What Are The OEM Alignment Settings?
The Yokohama/ Bridgestone tires that originally came on the NSX and the NSX-T were designed for this car. Very hard sidewall, built in bias, VERY soft compound. The target for the car was "The best handling production car." Many magazines have given the NSX that title.
Also see the Tire Tech section for more information on tires and tire wear.
1991-1992 Factory Alignment Specs
The original factory alignment specs for the rear were designed to provide maximum performance at the expensive of shorter tire life.
Front Total Toe: -3.5mm +/- 1mm Front Camber: -20 min +/- 30min (-0.33 deg +/- 0.5 deg) Front Caster: 8 deg Rear Total Toe: 6mm +/- 1mm Rear Camber: -1 deg 30 min +/- 30min (-1.5 deg +/- 0.5 deg)
1993+ Factory Alignment Specs
After a class action lawsuit about what they considered to be premature tire wear, the rear alignment settings were changed. With less rear toe, the rear tires last longer. There is no reason you can't run the original '91-'92 settings if ultimate performance is the goal and tire life is not a primary concern.
Front Total Toe: -3.5mm +/- 1mm Front Camber: -20 min +/- 30min (-0.33 deg +/- 0.5 deg) Front Caster: 8 deg Rear Total Toe: 3mm +/- 1mm Rear Camber: -1 deg 30 min +/- 30min (-1.5 deg +/- 0.5 deg)
1999-2001 Type S Factory Alignment Specs
Front Total Toe: (-0.28 deg +/- 0.08 deg) Front Camber: (-.50 deg +/- 0.17 deg) Front Caster: (8.23 deg +/- 0.25 deg) Rear Total Toe: (0.31 deg +/- 0.08 deg) Rear Camber: (-2.00 deg +/- 0.017 deg)
(Per Hunter Alignment database per pbassjo, [reference http://www.nsxprime.com/forum/showpost.php?p=371647&postcount=11].)
[KJ] The front tires typically wear out on the inside long before the outside is worn. Reducing or even removing the front toe-out and minimizing the camber improves the tire wear, at the cost of some turn-in crispness and, high speed stability. Even with no camber or toe, the front Yokos would wear on the inside due to their internal bias that pre-tensions them for turning. The rears have the opposite bias, so negative camber acts to balance the wear between outside and inside.
Total toe: -2.5mm
Camber: 00.00 degree
Caster: 8deg. Caster does not wear tires.
What the front tires do:
The front tires pull out (RF pulls to the right, LF pulls to the left) slightly to follow the alignment settings. The purpose of this is to remove the compliance or "slop" associated with moving parts, (ball joints, tie rod ends, pivot points, etc.) Each tire slips sideways 1.75mm with each revolution.
The Toe is there to make the car push (understeer) slightly. The camber on the front is to give you a better rubber patch on the ground when turning. The car wants the tire go straight when the alignment setting makes the tire want to turn, thus, (simplified) the car is dragging the inside of the tire more than the outside. and wearing the inside. Hard cornering does not effect wear as much as straight line driving.
What you feel when driving:
With the Yoko-Bridgestone tire and the stock settings, going down the freeway at 70 mph, a slight tug on the steering wheel would put the car in the next lane.
With Goodyear Eagle, Firestone, Comp T/A, Michelin, etc. the car will feel like it has low tire pressure when compared to the OE tires, and a quick lane change will give a *** wind-up/sling-shot ***effect before the car starts to go into the next lane.
Alternative rear alignment with OEM tires
Running 1.5mm toe-in per side seems to provide even tire wear on the rear tires and makes them last even longer. Again, but further reducing rear toe there is some performance tradeoff.
Total toe: 3mm
Camber: -1 degree
What the rear tires are doing:
The rear tires pull in (RR pulls to the left, LR pulls to the right) slightly to follow the alignment settings. The purpose of this is to remove the compliance or "slop" associated with moving parts, (ball joints, tie rod ends, pivot points, etc.) AND to help keep the rear of the car tucked IN when in turns.
What you feel when driving:
Take out the front toe AND/OR changing brands of tires will give you more of the low tire pressure feel. Acura does not recommend changing the brand of tire. It is advised to check the alignment each time new tires are installed.
How Much Should An Alignment Cost?
An Acura dealer should charge 1 - 1.5 hours of labor for a four-wheel alignment.
[LE - 2000/8/4] My dealer normally charges one hour labor to align my car. It is always the way I want it and I get the print-out to verify. During the summer every year they have a special for a couple months where they do a 4-wheel alignment on any Acura for $49.95
[LB - 2000/8/4] I pay $60 for a full alignment in my NSX. The car is actually very easy to align. I basically pay one hour labor.
[KHR - 2000/8/4] We have a special discount from our local Big O Tire store for NSXCA members for four 4 wheel alignment with Hunter laser equipment for $49.99.
How Can I Maximize Tire Life?
[KJ] If you don't take the car to the track or drive aggressively on the road, set the front toe to zero and camber to -0.3 (minimum). This will *almost* even-out the front wear, at the expense of less crispness in extreme maneuvers and on the track. This is how mine is set up now.
[AT] Your main culprit with the front tires is the "positive" toe-out setting on the car is too great. Positive toe aids in quicker turn in and tracking of the front in hard turns but at a price for excessive wear. You may also have too much negative camber if the car has been lowered in combination with the toe-out. I lowered my car and set the negative camber to around -1 1/2 degrees. The toe-out was removed to zero-toe. Yes "zero". The car understeers a little bit more now but the wear on the tires are even and I'm probably reaching 20k miles with 1/3rd the tread left.
I've driven the car hard and have autocrossed it on these tires which are Michelin MXX3's. I have 205x50x16" front and 255x40x17" rears. I'm going to a bigger tire in the front, hopefull 225x45x16" to help compensate for the understeer since changing the toe-out. The rear alignment specs for my car are the same as the 94+ factory specs. They are doing great with good cornering hold. Just thought you might want to know what someone else is doing out there to save on tire wear with some decent traction during cornering.
Decrease rear toe to the '93+ specs, or you can try even more radical settings. Here's what some people have reported:
[JG] I checked with my tuner and he showed me the specs of the alignments on my rear wheels. He reduced the factory toe-in to almost 0. I think it was 0.005 at the most. He said this is what he has found over the years to give the best performance on track (or street). This guy is known for his suspension and alignment work. He's got people coming from several states away for his work.
All along I've been wondering why my tires last so long on the street when everyone else gets less than 5K. I'm always driving them pretty hard, too. Max speed I've had my NSX up to is 150 MPH.
What Should I Know About Changing Alignment?
Suspension Tech Session by Don Erb, Comptech USA
Alignment of any car including the NSX can make a jewel or a sow depending on how it is done. There are several setup considerations that need to be looked at before the alignment is done, each one will also affect tire wear. So, do you want MAX mileage or ultimate performance? Is it strictly for the race track or just occasionally the track? As you can see you need to consider all these before you spend your hard earned money.
Today's new radial tires love camber and the more you five them the better the car will handle. If this is a track only car, we would aim for approximately 3 1/2 degrees to 4 degrees negative camber. This would use up the inside edge of the tires at a rapid pace if driven on the street.
Let's start with what is adjustable on your car and the affects each one can have on handling. The thing to remember is that everyone drives differently and what is the best setup for your friends NSX could seem evil to you. A good example of this was when Jimmy Vasser changed back to his old setups on his Reynard instead of using Alex's and he started winning again. Obviously Alex's setup worked for him but Jimmy's driving style was different enough that he needed his own.
Camber: This can and will, as said above, be the number one reason for rapid inside tire wear, 2nd is toe setting, but we will come to that later. The more camber you have the more high speed grip you will have, but be realistic, if you are excessively wearing out the inside of the tires, you not driving the car hard enough and should reduce what you are using. On a street driven NSX I would recommend setting the front to 1 1/4 degrees to 1 1/2 degrees negative camber and the rear to 2 degrees negative. Typically, the most you can get out of a stock NSX is 2 degree negative on the front and 2 5/8 degrees negative rear. This can be increased with offset bushings if it is track car. It will also change as you lower or change the ride height.
If you want MAX performance and you are going to the track, get yourself a tire pyrometer. This is the best way to test your setup. After doing several laps you should test the tire temps at three places across the tire(outside 1/4, middle and 1/4 inside edge). Start from the side of the car that you think the tires will be hottest (usually the most loaded corner of the car). You can tell several things from the temps as follows: hot in middle = too much air pressure; hot on each edge = not enough air pressure; equal temps across tire = not enough camber; hot on outside edge of tire = not enough camber; 5-15 degrees hotter on inside = camber is good!
Caster: the standard setting on the NSX is between 6-7 degrees, this is fine for all models and I would not change. You do however want it to be equal on each side. This in street car terms is 3 times higher than most cars. This is why non-power steering NSX's have fairly heavy steering. The reason for high caster is to give you more grip on initial turnin into the corner, as you turn the wheel the front end gains camber and this gives you more grip. As you can see the engineers refused to compromise in designing the NSX suspension.
Toe Setting: The toe on the front of the NSX should be approximately 4mm or 3/16" toe-out. This is a good spot to start with. If the car seems slow on turning into a corner you can add more toe out to give you more aggressive steering. Be careful, there is no such thing as too much toe out, but it will increase the tire wear and will decrease the straight line stability. Remember, what is comfortable for your friend may be different for you. Unless you are racing I would not recommend going over 8mm out.
Rear toe should be about 3-4mm toe in. The more toe in you have on the rear the more stable the car will be down the straight and the more stable understeer you will have in the corner. Some factory settings on certain models had up to 8mm toe in. This was to keep the car more stable. The tire wear was very high and many owners complained about it, so the next year they went back to lower settings in the 4-6mm range. In an ideal world, as the suspension moves the toe would never change, but it does. This is why we make the low compliance rear beam and toe links. If you don't believe me, do this simple test. Look at the rear wheel out your door and roll you car backwards and hit the brakes, see the wheel move in and out? This is toe change! The less you have the better.
More toe out in the front: Turnin quicker, also called Turnin oversteer, if excessive.
Car is darty: Reduce toe out in front. Toe in in the rear. If car pushes in mid corner add more toe in.
Remember it is always better to err on the safe side and run too much toe in than not enough.
These are just the basics and as you can see all these settings affect and interact with each other. This can be very difficult to grasp in one easy lesson.
What Settings Have People Tried?
[HM] Front Toe: Factory spec.
Front Camber: All the negative you can get out to stops (1.3 to 1.5 if you're lucky.)
Front Caster: Move it from 7.5 factory to what ever takes, even 8.0 to 9.0 because more caster usually rewards you with aditional negative camber.
Rear Camber: 2.0 negative
Rear Toe: Old factory setting (6 mm total). Grinds up tires but best for racing.
What is the correct Alignment Process?
It is critical that the alignment process be done correctly.
[A/H] The standard (non-NSX) procedure is to do caster, camber and then toe. However, on the NSX adjusting the toe will change the caster and camber so we suggest to do the rear first camber and toe on each side, then do Front Camber and Toe together on one side, then the other, then do caster both sides since it will change the other two the least. Then go back and readjust the camber and toe on each side. Toe and Camber are very interactive on this car. If done the conventional way of caster, camber, toe, the technician will get very frustrated and probably not do a proper alignment since he will secure one setting then the next setting will change the first.
The least labor intensive process to a proper alignment is to use a computer alignment machine that will give instant feedback to any turn of the wrench.
Adjust camber and toe on one side, then the other side.
Double check for correct thrust angle (centerline)
Adjust the camber and toe together on one side, then the other side.
Adjust caster on both sides together.
Fine tune the camber and toe on one side then the other.
[KP] I had my '91 aligned (after Eibach spring install) on a very computerized Hunter machine. The Hunter consists of two parallel *tracks* and you drive your car on these ramps to get up onto these two tracks. (This was the first trick since the lowered car wanted to high center on the top of the ramp as it transitioned to the horizontal track.) Once on the ramp, the technician raised the ramps until the car was about 6 feet up and we could easily walk under it.
He then positioned these sensors on each of my four rims.These sensors were positioend so that they could talk to each other (IR?) and they were all connected to the Hunter computer brain. The next step was impressive. Within the raised assembly were some additional air jacks. The technicial positioned these guys under the jack points in the front of the car and raised it so that the front tires were no longer in contact with the tracks.
He then pulled the pins on these *pads* on the track that would allow the tires (suspension) to move when he lowered the car back down. Same for the rear. So, now the car was 6 feet up, all connected to the computer and all four tires resting on pads that would *float* around.
On the computer screen, the instantanious display of toe, caster, and camber were displayed. The technician entered the VIN of my car (nothing else!) and the computer automatically brought up the alignment settings. Then, it displayed the real time readings within the specified tolerances of the info it retrieved for the NSX. A few of the settings were out of the specified band range so these were displayed in a different color.
To adjust, the technician stood under the car and made the adjustments while watching the monitor. As soon as the adjustment would come into the specified range, the color would change and the actual position of the value within the range would be displayed as well as the *dead nuts* value. The tech, just walked around and did all four corners using this method. Sure, some corner changes would slightly effect the other side (on the same axle) but he'd simply go adjust these.
After getting everything atached and into position, the whole process took about ten minutes. If there had been some component or reason that a corner couldn't have been brought into spec, it would have been real obvious, real fast.
I had heard horror stories from this list about the difficulty in aligning an NSX. However, like almost everything else, if you've got the right equipment, it's easy. I can highly recommend using a shop that has one of these machines. To be honest, I don't think the tech was highly skilled and I doubt whether he'd ever done an NSX before. The machine was so good, it just eliminated these other factors.
What Should I Know About NSX Alignment Work?
[MS, HS, KJ] If possible, go to a shop that caters or racers or otherwise understands custom specifications and wanting to do an alignment with the driver in the seat. In the NSX the weight of the driver can add almost another .3 degree camber on the left rear and alter the toe characteristics significantly, front and rear. Some shops do not allow customers back in the work area. Make sure they have some sandbags of the right weight to take your place.
The bump steer on the NSX is excellent -- much better than on most cars - a coup for Honda engineers. It basically means the wheels (front and/or rear) don't change toe as they go through the arc from full bounce (car pushed down to the ground) to rebound (wheels off the ground in full "droop"). In the front on many cars, the angle and length of the steering arms will cause the toe to change from large toe in at full bump to large toe out on droop -- with the correct toe at normal ride height only. With the NSX, you're only likely to need an adjustment if you lower your car dramatically.
I have been running somewhat non-standard alignment settings since early July, which covers most of the life of my current set of A022H tires. I have about 8000 miles on the rear tires and 6000 miles on the front tires. Current tread depths are 4 to 5 32nds of an inch on the rear tires and 7 32nds in the front.
On the early cars, it is easy to take out some of the rear toe, add a bit of negative camber and alter the handing from slight understeer to neutral to throttle induced oversteer. It is fun to play with. But adding negative camber will cause your rears to wear unevenly unless you drive aggressively from time to time. Reducing the toe in at the rear will dramatically reduce tire wear.
However, stating it strongly, be careful! A more neutral handing NSX will bite you with oversteer (read spins and the rear coming around if you are not smooth and careful).
Now for the critical advice. Have your car aligned with you in the car! If they have rules about customers in the shop, make sure they put your weight in the driver's seat. I tried it both ways and found a significant difference in specs, to the tune of more than half a degree in camber and 3mm toe.
I'm not sure but I think the brand new tires had about 8.5 32nds of tread depth. The wear bars appear at 2 32nds. So it's too early to tell whether the fronts will wear evenly or how long they will last. The rear tires are on track to wear out evenly at about 11000 to 12000 miles. Adjusting for the higher proportion of highway miles, this is about the same tire wear that I typically got on my 87 MR2, which would consistently need 4 new tires every year, with even wear on all four 185/60-14's.
Anyway, the alignment in front is zero toe, 0.3 or .4 degrees negative camber, as measured with me in the car. When I got out the readings changed by about 0.3 degrees and a bit in the front toe as well. Michael Sands found the same effect earlier, and suggested that I stay in the car. Front caster is stock.
Rear alignment is stock except that the toe-in is reduced to about 1.5 mm, is a bit less than the lower limit for the new Acura specs. I have noticed no tail-happiness that bears any resemblance to that of an early MR2, which actually toes out in back under braking. In one vacant parking lot test, I found the breakaway to be much slower to develop and easy to halt merely by stopping the provocation, rather than by counter steering or nailing the throttle. My guess is that the stock settings provide more margin for panic and bad driver inputs in emergency situations. I've long since learned how to keep my foot in the throttle if the back end is coming out.
Anyway, if you've learned to deal with the evils of rear engined cars, and if you've autocrossed them or the NSX, you will probably feel reasonably comfortable playing with the alignment. Otherwise, I'd have to say stay with the stock settings.
[KJ] The result of the new front alignment settings has been nearly even tire wear, as they wore down to about 3/32 of an inch tread depth on the outside and 2/32 on the inside after about 10,000 miles. The handling seems fine to me, but I have not taken the car on a track. Those who use their street tires on the track may find that the excess track wear on the outside balances the excess street wear on the insides with the stock alignment settings. Honda claims that removing the front toe-out will decrease the steering stability at the high speeds needed to earn cookies. I have not tested this, but if you intend to drive at high speed (say, above 135 mph), you might want to consider this caution.
All tires are run at the pressures recommended by Acura.
What Is "Toe"?
[AWN] "Toe-in" means that, when viewed from above, the tires point inward. A Car Set Up With Front and Rear Toe-In:
__________ __ | | ___ / /__| FRONT |__\ \ /__/ | | \__\ | | | | ___ | REAR | ___ / /__| |__\ \ /__/ |__________| \__\
Toe can be expressed in two ways: as either an angle or a distance. If you want to express it as a distance, measure from the car's centerline to the center of the tire tread at the front of the tire, then subtract this from the distance between the car's centerline and the center of the tire tread at the rear of the tire.
For the front wheels of mass-market street cars, front toe-in is used to overcome compliance in the rubber suspension bushings and ensure that the front wheels never toe-out under braking (if they do, the car gets very "darty" just when you want it to be most stable). For the rears, toe-in is used to imrove stability under acceleration.
For race cars (or an NSX), front toe can be used, not as a reactive "fix" for the compliant-suspension design problem, but as a proactive way of improving the car's straight-line and corner-entry behavior, i.e., more toe-in for straight-line stability and more toe-out to make the car turn in. With small amounts of front toe-out, at corner entry (before the inside front tire gets unloaded), the inside tire's toe helps to steer the car into the corner.
Toe-in is dynamically stable; it will tend to self-correctively counteract any sideways forces applied to the car. Toe-out simply amplifies those forces, with often-scary results.
Some autocrossers like to run toe-out at the rear, since it lets them rotate the car into a corner faster. I wouldn't recommend this for a car that's EVER driven on the street, and it's completely unsafe for any car that's running at high speeds on a real track.