But, what about Caster?

[mymomswagon]

Moved this generic "Caster" discussion to the Caster thread.

Is it a given that adjusting a camber plate to full caster reduces the static camber at full camber adjustment? I can max out the range of both on my plates but currently don't have a good tool to compare the differences.

No, it's not a given. The situation where you get "Camber OR Caster" is with a double wishbone suspension. Or, I suppose if you could adjust caster/camber with your lower control arm on a McStrut suspension.

If you're adjusting the lower control arm (as you would on a Miata, or any other car with a fully adjustable double-wishbone suspension), the Caster adjustment is done at the rear of the lower control arm. You move it in or out, and due to the shape of the control arm (the rear adjuster is typically considerably further back than the front adjuster, which is nearly straight inboard of the balljoint), it pulls the ball joint forward or back. But, because it's moving in and out, it's ALSO moving the ball joint in and out, thus affecting camber. If you adjust it all the way in (max caster), you're reducing the amount of static camber you can get by a little bit.

The forward adjuster on the lower control arm is primarily the camber adjustment. But, with this method of adjustment, caster and camber adjustment is very much "married". If you adjust BOTH adjusters by exactly the same amount, then caster stays the same and you just change camber. If you adjust either one alone, you're adjusting caster and camber at the same time by some amount. Takes a minute to figure it out. Helps to be under a car with wrenches in hand.

If you're just adjusting a caster/camber plate at the top of a strut... if you move it in or out, you're adjusting camber (and kingpin inclination!). If you move it forward/back, you're adjusting caster (and scrub radius!). The caster and camber don't cross-talk as they would if you were adjusting a control arm.

I'm certain that what I just said absolutely didn't clear anything up.

Where caster and camber will ALWAYS be related is in the fact that more caster with always equal more camber when you're turning.

thank you. my confusion could be due to vague comments made by plate vendors :}

great discussion, thanks for relocating comments to this thread.

[twistedwankel]

While I don't think everyone can, should, or even wants to learn about all of this stuff... I think it's part of the fun of motorsports. Trusting a mechanic is no fun. Not to mention the fact that finding a mechanic who ACTUALLY understands all of this stuff and is willing to apply it is both difficult and expensive!

To be fair. The old car I had professionally welded up stiff and light was a heavily modified "trailer queen" with an alignment ONLY suitable for autocrossing which it was built solely for. The speedo didn't even work as the worm gear in the trannie was shot. I put dots on the tach so I'd know how fast I was going in 4th gear so I could occasionally drive it on the street and put in an hour meter so I'd know when to change the oil on the new engine. The beauty of a solid rear end is you don't have to align it ever:) I really miss those old race mechanics who had lifts in their garages and knew all the tricks and were very affordable as I bought all the parts, pizza and beer. I had one ace younger guy up here for my RX8 but a car fell on his head or something bad and now he drives semi's for a living. Crap.

I have loads of respect for anyone who can do these things themselves. I limited my welding to tractors, yard art and mowers where it didn't matter what it looked like and they were very slow. Suspensions to me are a "black art". Joe's description of a raked MC steering is perfect having ridden a couple of those dangerous things. I also find your blogs very interesting but I won't try it at home. Even my personal physician (Dr Referral) wrenches on his own growing fleet of hotrod Chevys.

Keep up the good work. You will know when you have done something wrong when I can beat you again.

[Loren]

The beauty of a solid rear end is you don't have to align it ever:)

Still thinking inside the box, eh? Off topic for this thread, but you certainly CAN "camber" a solid rear axle. Very old-school trick. And if you don't put your solid axle in straight, you end up crabbing down the road. Alignment is still a factor!

I have loads of respect for anyone who can do these things themselves. I limited my welding to tractors, yard art and mowers where it didn't matter what it looked like and they were very slow.

I got a lot happier with modding cars as soon as I accepted that everything doesn't have to be "perfect" or "pretty".

Suspensions to me are a "black art". Joe's description of a raked MC steering is perfect having ridden a couple of those dangerous things. I also find your blogs very interesting but I won't try it at home. Even my personal physician (Dr Referral) wrenches on his own growing fleet of hotrod Chevys.

Keep up the good work. You will know when you have done something wrong when I can beat you again.

For all that I've learned about suspension over the years, I still feel like I will never be a true "master of the black art of suspension". There's just too much to know!

[CaptainSquirts]

Since the cars getting old I'm getting bushings here and there to replace later. Got a set of offset bushings for the front control arm. From my old alignment spec sheet from a long time ago the caster was at 3.5/3.6 degrees. Seeing people get up to 4.5 with the offset bushings.