Does lowering 911 front end require realignment?

[dave123]

My 77 911 ride height is 27" front and 25" rear (ground to wheel well).
I would like to lower front end 1.5". Will I need to do a new alignment?
The usual advice is 25/1/2" front and 25" rear
25/25 just gives more nose down assuming front and rear tires are close to the same OD

yes, realign
yes, corner balance

[Showdown]

Not necessarily but it’s probably well advised.

[winders]

Not necessarily????

At 1.5" lower? Yes, it will absolutely need an alignment.

[Nditiz1]

Also with Julian, not necessarily. I adjusted ride height to balance the car after setting toe, camber, caster. The balance, which changed the ride height, made the car track straight. Can't say this will happen with all rides, but as Julian also said check to be sure after. Most importantly is to maintain correct balance whenever messing with ride height. These cars are very picky with balance. You may lower the car and the alignment be off, but it's because you are now 3 legs long on a 4 leg chair.

[winders]

Originally Posted by Nditiz1

Also with Julian, not necessarily. I adjusted ride height to balance the car after setting toe, camber, caster. The balance, which changed the ride height, made the car track straight. Can't say this will happen with all rides, but as Julian also said check to be sure after. Most importantly is to maintain correct balance whenever messing with ride height. These cars are very picky with balance. You may lower the car and the alignment be off, but it's because you are now 3 legs long on a 4 leg chair.

Dude, an inch and a half!!!

The car will go from having some toe in to having toe out. Also, you are going to gain quite a bit of negative camber. You don't want toe out on a street car and too much negative camber will be problem too.

Of course the corner balance is going to change. Of course the roll center in the front is going to go underground which will actually increase roll.

[Showdown]

Counterpoint Scott, maybe lowering the car will return it to proper alignment that was thrown off when it was raised…

All I’m saying is that it may not be necessary but probably a good idea to check.

[winders]

Originally Posted by Showdown

Counterpoint Scott, maybe lowering the car will return it to proper alignment that was thrown off when it was raised…

All I’m saying is that it may not be necessary but probably a good idea to check.

I can't believe some the craziness I read here.

Terrible logic....

The car would have been aligned at the current ride height at some point unless someone raised it which is highly unlikely.

It would be a terrible idea to not check the alignment. It's not like the ride height is being changed 1/8" here. The 1.5" change is HUGE!!

[dtwa]

If you lower an inch and a half, the critical thing to deal with would be the change in toe. That can be a DIY fix.

If corner balance is a concern the tripod method (also DIY) will get you close.

Just my 2 cents.

—Dave


Sent from my iPhone using Tapatalk

[Showdown]

Originally Posted by winders

The car would have been aligned at the current ride height at some point unless someone raised it which is highly unlikely.

I can’t believe some of the craziness I read here!!!

Yup, because every time a car is raised or lowered it gets a proper alignment: wonderful assumption.

The point here is that the car should be checked now and after lowering to see what if anything it needs and then that should be addressed.

It may need a lot, it may not. Nobody knows, least of all us idiots barking back and forth on the internet.

OP; lower the car: there are plenty of threads on how to do it. The front is easy, the rear ain’t. Then check the alignment; again, plenty of threads on how to do that. It’s not terribly hard to align a car- it takes time, patience and a bit of tenacity.

[chapo]

minor changes in suspension settings absolutely require checking alignment. Nuts to think otherwise

[winders]

Originally Posted by Showdown

Nobody knows, least of all us idiots barking back and forth on the internet.

Please speak for yourself...nothing I have said here has been idiotic. I can't say the same for certain others that have posted in this thread.

[Showdown]

Love you, Scott.

[boyt911sc]

Originally Posted by dave123

My 77 911 ride height is 27" front and 25" rear (ground to wheel well).
I would like to lower front end 1.5". Will I need to do a new alignment?

Dave,

Stock ‘77 911 does not have adjustable spring plates. Even with the adjustable plates, it would only make approximately a 3/4” max. height change. In order to achieve a 1.5” height change, you have to re-index your rear torsion bars. And could require multiple trials to get to your goal. The change in ride height to 1.5” is quite significant and the wheel alignment would definitely be affected. The final measurements should tell you what parameter/s need to be corrected/adjusted.

The camber will be most affected by this alteration. Toe-In to be determined. Having an adjustable spring plates would make your job much easier. Good luck.

Tony

[J Geiger]

I heard American Porsches were raised 1”.

How much difference is there between European ride height an American?

[Bill Verburg]

Originally Posted by J Geiger

I heard American Porsches were raised 1”.

How much difference is there between European ride height an American?

'75-'83 US 911 were raised 9+/-mm compared to RoW versions

[J Geiger]

Hello
Sorry I didn’t mention my 911 is a 1988 Carrera Cab.

[76FJ55]

Originally Posted by J Geiger

Hello
Sorry I didn’t mention my 911 is a 1988 Carrera Cab.

No difference between US and ROW for yours.

[dannobee]

An inch and a half is huge. Unless you've fixed the bump steer in a way similar to what I've outlined here https://forums.pelicanparts.com/porsche-911-technical-forum/1119373-bump-steer-check.html and have corrected the toe change so that it doesn't change through a few inches of travel, then yes, it will definitely need an alignment.

[PeteKz]

Agre with dannobee and winders: 1-1/2 inch drop is significant enough to affect alignment. Based on my measurements, the front wheel arch ends up about 26-1/2" when the front suspension height is set according to specs. Of course, that depends on wheel and tire combos too, but your 27" measurement sounds like it's higher than the spec right now.

Winders also mentioned the roll center. If you go lower than the stock height, the roll center changes to cause the front of the car to roll more strongly than the rear, which causes changes in oversteer/understeer. You also will reduce the operating range of the front shock, and you will be almost riding on the rubber bumpers in the shock, which will change the ride harshness. Proceed carefully and incrementally. Don't drop it the full 1-1/2" at once. Do it in 1/2" steps and test drive in between.

Nditz1 mentioned corner balance. Listen to his advice. These cars are very sensitive to corner balance and will pull left or right, fooling you into thinking it's the alignment. Get the camber and caster set, then check the corner balance, especially if the car pulls slightly to one side.

IMO, the "right way" to lower the front is to spend the coins to raise the spindles on the struts, or buy new struts with that feature.

[nickelplated5s]

There's a thread over on Early911 about someone with handling problems with a 67. My user name over there would find it. I'm skeptical but here's the claim; OP cut 1" off of the shock rod and re-threaded the same. Thought about it and the only way I can think to do it is run a die down existing threads. Double nut the top to hold it for the die. Interesting idea and might work. My solution was short throw shocks with internal strut bushings. No need to raise the spindles.