Rebound on left front shock

[Matt49]

Because shocks can be used now to really control attitude more so than in the past, I really believe that the days of using shocks only to "fine tune" are far behind us. We all know somebody (or might BE somebody) that uses pretty much ONLY shocks and tire pressures to tweak their car through the night even with VERY different track conditions from hot laps to feature.
I also think that the old adage of "heavy spring gets the weight" and then only thinking about how the wedging or dewedging associated with that is going to affect handling are far behind us.
Two examples:
1) The old way of thinking told us that a heavier RF spring should help the car turn on entry due to dynamic wedge freeing the car on entry. A new way of thinking could tell us that a softer RF spring will help the car turn on entry due to increased rear steer because of the LR action that comes with pinning the RF. So just the opposite result.
2) The old way of thinking told us that a heavier LR spring should help tighten the car on exit due to dynamic edge. A new way of thinking tells us that the softer LR spring helps with LR hike-up and generates more LR thrust angle to tighten the car on exit. Again, just the opposite result.

Shocks are controlling all of this which just makes it all that much more complicated.

Whoever thought 15 years that adjusting rebound on the RR shock would change how the car handles on the gas. But today, we know that it makes a big difference.

My point is that shocks are no longer just fine tuning tools on these cars. Once you have a decent balance, you can do just about anything with shocks including tune yourself right out of a good setup.

[let-r-eat]

Weight transfer and understanding it is very simple. Put a cup of coffee on your truck dash and see which direction it spills when you hit the gas, brake, or go around a turn.Take a block of wood and attach a spring about 6" long with a 500 gram weight to the other end and drive around with it on your dash. See which direction the weight goes? Stiffen the spring and see how it reduces the amount of travel? How long it takes the weight to return and center?control your deceleration with the throttle into the corner and watch the weight? Use brakes and watch the weight.

[mab475]

That truck has a balanced front and rear suspension with shocks that compress and rebound at the same rate.

[7uptruckracer]

It's no different the two actions you do will effect it the same way all the car knows is 4 tires and the ground look at the gyro camera they put in the cup cars.

[fastford]

Because shocks can be used now to really control attitude more so than in the past, I really believe that the days of using shocks only to "fine tune" are far behind us. We all know somebody (or might BE somebody) that uses pretty much ONLY shocks and tire pressures to tweak their car through the night even with VERY different track conditions from hot laps to feature.
I also think that the old adage of "heavy spring gets the weight" and then only thinking about how the wedging or dewedging associated with that is going to affect handling are far behind us.
Two examples:
1) The old way of thinking told us that a heavier RF spring should help the car turn on entry due to dynamic wedge freeing the car on entry. A new way of thinking could tell us that a softer RF spring will help the car turn on entry due to increased rear steer because of the LR action that comes with pinning the RF. So just the opposite result.
2) The old way of thinking told us that a heavier LR spring should help tighten the car on exit due to dynamic edge. A new way of thinking tells us that the softer LR spring helps with LR hike-up and generates more LR thrust angle to tighten the car on exit. Again, just the opposite result.

Shocks are controlling all of this which just makes it all that much more complicated.

Whoever thought 15 years that adjusting rebound on the RR shock would change how the car handles on the gas. But today, we know that it makes a big difference.

My point is that shocks are no longer just fine tuning tools on these cars. Once you have a decent balance, you can do just about anything with shocks including tune yourself right out of a good setup.

good post matt , ive never tied the left front but ive got a shock that will almost tie it down, but like you said, with the new way of thinking and bump stops and such, I never use it.

[Lt.Stryker]

The theoretical aspects of weight transfer is an interesting line of conversation. I think there are some variables, which significantly affect the car that have yet to be discussed: how you set up the corner is going to affect weight transfers, how and when you pick up the throttle, your corner philosophy (squaring the corner versus slinging the rearend), and how you manage the throttle through the exit of the corner all affects weight transfer. When you set the corner, you load the right front spring and unload the left rear spring. As you begin to apply the throttle in the corner, the car seeks to return to balance (moment center). If you run a limiter chain on the left front, it's going to reduce the chassis roll when between the time after you've set the corner until the time when you begin to pick up the throttle if your feet are working independently. If you are a two footed driver - meaning you concurrently apply the brake and throttle to set the corner trying to keep the RPMs up in the corner - then there's less weight transfer (reduced suspension movement). So chaining the left front could affect the center of the corner off depending on your driving style. But, if you fail to adapt your driving style the car would likely push like a Minnesota snow plow.

[MADCAPRACING22]

Man, what a great discussion! This is what I look for right here. You have to sift through some BS to get to discussions like this. Thank you Matt49 for validating the Bloomquist Weight Article because that article is the foundation of my understanding! Matt49,GRT74 and some others have helped me a lot with their posts and I want to thank you!

[Bubstr]

Good post here. This is all about weight transferred by forces, or in this case, limiting the assistance of the spring to aid in this transfer. I think the biggest misconception is where or what path the weight takes on the transfer.

Every car has a center of gravity or mass if you choose. It has a specific position, front to rear side to side and maybe most important a height. What transfers weight is force applied to this center of mass, it sucks the weight there and transfers it from there. Every bit of weight in the car, down to the change in your pocket effects where this spot is. Make no mistake, this spot is the most important thing about making a car handle. The rest is just tools to modify the mistakes or compromises made here.

[7uptruckracer]

Your center of gravity is the moment arm that acts on your roll center it provides the "leverage" that causes the weight jacking. I can see why the good manfacturers get paid so well and why they guard their info so much. This will add gray hair to your head

[Bubstr]

Your center of gravity is the moment arm that acts on your roll center it provides the "leverage" that causes the weight jacking. I can see why the good manfacturers get paid so well and why they guard their info so much. This will add gray hair to your head

What gray hair? anyone with scales a jack and a couple blocks, bubble protractor a little simple geometry can find exactly where this center of mass is and it's height. Once you find that spot, by rigging a chain to hold that spot at any level angle that force would be applied threw braking, cornering or acceleration, you can find exactly where the weight goes under dynamic conditions, by simply jacking the car up any specific height opposite the hold back, then tightening the chain and block the contact patches from moving, let car down and measure difference in scaled weight. The force is constant from the chain. It will make your asymmetrical adjustments to roll centers, rear bars, panhard bar and control arms work just as on the track with oscillation from bump or ruts. The guy I learned this from said it was a chassis dyno. I'd say, unless you have the bucks for a 5 post shaker, it's the next best thing. What it won't do is chart the speed of transfer that you use shocks for. Note all hold backs and chain have to be level. Also note the steering angle will change the scaled weight due to king pin inclination. This may be old school but sound physical laws.

[7uptruckracer]

I'm talking about the roll center and geometry part I've done the COG scale measurement plenty of times. I'm talking about what everyone is doing these days with the spindle inclination, their roll centers static and dynamic (which is the important part), what camber curves they run etc. etc. Its not hard to take all the measurements but deciding what direction is the new cutting edge and keeping up with the tech curve while still winning races and developing new things seems like it would be a handful, I guess that's why you see people just getting a new chassis year to year whatever they see winning races they switch too. One year its the Rocket next year it Genx, then they will get an MBH, or BWRC. I saw one recently, Austin Hubbard's car (The Charlotte Car) they had Data Acquisition data on and they had it on the rig running it through a laps of data to see where everything moved, it was cool to watch for sure.

[Bubstr]

The process I out lined will not show exactly how many lbs will be on each wheel going threw a corner at FALs or EastBay, as there are too many variables in forces, traction, banking and track shapes, but what it will tell you is balance at any degree of force applied. If the force is greater, more weight will be transferred, but at the same proportions at a lesser force. One of the variables is banking of the track. This changes applied force and can be replicated by changing the angle of the hold back chain up or down on the anchoring end.

Balance is the important part, example= chain 90 degrees off the right side. This would represent the time in the corner, where no brake or gas is applied, rolling the corner.The weights would represent a guide to a neutral, tail loose or pushing car. The roll centers are active, because they deterine to some extent where the weight moves to. This gives yo a multitude of changes that you can research at the shop, for possible changes at the track later, like moving weight, changing pan hard bars or 4 link bars, ride height adjustments or spring changes. The beauty is you get no surprises. Entering the corner, move the chain to the front quarter and turn the wheel, read the scales for balance under breaking and turning. Exit, apply gas by moving chain rearward and reading the scales. What you will see is one of the most under looked things is weight height. In engineering terms, it would be force vectors, I think, but in simple terms low eight can push a tire sideways, reducing traction and high weight can push down on a tire increasing traction. Of course too much will turn your car into a bicycle and if you transfer weight to one wheel, it comes from another, that's where balance comes in. At minimum, it will give you a better understanding of dynamic wight transfer.