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Fc front camber

Old 12-29-15, 08:21 AM
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Fc front camber

I'm interested in moving my front ball joint to the top of the LCA to change the angle of the LCA and make the camber curve better. Anyone tried this? Will it even improve the camber curve?
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Old 12-29-15, 10:19 AM
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it won't do anything at all to the camber curve.

what dictates the camber curve is the virtual line between the inner control arm mount pivot and the center of the balljoint. both these things won't move when you swap your balljoint to the top of the LCA.

the only things you can do is get a roll center correcting ball joint (which moves where the center of the pivot is), or add more camber with camber plates which changes the SAI and affects when the control arm goes past 90* with the strut (the actual angle that matters, because that's when your camber gain goes positive)
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Old 12-29-15, 11:43 AM
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Don't mean to be argumentative, but if the virtual line is below horizontal, the ball joint will move out in relation to the inner pivot and if above horizontal it will move in. I was wondering how much camber change would happen.
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Old 12-29-15, 11:54 AM
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The virtual line won't move. The ball joint stays in the same place, the physical control arm just moves from above it to below it.

where the ball joint sits is completely dependent on the strut/spring length above it, nothing can change where it sits except for adjusting strut/spring length or adding a spacer to the ball joint shank to make the ball joint sit lower. swapping what side of the control arm it's on is adjusting the wrong side of the joint.

Last edited by eage8; 12-29-15 at 12:08 PM.
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Old 12-29-15, 04:22 PM
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Not talking about the virtual line...I understand that. In actuality, lowering the control arm (pointing it toward the ground, if you will) will cause the ball joint to move away from the LCA pivot during compression thereby increasing camber. It must. My question is how much?
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Old 12-29-15, 05:47 PM
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Originally Posted by Chuck Baader View Post
Not talking about the virtual line...I understand that. In actuality, lowering the control arm (pointing it toward the ground, if you will) will cause the ball joint to move away from the LCA pivot during compression thereby increasing camber. It must. My question is how much?
Sorry, I understand now... I would say "not much". and the amount would change depending on the angle of your control arm, and the closer to parallel the arms are, the less it matters. You're talking about a mm or so of arm length change, if you changed the top pivot by 1mm you'd get a tenth or two?

That being said... I still have mine mounted on the side which gives me the most camber. (this changes side depending on what direction your control arm points.)
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Old 12-30-15, 09:16 AM
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I am pulling my arms to replace bushings with spherical bearings next week. I'll get accurate measurements and lay out exactly how much the ball joint moves through 4"ish of travel.

" (this changes depending on what direction your control arm points)" Elaborate please. I would think on top would be preferable no mater what.
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Old 12-30-15, 09:59 AM
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Originally Posted by Chuck Baader View Post
I am pulling my arms to replace bushings with spherical bearings next week. I'll get accurate measurements and lay out exactly how much the ball joint moves through 4"ish of travel.

" (this changes depending on what direction your control arm points)" Elaborate please. I would think on top would be preferable no mater what.
If your control arm is pointing up I'm pretty sure the ball joint on the bottom would actually give you slightly more static camber.

if your control arms are pointed down it's the opposite, the ball joint being on the bottom will give you more static camber because the control arm is slightly longer in the direction parallel to the ground.

if the VIRTUAL arm is exactly parallel to the ground, it doesn't matter, they'll both be the same.

all your changing is where the ball joint bolts to. and when the arm is angled, so are the bolt holes the bolts are going through. one side will be slightly closer to the hub side than the other.

Sorry if this doesn't make sense, I'm having a hard time writing it but this won't change the camber curve at all. just the static camber setting. the actual control arm isn't changing length. I'm still not convinced it'll make any difference.

But please post back what you find. I think any data you get though might get lost in the noise of the play of the bolt holes.
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Old 12-30-15, 10:35 AM
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Here is a cool tool you can use to play around with stuff:

Vehicle Suspension: Front View Online Suspension Simulator

I roughly measured my car up and here is what I came up with:
My Car
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Old 01-01-16, 11:10 AM
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Originally Posted by eage8 View Post
If your control arm is pointing up I'm pretty sure the ball joint on the bottom would actually give you slightly more static camber.

if your control arms are pointed down it's the opposite, the ball joint being on the bottom will give you more static camber because the control arm is slightly longer in the direction parallel to the ground.

if the VIRTUAL arm is exactly parallel to the ground, it doesn't matter, they'll both be the same.

all your changing is where the ball joint bolts to. and when the arm is angled, so are the bolt holes the bolts are going through. one side will be slightly closer to the hub side than the other.

Sorry if this doesn't make sense, I'm having a hard time writing it but this won't change the camber curve at all. just the static camber setting. the actual control arm isn't changing length. I'm still not convinced it'll make any difference.

But please post back what you find. I think any data you get though might get lost in the noise of the play of the bolt holes.
On point as usual. Any gain from going ball joint on top or bottom will be minimal. I almost think the slightly wider track width might net you more than the slightly different camber curve. There probably is slight value in taking measurements and seeing which mounting method might give you a more desireable curve given your suspension travel and ride height. If you are there with the arms off, why not?

Speaking of that I need to rebuild my front arms or switch to my needle bearing units.

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Old 01-02-16, 10:43 AM
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Have just designed and sourced spherical bearing pivots for my front LCAs. Waiting for parts.
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Old 01-04-16, 11:27 AM
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Originally Posted by Chuck Baader View Post
Have just designed and sourced spherical bearing pivots for my front LCAs. Waiting for parts.

I'd be interested to hear what you come up with.

I have a set of AWR arms in the garage.
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Old 01-04-16, 11:30 AM
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likewise... though it probably won't be useful to me. Silly class rules mean I need to keep a stock sized non-metallic rear bushing (because it doesn't move, so it's no considered "suspension"), so when I finally get around to making control arms they're going to be a bit odd...
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Old 01-04-16, 01:07 PM
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Have not seen the AWR arms but have heard about them. I'm using one spherical bearing in the front, and one in the rear. Thought about using two in the front, but I don't think the chassis is stiff enough to keep the bearings from binding (trying to move in two planes). Have also been told that needle bearings are used but I discounted that for the same reason as two sphericals, plus diminished impact resistance.

Originally Posted by eage8 View Post
likewise... though it probably won't be useful to me.

Silly class rules mean I need to keep a stock sized non-metallic rear bushing (because it doesn't move, so it's no considered "suspension"), so when I finally get around to making control arms they're going to be a bit odd...
Can't understand that...the front pivot moves the same amount as the rear therefore, suspension!! Must be NASA
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Old 01-04-16, 01:10 PM
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Originally Posted by Chuck Baader View Post
Can't understand that...the front pivot moves the same amount as the rear therefore, suspension!! Must be NASA
SCCA solo

the front bushing actually spins as the control arms moves up and down, but the rear bushing is stationary and the arm pivots inside of it.
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Old 01-04-16, 01:16 PM
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OEM, the front bushings is stationary to the control arm. The rear is to the chassis. Control arm moves in both...think that might be very gray.
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Old 01-04-16, 09:37 PM
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Originally Posted by eage8 View Post
likewise... though it probably won't be useful to me. Silly class rules mean I need to keep a stock sized non-metallic rear bushing (because it doesn't move, so it's no considered "suspension"), so when I finally get around to making control arms they're going to be a bit odd...
So you can run delrin for the rear bushing then right?

You could do a needle bearing that bolts to arm with the outer race held on by the bolt. Then have that assembly slide into your delrin bushing.

Although I've been able to keep my delrin front bushings relatively bind free.

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Old 01-04-16, 10:07 PM
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Originally Posted by LargeOrangeFont View Post
So you can run delrin for the rear bushing then right?
Yes, which is what I'm currently running, delrin/UHMW Plastic with the barbs ground off the control arm. delrin = non-metallic

Originally Posted by LargeOrangeFont View Post
You could do a needle bearing that bolts to arm with the outer race held on by the bolt. Then have that assembly slide into your delrin bushing.
yeah... but I'd be a bit afraid of the bending forces going through that bolt. I've heard that's an issue with the AWR arms... they ground the aluminum arm down and it's it actually breaks at the stress riser. (sorry if that makes you paranoid about your control arms, but last time sometime told me about AWR stuff breaking I didn't believe them and then my ball joints broke in half...)

Originally Posted by LargeOrangeFont View Post
Although I've been able to keep my delrin front bushings relatively bind free.
yeah, mine are the same way relatively bind free. but who knows what they're like when they have full load on them... I'd rather have some bearings.


Sorry to completely derail the thread, but I was actually planning on putting a very large bolt through the stock bushing with a bracket on the front and a large washer/spacer on the back and then attach a large rod end to the bracket... this is a grey area in the rule, because I'm making something that used to be moving not moving, but it should be fine.
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Old 01-04-16, 11:57 PM
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https://www.rx7club.com/2nd-generati...ctors-1092427/
Some people were asking if I could make some longer so they could have longer control arms and more camber, but I kept it stock length to not effect my fender to wheel clearance. But after looking at my clearance, I could have probably added half of inch length. Doh!
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Old 01-05-16, 09:36 AM
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Originally Posted by eage8 View Post
Yes, which is what I'm currently running, delrin/UHMW Plastic with the barbs ground off the control arm. delrin = non-metallic



yeah... but I'd be a bit afraid of the bending forces going through that bolt. I've heard that's an issue with the AWR arms... they ground the aluminum arm down and it's it actually breaks at the stress riser. (sorry if that makes you paranoid about your control arms, but last time sometime told me about AWR stuff breaking I didn't believe them and then my ball joints broke in half...)



yeah, mine are the same way relatively bind free. but who knows what they're like when they have full load on them... I'd rather have some bearings.


Sorry to completely derail the thread, but I was actually planning on putting a very large bolt through the stock bushing with a bracket on the front and a large washer/spacer on the back and then attach a large rod end to the bracket... this is a grey area in the rule, because I'm making something that used to be moving not moving, but it should be fine.
Yea I am with you on the AWR arms, that is why I have not installed them. I think I am going to stay with delrin and put zerk fittings on the arms.
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Old 01-05-16, 05:10 PM
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http://http://i1368.photobucket.com/...psvcjmwtw0.jpg

Photo-uckit has been screwing me for the past hour while I tried to post the picture of the LCA bearings (front). Spacer keeps bearings apart but also adds tension to flanges on bushings.

I'll have design on rear mount shortly.
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Old 01-05-16, 06:51 PM
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Originally Posted by Chuck Baader View Post
http://http://i1368.photobucket.com/...psvcjmwtw0.jpg

Photo-uckit has been screwing me for the past hour while I tried to post the picture of the LCA bearings (front). Spacer keeps bearings apart but also adds tension to flanges on bushings.

I'll have design on rear mount shortly.
image link fixed for you

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Old 01-05-16, 10:35 PM
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Which bushing is this replacing? I think I see, both bushings right?
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Old 01-06-16, 08:26 AM
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Center bushing only...both sides. I only ordered two bearings to start with, so I have a couple more coming. Top unit is with bearings, spacer, and bolt. Bottom is just the bearing holders and spacers.
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Old 01-06-16, 10:17 AM
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Originally Posted by Chuck Baader View Post
Center bushing only...both sides. I only ordered two bearings to start with, so I have a couple more coming. Top unit is with bearings, spacer, and bolt. Bottom is just the bearing holders and spacers.
Oh, I was talking with my coworker about the FC lca design. The nice thing is that in theory it should just swing up and down. So going through the trouble of making spherical or roller bearings didn't seem as urgent as correcting roll center.

The only issue was the delrin being able to move freely. LargeOrangeFont suggesting grinding down the barbs on the rear mounting. I did that. For the other bushing, I used a longer bolt so I could double nut it. First but I just tightened snug so there is no freeplay, but allowed the arm to move without a ton of force, then I used the 2nd nut to make sure it doesn't back out. I'll have to check it here and there.

Keep us posted on your bearing project, looks cool!

I was thinking of the same thing before, but one issue I thought of was that the bore in the factory arm only allowed for a small bearing. I was wondering on how long it would last.
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