Rf wheel spacer

[Matt49]

Static load is not wheel rate. The reason the wheel is lighter at static load is because you've moved it further from the center of gravity of the car.
You can't think of the spindle as a lever which is what confuses people on this. If it were a beam axle, the distance between the wheel and the spring mean everything. But all that matters on a double wishbone is the distance between the lower ball joint and the spring (assuming the spring is on the lower ball joint). All of the "leverage" that the spindle gives you, no matter how long the spindle is or where the wheel is mounted on it, is completely absorbed by the upper ball joint and and upper control arm. The spring only feels the wheel's ability to move the the lower ball joint UP. The wheel's ability to do so will never benefit by being placed further away.

[collateralDamage]

I understand the argument being made, and it's a really fun fact. Maybe there needs to be more clarity on the definition of "wheel rate" and "wheel load".

Unless the laws of physics have changed, there is no way that the upper control arm and the ball joint "absorbed the leverage". That force went somewhere.

We are all concerned with, and hopefully aware of, the load at the contact patch of the tire and how it contacts the track. There's just no way to ignore camber, distance from CG, etc. when it comes to how a wheel spacer affects load on the tire.

[Matt49]

I understand the argument being made, and it's a really fun fact. Maybe there needs to be more clarity on the definition of "wheel rate" and "wheel load".

Unless the laws of physics have changed, there is no way that the upper control arm and the ball joint "absorbed the leverage". That force went somewhere.

We are all concerned with, and hopefully aware of, the load at the contact patch of the tire and how it contacts the track. There's just no way to ignore camber, distance from CG, etc. when it comes to how a wheel spacer affects load on the tire.

Well, brush up on your physics because this is perfectly applied.
The force did go somewhere. It went into the upper control arm which is NOT a spring (at least not an easily measurable one) which is why it doesn't change the wheel rate.
When you push up on the spindle snout, all of that force is NOT going into the spring. Think about it. The only upward force the spring can possibly feel is what is being applied at the lower ball joint. The mechanical advantage being gained by distance between the wheel and the lower ball joint is being applied as force into the upper ball joint and control arm in a vector facing roughly perpendicular to the control arm which is NOT felt by the spring. Just take the upper control arm off and conduct this experiment and tell me what point matters as the spindles moves and the lower control arm doesn't move at all. How can the distance from the wheel to the lower ball joint come into play if you can't even move the lower ball joint WITHOUT the spindle being connected to the upper control arm.
These are the laws of physics and it's pretty tough to argue against them. I guess I'm going to have to mock this up and do a video to prove it.
It's easy to apply beam axle physics to double wishbone suspensions but it is WAY off. Easy, is why so many people do it.

[Matt49]

Wheel load - amount of weight on the tire contact patch
Wheel rate - weight required to move the tire contact patch one inch under compression suspension

[collateralDamage]

Everything you are referring to is concerning wheel rate. When you add a 1" spacer and do nothing else YOU WILL REDUCE WHEEL LOAD. The leverage of the spindle on the upper and the frame doesn't just vanish. Although maybe insignificant it goes into the frame and other wheel loads.

[hunterracing]

Has anyone tried it and felt diffence with or without it

[Matt49]

Everything you are referring to is concerning wheel rate. When you add a 1" spacer and do nothing else YOU WILL REDUCE WHEEL LOAD. The leverage of the spindle on the upper and the frame doesn't just vanish. Although maybe insignificant it goes into the frame and other wheel loads.

Yes, I explained why wheel load decreases when you move the RF wheel out. And why wheel rate does not change. Wheel load and wheel rate are two completely different things.

[collateralDamage]

If you reduce the WHEEL LOAD on the RF by putting on a wheel spacer, you will adjust the WHEEL RATE to maintain the WHEEL LOAD. Whether the WHEEL RATE changes IN THIS CASE or not doesn't matter. It's the change in WHEEL LOAD that matters.

That being said, the interesting fact that Matt49 is talking about, is good to keep in mind when determining HOW to change the WHEEL RATE.

If you do nothing more than bolt a RF wheel spacer on, the reduced wheel load should make the car feel tighter. If you make adjustments to maintain the wheel load you will change the way the front end "feels" to the driver and not necessarily change anything measurable on the stopwatch. Its not something I consider an at-the-track adjustment. You either set the car up to use a wheel spacer and you weld it on, or you leave it off -JMO

[matchbox]

What if my chassis has a option to move whole right front assembly out 1 inch. What will it do?

[Mr.Kennedy777]

And before you argue with me on this, pick up the phone and argue with the people at Koni and Hyperco, or the authors of any number of automotive engineering books the explain this clearer than I can.http://www.truechoicekoniracingservi.../worksheet.pdf

I don’t need to lol! Wheel rate that they talk about in that work sheet is actually ball joint rate, they use it to avoid having to complicate that work sheet to help guys get close enough. Anytime you have anything travelling a radius, extending it out further on that radius, while creating the same degrees of movement, you will experience more motion. If the point of rotation is 1” away from the ball joint, 1 degree change isn’t very big. If you’re 36 feet away, one degree is quite a bit. Even on a beam axle wheel spacing changes wheel rate.

[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.