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Suspension Judder

Saksak said:
Did they test drive it? If the air suspension isn’t leaking, there are a host of other suspension parts that could be the cause. It could even be a control problem from flaky signals due to wiring harness or sensor. I would think monitoring the sensors and control inputs to the suspension would give more insight.
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Between the 4 different wheels, there are a lot of articulation points in the suspension. The air part might be fine, but there could be a bad/loose joint, and it seems worth getting them all checked. Asking them specifically about the air suspension might have given them tunnel vision about what to check for.
 
Saksak said:
Did they test drive it? If the air suspension isn’t leaking, there are a host of other suspension parts that could be the cause. It could even be a control problem from flaky signals due to wiring harness or sensor. I would think monitoring the sensors and control inputs to the suspension would give more insight.
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Thanks @Saksak, I hadn't thought about that but it makes sense given that apparently there's nothing physically broken in the suspension; this gives me something substantial to get back to them.
They did ride with me but were dismissive. The tech said "since it's up to spec, other drivers might have the same but don't notice it". All BS, as every person who's been in my car has noticed and mentioned it.
 
TahoeMichael said:
Between the 4 different wheels, there are a lot of articulation points in the suspension. The air part might be fine, but there could be a bad/loose joint, and it seems worth getting them all checked. Asking them specifically about the air suspension might have given them tunnel vision about what to check for.
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Thanks @TahoeMichael, I think you're right as I went to the SC convinced it was the air suspension and that's what I asked them to check.
 
Excessive side-to-side play when going over bumps could be a loose ball joint or an alignment issue. I'd press for them to check both.
 
EarlyAdopter01 said:
Excessive side-to-side play when going over bumps could be a loose ball joint or an alignment issue. I'd press for them to check both.
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Thank you! Making notes with all these useful suggestions to press them for a round 2.
 
Subscribed. With just inventory, I supposedly am in the cue to test a non-DHP car. I'm optimistic. I originally found DHP too soft, in Soft mode.
The two suspensions both have adjustable Bilstein shock valving, "adaptively" changing for each Soft, Swift, Sprint. These could be stuck. Also the valves between the three chambered air, or DHP, could also be stuck closed. Gemini affirmed a couple things for me:
-Single chamber air is a bigger chamber than one chamber of the 3-chamber suspension
-Three chamber air, combined, is a greater volume than the single chamber.
-Three bags of lower volume, than single, can have their valves closed creating a higher spring rate, despite a larger sum of air.
The central goal of 3-chamber, I think, was getting away from how air suspensions firm as they lower (lower air volumes progress the spring rate), but it can also offset stiffness when the rubber airbags over-fill (higher volumes tension the rubber bags). (I wonder if the latter issue is mitigated by some break-in X000's miles. Maybe driving in Sprint mode, highest possible setting, can stretch them?). Either way, the shock valving has a 500hz (500 times a second) ability to adjust its valves and the air valves are also continually active (they aren't just for height). Lots can go wrong. IMO, bad ball joints make noise, or affect steering / vibrations. They don't typically create vertical stiffness.

It would be good to know DHP, non-DHP, and in what mode folks experience these issues? I'm used to coil suspensions and finding a happy place with shock valving, while keeping spring rates constant.
 
gamix said:
Subscribed. With just inventory, I supposedly am in the cue to test a non-DHP car. I'm optimistic. I originally found DHP too soft, in Soft mode.
The two suspensions both have adjustable Bilstein shock valving, "adaptively" changing for each Soft, Swift, Sprint. These could be stuck. Also the valves between the three chambered air, or DHP, could also be stuck closed. Gemini affirmed a couple things for me:
-Single chamber air is a bigger chamber than one chamber of the 3-chamber suspension
-Three chamber air, combined, is a greater volume than the single chamber.
-Three bags of lower volume, than single, can have their valves closed creating a higher spring rate, despite a larger sum of air.
The central goal of 3-chamber, I think, was getting away from how air suspensions firm as they lower (lower air volumes progress the spring rate), but it can also offset stiffness when the rubber airbags over-fill (higher volumes tension the rubber bags). (I wonder if the latter issue is mitigated by some break-in X000's miles. Maybe driving in Sprint mode, highest possible setting, can stretch them?). Either way, the shock valving has a 500hz (500 times a second) ability to adjust its valves and the air valves are also continually active (they aren't just for height). Lots can go wrong. IMO, bad ball joints make noise, or affect steering / vibrations. They don't typically create vertical stiffness.

It would be good to know DHP, non-DHP, and in what mode folks experience these issues? I'm used to coil suspensions and finding a happy place with shock valving, while keeping spring rates constant.
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While my GT was at the shop for a month while they tracked down a front-end droning noise, I had a loaner GGT. (They did find the issue thankfully, wheel bearings and a half-shaft were replaced on one side.)

Now that I have mine back, the loaner seems to have ridden softer than mine does in general and felt less "busy." They both have 20/21's and were at the same tire pressure. I'm now wondering if there is something amiss with one or more of my shocks. The loaner did have maybe 500 more miles on it, so that could be a factor too.

Is this something that is easy to check?
 
eelpout said:
While my GT was at the shop for a month while they tracked down a front-end droning noise, I had a loaner GGT. (They did find the issue thankfully, wheel bearings and a half-shaft were replaced on one side.)

Now that I have mine back, the loaner seems to have ridden softer than mine does in general and felt less "busy." They both have 20/21's and were at the same tire pressure. I'm now wondering if there is something amiss with one or more of my shocks. The loaner did have maybe 500 more miles on it, so that could be a factor too.

Is this something that is easy to check?
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There can be weird issues. On mine they took it three times for over two months to try and diagnose suspension clunk. Eventually it turned out to be a loose main HV battery tray that was shifting the chassis over bumps, and not the suspension at all. They will keep throwing parts at it until they find what it is. For better or worse.
 
What if you cycle it through the drive modes? Can you feel the dampers tighten up progressively?
 
I've got a loaner now too, but my car has the "big" wheels. The loaner has the 20/21 combo and I can tell it rides smoother. Some of this is down to the increase in sidewall. However over larger bumps, even the lower shimmies. The good ole wag of the body, which I think is something you can't get rid of.

I fully admit though, the 22/23 might have been a mistake. The car looks great hard parked and slammed but the ride quality definitely isn't the best. In fact I wonder how the Gravity with the smallest wheel combo rides.

I want to test the grip on the 20/21 Primacy, but the damn loaner has a speed limit of 88. I've bumped into the limiter so many times in the past week. I didn't realize how often I make it past 88 when just making quick passes or coming off a cloverleaf into the freeway.

The grip from the 22/23 tire is great and I owned the car and didn't lease I consider getting a second set of wheels, the smaller aero wheels, just for comfort.
 
NoseyReporter said:
I've got a loaner now too, but my car has the "big" wheels. The loaner has the 20/21 combo and I can tell it rides smoother. Some of this is down to the increase in sidewall. However over larger bumps, even the lower shimmies. The good ole wag of the body, which I think is something you can't get rid of.

I fully admit though, the 22/23 might have been a mistake. The car looks great hard parked and slammed but the ride quality definitely isn't the best. In fact I wonder how the Gravity with the smallest wheel combo rides.

I want to test the grip on the 20/21 Primacy, but the damn loaner has a speed limit of 88. I've bumped into the limiter so many times in the past week. I didn't realize how often I make it past 88 when just making quick passes or coming off a cloverleaf into the freeway.

The grip from the 22/23 tire is great and I owned the car and didn't lease I consider getting a second set of wheels, the smaller aero wheels, just for comfort.
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I have the 20/21s on my Gravity GT with the Hankook all seasons and the corning grip is surprisingly good. I'm actually blown away honestly. And this is coming from someone who regularly tracked an Audi S4 and a Tesla Model S P85D with Michelin summer tires.
 
illopp00 said:
What if you cycle it through the drive modes? Can you feel the dampers tighten up progressively?
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me? nope, not that I can discern.

There were a fair number of things that were different in the GT loaner: it was a 7-seater, no comfort and convenience package, no tech package nor DD2Pro and built three months earlier. both mine and the loaner have the Dynamic Handling package so the three-chamber Bilsteins should be the same.

One other thing that's a possibility. Since the loaner didn't have the Tech package there was no HUD. Since I have that, I set the seat lower on mine as that gives more of a straight-on view to the HUD for brightness & clarity. Something that I find greatly annoying and I guess has something to do with the chosen polarizer. What I could be partially feeling is the seat being closer to the chassis/frame and vibrations hit differently.

I watched a Bilstein tech video of what it takes to replace their adaptive shocks. Way more involved than I imagined (this was a Mercedes).

Next time mine is in for something... because, well ahem, it's a Lucid (we're going to have a recall later in the year for the back seat motors it seems anyway), I'll definitely have them make sure all four shocks aren't damaged and run diagnostics for proper pressures.
 
With the dynamics I experienced in non-DHP, between Smooth to Sprint, I'd hope it is easily noticeable with DHP. The OP mentioned tracking, where going through tires faster is what acquainted me with how "Yoko's" have much more sidewall flex, than "BFGs" despite being the same size, same pressure. Different tire brands/models sort of prove rubber a variable, possibly in airbags too.

I have my own spring compressors, etc., but still am tempted to go air. So masochistic, I think, as I own RIVN and read about sheering toe-links and this week's NHTSA investigation, not helped by air-ride height adjustments. I also did inboard SDU seals, for coil Model S, and found the SC doesn't even stock them because of all the half-shafts, and a seal revision, the vast majority of air-suspended Model S's have gone through. I love the coil sprung Lyriq's luxury ride, just not its range/charging.

Without my digging its sources, AI offered that Gravity may fit 19" square setups (all 4 corners same) and warned to be sure wheels can support ~2k pounds. I'd seriously consider not limiting to 20/21, if I ever pull the trigger, as the possibility of cross-rotating square 20's or 19's would likely have me dumping whatever a Gravity comes with. No mystery, its the larger wheels that can sell for less in the used market, despite the upcharge. Just wait.
 
my GGT shudders like the warning for lane deviation warning when in my lane and hit a bump and if if put on blinker it goes away....
 
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