European vs USA ride height for pre 78 cars

RPMClassic · 05-23-2003, 05:05 AM

Alot of talk about this with the newer cars. What about the older ones? IS there a bench mark that is used for proper US ride height verses euro? Thanks.

k9handler · 05-23-2003, 05:35 AM

not sure, but I like em lower than euro stock ride height. My guess for the euro ride height is 25.0 front and 25.5 rear...and I like it around 23.5 front and 24.0 rear.

now I would like to add a question to your post...how do I lower the rear of my pcar? The front is pretty simple...but I have no idea how to lower the rear.

RoninLB · 05-23-2003, 05:51 AM

k9handler · 05-23-2003, 11:01 PM

Ronin...
could you post some instructions on how to lower the rear?

I just can't seem to get the details in my head where I can understand how it works.

Thanks.

speeder · 05-23-2003, 11:34 PM

The way to lower the rear, or the front for that matter, is to turn the torsion bars. The cars have a *fine tune* adjustment possible F/R w/o removing bars, (probably what you are refering to on front, the screws), but it is really for corner balancing.

If you want to significantly change the ride height, you must remove the torsion bars, turn them a spline or two, then put them back in. After you accomplish your height goal, the car should be corner balanced. You can have even ride heights across an axle and still have a "three legged chair". And that will not be fun at the next auto-X.

The page that Ron printed from the spec book shows the factory way of measuring ride height; instead of measuring the height of fender lips, they measure the distance between center of wheel and T-bar. This is not neccesary, fenders can be measured for a preliminary target, then corner balancing will usually change the height(s) slightly. And BTW, the fender heights that you mention sound backwards, stock euro height would be approx. 25" rear fender and 25.5" front, which actually gives the car a slight forward (downhill) pitch due to the lower rear fenders. On most cars this rake or pitch is desirable for weight transfer F/R, or so I am told.

Lastly, I would strongly recommend that you pay a pro to do this and set up your suspension properly, (alignment, balance, etc.). I am a major DIY guy, rebuilding my engine as we speak, but I send the car out for this work, as does any Porsche shop that does not specialise in suspension work. A good 911 suspension guy can do this quickly and right for reasonable $$, it would take you mucho time and you would still have to send it for align and balance. Good Luck!

RoninLB · 05-24-2003, 12:24 AM

Quote:

Originally posted by speeder
A good 911 suspension guy can do this quickly and right for reasonable $$, it would take you mucho time and you would still have to send it for align and balance. Good Luck!

Hey H.D... Denis is ultimately correct.. do you still want info? What do you want to do to your car?...........Ron

k9handler · 05-24-2003, 05:15 AM

thanks...
I am attempting to lower the rear of my 911 since it currently has a nose down posture...where I am looking to level it out a bit. Granted I could simply raise the front to correct this...but I want the car lower.
I had the chance to have a very good Porsche guy drive a few laps in my car at the last event and he stated the rear needed to come down appx 1" and to have a corner balance done since the car was not balanced properly. So I guess I am in search of another wrench to take my money and my DIY list is a little smaller. This sucks!

Bill Verburg · Bill Verburg's Garage

The factory procedure posted by RoninLB is theoretically the best way to do it. But in practice most everyone just measures the fender heights as Denis posted.

My '76 C3 w/16" 205/55 & 245/45 tires and new Bilsteins at a tad lower than euro height measured ~25 3/8"f 25 1/4" r with a bit of l/r variance to get the corner balance right(ie rf/ rr were a tad higher and lf/ lr were a tad lower) The car had a slight nose down attitude which is an aero aid more than anything else

You might want to update the nonadjustable '75 arms to the later '77 on adjustable type prior to corner balance and ride height adjustment. It makes fine tuning a lot easier. WYIT the Elephant bushings look like a nice addition as well.

RoninLB · 05-24-2003, 07:54 AM

Quote:

Originally posted by k9handler

So I guess I am in search of another wrench to take my money and my DIY list is a little smaller. This sucks!

OK... now I have a clearer picture of what's happening..
- the factory method is great to measure relative to the fender method to see if your tub is twisted.
- I use a 3ft wood ruller and a level along the ruller side for consistant fender readings.
- adjustable rear spring plates make the job good entertainment.
- eyeball this thread for some serious DIY fun.

Toe Adjust Techniquest

Party hearty..................Ron

stlrj · 12:40 AM

Quote:

stock euro height would be approx. 25" rear fender and 25.5" front, which actually gives the car a slight forward (downhill) pitch

Try 27 1/2" to be more precise. I had to do it the factory way, just for smiles, and that's what European height equates to when using 108 mm from torsion bar center to wheel center. US height at 93mm came out to 27 3/4".

Where are people getting 25" from?

It took me 15 min. on my back, an 11mm socket and a tape measure to verify this.

The only reason I can think of why nobody bothers to do it the correct way is because it does require the abilty to convert mm to inches and then subtract which is lot to ask compared to putting a tape measure on a fender and a lot of assumptions.

Cheers,

Joe

stlrj · 12:41 AM

[oops!

speeder · 05-25-2003, 02:47 PM

Joe, I think that you f'ed-up your calculations somewhere, (maybe the mm to inches),

, because you are way off on stock ROW, (euro), ride height. Any one of the European or Scandinavian posters here can verify this.

RoninLB · 05-25-2003, 04:12 PM

Quote:

Originally posted by speeder

you f'ed-up your calculations. Any one of the European or Scandinavian posters here can verify this.

how about 3rd generation wetback from Ziti land?

I did a quick check from the factory numbers awhile ago.. don't remember the exact numbers.. but it was close enough to the fender act that it didn't cause a concern................Ron

stlrj · 11:41 PM

Quote:

Joe, I think that you f'ed-up your calculations somewhere

Denis,

Maybe I did. I'll double check my measurements tomorrow. I used 25.4mm to convert to inches...maybe that's where I f'ed-up.

What should I be using to convert from mm to inches?

Joe

speeder · 05-26-2003, 12:50 PM

Yes, 25.4 mm=1 inch, so that is not your problem, maybe you are not understanding the way that factory measures ride height? Stock height in front would be: Center of torsion bar, (body of car), 108mm below center of wheel hub. When I get the chance, I will measure the center height of front fuchs, height of T.bar center from ground, difference between the two, and fender height. How are you calculating fender height??

RoninLB · 05-26-2003, 01:47 PM

Quote:

Originally posted by speeder

When I get the chance, I will measure.
How are you calculating fender height??

yeah Den... and a sissor jack could move the height around for more info.. if your tire diameter is a stock number, then 4 corners would tell if your tub is twisted, I think..
I use a 36in wooden ruller and a small level to get the ruller perpendicular...............Ron

stlrj · 03:18 AM

I double checked everything and I still came up with the same 27 1/2" fender height. I found on ebay, what looks to be a very stock looking 911 whose height seems to be about the same heght if you gave it the yard stick test:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2416102832&category=10156

Speeder, which factory manual says anything about a slight downward pitch? Factory specs look pretty level to me.

Whenever I browse through ebay, I can always tell which ones were f'%*#d with by all the rake. Seems the only reason you don't see all the rake on 964s, 993s and 996s is because you need more then an 11mm socket...like lots of moolah for springs and things.

Joe

speeder · 05-27-2003, 02:22 AM

The factory spec book only tells ride height F/R, but if set to spec the car will have a slight forward rake. Like the one that you posted link to, if you look at the top of driver's door or rocker molding in the left profile shot you can see it. That car is pretty high, looks like stock U.S. height to me. My '82 was even higher, especially in the rear, w/ Bilsteins from factory the U.S. cars were sky-high in those days. I would believe that the specs for U.S. ride height would equal ~27", but the euro?

Here is a pic of my car after lowered to approx. 25", w/ slight rake as per factory, (w/ thigh-high dog for scale/comparison):

stlrj · 05-27-2003, 03:25 AM

Denis,

Your car looks stunning. The height looks about perfect. So if your rear is about 25", it looks like the front must be about 26". Am I close?

Joe

stlrj · 08:12 PM

Just wondering...does anyone else besides me own an 11mm socket and a steel tape?

I really would like to have someone verify the factory method and show me where I screwed up.

Thx
Joe