Rf wheel spacer

[hunterracing]

What would be affects of a 1 inch or 2 inch rf wheel spacer with convential shock and spring setup on rf

[Matt49]

What would be affects of a 1 inch or 2 inch rf wheel spacer with convential shock and spring setup on rf

All else being equal it would tighten the car all the way around. But all else won't be equal. You will likely see a decrease in static wedge. Front end geometry changes if that matters to you. This change also increases scrub radius which will change the weight jacking affect the RF provides with steering input.

[Kromulous]

More or less Matt49? i would think more but asking.

[hunterracing]

So more then likely throw how the car turns into the corner and not plant the rf? Would it affect how much the car rolls on rf since wheel and spring are farther apart?

[Mr.Kennedy777]

Increasing scrub radius reduces the jacking forces from the spindle.Decreasing scrub radius increases. Another way to look at it is this. If the top of the spindle is laid back towards the engine bay more, you will create more jacking forces along the radius the tire follows when you turn the wheel. The more upright it is, the less jacking force is created. If the spindle inclination is the same, and you move the wheel out further, you increase the scrub radius and what that means is you increase the path at which that jacking force is applied. The spindle will create the same force but it’s spread out over a bigger radius now, which results in a net decrease of that jacking effect at the wheel.

[Matt49]

Wheel and spring being further apart don't matter other than the motion ratio created by camber gain. This is, however, a common misconception. The static motion ratio is the distance from inner lower control arm to shock mount on the control arm, divided by the total length of the control arm. People think that moving the wheel way out lowers the wheel rate but it does not. You still have the upper control arm pushing back against the spindle that you are trying to move up. But it CAN lower the wheel rate due to the fact that camber gain becomes a negative weight jack due to the larger scrub radius.

[hunterracing]

So maybe putting a wheel spacer might be a bad idea then?

[Mr.Kennedy777]

Wheel and spring being further apart don't matter other than the motion ratio created by camber gain. This is, however, a common misconception. The static motion ratio is the distance from inner lower control arm to shock mount on the control arm, divided by the total length of the control arm. People think that moving the wheel way out lowers the wheel rate but it does not. You still have the upper control arm pushing back against the spindle that you are trying to move up. But it CAN lower the wheel rate due to the fact that camber gain becomes a negative weight jack due to the larger scrub radius.

Not entirely true. Moving the wheel out doesn’t change the arm length but it changes the wheel length which changes wheel rate. Wheel Rate = Spring Rate * (Motion Ratio ^ 2) * Spring Angle Correction( the cosine of angle) Motion ratio = arm length/wheel length If the arm is 18” and the wheel is 20” then you have a 0.9 motion ratio of the arm to the wheel. Motion ratio of the coil over you would find by taking the shocks lower mounting point, and determining shock length. You would then take the shock length and divide that by the wheel length. In this case let’s say the shock was 14” from the inner pivot. This would mean that the shock has a 0.7” motion ratio to the wheel. You could also figure out the movement of the shock in relation to the ball joint, and this case it would be 0.77 repeated. But if your coil over is angled you need to apply the spring angle correction to get an accurate number. If your coil spring is inside the control arm, you could use the center of the spring seat as a rough guide although the inside and outside of a 5” spring do have quite different ratios especially if the inside of the spring is quite close to the attachment points. But as far as I have ever learned, THAT is how you calculate wheel rate.

[Mr.Kennedy777]

And as you have mentioned as well, camber curve also changes the movement of the wheel, and must also be factored in. But the change in the wheel spacing, doesn’t JUST effect the camber, it does provide a different motion ratio for the lower arm as well as wheel center line.

[Mr.Kennedy777]

And saying that, your motion ratio of the tire to the arm, is actually going to be different at different stages of travel depending on your arm configuration and what they’re doing not only under compression but also when the chassis rolls. You can’t determine actual wheel rate without combining the entire system together on one corner of an SLA suspension. And then all this is done assuming the tire is rigid. So that also changes things a bit on a guy.

[hunterracing]

Guess there’s a lot of factors to go into before bolting on and testing it

[Mr.Kennedy777]

I would say a 1” spacer would be alright to try. But sticking a 2” spacer on there is not that great a deal and might make everything move way more than it should.I’ve also heard it can be harder on the wheel bearing by creating too much a lever. If you’re looking for the wide front kinda deal I think changing mounts/links is the best way to do that.

[collateralDamage]

If you bolt a 1" or 2" or whatever spacer on the RF and do nothing else you will need more spring load to accomplish the same wheel load at the same travel, THAT'S ONLY ASSUMING you can generate the same wheel load to accomplish the same travel. In walks camber....

[hunterracing]

I can see more stress on the wheel bearing for sure

[fastford]

except maybe toe gain , i would think every aspect of geometry concerning the right front , would be effected going from static to dynamic conditions by moving the tire out.....Mr. kennedy , do you work for NASA ???? LOL.....

[Kromulous]

I have ran as much as 3" of offset, more than std., some cars like it, black front rockets for one.

Anyway its a tool in the box, track gets super slick in the summer, throw it on there and see if you like it.

What has me interested is the LF, if it reduces the jacking effect of counter steering i could see it being beneficial there, but you might have to add back in some spring rate. My knowledge of using it on the LF is it makes a car steer thru the center better.

Anyway seems like adding it to the LF on along with more spring, would really help on super slick to keep the car smoother on entry, no swings tight to loose entering. Anyone ever try it?

[Kromulous]

https://www.youtube.com/watch?v=SUDMEd1bMZI

This guy talks about the effects while breaking...

[Matt49]

Mr.Kennedy777,
Sorry but you're incorrect on this one. Wheel rate is not affected by the distance between the wheel and the spring on a double wishbone suspension. Again, NOT taking caber changed into account.
If you had a double wishbone suspension with equal length uppers and lowers (let's say 20 inches) and both at the same static angle, this would yield no dynamic camber change. Then let's say you put a 200 pound spring perpendicular to the ground at 10 inches between the frame and the ball joint on the lower control arm. The wheel rate is going to be 100 pounds. I don't care if the wheel is centered with the ball joint or the wheel is 500 feet away. The wheel rate will be 100 pounds. This is because the upward motion you try to place on the wheel is being pushed in two vectors. One is the top of the spindle pushing in on the upper control arm and the other is the lower control arm pushing up on the spring. If the upper control arm were a spring and not stiff, the distance to the wheel would matter, but it isn't so it doesn't. But don't take my word for it, go mock it up in your shop and test it yourself.

[Matt49]

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

[fastford]

I guess im a little confused my self , I always considered wheel rate the weight or weight change at the wheel , if you put the car on the scales and move the wheel out 2 inches and nothing else , that wheel weight will lessen , which i assumed was wheel rate , of course we all know what assume does.........