How low is too low?
 

My car rides rough. It's great if you want to loose some tooth fillings, but otherwise annoying. Could it be that it was lowered too far by a previous owner? Here is a photo: http://www.pelicanparts.com/pmpre/im..._Left_Side.jpg

The best way to tell is to measure from the ground to the top lip of a front and rear fender lip. Measurements are generally in the range of 24"-26". Going by your picture I would say your car is not too low, but if it has aftermarket torsion bars then it will be stiffer. Have you driven other 911's? Is it worse than usual?

It looks to me like your car is too low in the rear?? Maybe it's just the way the picture was taken.. Mine is 23.5 to fender in the rear and 23.625 in the front( give or take, I can't remember the exact #). Mind you, this is on my Club Racing car. If you are just street driving I would recommend raising it a bit. I can get you some numbers or hopefully another member will chime in here.

Cheers, James

Generally accepted numbers are 25" at the rear and 25.5 in the front, many people have gone lower, but I wouldn't go lower than by more than about .5" because you can run into problems blowing the shocks struts if you go to low among other things.

Wow, mine is darn near identical.....23.45 front & 23.55 rear. My car actually has a slight rake to it as well. fyi it has after market SB's & TB's w. revalved Bilstien sport shocks - very stiff - but I want it like that for AX/ DE/ TT purposes. Although stiff it is not jarring like the shocks are bottomed out (the way it used to be...!!)

I suggest getting your 911 suspension professionally set up, including corner balence, ride height and frt/rear alignment. It will make such a world of difference you will wonder why you waited... I just did and am very pleased !!!

Too low would be if the front lower A-arms are "beyond horizontal". When nearly stock, the arms angle downward toward the ball-joint. Acceptable lowering brings these A-arms flat ( with about 1-1.5" further lowering beyond "Euro"). Go beyond that and the A arms angle down toward the center of the car...no good!...very bad camber curve and diabolical handling !!!

---Wil Ferch

If you are riding rough, is it possible that the shocks are bottoming out. Some people (not recommended) remove the rubber bumpers that keep the shocks from bouncing when the car has been lowered, but that will eventually blow out the shock.

Unless you have documentation on the size of the torsion bars, the only way to find out is pull one and measure at the center with an open end wrench. If a 19mm open end just fits you have 19 mm t-bars, yada, yada. The rears are not easy. If you really want to get to the bottom of your problem, you will have to know the size of parts involved.

BTW: '77s came with a Huge washer on top of the front shocks (underneath and on top of the strut cover). That need to be removed before finalizing the height adjustment.

Good luck.