dfinnegan

I've just seen a post from the 964 smartgroups list that suggests that lowering a 964 is not a good idea because it can have adverse effects on the rear bushings.

Quote (from 964porsche@smartgroups.com) regarding not lowering the 964:

I quite agree with you. The 964 does look better when it is slightly lower but there are major payoffs:
i) ground clearance is compromised and
ii) more importantly, the rear suspension was designed to have self-adjusting toe-in and when you lower the rear, you put extra pre-load into the flexible bushings that isolate the trailing arms from the body
No. I'd leave well enough alone unless you intend to do a lot of track work, or live somewhere that has very smooth roads! Cheers!

I have a lowered car and am curious if anyone has any input on this statement.

In particular, am I shortening the life of components of my rear suspension?

It seems to me that the suspension parts and design would be the same for US and ROW. That would suggest that the car was designed for the lowered height and, if anything, the US versions could provide some compromise.

N.B. I'd post to smart groups, but I can't seem to get reigstered as a poster! I'm not quite sure how I got registered for email. One of my browsings found me registered, but now I can't seem to get back to register for posting priveleges.

Cheers,
Dave

garrett376

I would not worry about the rear bushings. Bushings are bushings - when they wear out, replace them! I can't imagine that lowering the car will have any effect on increasing their wear rate.

RSAErick

European ride height is much lower than U.S. ride height - with the same bushings. I think that these cars were actually designed to ride lower than they do in the U.S., and are actually modified to meet U.S. ride height standards. I wouldn't worry too much about it.

Greg_L

why does the US have a standard for ride heights, is it due to road condition? Do manufacturers really have to up the ride height on certain sports cars?

garrett376

If I were to make an educated guess, I'd say it has to do with bumper height and the 5mph bumper regulations. A bumper is no good if it's much lower than everybody else's... so by keeping the bumpers at a particular height, a car can hit another car at 5mph and sustain no damage (my take on the 5mph bumpers!).

ltc

PAG does offer stiffer rubber bushings used on the 964 Cup cars:
Ride height 100mm (road surface to bottom of trunk)
Front and rear control arm bushings made from stiffer rubber
http://www.cupcar.net/92cup.asp
As for worrying about it, I leave that up to my mechanic each time he puts the car up on the lift!

ltc

964 Cup parts list (in case anyone is so inclined):
http://www.cupcar.net/techlib/92CupParts.htm

DarrylH

I'm sure this must be the reason. My car is lowered and it makes me nervous leaving it in a parking lot with tall SUVs, it would only take a small miscalculation while they're being "berthed" to crunch my rear decklid, front hood, etc. - I'm sure my bumpers wouldn't even come into play...it must also be the reason for those very attractive rubber bumperettes.

Bill Gregory

Easier said than done (that's a $ statement, as 964 rear bushings are replaceable by either monoballs or new spring arms...although I believe a company in the UK was developing bushing replacements?).

However, I agree that no one should get their pants in a bunch over lowering their 964. People have been lowering them for 15+ years, and I've yet to hear of one needing new bushings due to lowering.