Ride Height - Fender Method vs. Torsion Bar Center Method

burgermeister · burgermeister's Garage

After getting my front suspension back together after a recent front pan replacement, I set the front height to what it was before the replacement, measuring 26 3/8" at the front fender (it's 25 7/8" at the rear).

Based on the generic accepted 25.5" front / 25" rear values from the Wayne & Bruce books, as well as this board, the car is a bit high, which is probably a good thing on Michigan roads.

When I measure using the Porsche spec (wheel center minus torsion bar center) I end up with a front "A" height of 302mm - 170mm = 132mm. That suggests my car is 24mm lower than the 108mm "euro spec" in front.

I have not taken the pain to accurately measure the rear torsion bar center, as this is slightly more involved on those pesky G50 cars. The car has a 13mm difference in rocker height rear to front (rear being higher), which works out to a bit more than 1 degree.

What's the scoop? Am I doing something really stupid (not totally out of character...)?

Is the 25.5 / 25.0 fender "spec" really 1" lower than the factory euro spec, and therefore 1.5 to 2.0" lower than US spec?

I can't imagine setting the front "A" height to the US spec 95 - 98 mm. The car would look ready for the Baja 1000. I don't remember them looking like that when I was a kid....

burgermeister · burgermeister's Garage

bump....

stlrj · 10:45 AM

Me thinks you hit a nerve here and confused us with the facts.

The term "Euro height" as used in this forum is a term used very loosely and is more about aesthetics than the true meaning as defined by the factory specifications.

Perhaps it would be better if we could all agree in calling it something else, like "looks good to me height" or "cool height," to avoid the confusion of factory Euro height specifications.

Personally, I'm with you all the way and have my suspension set by the book(strictly and not subject to interpretation, European height), which might seem a bit high to some, but from my drivers seat, there's no argument about the way it feels or handles.

Cheers,

Jose'

livi · 10-17-2007, 10:36 AM

Mine is set exactly to euro spec height (not surprisingly) and I think it "looks good to me".

stlrj · 10-17-2007, 10:54 AM

Hate to admit it but my Euro height ride "looks good to me" too.

nesslar · 10-17-2007, 11:09 AM

Quote:

Originally Posted by livi

Mine is set exactly to euro spec height (not surprisingly) and I think it "looks good to me".

How about a quick pic, please? Thanks!

burgermeister · burgermeister's Garage

Mine at what appears to be 1+" below actual (not "fender") euro ride height (this is as I bought the car, 25 7/8" rear fender and 26 3/8" front fender). It's been raining, so I haven't had a chance to get the car out for a shot with its current height - should be pretty similar though, I aimed not to change it much. Maybe a tad higher in front....

Looking forward to a pic from one of you "true euro height" guys! I might just change mine upward when I get into the rear suspension next spring...

Zeke · 10-17-2007, 03:58 PM

This has everything to do with overall tire diameter and less to do with comparing one car's height to another's. I can't tell from the pic because of the uneven ground, but the back "looks" high (if you're going by looks).

masraum · 10-17-2007, 04:08 PM

The pic above looks about like my '88 used to look, and I'm pretty sure it was at stock height.

burgermeister · burgermeister's Garage

Quote:

Originally Posted by milt

This has everything to do with overall tire diameter and less to do with comparing one car's height to another's.

As I see it, the Fender method (as well as the 'picture method'

) measures car height including tire. The torsion bar method measures available suspension travel, regardless of tire or wheel size.

I have stock sized tires on the car (205 front, 225 rear) in the stock aspect ratios. My wheel center to ground is right around 300 mm.

I think I need to get a torsion bar measurement on the rear of my car...

burgermeister · burgermeister's Garage

Quote:

Originally Posted by milt

I can't tell from the pic because of the uneven ground, but the back "looks" high (if you're going by looks).

Milt, your eyecrometer is beyond reproach!

I measured the rear "a" height as 5mm (tire radius is 295mm).
I re-measured the front, a bit more carefully. I get 128mm (tire radius is 298mm).

When I first read my Bentley, it said (I paraphrase) spec is for new cars, 10mm +-5mm lower than spec is for older cars. I assumed it was talking about SCs and longhoods when it referred to older cars. Then it occurred to me that the manual is a Carrera specific manual (84 - 89), so it must be talking about my car - and 19 years and 145K miles qualifies as older....

Soo... front "a height" spec for an older car can be taken as 118 +-5mm, and the rear as 6 +-5mm.

Thus, the rear is right on for an older car (11mm lower than new). The front is about 10mm too low even for the "older car" spec. And the fender method 25.5 front / 25 rear numbers appear to be quite a bit lower than european spec, even adjusted for older cars.

And Milt picked out a 10mm discrepancy from factory spec between front and rear ride heights, all from a semi-blurry photo of my car sitting on our gravel driveway. Hats off to Milt!