I am looking at getting some Long acre toe plates. I know you can supposedly do it with some wood and string, but I'd rather not. One question I had is whether I can use these toe plates to also measure camber. My thought is the plates are flat enough that I could use my pocket pit app to find camber.
The other question I have is when it comes to caster, Do I just want the maximum amount or what? Is there some sort of formula that says "hey don't use all of it"?
Ideal caster will depend somewhat on the car and your driving style. You may have to experiment a bit to see what feels best or is fastest.
In reply to rslifkin :
Nc Miata, on my NA everyone said "run as much as you can get once toe and camber are set". I'm sure it's the same on the nc.
and if I remember right, more positive caster gives you more dynamic camber?
I bought these years ago: https://www.summitracing.com/parts/tnh-3300
But back then it was $150 for the plates and camber gauge. I've saved myself money on at least a dozen alignments with those, and at $50 a pop they've more than paid for themselves
In reply to bobzilla :
Thanks Bob! That's kind of what I am going for right now. The local place that does a good job on alignments wants $100 per side of the vehicle. At that much money I may as well buy the stuff myself and then I can change my alignment and experiment anytime I want
In reply to Vajingo :
the downside is if you need to do a 4 wheel you need to learn strings and things. At the time, literally every vehicle I owned was a solid rear beam axle so 2 wheel alignments where all I needed. THe Tib complicates that a little.
Caster is not very easy to DIY. It's hard to measure and hard or at least tedious to adjust because every time you touch it you basically have to redo your camber and toe as well. More positive caster will give you more negative camber on your outside wheel the farther you turn the steering. How much of that you need depends on how much the car rolls in general. Because it also changes camber it basically tries to tilt the tire to one side (thats what camber is) which ends up trying to lift the car the same way standing on tip toe lifts your body weight. That gives the steering a tendency to 'return to center' because the weight of the car will try to push the tires back to level and the most level point will be with the steering in the middle. It's really only useful to amplify this if you plan to swing the steering across large angles real quickly, like how drifters let go of the steering wheel as the car transitions from one drift to another and then grab it again after its done most of the turning itself. Without enough caster that self-turning wouldn't happen and it would be impossible to move your hands fast enough to recover that oversteer. The same effect, depending on how much it's muddied by your power steering system, also gives you the buildup in steering effort the farther you turn from center (since you are using the steering system to lift weight), and some people care about that even though it's not an objective performance measure.
Downside of excessive positive caster is it degrades ride quality and can lead to a wheel shimmy or side to side vibration in the front wheels. Luckily, there are almost no vehicles capable of having 'way too much caster' except old cars that you can stick shims under the upper control arm mounts. Pretty much any other type of car, the factory adjustment won't get you anywhere near 'way too much' and even adding adjustable ball joints or caster plates usually wont either. So just max it out as much as you can while being fairly even side to side (uneven will cause a steering pull) and see how it feels to you. In actual performance terms the tipping point of 'too much caster' would probably be dictated mostly by tire temp or wear across the face of the tread under racing conditions as that will reflect whether the dynamic negative camber is appropriate or not.
Caster also has a weight jacking effect that pulls weight off the inside rear tire, which impacts how the car responds in transitions and can be an issue in tight turns with an open diff.
does camber push the front inside tire down or front outside tire? Inside, right?
Robbie (Forum Supporter) said:does camber push the front inside tire down or front outside tire? Inside, right?
Caster pushes down on the inside front, which is why it tilts the car to the outside and pulls weight off the inside rear.
In reply to rslifkin :
doh I meant caster. thanks!
I'm looking through the archives to see what I can find, but in the meantime, here's an article that has some good information about alignment: Simple Chassis Alignment.
If you want repeatable results you'll want slip plates of some kind, and either stands or a drive on lift to actually make adjustments in most cases. The thing I don't like about toe plates is that it only tells you the total toe, not per side, ie it doesn't help to get the steering wheel centered. Strings don't have that problem. If I was diy-ing my alignments, I'd get a camber gauge and build some kind of string setup.
In reply to dps214 :
Made stands out of scrap wood and slip plates from two pieces of laminate with the slick surfaces facing each other. Works quite well.
After years of string alignments (you get good at them after screwing with Formula Fords and no budget for fancy tools), built some trammel bars that bolt/clamp to the front and rear of the cars to make it less painful to use strings.
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