How much coilover height adjustment can I get away with before it effects my alignment?

Hi everyone,

I’m an occasional autocrosser and I love the handling performance of my 84 VW Rabbit GTI that I own.  I’ve tried to keep the height of my suspension at a moderate drop and to keep as close to parallel on my control arms as possible, but now that I just bought new “show wheels” that have lower profile tires the urge to lower it some more is really gnawing at me.

I am of the age demographic that loves to slam their cars on the ground but I’ve always thought of extreme offsets and excessive camber as silly and a detriment to the handling and functionality of the car. 

With the new wheels however the itch to lower it a bit more of aesthetic reasons is very strong though. 

So here’s what I’m wondering:

If I were to adjust my coilover sleeve perches down an extra half inch roughly how likely is it that I upset my alignment on the car?

Is that small of a difference going to matter or not?

I had an alignment done recently and I would rather not have to have that redone just for a marginal amount of “cool points” considering the crowd I am trying to appeal to has airbags and/or camber that makes their car look like a stepped on Hot Wheels car so they won’t be impressed with how low I am anyway.

Only someone well-acquainted with the details of '84 Rabbit suspension geometry could give you an answer, but I wouldn't do it solely to impress stancebros. Maybe just leave it until you want to make another more practical suspension change that would require re-alignment and then do them all at once.

There are a lot of suspension designs out there where lowering by 1/2" would make a driver-noticeable difference to toe and camber so there is a potential to mess things up.

The Mk1 VWs are McPherson strut in the front. Camber isn't adjustable unless you have camber plates or your coilover has a provision for it. I wouldn't worry about messing up the camber, but you'll definitely want to do something with the toe once you've set your new ride height.

I don't know the answer to your question, but I couldn't help but think of a recent experience I had. 
 

Laserface said:

The Mk1 VWs are McPherson strut in the front. Camber isn't adjustable unless you have camber plates or your coilover has a provision for it. I wouldn't worry about messing up the camber, but you'll definitely want to do something with the toe once you've set your new ride height.

Lowering the car will mean more negative camber due to the camber gain built into the suspension. It doesn't need to be adjusted specifically, a change in camber is a side effect of a ride height change if nothing else is altered. It won't affect toe unless the Rabbit has terrible bump steer. Adjusting camber with camber plates, however, will affect toe.

My rule of thumb for Miatas is that you gain very roughly 1 degree of negative camber for every inch of ride height you lose. A strut car will lose less. So it comes down to how precise you want your alignment to be. 

Keep in mind that you'll also increase the amount of time you spend on the bumpstops - decreasing your static ride height without changing spring rate or anything else means you have less travel available to absorb a bump. This can be unpleasant and slow. I don't know the motion ratios of a Rabbit so I don't know how much wheel travel you'll lose with a 1/2" drop at the perch. That's likely to be a more noticeable effect than alignment changes.

So the answer to the original question - how much can I lower before it affects my alignment - is "none". Any adjustment will affect your alignment. Will it be enough to matter? That's a different question, and it depends on how sensitive you (and your car) are to alignment.

As said someone intimately familiar with the chassis would need to answer for sure. The op suggests that the control arms are close to parallel to the ground which means further lowering could actually lose camber, or be basically a wash. In theory there would be no toe change, but very few cars actually have zero bump toe, especially older cars and extra especially ones that have suspension modifications. Unless someone knowledgeable says it's not a concern, I'd want to at least check it afterwards.

Probably not a ton, but why do you want to appeal to stance bros anyway?

I built my car for me and no one else.

I get it, I'm a bit of a slave to fashion.

On the Miata, I'm lucky the ride height I have it at, and really like, works with the coilovers I have on the car (i.e. enough travel/spring rate).

On the E21, pretty much the same, though if I had my druthers, I'd go anywhere from a 1/4 to 1/2 inch lower.  I mean, I could...

Car looks really good where it is, so I'm ok with it.  I also have just a touch of bump steer.  I REALLY like how the car drives and handles, do I don't feel the need to go any further.  Even slave to fashion has it's limits for me.

You could always mark where the perches are, get a point of measurement for toe and do some before and after work.

I'd be surprised if a half inch would make it radically different, but then if it's enough that it accelerates tire wear, I also don't want to be the guy you blame for encouraging you.

Keith Tanner said:

Laserface said:

The Mk1 VWs are McPherson strut in the front. Camber isn't adjustable unless you have camber plates or your coilover has a provision for it. I wouldn't worry about messing up the camber, but you'll definitely want to do something with the toe once you've set your new ride height.

Lowering the car will mean more negative camber due to the camber gain built into the suspension. It doesn't need to be adjusted specifically, a change in camber is a side effect of a ride height change if nothing else is altered. It won't affect toe unless the Rabbit has terrible bump steer. Adjusting camber with camber plates, however, will affect toe.

My rule of thumb for Miatas is that you gain very roughly 1 degree of negative camber for every inch of ride height you lose. A strut car will lose less. So it comes down to how precise you want your alignment to be. 

Keep in mind that you'll also increase the amount of time you spend on the bumpstops - decreasing your static ride height without changing spring rate or anything else means you have less travel available to absorb a bump. This can be unpleasant and slow. I don't know the motion ratios of a Rabbit so I don't know how much wheel travel you'll lose with a 1/2" drop at the perch. That's likely to be a more noticeable effect than alignment changes.

So the answer to the original question - how much can I lower before it affects my alignment - is "none". Any adjustment will affect your alignment. Will it be enough to matter? That's a different question, and it depends on how sensitive you (and your car) are to alignment.

Learn me.

I just walked out and took a look at my Rabbit. Its lowered a good bit on coilovers, and the tie rods and control arms are both basically parallel with the ground. If I were to raise/lower it, this is going to change the angle of the tie rods in relation the knuckles. In my case, with the rear mounted R&P, raising the coilovers would pull the rears of the wheels together creating a bit of toe out.

Depending on the angle of OPs tie rod ends at the current ride height, he might gain or lose toe, but tow would change. Right?

I would say get it aligned. If you make a material difference to ride height it will affect things. I've done a bunch of alignments, granted I don't do the super precise race stuff many of the guys on here do, but I've seen how sometimes relatively small changes can make a material difference in the angles.

Tire are expensive compared to alignments. Lots of the chains will check it for free, atleast go get it checked before you eat up a grand in tires

Laserface said:

Keith Tanner said:

Laserface said:

The Mk1 VWs are McPherson strut in the front. Camber isn't adjustable unless you have camber plates or your coilover has a provision for it. I wouldn't worry about messing up the camber, but you'll definitely want to do something with the toe once you've set your new ride height.

Lowering the car will mean more negative camber due to the camber gain built into the suspension. It doesn't need to be adjusted specifically, a change in camber is a side effect of a ride height change if nothing else is altered. It won't affect toe unless the Rabbit has terrible bump steer. Adjusting camber with camber plates, however, will affect toe.

My rule of thumb for Miatas is that you gain very roughly 1 degree of negative camber for every inch of ride height you lose. A strut car will lose less. So it comes down to how precise you want your alignment to be. 

Keep in mind that you'll also increase the amount of time you spend on the bumpstops - decreasing your static ride height without changing spring rate or anything else means you have less travel available to absorb a bump. This can be unpleasant and slow. I don't know the motion ratios of a Rabbit so I don't know how much wheel travel you'll lose with a 1/2" drop at the perch. That's likely to be a more noticeable effect than alignment changes.

So the answer to the original question - how much can I lower before it affects my alignment - is "none". Any adjustment will affect your alignment. Will it be enough to matter? That's a different question, and it depends on how sensitive you (and your car) are to alignment.

Learn me.

I just walked out and took a look at my Rabbit. Its lowered a good bit on coilovers, and the tie rods and control arms are both basically parallel with the ground. If I were to raise/lower it, this is going to change the angle of the tie rods in relation the knuckles. In my case, with the rear mounted R&P, raising the coilovers would pull the rears of the wheels together creating a bit of toe out.

Depending on the angle of OPs tie rod ends at the current ride height, he might gain or lose toe, but tow would change. Right?

Change of toe with suspension movement is called bump steer. If you've got significant bump steer, you'll find handling problems as the car changes toe depending on how the suspension is compressing or extending. It's usually zeroed out as much as possible with carefully set geometry of all the various parts. It's a game of millimeters.  It's almost impossible to get to absolutely zero bump steer at the ends of the range, but as long as we're not talking about totally slamming the car the toe change should be minimal with a ride height change. This slamming problem is why drifters usually try to correct bump steer, but I suspect most of them are just buying shiny parts.

Remember, changing ride height just means you're sitting in a slightly different part of the suspension's arc when the car is at rest. It doesn't change the actual kinematics of the wheel. 

Keith Tanner said:

Adjusting camber with camber plates, however, will affect toe.

You can get away with a lot of camber plate adjustment on a car where the steering rack & tie rods are inline with the LCAs, but that's an odd case.

I would expect you are more likely to run into issues with roll center & limited travel than alignment but I am not too familiar with the rabbit.  If you have not welded the coil over sleeves yet you should be able to adjust the spring perch to limit suspension travel loss.  Keep an eye on the lower control arm angle & add roll center spacers if needed, you don't want to get into camber loss under compression.

When I revamped the suspension on my street Solstice,  which even at stock height is lowish, the shop I used were surprised that I didn't want to drop the car at all - that was about all they did for the kids bringing  their Japanese low riders in.

Bottoming your suspension to get in or out of your driveway would suck, as would suffering excessive bump steer trying to look 'cool' but apparently that is what motivates an awful  lot of owners.  Tire shops must love them!

In reply to Contradiction :

I've owned a Mk I chassis VW. (1988 Scriocco) IF the lower arms are only a bit off parallel the only thing you need to check is if the wheels are toed in or out. That you can check yourself with the help of a friend and a couple of straight edges and a tape measure. Look it up on how to measure toe. A bit of tow out is OK. Anything from "O" toe to 1/8" toe out is within spec.  The main thing with the arms past parallel is that as the car rolls in a turn you're going to lose camber. 

I wouldn't mind having my old wheels back (and my old car) if you run some new cool wheels....