getting gives you more "control" on what happens with the rear wheel , verses a little "pebble" starting the loss of traction untill your face down in the dirt.

 

[will pattison]

Originally posted by stormer94
Will,

I thought we were supposed to keep the weight centered on the seat? So sliding the butt crack over onto the edge is the ticket 'eh? I had been thinking the more inline with the bike your body was, the more it drove the tire square into the ground.

moving over to the edge of the seat makes it easier for you to get a mechanical advantage on the outside peg. it also helps shift some of the inertia of your body's mass out of a vector that would increase the bike's tendecy to slide out. as **** burleson says, a "quiet upper body" will help you through the turn faster. further, that body position is also a natural result of countersteering, which you should also be doing, but that's another conversation...

wp.

 

[ET]

I have wondered about this too, and have read the explanations in various publications, and most of them didn't seem to explain it correctly.
In a turn, it doesn't matter if your weight is on the inside or outside footpeg, the combination of centrifugal force and gravity will go through the tire contact patches, or the bike will fall over, either high side or low side.
The only difference weighting the outside footpeg can make, is to cause the bike to become more vertical. This apparently allows the tire to get more sideways traction, enabling the bike to pull more G's without sliding out.
I have never read any scientific explanations for tire traction in dirt, and I doubt that there are more than a handfull of tire engineers in this country who do know anything about it.
If there are any reading this thread, please enlighten us.

 

[Kramer]

ET,
Weighting the outside peg will actually force the bike to lean more, that is if you want to stay balanced... when all else fails, draw a free body diagram. Or, get on your bike and experiment with the extreme cases.

 

[Bill_yz]

How about standing?

Weighting the outside peg while sitting through a turn seems to make sense and feel right. But, while standing through a turn it feels unstable to me. Does it only apply to turning while sitting? Or maybe I don't have the right technique.

 

[duke]

Could Will Pattison, elaborate a bit more on what Burleson meant when he made reference to "quiet upper body" as being the key to taking corners with greater speed?

 

[will pattison]

my interpretation, based on his comments and demonstrations, was that the majority of the action required to make a good turn takes place from the waist down. the knees, the legs, and the hips all get moved or adjusted in some way, but the upper body doesn't do much other than maintain an orientation. an example is keeping the upper body mostly vertical when negotiating a flat corner.

wp.

 

[bud]

ET, weighting the outside peg does give more traction - allows more of a lean without sliding sideways. Explanations of physics aside, doesn't your personal experience back this up?