some good info in regards to suspension adjustment.(meant mainly for FR cars)

[Mr.SelfDestruct]

Advanced Suspention Setup, Toe? Camber? Spring Rates? Learn here!

*NOTE*when you increase spring rate you need to match the damping rate to the new spring rate*/NOTE*

Front spring rate increase:
More under steer; increase in proportional weight transfer to the front when rear wheel rate is not increased; reduces front traction when rear rate is not changed.
Usable adjustment: 150-600 lbs/in
Symptoms of too much adjustment: terminal under steer; front of car hops in corners; excessive wheel spin on inside front tire on FF cars.

Front spring rate decrease:
Less under steer; decreases proportional weight transfer to the front when rear wheel rate is not increased; increases front traction when rear rate is not changed.
Usable adjustment: 150-600 lbs/in
Symptoms of to much adjustment: Too much over steer; over steer then under steer if spring is so soft that the car bottoms out on lean, car bottoms out excessively with a jolting ride.

Rear spring rate increase:
More over steer; increase in proportional weight transfer to the rear when front wheel rate is not increased; increases rear traction when front rate is not changed.
Usable range: 100-600 lbs/in
Symptoms of too much adjustment: too much over steer; sidestep hop in corners; twitchy; pretty scary.

Rear spring rate decrease:
Less over steer: decreases proportional weight transfer to the rear when front wheel rate is not changed; increases rear traction when front rate is not changed
Usable range: 100-600 lbs/in
Symptoms of too much adjustment: car under steers; if way to soft car under steers then over steers as car bottoms out on lean; car bottoms out excessively with a jolting ride.

Front anti-roll bar stiffer: more under steer
Usable range: none to 1.25 inches in diameter
Symptoms of to much adjustment: terminal under steer; lifts inside front tire off the ground witch can cause massive wheel spin on FF cars; also not good for most effective tire usage as inside tire is now doing nothing.

Front anti-roll bar softer: less under steer
Usable range: none to 1.25 inches in diameter
Symptoms of to much adjustment: overstate scary; more like fun

Rear anti-roll bar stiffer: more over steer
Usable range: none to 1 inch in diameter
Symptoms of too much adjustment: Big-time over steer. Can cause inside rear tire to lift off the ground.

Rear anti-roll bar softer: less over steer
Usable range: none to 1 inch in diameter
Symptoms of to much adjustment: under steer; slow and boring

Front tire pressure higher: less under steer by reducing slip angels on most tires
Usable adjustment: up to 55psi hot
Symptoms of too much adjustment: no traction- tire crowned so more under steer; adds wheel spin in FF cars; jarring ride; center of tire wears out

Front tire pressure lower: more under steer by increasing slip angles on most tires
Usable adjustment: not less then 20psi
Symptoms of too much adjustment: edges of tire wear quickly because tire is folding over; feels mushy; tires chunk because low pressure means heat build up.

Rear tire pressure higher: less over steer by reducing slip angles on most tires
Usable range: up to 45psi hot
Symptoms of too much adjustment: no traction—tire is crowned so more over steer; bad wheel spin on FR cars; jarring ride; center of tire wears out.

Rear tire pressure lower: more over steer by incresing slip angles on most tires.
Usable range: not less then 20psi
Symptoms of too much adjustment: edges of tire wear quickly because tire is folding over; feels mushy; tires chunk because low pressure means heat build up

More negative camber front: less under steer because of better lateral traction as tread is flatter on the ground under side load.
Usable range: up to 3.5 degrees negative
Symptoms of too much adjustment: poor braking; car is road crown sensitive; twitchy; front tires wear on inside edge

More negative camber rear: less over steer because of better lateral traction as tread is flatter on the ground under side load. More rear grip
Usable range: up to 2.5 degrees negative
Symptoms of too much adjustment: more over steer; car feels twitchy in back; tires wear out on inside edge; less breakaway warning when limit is exceeded.

Ride height to low (typical beginner mistake): car is twitchy with unpredictable dynamics. Bump steer make you life miserable.
Usable range: usually 1.5-2.0 inches lower then stock unless car has been modified to go lower.
Symptoms of too much adjustment: everything that could possibly go wrong: sudden over/under steer; twitchy due to bump steer; very harsh ride; premature tire wear.

Toe in – front: car is stable going straight. Turn in is average
Usable range: 0-1/8th inch
Symptoms of too much adjustment: car has slow twitchiness under braking; feels odd; kills outside edge of tires

Toe out – front: Car turns in well; works pretty well on FF car as they tend to toe-in under load.
Usable range: 0-1/4 inch
Symptoms of too much adjustment: Car is really twitchy under braking; car wanders on straight road; kills inside edge of tire

Toe in – rear: car is less likely to over steer when the throttle is lifted
Usable range: 0-1/8th inch
Symptoms of too much adjustment: weird, slow, rocking movement in back; feels slow but still unstable; wears outside edge of tires.

Toe out – rear: Helps car rotate useful in low speed and slalom courses; very common on FF pro rally cars.
Usable range: 0-1/8th inch
Symptoms of too much adjustment: not to good for street driving; causes lift throttle over steer; makes violent side to side rocking motions in the rear; tie wears on inside more.

Positive front caster: helps stability; suspension will get more negative camber when turning; reducing positive caster reduces steering effort. (Negative caster is not usable)
Usable range: 4-9 degrees positive
Symptoms of too much adjustment: can increase under steer especially in cars with wide low-profile tires. Can increase steering effort.

Single adjustable shock stiffer: Better turn in; better transient response; causes slower onset of over/under steer by slowing weight transfer depending on what end of the car is adjusted.
Symptoms of too much adjustment: suspension becomes unresponsive; ride gets harsh; car skips over bumps, loosing traction; Causes a big delay in weight transfer resulting in strange handling like under steer then late corner stage over steer.

Single adjustable shock softer: slower transient response; quicker onset of over/under steer
Symptoms of too much adjustment: car oscillates due to under dampened spring motion, like a boat. Car gets twitchy in turns. Feels unstable.

 

[Wiisass]

I would first like to say that most of this is good info, so thanks Mr. Self Destruct. But I really do hate these things, they much too general and somewhat vague, so I'm going to add my input and make things a little more applicable to the supra.

Advanced Suspention Setup, Toe? Camber? Spring Rates? Learn here!

*NOTE*when you increase spring rate you need to match the damping rate to the new spring rate*/NOTE*

You also need to adjust/revalve the dampers with a weight increase/decrease. People tend to forget or not know that weight plays a major role in the amount of damping needed to control the car. This goes for both sprung and unsprung weight.

Front spring rate increase:
More under steer; increase in proportional weight transfer to the front when rear wheel rate is not increased; reduces front traction when rear rate is not changed.
Usable adjustment: 150-600 lbs/in
Symptoms of too much adjustment: terminal under steer; front of car hops in corners; excessive wheel spin on inside front tire on FF cars.

Front spring rate decrease:
Less under steer; decreases proportional weight transfer to the front when rear wheel rate is not increased; increases front traction when rear rate is not changed.
Usable adjustment: 150-600 lbs/in
Symptoms of to much adjustment: Too much over steer; over steer then under steer if spring is so soft that the car bottoms out on lean, car bottoms out excessively with a jolting ride.

Rear spring rate increase:
More over steer; increase in proportional weight transfer to the rear when front wheel rate is not increased; increases rear traction when front rate is not changed.
Usable range: 100-600 lbs/in
Symptoms of too much adjustment: too much over steer; sidestep hop in corners; twitchy; pretty scary.

Rear spring rate decrease:
Less over steer: decreases proportional weight transfer to the rear when front wheel rate is not changed; increases rear traction when front rate is not changed
Usable range: 100-600 lbs/in
Symptoms of too much adjustment: car under steers; if way to soft car under steers then over steers as car bottoms out on lean; car bottoms out excessively with a jolting ride.

Front anti-roll bar stiffer: more under steer
Usable range: none to 1.25 inches in diameter
Symptoms of to much adjustment: terminal under steer; lifts inside front tire off the ground witch can cause massive wheel spin on FF cars; also not good for most effective tire usage as inside tire is now doing nothing.

Front anti-roll bar softer: less under steer
Usable range: none to 1.25 inches in diameter
Symptoms of to much adjustment: overstate scary; more like fun

Rear anti-roll bar stiffer: more over steer
Usable range: none to 1 inch in diameter
Symptoms of too much adjustment: Big-time over steer. Can cause inside rear tire to lift off the ground.

Rear anti-roll bar softer: less over steer
Usable range: none to 1 inch in diameter
Symptoms of to much adjustment: under steer; slow and boring

Increasing the front spring rate whether through the sway bar or the springs will increase front roll stiffness and the total lateral load transfer distribution will move more towards the front. This does not necessarily mean understeer, understeer will happen if the fronts are taking more of the load transfer. It only means that they will be seeing more load than before. It really depends on how far off the base setup of the car was. But if the car was setup as neutral, then with the increase in front roll stiffness, the front of the car will be seeing more of the lateral load transfer distribution. Most cars come this way from the factory and a lot of race cars are setup with a little front bias on the load transfer distribution for stability reason.

Same goes with increasing the rear spring rate or sway bar, it's an increase in rear roll stiffness. Or decreasing any of the spring front or rear will just do the opposite.

Also keep in mind, that more understeer or more oversteer does not mean that the car is going to be sliding all over the place, it purely means that at the limit, that end will slide first. Understeer doesn't mean you're flying off the road outside of the corner you're trying to make. And oversteer doesn't mean you're drifting the turn. It just describes the amount of steering that you will need for a steady state turn. So if you're in a steady state turn in an understeer car, you will be turning the steering wheel a little more than you would have to at a lower speed. If it's an oversteer car, the wheel will be turned slightly less than it would be at a lower speed.

Also the adjustment ranges seem off or generic from something else. On supras, front spring rates can approach well over 1000lb/in. This is due to the geometry. Rear spring rates could be approaching 800lb/in. On my brother's car with my suspension we're running 1000/600 and it's a very balanced setup. But that car is also 500lbs. lighter than most Supras, so more spring could definitely be used on a heavier car. And those spring rates aren't even at the upper limit of what you could run on these cars.

As for sway bar diameters, I don't recall off the top of my head what the actual numbers are for their diameters. But hopefully the testing I have planned will show what each bar really does. But outside diameter only tells you so much, without knowing inside diameter, you can't even estimate how stiff the bar will be. Also with all the bends needed to fit sway bars, the bars lose a lot of stiffness. So it depends on many factors.

Also for adjusting sway bars, adjusting the moment arm length is a very effective way of adjusting the stiffness. Moving the endlink closer to the bar will increase roll stiffness and moving it further away from the bar will decrease roll stiffness. This is because you are giving the suspension more leverage against the bar at a further distance from it's center of rotation.

Wheel travel is another concern for spring rates. Too soft of spring could cause bottoming out under certain conditions, too stiff of spring could not allow tractive efforts to be effectively put to the ground, meaning you're going to have trouble acclerating or braking.

Also important to note is the balance between the roll rate coming from the springs versus the roll rate as a result of the sway bar. I don't like it when the sway bars provide too much of the roll rate. Sway bars will allow the body to resist rolling in a corner, but they also transfer load to the outside wheel. This decreases the load capacity of the front when the bar is too stiff. It will overload the outside tire and unload the inside tire, this is when they're too stiff. Too stiff of a bar will also increase the one wheel bump rate and can make handling over rough roads harsher than it should. You just have to be careful and not think that the decrease in body roll will always mean an increase in grip. Of course, this depends on a couple other things such as wheel travel and camber control. So sway bars can increase the amount of available grip, but they can also decrease it. But either way, adjusting them as said before will adjust the oversteer/understeer balance of the car.
[/QUOTE]

Front tire pressure higher: less under steer by reducing slip angels on most tires
Usable adjustment: up to 55psi hot
Symptoms of too much adjustment: no traction- tire crowned so more under steer; adds wheel spin in FF cars; jarring ride; center of tire wears out

Front tire pressure lower: more under steer by increasing slip angles on most tires
Usable adjustment: not less then 20psi
Symptoms of too much adjustment: edges of tire wear quickly because tire is folding over; feels mushy; tires chunk because low pressure means heat build up.

Rear tire pressure higher: less over steer by reducing slip angles on most tires
Usable range: up to 45psi hot
Symptoms of too much adjustment: no traction—tire is crowned so more over steer; bad wheel spin on FR cars; jarring ride; center of tire wears out.

Rear tire pressure lower: more over steer by incresing slip angles on most tires.
Usable range: not less then 20psi
Symptoms of too much adjustment: edges of tire wear quickly because tire is folding over; feels mushy; tires chunk because low pressure means heat build up

This is all a little too vague to really apply. Tires are a lot more complicated than many people think. Usually once you get too high of tire pressure, the tire is more prone to losing traction. Less pressure will increase grip up to a point. There is a good working range of pressure for force generation. Once you get in this range, with most tires, it's not effective to really adjust the car with tire pressure. The tires are the most important part of the whole system, so there is no reason to sacrifice their performance when another change to the suspension would be a much smarter move.

Basically, you don't want the pressure too high and you don't want them too low, finding that range would be a lot easier if tire companies produced or shared any kind of tire data, but that's probably never going to happen, so it's not even worth getting into.

So start at a guess for starting pressure, usually somewhere low to mid 30s is a good place to start for a cold pressure with a lot of street tires on the market. And then mess around with it a little, get them hot, measure temps and see how they feel.

There's a lot more that goes into all of this, but it's a little too much and not really needed to know, so I'm not going to get into it. There are some good articles and information on tires and how they work in some books and probably on some sites if you really want more information about that.
[/QUOTE]

More negative camber front: less under steer because of better lateral traction as tread is flatter on the ground under side load.
Usable range: up to 3.5 degrees negative
Symptoms of too much adjustment: poor braking; car is road crown sensitive; twitchy; front tires wear on inside edge

More negative camber rear: less over steer because of better lateral traction as tread is flatter on the ground under side load. More rear grip
Usable range: up to 2.5 degrees negative
Symptoms of too much adjustment: more over steer; car feels twitchy in back; tires wear out on inside edge; less breakaway warning when limit is exceeded.

Ride height to low (typical beginner mistake): car is twitchy with unpredictable dynamics. Bump steer make you life miserable.
Usable range: usually 1.5-2.0 inches lower then stock unless car has been modified to go lower.
Symptoms of too much adjustment: everything that could possibly go wrong: sudden over/under steer; twitchy due to bump steer; very harsh ride; premature tire wear.

Toe in – front: car is stable going straight. Turn in is average
Usable range: 0-1/8th inch
Symptoms of too much adjustment: car has slow twitchiness under braking; feels odd; kills outside edge of tires

Toe out – front: Car turns in well; works pretty well on FF car as they tend to toe-in under load.
Usable range: 0-1/4 inch
Symptoms of too much adjustment: Car is really twitchy under braking; car wanders on straight road; kills inside edge of tire

Toe in – rear: car is less likely to over steer when the throttle is lifted
Usable range: 0-1/8th inch
Symptoms of too much adjustment: weird, slow, rocking movement in back; feels slow but still unstable; wears outside edge of tires.

Toe out – rear: Helps car rotate useful in low speed and slalom courses; very common on FF pro rally cars.
Usable range: 0-1/8th inch
Symptoms of too much adjustment: not to good for street driving; causes lift throttle over steer; makes violent side to side rocking motions in the rear; tie wears on inside more.

Positive front caster: helps stability; suspension will get more negative camber when turning; reducing positive caster reduces steering effort. (Negative caster is not usable)
Usable range: 4-9 degrees positive
Symptoms of too much adjustment: can increase under steer especially in cars with wide low-profile tires. Can increase steering effort.

Alright, let's start with camber. You don't want too much camber, but you also don't want too little. Camber is important for grip and the common misconception is that a totally upright tire will produce the most grip. This is not the case. Most tires will produce more grip with some negative camber. But like was said, too much camber can affect braking performance. It also needs to be noted the difference between static camber and dynamic camber. This depends on suspension geometry and ride height and roll stiffness. Depending on where the wheel is in the camber curve, more or less static camber will be required to keep the wheel in a good position. When the car rolls, depending on the roll stiffness there will be a certain amount of wheel travel depending on the amount of lateral acceleration. Sometimes the amount that the body will roll will be greater than the camber change with wheel travel, so more static camber is needed to keep the wheel camber negative relative to the road.

The best way to camber without doing a ton of modeling and calculations is to check tire temperatures. There should be a 10-20 degree temperature gradient across the tread of the tire with the inside of the tire the hottest. If it's not like this, then an adjustment will be in order. The main thing to remember is that positive camber, at any time, is a bad thing.

Ride height is one of those things that is going to affect every car differently. Adjusting the ride height is essentially adjusting the mid-point of suspension travel in relation to the chassis. So depending on camber curves and toe curves, you're going to be affecting what the alignment needs to be and what things need to be accounted for. Also your roll centers may get too low or they may change relative heights front to rear. The roll center is very important for lateral load transfer distribution. With supras, the front roll center will drop quicker than the rear roll center, this will increase front load transfer, so without changing anything, the front load transfer will increase relative to the rear just because of lowering the car an equal amount. So this is something that needs to be considered as well when looking at springs and sway bars.

But also keep in mind that a lower ride height also lowers the center of gravity which will decrease all load transfer. The less load transfer, the more evenly the tires will be loaded and the more grip will be available.

For toe, toe in is more stable for straight line running because the force lines or the tires intersect each other. Toe out, in the front will help turn in. In the rear, it should never be used, it makes the car very weird and unpredictable. I usually run a little toe out in the front and a little toe in in the rear. Usually about 1/16" at each wheel, too much more than that is just causing problems. But again, it also depends on the geometry and what the suspension is doing.

For caster, more will increase steering effort and wheel self centering. It will also increase the amount of negative camber gain with steering angle. This negative camber gain with steering angle on the outside wheel is balanced by kingpin angle which has positive camber gain with steering angle on the outside wheel. Too much caster is bad, it can cause the wheel to get stuck at steering lock because of the direction of the forces acting on the tire.

Caster really adjusts the mechanical trail that the suspension has. Mechanical trail is the distance from the intersection of the caster line with the ground to the center of the contact patch. This is in the front of the wheel. This needs to be balanced with pneumatic trail which is based on tire slip angles and is behind the center of the wheel. This is the point that lateral force is applied. So the overturning moment that the tire sees is the lateral force times the distance of pneumatic trail plus mechanical trail. Pneumatic trail peaks at low slip angles and falls off at higher slip angles, when this curve is known and there is some freedom with the suspension setup, these variables can be balanced to give feedback at the steering wheel when the tire is approaching its limit.

Single adjustable shock stiffer: Better turn in; better transient response; causes slower onset of over/under steer by slowing weight transfer depending on what end of the car is adjusted.
Symptoms of too much adjustment: suspension becomes unresponsive; ride gets harsh; car skips over bumps, loosing traction; Causes a big delay in weight transfer resulting in strange handling like under steer then late corner stage over steer.

Single adjustable shock softer: slower transient response; quicker onset of over/under steer
Symptoms of too much adjustment: car oscillates due to under dampened spring motion, like a boat. Car gets twitchy in turns. Feels unstable.

Shock adjustment is a huge thing. In order to properly adjust shocks, they need to be properly valved and have good adjusters. Neither of these seem to be true for a lot that is on the market. But I'll assume that they're close to properly valved at least for this discussion.

Single adjustable dampers, if they're good single adjustable dampers, read Koni, then they will adjust the rebound side of the curve. But most of the adjustable dampers on the market adjust both the rebound and compression side of the curve making it impossible for the curve to ever work well on both sides. So by adjusting these, you can either get the compression side right or the rebound side right unless somehow you get incredibly lucky and get both right, but that's probably not going to happen.

Anyway, with too much rebound damping, transitions will be slow, the car can jack down over a series of bumps meaning that the wheel will get sucked into the wheel well because of too much rebound. It can also unload the inside wheel during manuevering.

With too little rebound damping, things are floaty, transitions are slow, the car doesn't take a set. Car just sucks.

With too much compression damping, ride quality is horrible. If you've ever rode or driven a car with any of the entry level JDM dampers, you will know what too much compression damping feels like. This is bad for grip because it knocks the tire around.

With not little compression damping, the unsprung mass isn't properly controlled. The wheel will take longer to settle after bumps. This is usually the most acceptable thing to not have enough of.

But with damping, both sides of the curve need to be matched to each other and the weight and springs of the car. With a good compression curve and crappy rebound curve, you end up with poor performance. Same as with a good rebound curve and bad compression curve.

I've written a ton on dampers, there's more on my site or we can get into it a little more if you want. But I think I've said enough for now.


So I'm guessing you can see why I hate these things. Each of these variables have many different effects and ranges depending on all of the other variables. Everything with suspension is related and changing one thing affects another. So everything needs to be considered.

Well let me know if there are any more questions and I will do my best to answer them.

Tim

 

[supraguru05]

Anyway, with too much rebound damping, transitions will be slow, the car can jack down over a series of bumps meaning that the wheel will get sucked into the wheel well because of too much rebound. It can also unload the inside wheel during manuevering.

Tim

i agree that it can cause jacking down but to much rebound causes the cars weight to transfer fast resulting in quick transitions neeeding quick reactions. i thought to little rebound makes the car lean slower

 

[Wiisass]

This gets a little complicated.

There is a critical damping value, this is the value with which there will be the least amount of overshoot and the quickest settling time. With damping values over this critical number, settling time will take longer but there will be no overshoot, the rebound force will actually hold the car back. With values under this, there will be overshoot, meaning that the car will lean more than it should, and settling time will increase the further the rebound damping value gets from the critical value.

Just think about a car with blown shocks, there is nothing slowing the transition or controlling it. So the car will transition faster, but it won't settle as quickly, there will be overshoot and it will oscillate.

With rebound values close to, but below, critical, the car will transfer weight much more smoothly, it will seem quicker because the car is settling quicker. I wish I could find the graph that I'm thinking of that will illustrate this point, but it's not showing up in a quick search.

So it really depends on what side of that critical number you are on. When I said too much rebound damping, I meant above that critical value. Which will slow weight transfer and settling time.

But again, it's a balance with compression damping. But usually if the car is transitioning too quickly in a certain direction, increasing the rebound damping on the end that is getting unloaded or increasing compression damping on the end that is getting loaded, is the way to tune it.

But again, this depends on what it's doing. Say it's straight line braking. Under braking, the rear is losing grip. Now is this because there is too much rebound damping and the rears are getting pulled up and unloaded because of the weight transfer to the front or is it because there is not enough rebound damping and the rears are getting unloaded too quickly? This is why suspension tuning is hard to do. Extreme circumstances at both ends of the spectrum can cause similar problems and sometimes it's hard to know which direction to go in. When you have time to test a change and see how it works and then try the other direction, it's not too big of a deal. But many times, that kind of luxury isn't available, and you have one chance to make the correct change.

So let me know if all of that made sense or if you still have any questions. If so, I can probably find some more data sometime in the next couple days that may illustrate this a little better.

Tim

 

[Van]

A question that comes to mind; why are our cars set up a little higher in the rear suspension? Is there more stability doing it that way?
I ask, as I'm planning on lowering the rear to nearly the same height as the front. Van

 

[Van]

Well, this seems a dead hole...
I've been told Toyota set up the suspension higher in the rear so it wouldn't bottom out under a hard launch? Yeah... I asked fellow road racing club members at Cascade Sports Car Club and I was told to cut off 1/4 of the bottom winding on each spring and go out for a test run to see how well it handles. That's what I'm going to do... Van

 

[supraguru05]

Van the rear elevation may have been related to tire clearance on the group A cars also. Personally I am lowering the car as much as possible while maintaining appropriate travel. I dont see any concern with leveling the car. However more importantly is to get your corner weights correct. What front and rear spring rates are you running. I am finding that I am continually having to increase my front rate as I go faster and faster because of excessive travel.

 

[Van]

Van the rear elevation may have been related to tire clearance on the group A cars also. Personally I am lowering the car as much as possible while maintaining appropriate travel. I dont see any concern with leveling the car. However more importantly is to get your corner weights correct. What front and rear spring rates are you running. I am finding that I am continually having to increase my front rate as I go faster and faster because of excessive travel.

Supraguru,
Thanks for getting back to me... The Supra is shod w/ RSR race springs front and rear, 700Lb/inch and 400Lb/inch. The car is DD and is tracked six times a year for HPDE track days. Consequently, inherent compromises the result. The weight is 3320 ((1680fr/1640r) on a truck scale. I have access to a corner weight scale and knowing the importance of having a stable platform, I'll have the springs cut at the shop and get the weight correct.
What is your set up? Van

 

[te72]

I would have thought the rear was a little higher for a couple reasons. Looks better IMO (just a bit more height though, nothing crazy), and shouldn't a higher rear ride height reduce understeer a bit? My understanding of these things is fairly basic, so please bear with me here.

 

[Van]

Update on the Supra's weight: 3364. The shop (VIP Performance), corner weighed it to get the total weight. They only managed to get the weights to w/i 15 Lbs a corner, so they are recommending coil over suspension the next time it needs springs or shocks.
In another vein; I had the alignment changed to 2.5 degrees neg camber left and right front and 8 degrees pos caster on the left and 8.5 degrees pos caster right front with a little toe in. 1.5 degrees neg camber left and right rear and a little toe in.
I'm finding the tire feel in the steering wheel a little numb. I'm planning on taking a little caster out... We'll start by taking out 1 degree caster on the front suspension.