If you think the string setup when done properly is back yard shade tree mechanics, you need to do a little more homework on the topic.If you have an alignment issue take it to a qualified professional... Its absurd to consider making adjustments using backyard mechanic tricks.
I do. Method:
I set the front camber first, if I'm changing it - usually either just check it or change it between street and track/autox. During autox season I'll just leave it maxed out negative camber<1>. I use a Longacre camber gauge although you can now get pretty decent camber readings using a straight edge on the rim lip and a level app on the phone.
Next I'll check the rear toe using the same toe plates. I'll also check the thrust angle using a laser pointer on the straight edge on the rim lip, shooting to the front where I put a steel ruler against the center of the hub of the front wheel. If the reading is different from one side to the other, the thrust angle is off. Adjust the toe until they match and the toe in is where you want it. Finally, check the camber in the rear using the same method as the front. It gets VERY tricky because changing the camber will change the toe and vice-versa. It's complicated by the fact that the upper link is where you set the camber and it's difficult to get to the bolt, and the hole is just slotted instead of using an eccentric/cam like the toe link has. Having an extended 18mm ratcheting end wrench with a flex head is really the only way to get to that bolt.
Because the rear camber link is such a pain to set if it's out I'll usually mess around with it for several hours, then decide to take it to a local shop and let them set it. Not an option if I'm doing it at the event.
The front end is really the only thing I tweak and it's pretty painless. I'll check the rear just to make sure nothing has moved.
<1> No, running max negative camber on the street/road will not destroy your tires. Running even a little bit of toe-out will. However, if you hit a rut/pothole/rough track crossing hard the risk of bending a wheel is higher than if you're at normal camber and yes, that happened to me.
Longacre camber gauge
18mm long wrench that makes the rear camber adjustment possible
Thanks, and I agree. A friend and I figured out the laser pointer method many years ago. I have a 24" level that has one built into it that works great for this. It's much easier with two people, one to position and hold the laser/level and the other to take the readings on the scale on the front. You can also use the same process in reverse to center the steering wheel for the front wheels.DUDE!! I never even considered how simple thrust could be! I've just been extremely careful to adjust both sides equally and was getting close to taking it in just to have my work checked in the near future as I didn't trust the thrust part at all.... this is awesome! This is my first IRS car so previously never had to deal with rear settings haha.
As far as needing a pro to do it... I'm sure there are a LOT of people that have no desire to learn and buy tools to do this stuff, but I started doing my own when I started autocrossing back 10+ years ago... it's not rocket science once you understand the concepts and 100% certain you will end up with a faster car with better tire wear if you take the time to do learn this. Proper alignment can do wonders for a car and it's usually not the specs that the fancy lazer machines will tell the tech to set it to. Most people don't care about that last little edge of performance either though, which is why fancy lazer machines exist....
Caster can be determined by making camber measurements with the wheels steered some fixed amount to the left and again with the wheels steered the same amount to the right. Most of the commercially available DIY caster-camber gauges will have you use 20° steering (at the wheels), but that's not the only angle if you understand the math behind it.How about castor
Better if you start by hunting down your thinking cap before you even touch a wrench.rear wheel/four wheel alignment? All this with a string? Or are we going to bring in a 2x4 and protractor lol.
I've used string for years. A string setup gives you toe and thrust angle, and a bob-weight gives you camber. The car has to be level when you start, but you get exactly what you want if you know what you're doing.... Oil changes are a little less complicated, and Im not sure where you adjust an oil change.
Have you seen what alignment equipment looks like these days? I find it hard to believe anybody could think they could come close with a string compared to the technology a properly equipped shop has (assuming they know what they're doing, if not find a shop that does).
How about castor and camber? rear wheel/four wheel alignment? All this with a string? Or are we going to bring in a 2x4 and protractor lol.
Also - I think you have unfortunately little distorted view of "professionals" how you called them - vast majority of shop will just get the readings within spec, not really trying that hard to get camber/toe on both sides (relatively) equal. If you have any aftermarket part (camber plates, toe links, camber arm), most will decline doing anything (since they pull up manual and look up what manufacturer specifies as adjustments), also how calibrated their rack is...I stand corrected.
However... looking at that video and reading gears post confirms that theres a little more to it than simply stretching a string down the side of the car. I guess if you are regularly planning on changing your settings it would be worth buying all the equipment and learning the process. Certainly doesn't apply to me