Tell me about corner balancing....
 

I just finished installing RSR sport-I coilovers in my car. Front is lowered 3/4", rear is lowered 1/2". I now need an alignment and am deciding if I want to get the car corner balanced or not. I think I have hit the limit of my understanding and could use some help.

1. Is corner balancing a street car worth it? With a few track days per year anyway....
2. With the RSR's, you can corner balance and still maintain an even ride height, correct?
3. Could I set ride hieght and get an alignment now and corner weight later if I wanted?

For reference, I have the sport-i's, RacerX rear control arms, whiteline toe arms, front crash bolts, whiteline roll center kit, and every suspention bushing has been replaced with poly.

The thing to understand I think about corner balancing is, the stiffer you go with your suspension, the more important it becomes. As an extreme example, take a Cadillac... (non "V" model) soft, compliant suspension soaking up all the bumps. If you have one shock/spring that is 1" shorter than the other three, you probably won't even notice it. Now take a gokart...stiff chassis, practically zero suspension. If one wheel is 1" higher off the ground than the other three, it's going to teeter on two opposing wheels like a chair with a short leg.

So to answer your questions:
1) Yes, because it can bite you in everyday driving situations like just going onto an on-ramp. If the car "teeters" suddenly on those two diagonally-opposing tires from one side to the other as you enter the turn, funky things can happen and you could lose control. Proper balance will also minimize excessive tire wear by keeping the weight evenly distributed rather than riding on three tires most of the time.

2) If by ride height you mean having the same gap from the tire to the edge of the fender, no, that is not a guarantee. You may luck up and get it dead even once balanced, but the odds are slim. Fortunately though, it's usually in the order of a millimeter or two difference around the car, so it's really hard to notice.

3) Absolutely you can. Many people do just that without meaning to when they learn of corner balancing later after getting coilovers. Be aware though that adjusting the ride height of your car by corner balancing affects your alignment equally. (more CB change = more alignment change) And the alignment can affect the corner balance. It's a vicious cycle man! Ideally you would bounce back and forth between aligning and CB make gradually smaller and smaller adjustments 2 or 3 times to get it just right, but anything is a step in the right direction, even if you only do it once.

I hope that helps. Others may have more/better info, that's just what I've learned so far. I own my own scale set since you can get them used for about the cost of 2-3 corner balance/alignment sessions anyway. ;)

The RSR's adjust height independent of pre-load. I thought that meant I could get it corner balanced and keep a perfectly even ride height....

I have read that one shouldn't use the bottom mounts to adjust ride height as the damper limits bump and droop travel. According to the article one should always adjust height using the spring perch.

Corner balance is to get the cross weights (LF/RR vs RF/LR) even, so when the car corners it has even weight distribution going left or right.

Will it make a difference? Entirely depends on you as a driver. A lot of people can't tell the difference between tread pull vs bad alignment, so a corner balance may not make a difference to them.

Corner balance is set using ride height, not from preload. Your preload should be the same on each axle at the very least, if not identical all around.

-alex

Corner balancing is done by adjusting ride height based on how much pressure each tire is exerting on the ground, which you would typcially do by utilizing those ride height adjusters on the coilovers. (You could also do this by changing the pre-load settings, which may be the better method anyway...see reply below.)

After you finish corner balancing, if you do anything to try and even out the ride height, you will affect that corner balancing job and change how much each tire is "pushing" down onto the ground again. Does that make sense?

The benefit of having coilovers with ride height separate from pre-load is that you can set your preloads evenly across each axle, then corner balance the car without screwing those preload settings up. (or change your ride-height without affecting pre-load if you're more concerned with looks than corner balance)

This could be totally true, and the reason some of the higher end coilovers don't even come with separate ride-height adjusters, like KW. You just set it with the pre-load adjuster rings.

I am going to have to disagree with you there. I have read multiple times that corner weighting is done via pre-load.

Yeah like I said previously, many top level coilovers don't even utilize ride-height adjusters. You do everything with pre-load.

I don't understand this..... If the preload is constant how can moving the bottom mount up and down, lengthening or shortening the body, have an effect on suspension travel? The advantage of this type of set up is that you can lower your car without taking away any travel as you shorten the sturt body and leave the spring alone.

But on a system like KW the height and pre-load are adjusted together because you are adjusting the perch, right? So you change the pre-load by adjusting the ride height. This makes your statement contradictory I think....

This makes the most sense to me at the moment.....

Not making sense to me... I thought if you adjust height at the top perch you lose both bump and droop travel. I mean, how could you not lose travel in this manner? you are essentially shortening the spring, are you not? And by shortening the body I still see you not effecting travel, despite what a marketing flyer has to say about it..... I will concede that it not making sense to me doesn't mean it isn't true.

Edit:
Seems he is referring to bump and droop length, and not travel. My bad. The shorter your body, the shorter your full bump length. The need for this length to be correct is very apparent.

With the above article on the table I am even more lost in understanding how to adjust these things. I adjusted height on all four corners but the lower perch on the fronts is not even left to right. That is, there is about 1/2" more threads showing on one body than the other. I had thought I would set the ride height and then get it corner balanced but now I am coming to uderstand that this means my full bump length will be different left to right, which doesn't sound good.... Very lost on what to do here....

I am out of my league here.
But the way I have understood corner weighting it will result in the bold in your quote. Not necessarily 1/2" but a difference in perch height.

Have a read of this forum post.
http://www.lotustalk.com/forums/f91/...ustment-77759/
And have a read of this.
http://farnorthracing.com/autocross_secrets11.html

Correct, there will be variations from shock to shock on where the adjuster collars end up sitting on the shock body due to variations in weight distribution of the car, variances in the springs during manufacturing, etc. That is the whole point of corner balancing...if you could just set all of the shock collars at the same position on the body and slap them on the car and it then be properly corner balanced, there would be no need to break out scales and go through the process. Every car and shock is a little different, and most people never even realize how good or bad their car is balanced after they put coilovers on. One indicator that it's REALLY off is if the car seems to turn better in one direction than the other, assuming all tire pressures are correct.

In fact OP, you might just ask if you can get it scaled for a small fee/free and decide from there if it's worth the hassle if you're already close to balanced by some chance. (within ~5% cross-balance)

I like this a lot.

Are your spring pre-load adjuster collars the same across that axle? They would work in combination with your ride height adjuster collar/cup to set the amount of support for that corner. So for instance if you tightened up the spring pre-load, you would effectively be "raising" that corner due to stiffening the spring so to speak, so you would then have to loosen the ride height collar/cup and run the body down into it to bring that corner back down to level. If you did the opposite to the spring pre load on the other side of that axle, you would also have to do the opposite to that ride height collar/cup, and you would end up with what you are describing.

According to that PDF article, the ideal thing to do would be to center up the bottom collar/Ride Height Adjustment to about the middle of it's adjustment range, then use the spring preload collars to set your ride height.

The 1/2" difference I see is on the lower body perch, which means something has to be wrong. I understand the upper perch will be inconsistent on each corner, particularly after I get it corner balanced. But the lower body perch, which defines bump and droop length, should be equal right to left. My pre-load must be different right to left and causing the discrepancy. So that's going to take a bunch more adjusting to get right I suppose.

Setting the lower perch in the middle of the adjustment range will mean I am going to lose a ton of bump travel to get back to my desired ride height. There is a TON of adjustment on that lower perch. It changes ride height from something like +3/8" to -2.5". I like the idea of slowly raising the low side and dropping the high side of the lower perch until they show equal threads and then returning the height back where I want it via the upper collar. That seems the most logical at this point. Does that sound reasonable?

still not clear what the advantage of these types of systems are. I may call RSR today and chat with them before I do anything else. Any other ideas and thoughts are welcome.

[ame="https://www.youtube.com/watch?v=5ayTgBT0uLw"]How to adjust ride height & corner balance your car - KW Suspension DDC - Technik - YouTube[/ame]

I always thought this video explained corner balancing well.

Thanks for the post.

The posts seem to only deal with single adjustable collars. I am guessing in my situation you are suppose to shorten the bodies via lower perch to get the ride height in the ball park and then adjust final height and corner balance via the collar. I suppose there is also a way to determine the best body length for optimal bump and droop length.... But I have no idea how to determine that either. Perhaps I can measure the stock suspention and shorten the coilover bodies 1/2".....

Just got off the phone with RSR. I am not sure I talked to the best guy, but I asked for a technician and there were none available so he was all I had. In any event, he said the advantage of the dual adjustment is that you can set ride height independently of preload. This way you get the same pre-load on each corner despite the height of the vehicle. You also lower the car without sacrificing travel.

On the other hand, I gather this type of system loses or gains bump and droop length as you adjust ride height. This could potentially not allow you to take advantage of the travel you have, depending on how you set them up. In the bigger picture I am not sure if this is an advantage or not when comparing them to other systems, but for my purposes I think I'll be fine so long as I stay within RSR's specs.

I still don't have a good explanation as to why my lower perches are not even. Is it really due to the uneven weight distribution on each corner? I am thinking maybe my pre-load was adjusted previously so I will have to measure it and make sure they are even. It's the only thing that makes sense to me at the moment...

Dual height adjustable coilovers do not alter bump or droop travel when you adjust with the lower mount. That's good, but they generally do not have a ton of bump or droop (especially droop) but it varies.

Single height adjustable coilovers trade bump for droop travel when you lower. Most of the time the body is shorter than stock so it's like a dual height adjustable coilover that's already adjusted down. It might mean that you can't go super low though because you won't have enough bump. You usually have a helper or tender spring so you're not actually preloading the main spring when adjusting height.

- Andy