Removed spare a while ago and...

[kam3ham3]

I couldn't find anything in the search so here goes..

I removed my spare tire a while ago and I recently noticed that the front is slightly higher than the rear...:frown: You can't really tell by looking at the car but it bothers me. The jacking points are about an inch higher in the front and the wheel gap about a 1/2 inch difference. Am I being subjected to more lift during driving? Maybe even getting worse gas mileage? Or is it too mild to do anything? I guess my only options are to live with it, lower it, or try to lighten up the rear. Maybe this is an excuse to start modding!:biggrin:

 

[Daedalus]

I couldn't find anything in the search so here goes..

I removed my spare tire a while ago and I recently noticed that the front is slightly higher than the rear...:frown: You can't really tell by looking at the car but it bothers me. The jacking points are about an inch higher in the front and the wheel gap about a 1/2 inch difference. Am I being subjected to more lift during driving? Maybe even getting worse gas mileage? Or is it too mild to do anything? I guess my only options are to live with it, lower it, or try to lighten up the rear. Maybe this is an excuse to start modding!:biggrin:

You're thinking that increased lift has permanently deformed your suspension such that the front sits 1/2" higher now than it used to? Not possible. Leaving springs completely relaxed for extended periods won't cause a permanent set. They are completely elastic in that range.
Regarding the 1/2" height difference, a 29.5-lb object-- ~15 lbs on each front tire--won't have much impact on stance. How much does 1 corner drop when you put your entire body weight on it? Say you put 200 lbs on a corner and it drops 1" (probably less). 15 lbs would equate to just over 1/16" movement at that rate, or way less than 1*. Even if you were getting some lift it would only improve gas mileage.
If you're looking to save weight in back, the exhaust is the easiest place to do it.

 

[nsxtasy]

A one-inch difference in the height of the jacking points is huge and is not normal.

Is it possible you are using oversized tires in front, or undersized tires in the rear? What are your tire sizes?

(Keep in mind that new tires have about 1/4 inch more tread depth, and ride height, than worn tires that need to be replaced, so this can be a contributing factor, too.)

Do you have the original stock suspension?

 

[kam3ham3]

So I guess that means the wheel gap was larger in front even with the spare. I sure need to lower it then. '92 Stock suspension with 95+? wheels. Tires say 225/45Z R16 and 255/40Z R17 and still have plenty of tread. Bought the car this way. I'm glad you guys know about this stuff because I sure don't.

 

[Daedalus]

There's just something not right about the measurement method. It's not possible to be 1" higher at the lift point but only 1/2" higher at the wheel well. Measure ground clearance while on level ground at the points shown in the manual.

 

[nsxtasy]

My '91 is stock ride height and has stock sized tires. Measuring from the flat ground to the bottom of the tabs for the four jacking points (not the ones in the middle), all four are between 4.5 and 4.75 inches. If yours is stock ride height and has stock sized tires, yours should be, too.

 

[kam3ham3]

It's probably my error. I basically raised the jack in the rear until it barely touched the jacking point then moved the jack to the front and measured the difference. This was all done on a driveway. I'll measure again on the street in the morning. Thanks for the input guys!

 

[Hugh]

On a stock car the distance from the bottom of the jacking tabs to the ground is 5.3". Get a few paperback books and slide them under the car until you get the right thickness. Measure the height of the books and check the four corners. You can also use a really thick phone book opened up to the right thickness.
If you have a quality tape measure you can use that too. Most tape measures measure exactly 3" on the side so get down there and slide up the tape and see the total distance.

 

[nsxtasy]

On a stock car the distance from the bottom of the jacking tabs to the ground is 5.3".

That's what the manual says. In reality, it can be less (as I noted above). There are various possible explanations for the difference. As I mentioned above, tread depth alone can account for a variation of 1/4".

In any case, there shouldn't be a significant difference between front and rear, other than due to tire tread depth.

Again...

What are your tire sizes?

Do you have the original stock suspension?

 

[kam3ham3]

225/45Z R16 and 255/40Z R17 on stock suspension

 

[ATERPAK]

The tire sizes you mentioned are not a problem for this car and will not cause the problem you are suggesting. Since they are within a 1/4" in circumference and well within the normal tire diameters of the stock sizes, your ride height differences are caused by something else. Make sure when you make your ride height measurements that the car is completely settled by either bouncing the suspension up and down or driving it a little and then back on a true flat surface. That should settle the suspension and then you will get your true ride height. Also when did you first notice this? Basically the NSX prefers a negative rake for proper handling. That is the front is lower than the rear.

 

[nsxtasy]

The tire sizes you mentioned are not a problem for this car

Yes, they are. The front size is much too big (3.9 percent larger than '91-93 stock, and larger than other years by smaller percentages) and may rub on the wheel wells. With 16" front wheels, you would be better off with the more commonly used 215/45-16 (the stock front size for '94-01) or even 205/45-16.

and will not cause the problem you are suggesting. Since they are within a 1/4" in circumference

Not necessarily true.

Depending on the year of your NSX, here is how the sizes you are using will change the ride height of your car:

'91-93: front +0.45", rear +.09"
'94-01: front +0.18", rear +.18"
'02-05: front +0.10", rear stock size

If your car is a '91-93, the oversized front tires are raising the front end by 0.36" more than the rear. If you were using 215/45-16, the front would be raised by 0.27" (0.18" more than the rear), and if you were using 205/45-16, the front would be raised by 0.10" (0.01" more than the rear).

As previously mentioned, the difference in tread depth between new tires and worn tires ready for replacement can be up to 0.25" at each end, and may also explain a portion of the difference, particularly if your rears are very worn and your fronts are not.

Basically the NSX prefers a negative rake for proper handling. That is the front is lower than the rear.

This is not a matter of looks. The jacking points should be the same distance from the ground, front and rear. His are not.

 

[ATERPAK]

Sorry Ken but I will have to disagree with you on the front tire size. I've been using that size for over 4 years now both for street and the track and have no fitment problems with rubbing or fender well clearance even on my lowered car. It fits and is a good match for the 255's in the rear.

 

[Hugh]

There's just something not right about the measurement method. It's not possible to be 1" higher at the lift point but only 1/2" higher at the wheel well. Measure ground clearance while on level ground at the points shown in the manual.

It is possible if you're using one of those bubble gum rulers on a hot summer day while under the influence of an illictly obtained recreational hallucinigenic. Then again he might have a 300lb bloated corpse in his trunk that he's failed to notice.

 

[nsxtasy]

Sorry Ken but I will have to disagree with you on the front tire size.

225/45-16 is significantly bigger than the stock front tires on any year NSX. On the '91-93, it is 3.9 percent larger in diameter than the stock tire, and the larger diameter raises the front end by almost a full half inch; when the rear tires aren't brand new, that - all by itself - is enough to create problems with the traction control system (unless you then get oversized rear tires to compensate for the oversized front tires). These are facts, not opinions. NOT RECOMMENDED.

 

[docjohn]

When I used to use 225/45/16 fronts the car did appear to be slightly higher in front,this plus if you were not on perfectly level ground could give the heads up stance you were mentioning.