Rf wheel spacer

[Mr.Kennedy777]

When both wheels are in compression it’s 1:1, but one wheel bumps and roll, it’s different.

[Mr.Kennedy777]

Checking wheel rate at a ball joint is not accurately measuring wheel rate. It can give you simple motion ratios to give you an idea roughly how much stuff is moving with what and approximate load at the ball joint, but there are way more calculations that need to be considered to get wheel rate. One of which includes measuring the distance of the wheel compared to distance of the lower ball joint.

[Matt49]

Okay...so, like I've said 100 times, taking camber gain OUT of the equation. Grab the end of a spindle and move it up one inch. How far did the spring compress? Now imagine the spindle is 50 feet long and that is where the wheel is. Move the wheel up one inch and how far did the spring compress? The EXACT same amount as when the wheel was right next to the ball joint! Therefore the exact same wheel rate. The distance from the wheel to the lower ball joint makes ZERO difference on the wheel rate on a dual wishbone suspension. Even if you put camber gain back into the equation, you would have to move the wheel a great distance out for it to significantly impact wheel rate. People seem to be stuck with thinking that the distance from the wheel to the lower ball joint gives the wheel some mechanical advantage on the spring but that simply isn't true. The spring only moves as far as the motion ratio to the lower ball joint dictates. Where the wheel is doesn't change that in any way.

[fastford]

Checking wheel rate at a ball joint is not accurately measuring wheel rate. It can give you simple motion ratios to give you an idea roughly how much stuff is moving with what and approximate load at the ball joint, but there are way more calculations that need to be considered to get wheel rate. One of which includes measuring the distance of the wheel compared to distance of the lower ball joint.

this is the way i have always considered wheel rate as well , there is no doubt , both you guys are smart , but to me , wheel location has to play a role in wheel rate...

[Kromulous]

Matt49 i agree with you, but would some of the force get reduce by the leverage of the wheel location to the ball joint if if it was excessive? It would be small but you are introducing a moment there, correct?

I think you talked about that before, some of the load getting transferred thru the upper ball joint, but just making sure.

[dirtrace09]

The distance the wheel is from the spring does have an effect on the wheel rate. We use this idea constantly in the hydraulic world. The movement of 1 inch is still 1 inch no matter the distance. However; the rate at which you can and will move that wheel, bucket, claw, etc... is changed due to leverage from the distance. Is it major for a race car? Not seriously significant but can be at a different location.

[Mr.Kennedy777]

Taking the wheel out of the picture yes, but then you’re just getting BALL JOINT RATE. You can’t take camber change out of the picture because if you have zero camber change during bump, you’ll have camber change in roll, if you have zero camber change from roll, you have camber change during bump. If you split the difference for bump, roll and pitch then you’re getting less overall camber change for that total motion but for each individual motion you must be gaining and losing camber which changes the wheel rate in bump, roll and pitch differently. Moving the tire away from the spindle changes wheel rate because it changes the angle of the line of action the tire has that is connected to the intersection of the lines of action of upper and lower control arms and tie rod as well as the forces of the into the spindle. Therefore wheel rate is changed. The force at the wheel does change, and the spring motion may not be affected greatly in relationship to the ball joint of the lower control arm because that length always stays the same, but when you put a spindle and upper into the picture and a tie rod, the amount the wheel center moves compared to the lower and upper ball joint changes way more, and that’s why I am saying what you’re measuring at the end of the lower control arm is ball joint rate, not wheel rate. As you have mentioned before moving the wheel further away from the car changes the weight on it because it’s further away from the center of mass concentration. This changes lateral weight transfer amount not motion ratio. To get the same weight on the wheel as before you need a stiffer spring to even out the lateral load distribution. That’s not what I am talking about right now though. What I am saying is that the wheel movement at the wheel center, to the lower ball joint is changed greatest when a spacer is put on because both the lower and the upper both travel in a radius. The motion ratio of ball joint movement to the spring movement isn’t changed no. But the movement of the wheel center, the axis of the rotation of the tire, does change, And that’s why wheel rate cannot be accurately measured at the ball joint.

[Mr.Kennedy777]

And when I’m talking about axis of rotation, I’m taking about the axis the wheel rotates about the hub when rolling, not the rotation of the tire on its camber curve from a front view.

[swingarm4life]

We use to do this all the time back in the day on the Rayburns for obvious reasons. Never had any problems with bearings. We would put the 1" on the LR when the track started blowing, then later in the night we would move it to the RF and put a 2" on LR.

[Kromulous]

I'm not sure about now, maybe somebody can say but back in the day LOL (2003 ish) we used to work with rim offsets all the time running mods. It was a nice easy way to tune a car. I am not real sure why its not used more in SLMs.

Just like swingarm said, RF & LR would be a good adjustment for the feature.

[collateralDamage]

Matt49 i agree with you, but would some of the force get reduce by the leverage of the wheel location to the ball joint if if it was excessive? It would be small but you are introducing a moment there, correct?

I think you talked about that before, some of the load getting transferred thru the upper ball joint, but just making sure.

No, I'm pretty sure Matt49 stated that the force is "completely absorbed" by the upper ball joint/upper control arm.

[Matt49]

No, I'm pretty sure Matt49 stated that the force is "completely absorbed" by the upper ball joint/upper control arm.

That's right. The wheel is pushing up on the spindle snout and the force that goes into the spring is not on a solid beam. It has a point of articulation (the lower ball joint) so some of the upward force on the spindle snout goes into stress on the upper control arm and ball joint. Just take the upper control arm off and see how that works. There is NO mechanical advantage gained by lifting up on the spindle further from the ball joint. Again...other than the VERY small amount of motion ratio gained by the affect that camber gain may have on the distance the end of the snout can travel without moving the spring the same amount. But on a setup without camber gain, if the end of the snout moves up one inch, the ball joint moves up one inch. Therefore the spring moved the exact same amount. Motion ratio the same means rate is the same. It doesn't get any simpler than that.
Now I realize that we ALL have camber gain in our suspension geometry. But the point that I've been trying to make is that the distance between the wheel and the ball joint has no affect on motion ration OTHER than the camber gain factor of it. There is no leverage being gained by the distance but it isn't a solid "lever" like a beam axle. All of the upward motion is at the lower ball joint. So moving the wheel out two inches is not going to have any noticeable impact on wheel rate. Wheel load? Yes. Wheel rate? No.

[fastford]

if the ball joint moves up 1 inch and the spring is mounted in board of the ball joint , how can the spring travel the exact same distance?

[Matt49]

if the ball joint moves up 1 inch and the spring is mounted in board of the ball joint , how can the spring travel the exact same distance?

That's not what I'm saying. I'm saying if the ball joint moves up one inch and the wheel moves up one inch, the spring will travel some distance (call it X) depending on it's location on the LCA and that will dictate wheel rate. Moving the location of the wheel away from the ball joint doesn't change the distance that the ball joint travels relative to the travel of the wheel therefore it does not change wheel rate.
If there were no camber gain, the wheel could be 10 feet from the ball joint and it would take the same amount of force to move it up one inch because you still have to move the ball joint up one inch to compress the spring X amount. You don't have any leverage on the spring by moving the wheel out which is why moving it out doesn't change wheel rate. It is NOT a beam axle and people seem to be stuck in the mindset of treating it like one.
Camber gain would generate a certain amount of motion ratio change but only a very minute amount at the distances we're talking about moving the wheel.

[fastford]

i guess im still confused , if the wheel travels 1 inch up , then you move it out 5 inches and it moves up 1 inch , the ball joint is not gone travel up as much as it did to begin with before you moved the wheel out , this is what i would consider a change of rate at that wheel....