questions about suspension geometry 101

[NissanMan97]

Im reading up on suspension and im coming across questions I cant answer for myself. Im only posting this thread so that some will PM me and possibly help me with my question or at least help me to work them out myself. I will delete the thread tomorrow or a MOD can do so now. I dont want to waste thread space with dumb noob questions. Thanks in advance

B

[MorpheusZero]

Ask away. Nothing wrong with posting it publicly.

[NissanMan97]

Originally Posted by MorpheusZero

Ask away. Nothing wrong with posting it publicly.

in reference to the camber curve:

Am I to understand that if you dropped you car 2" you would be at -1 camber? But by adjusting the camber back to static (0 on the curve), that if the car where to travel UP 2" on the lowered suspension you would be at a +1 camber? or is it the other way around? If i were to lower my car do i want to adjust the camber or leave it alone? Im completely new to this, the extent of my knowledge is that you can lower a car and it looks better that's it, so apologies for the noobness i exude.

B

[MorpheusZero]

Originally Posted by NissanMan97

in reference to the camber curve:

Am I to understand that if you dropped you car 2" you would be at -1 camber? But by adjusting the camber back to static (0 on the curve), that if the car where to travel UP 2" on the lowered suspension you would be at a +1 camber? or is it the other way around? If i were to lower my car do i want to adjust the camber or leave it alone? Im completely new to this, the extent of my knowledge is that you can lower a car and it looks better that's it, so apologies for the noobness i exude.

B

That's fine. Your first assumption is correct, although really that curve I had thrown up was just an estimate so you'd "get the gist" and not at all exact.

Whether you correct the camber is up to you. There are a few upsides and downsides to having negative camber. Either way, if you lower your car your toe will be off so you'll probably want to get an alignment afterwards.

Camber correction methods either come in the form of bolts (cheap, not very exact and some say they can break) or camber plates (very hard to find if you don't have coilovers). I had my camber set to around -1.8 degrees for my purposes, I found with my driving it suited me well and wore the tires pretty evenly. But I drive aggressively and like taking corners quickly. If you don't, then you might want less camber. But I'd never leave it at 0, maybe .75 degree of negative camber is what I'd use for a DD.

While we're at it though, you probably don't want to lower the car 2" unless you like bottoming out or you have full-tap coilovers.

[NissanMan97]

Originally Posted by MorpheusZero

That's fine. Your first assumption is correct, although really that curve I had thrown up was just an estimate so you'd "get the gist" and not at all exact.

Whether you correct the camber is up to you. There are a few upsides and downsides to having negative camber. Either way, if you lower your car your toe will be off so you'll probably want to get an alignment afterwards.

Camber correction methods either come in the form of bolts (cheap, not very exact and some say they can break) or camber plates (very hard to find if you don't have coilovers). I had my camber set to around -1.8 degrees for my purposes, I found with my driving it suited me well and wore the tires pretty evenly. But I drive aggressively and like taking corners quickly. If you don't, then you might want less camber. But I'd never leave it at 0, maybe .75 degree of negative camber is what I'd use for a DD.

While we're at it though, you probably don't want to lower the car 2" unless you like bottoming out or you have full-tap coilovers.

thanks.

that makes a little more sense now.

as for the last part, i dont plan to drop my car 2", id like a nice drip for visual purposes and a lower center of gravity along with anti sway bars and the such to control body roll (at least this is what people are telling me). I want to drive aggressively when i get the urge but i want an all around smooth ride if i decide to take her out of town.

my next question is: you talk about custom extendable ball joints, tie rod relocators and LCA's ( im guessing this is lower control arm? i want to have my acronyms correct). this sounds like a lot of work, is it? is it necessary to have? what adverse driving issues will it have? what will it do to the rest of the car if you dont have these? ie: more wear and tear than normal

B

[MorpheusZero]

Originally Posted by NissanMan97

thanks.

that makes a little more sense now.

as for the last part, i dont plan to drop my car 2", id like a nice drip for visual purposes and a lower center of gravity along with anti sway bars and the such to control body roll (at least this is what people are telling me). I want to drive aggressively when i get the urge but i want an all around smooth ride if i decide to take her out of town.

my next question is: you talk about custom extendable ball joints, tie rod relocators and LCA's ( im guessing this is lower control arm? i want to have my acronyms correct). this sounds like a lot of work, is it? is it necessary to have? what adverse driving issues will it have? what will it do to the rest of the car if you dont have these? ie: more wear and tear than normal

B

More wear and tear if you toe steer off the road into a ditch but other than that, not really. The entire post explains why you'd want that stuff, and it won't be cheap to get it custom made (no one makes them for the A32), think $1.5k for custom control arms and everything. You can do stuff yourself but no one here has had the means and cared enough to do so (not even me).

All of the cons that come with crappy geometry are felt when you drive the car, besides that your tires may wear a more due to a different ackerman and dynamic toe changes. You will be ok lowering the car, but it'll start to behave differently if you lower it too much. You can generally lower an A32 by about 1.5" before you'll notice a lot of that stuff.

And as for sway bars, I haven't seen any sways for the front, and the rear sway bar is rather controversial (although it does tighten things up in the rear it adds another 15lbs unsprung weight and makes the rear even less independent). I had a rear sway bar and liked how it made the car feel. The stock front sway bar didn't do all that much for the car to be honest, just get stiffer springs and good dampers (Konis).

[SALTIMA02]

MorpheusZero great info...mind if i ask you question. I have a 02 altima 5spd, d2 coilovers and adjustable rear endlinks. My car is pretty low and i know im cambering in the rear. What i wanted to know is to what degree should i put the negative on? I love taking corners plus im always challenged by some my of buddys with z's.

[SALTIMA02]

Sorry nissanman97 not trying to thread jack, just wanted to get alil more educated on negative camber

[NissanMan97]

Originally Posted by MorpheusZero

More wear and tear if you toe steer off the road into a ditch but other than that, not really. The entire post explains why you'd want that stuff, and it won't be cheap to get it custom made (no one makes them for the A32), think $1.5k for custom control arms and everything. You can do stuff yourself but no one here has had the means and cared enough to do so (not even me).

All of the cons that come with crappy geometry are felt when you drive the car, besides that your tires may wear a more due to a different ackerman and dynamic toe changes. You will be ok lowering the car, but it'll start to behave differently if you lower it too much. You can generally lower an A32 by about 1.5" before you'll notice a lot of that stuff.

And as for sway bars, I haven't seen any sways for the front, and the rear sway bar is rather controversial (although it does tighten things up in the rear it adds another 15lbs unsprung weight and makes the rear even less independent). I had a rear sway bar and liked how it made the car feel. The stock front sway bar didn't do all that much for the car to be honest, just get stiffer springs and good dampers (Konis).

thanks for the info.

like I said i dont want to low and 1" or so all the way around and the ability to take corners a little faster that normal, so im guess 1 to 1.25 in the negs on camber would suit me fine, that sound about right?. i dont mind spending money for good springs/shocks or coilovers but i dont want to spend extra on stuff that i dont NEED or that Im not going to take advantage of (to me its like nitrous, yea its cool as hell but ill never use it).

now i mentioned spring, shocks and coilovers. i know those are a whole new monster. can we discuss them?

B

[MorpheusZero]

Originally Posted by NissanMan97

thanks for the info.

like I said i dont want to low and 1" or so all the way around and the ability to take corners a little faster that normal, so im guess 1 to 1.25 in the negs on camber would suit me fine, that sound about right?. i dont mind spending money for good springs/shocks or coilovers but i dont want to spend extra on stuff that i dont NEED or that Im not going to take advantage of (to me its like nitrous, yea its cool as hell but ill never use it).

I think factory spec is in between +.5 and -1.5 degrees of camber. If you're going to drive aggressively then I'd say between -1.2 and -1.5 would generally do you well. The maxima can never really have too much negative camber up front.

However, honestly, you will already get around that area if you lower your car by an inch or an inch and a half. It will probably be better just to get suspension, set it at the ride height you want and leave the camber alone.

now i mentioned spring, shocks and coilovers. i know those are a whole new monster. can we discuss them?

B

Sure. What do you want to know?

[MorpheusZero]

Originally Posted by SALTIMA02

MorpheusZero great info...mind if i ask you question. I have a 02 altima 5spd, d2 coilovers and adjustable rear endlinks. My car is pretty low and i know im cambering in the rear. What i wanted to know is to what degree should i put the negative on? I love taking corners plus im always challenged by some my of buddys with z's.

Well, your altima really is not the same caliber car as a Z33, but having owned a highly modded max I can safely say that doesn't necessarily mean that balls of steel won't overcome the two cars' potential difference.

It really depends on a bunch of stuff and is dependent on your car. If you want to be really aggressive, start with some wide wheels (on the light side), sticky tires (think Z1 star specs, kumho XS, bridgestone RE11, or some street legal track tires like the Nitto NT05 or Toyo R888) hopefully at least 8" wide and 225-245 on the tire width. As far as camber goes, you will probably want to consult other knowledgeable Altima drivers but I'd say -2 in front and -1.5 in the rear is a good starting point to really start reeling in the Zs on the corners. Also try zero toe in the front (a little bit of toe-out in front for better turn in but more vague steering feel and tire wear) and the rear.

Don't forget to get some in the proper fitment (offset) for your car.

[98SEBlackMax]

Originally Posted by NissanMan97

in reference to the camber curve:

Am I to understand that if you dropped you car 2" you would be at -1 camber? But by adjusting the camber back to static (0 on the curve), that if the car where to travel UP 2" on the lowered suspension you would be at a +1 camber? or is it the other way around? If i were to lower my car do i want to adjust the camber or leave it alone? Im completely new to this, the extent of my knowledge is that you can lower a car and it looks better that's it, so apologies for the noobness i exude.

B

IMO 2" drop on a A32 is too much for optimal handling and ride quality, it looks good though. I've run several ride heights on a similar road course (NHMS) and found that stock and near stock ride heights had the best performance and decent ride quality. Granted it looks goofy on 17s without a drop.

I would lower the front suspension with coilovers until the lower control arms are parallel to the ground and no more. Any more of a drop messes with the camber curve and requires you to dial in static negative camber to compensate. However even with the LCAs nearly parallel I still use -1.4 camber with the Stillen plates, as was said negative static camber on these cars is a good thing. Howerver until someone makes adjustable LCAs for A32s I am sticking with this method of lowering.

I try to "cheat" on lowering to get a lower center of gravity without messing up the suspension geometery. To get the COG lower I run shorter tires on the track and have weight reduced alot of stuff above the COG (ex. CF Hood/Trunk, stuff on top of the engine, etc). I'm also going to machine some 1/2" engine/transmission spacers to lower the engine and transmission.

Also if you can't find camber plates you can notch the upper strut housings and the strut bolt hole for a cheap way to get more negative camber and positive caster. Definitly something you would want a pro to do if your not familar with the process. I'm notching the upper strut towers this winter so I can get some more positive caster/negative camber. Never use those "camber bolts" on a track driven car I've heard of to many bad stories.

But most of important of all is a good set of sticky tires. I run 235/40/17 Nitto NT01s on 17 x 8.5 Enkei RFP1s. With all the suspension work and tires the car corners pretty well with a little bit of nagging understeer. I even managed on my last track event to elongate my front NISMO wheel stud threads, I now have to run ARP wheel studs. I don't know if it is an indicator of how good the car handles but gives an idea of how much force the wheel studs/rims are subjected to.

[NissanMan97]

Originally Posted by MorpheusZero

I think factory spec is in between +.5 and -1.5 degrees of camber. If you're going to drive aggressively then I'd say between -1.2 and -1.5 would generally do you well. The maxima can never really have too much negative camber up front.

However, honestly, you will already get around that area if you lower your car by an inch or an inch and a half. It will probably be better just to get suspension, set it at the ride height you want and leave the camber alone.



Sure. What do you want to know?

other than the obvious difference with them what other differences do they have? is one better than the other? do springs/struts have an advantage over coilovers and vice versa?

B

[MorpheusZero]

Originally Posted by NissanMan97

other than the obvious difference with them what other differences do they have? is one better than the other? do springs/struts have an advantage over coilovers and vice versa?

B

The term "coilover" can be misleading. Coilovers are basically a full suspension package that replaces your entire spring/strut assembly. So, included are struts, springs, and generally camber plates and rear strut mounts, although not always.

The more important part, though, is that coilovers are a full conversion to generic springs so you aren't limited to the springs available specifically for your car, you can get any 2.5" (or whatever) diameter spring in any rate and run them. Also important, and the main defining characteristic for coilovers, is that they have a threaded body, so you can move the spring perch up or down and adjust ride height.



The regular strut's on top, coilover conversion is on the bottom. Note a few things:

The lower spring perch for the non-coilover system is huge. That's because it has to hold these springs, which are also huge, and specialized:



The lower spring perch on the coilover conversion is smaller, and is on a threaded strut body so you can adjust the perch height, effectively adjusting ride height.

Here's the assembled coilover:



It uses small, standardized, linear rate springs instead of the specialized "maxima only" springs that a spring/strut setup would use, which I don't have a picture of besides the above. Coilovers also typically come with shortened struts, allowing you to go lower without bottoming out.

Coilovers:
Ride height adjustment, you can generally go lower than conventional springs
Widely available standardized, linear rate springs that are light, cheap and easy to find different rates for
Shave some weight off (generally around 30lbs of partially unsprung weight, no huge deal but it's nice)
Most of them come with camber plates so camber is adjustable and pillow ball upper mounts lead to more responsive handling (although also more noise and a less compliant ride)
The GOOD off-the-shelf coilovers will have dampers that are valved for their spring rates, and they tend to offer a lot of adjustability.
Tend to be expensive.

Springs/struts:
Cheaper
Tend to be progressive-rate
Are typically easier to work with
Offer no camber adjustment in the package, you'll have to source camber plates (very hard to find) or crash bolts if you really want camber adjustment
Valving for the struts is ambiguously matched, although most of them are adjustable, as a suspension noob you probably are not going to know what to adjust them to
Can't go as low (but a 1.5" drop should be ok, just cut an inch or so off your bump stops and don't go any lower than that)

[NissanMan97]

Originally Posted by MorpheusZero

The term "coilover" can be misleading. Coilovers are basically a full suspension package that replaces your entire spring/strut assembly. So, included are struts, springs, and generally camber plates and rear strut mounts, although not always.

The more important part, though, is that coilovers are a full conversion to generic springs so you aren't limited to the springs available specifically for your car, you can get any 2.5" (or whatever) diameter spring in any rate and run them. Also important, and the main defining characteristic for coilovers, is that they have a threaded body, so you can move the spring perch up or down and adjust ride height.


The regular strut's on top, coilover conversion is on the bottom. Note a few things:

The lower spring perch for the non-coilover system is huge. That's because it has to hold these springs, which are also huge, and specialized:


The lower spring perch on the coilover conversion is smaller, and is on a threaded strut body so you can adjust the perch height, effectively adjusting ride height.

Here's the assembled coilover:



It uses small, standardized, linear rate springs instead of the specialized "maxima only" springs that a spring/strut setup would use, which I don't have a picture of besides the above. Coilovers also typically come with shortened struts, allowing you to go lower without bottoming out.

Coilovers:
Ride height adjustment, you can generally go lower than conventional springs
Widely available standardized, linear rate springs that are light, cheap and easy to find different rates for
Shave some weight off (generally around 30lbs of partially unsprung weight, no huge deal but it's nice)
Most of them come with camber plates so camber is adjustable and pillow ball upper mounts lead to more responsive handling (although also more noise and a less compliant ride)
The GOOD off-the-shelf coilovers will have dampers that are valved for their spring rates, and they tend to offer a lot of adjustability.
Tend to be expensive.

Springs/struts:
Cheaper
Tend to be progressive-rate
Are typically easier to work with
Offer no camber adjustment in the package, you'll have to source camber plates (very hard to find) or crash bolts if you really want camber adjustment
Valving for the struts is ambiguously matched, although most of them are adjustable, as a suspension noob you probably are not going to know what to adjust them to
Can't go as low (but a 1.5" drop should be ok, just cut an inch or so off your bump stops and don't go any lower than that)

wow thats a lot bigger difference than i was expecting. so basically is down to money and how picky you are?

you talked about progressive rate and liner rate...im guessing you are talking about the spring rate, right? (no laughing people serious noob when it comes to this ). I know enough about math to see the measurement that is used and understand it somewhat but how does it apply to the car world? what the advantage of changing to a higher or lower one?

B

[MorpheusZero]

Originally Posted by NissanMan97

wow thats a lot bigger difference than i was expecting. so basically is down to money and how picky you are?

Pretty much. If you don't mind a lack of ride height adjustability and just want a lower car with a more aggressive feel, go for springs/shocks. If you want the "cream of the crop" or want a really aggressively sprung car or like to be able to dial in spring rates, ride heights and damper firmness, go for coilovers. My personal favorite (and the pictured suspension) was ground control coilovers with shortened Koni struts, but this is much more of a pain to piece together than off-the-shelf coilovers, but the good ones will run you $1k+ for a set.

you talked about progressive rate and liner rate...im guessing you are talking about the spring rate, right? (no laughing people serious noob when it comes to this ).

Yes. And don't worry, you're doing pretty well.

I know enough about math to see the measurement that is used and understand it somewhat but how does it apply to the car world? what the advantage of changing to a higher or lower one?

B

Linear rates tend to be more predictable

Progressive rates are an attempt to ride well and handle well since under severe body roll your outside spring will have an elevated rate, as well as sort of helping prevent bottoming out at any given ride height and static spring rate. Personally I don't like them, to me they are like a crappy damper--unpredictable.

Higher spring rates tend to be harsher and tend to overpower most dampers more (creating uncontrolled oscillations, i.e. a "bouncy" ride), but they also make for more responsive handling, less body roll, dive and squat, and they communicate the road surface to the driver better, much like a heavier steering feel. Most coilovers have a much higher spring rate (generally ~2x as high) as aftermarket maxima springs.

[DAVE Sz]

Originally Posted by MorpheusZero

The lower spring perch on the coilover conversion is smaller, and is on a threaded strut body so you can adjust the perch height, effectively adjusting ride height.

Here's the assembled coilover:

How do you adjust height on those since the mounting bracket itself isn't movable like on the ksports, for example? The one perch I see is the one you would use to adjust preload...

[MorpheusZero]

Originally Posted by DAVE Sz

How do you adjust height on those since the mounting bracket itself isn't movable like on the ksports, for example? The one perch I see is the one you would use to adjust preload...

Ground controls are single-tap, so there is only preload adjustment.

I could have gone into single and full-tap coilovers but there would have been a lot more explaining to do and I wasn't sure if he was interested.

[98SEBlackMax]

Ground controls only adjust the ride height. IIRC they come close to have little to no preload when the collar sits on the spring perch. I never installed them like that on my car, I did this instead.



If you see in between the threaded collar and painted welded pipe there is a dull black metal spacer. This was done so that the springs have no preload other than the helper springs when the car is jacked up.

Any slop or loose springs when the suspension is jacked up and they fail it for safety inspection in Mass, well depends on the shop doing the test.

[NissanMan97]

Originally Posted by MorpheusZero

Ground controls are single-tap, so there is only preload adjustment.

I could have gone into single and full-tap coilovers but there would have been a lot more explaining to do and I wasn't sure if he was interested.

Please do explain if you dont mind

B