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Join Date: Jul 2003
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Ride height too low?

Hello,

Before installing my new front Bilstein HD inserts in Boge strut I did measure the ride height.
The center of the wheel (16") comes on 302 mm and the center of the torsion bar on 151 mm. The result would mean my ride height is 151 mm instead of the factory setting of 108 mm with a variance of 5 mm

Does this mean my car is already lowered entensively or did I mis-measure?

Should I get it back to the fact specs?

Any comments welcomed

Mike
Old 07-03-2003, 12:25 PM
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Can you tell me what the measurement is from the ground to the top center of the wheel arch. A normal measurement is in the 630mm - 650mm. If you are within that range then you are probably ok.

The Bilsteins may raise your car by 5 - 15 mm.
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Old 07-03-2003, 12:30 PM
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Why do most people on this board use ground to wheel arch height as an important measuement. Shouldn't we be using center of wheel/spindle to wheel arch. This will leave the measurment invariant of tire size/aspect ratio. I assume the purpose of ride heigth questions are for bump stops and suspension geometry.
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Old 07-03-2003, 12:43 PM
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Hi,

I'll check fender height tomorrow but on first sight it didn't appear to have raiseda lot but 15mm on the eye...hmm

I'll come back after the measure

Thx

Mike
Old 07-03-2003, 01:19 PM
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Quote:
Why do most people on this board use ground to wheel arch height as an important measuement. Shouldn't we be using center of wheel/spindle to wheel arch. This will leave the measurment invariant of tire size/aspect ratio. I assume the purpose of ride heigth questions are for bump stops and suspension geometry.
Because it's much easier!
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Old 07-03-2003, 01:43 PM
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Quote:
Why do most people on this board use ground to wheel arch height as an important measuement.
The physical measurements give a basic understanding of the car set up and ground clearance. The P-car should have a nose down attitude of about an inch. The ground to wheel well arch provides a basic measurement. After the car is corner balanced, that will most likely change. If corner balancing was only as easy as obtaining equal measurement . . .
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Old 07-03-2003, 01:50 PM
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If most cars are built close to the same and have close to the same height tires then it is an easy way to measure. I believe most people try to keep their aftermarket wheels pretty close to stock height, so the comparison should be possible, not as accurate, but a decent rough comparison.
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Old 07-03-2003, 02:15 PM
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It's a whole lot easier to just hold up a yard stick than crawl under there and measure the center line of the torsion bar to its axle.
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Old 07-03-2003, 02:59 PM
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I always measure it from the ground to the bolt heads that holds the cross member at the front, and to the center or bottom of the rear torsion bar. these two points eliminate the variance in the body work. To the fneder lip is OK for quick compairs, but to set the ride height I prefer the more consistant points represented by those I listed above.

Jim
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Old 07-03-2003, 04:12 PM
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Hello,

Did my indicative measurements before and after the fitting. Most of it seems to be 'in spec' of the 630-650 range.

With the initial measurement I already had the right frnt Bilstein installed.

Left front 635 mm (still Boge), right front 647 mm (new Bilstein)
Left back 643 mm, Right back 655 mm

After installing the second (left front) Bilstein I took the measurement twice to flatten the measurement. All done with full gas tank.

1st measurement:
Left front 634 mm, right front 642 mm
Left back 648 mm, right back 657 mm
Front rides some 15 mm lower than back.

2nd measurement after some bouncing:
Left front 632 mm, right front 640 mm
Left back 655 mm, right back 647 mm

So quite some different values. The back shocks seem shot too. On the rebound the lift up and back to balance, so don't work right. I will do my rear shocks next weekend, also HD's.
I guess I start with bringing the front both to 640 mm by highering the left front. At least this brings the front in balance and as a result will also lower the right back.

Any comments on these figures?

TIA
Mike
Old 07-05-2003, 12:41 PM
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Be Careful with just raising and lowering to get the car to look the same. By doing that without corner balancing you can end up with an unbalanced car that looks good, but handles poorly.
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Old 07-05-2003, 02:09 PM
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As you realize, the height at each corner is influenced by what happens at the opposite end of the car (more accurately, the opposite diagonal end of the car). There have been many examples here of car heights that seem to be fine, but have corner weights that are "weigh" off. This is a result of unequal weight jacking to adjust corner heights - car looks fine, but it's not balanced.

Here's a method to verify front or rear side-to-side heights are not being influenced by the opposite diagonal.

Transform your "4-legged stool" into a 3-legged stool. In this way, diagonal corners are eliminated and the rear (or front) corner heights sit at their own independent height, not influenced by anything else.

For example: If measuring the rear corner heights, jack up the front end using a single lift point at the middle front of the car. You can use the middle of the suspension crossmember as the midpoint. You now have a tripod; the front wheels no longer influence the rear wheels.

To measure front corner heights, use the middle of the transaxle mount bracket for the lift point.

The above has little to do with setting actual corner balance and exact corner heights, but I bet if you equalize side-to-side front and rear ride heights in this manner, the corner balance comes out pretty close.

Just an exercise in "what if".

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Old 07-05-2003, 06:15 PM
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Hi all,

I've finally made my measurement after installing the shocks at the back. I was planning to take a picture but the battery was flat...

Final heights now are:

left front 63.6 and right front 64.5; max diff 8mm
left back 65.3 and right back 66; max diff 12 mm

any comments on these final heights?

So it seems to be within the margin for difference between left and right. Also the back is some higher than the front, so nose down.
It seems the Bilsteins at the back lifted more than the front.

The car feels much better and the back isn't swaying anymore.

Next step will be to get the car aligned and corner balanced and this should complete the overhaul.

Thx fr all the assistence and comments still welcome.

Mike
Old 08-15-2003, 01:43 PM
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Quote:
Originally posted by masraum

The Bilsteins may raise your car by 5 - 15 mm.
It is not a 'may' condition......... Bilsteins will raise the ht. Take that into consideration before you ending up paying twice for lowering and alignment.

Sorry! This is somewhat a Bilstein-sore subject to me.
Old 08-16-2003, 12:00 AM
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My research indicates that the A arms should be level with a flat road surface. Any lower wil create problems. If you want to go much lower, you should consider raised spindles.
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Old 08-16-2003, 07:45 AM
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Actualy the A arms should angle downward slightly. With a slight downward inlcination they will cause the wheel to gain negative camber when the suspension compresses in a corner.

Horizontal or upwardly inclined A arms actually cause the wheel to lose negative camber when compressing in a turn! Not a good thing.
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Old 08-16-2003, 09:14 AM
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Thx guys,

Yes you're right in your comments and I haven't been clear on activities as part of the above mentioned aligment.
The guy from the aligment also mentioned the neg camber.

So as part of the alignment also ride height will be set to fact spec likely since I haven't cut the bumps tops of the HD's at the back - the front has none.

So I'll settle for the complete alignment incl camber/caster, corner weight and ride height.

Mike
Old 08-18-2003, 12:09 PM
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