Show of hands… Adaptive Suspension

[SteveSchweer]

How many new Model S owners out there can actually FEEL the difference between “Sport” and “Comfort “? I know I can’t.… even though Tesla Service says it is functioning normally. No matter what I do with the suspension controls, my ride is the same… punishingly harsh. Yet, from these forums and YouTube, I see that many of you think the suspension is great. As this is probably one of the most sophisticated suspensions ever put in a car, I have trouble believing that mine is “functioning normally “. I think the key objective question here is “can you actually FEEL a difference in ride quality when you change suspension modes?” (By ”feel” I mean you KNOW it changed, if you just THINK it changed then it didn’t). It would really help me and, I know, a number of others out there to find out if our suspensions are screwed up or if that’s just the way they are. Thanks for any input you can provide.

 

[Veregon]

I tried to watch the g forces displayed on the screen. They move at millisecond speed so they are difficult to see. They did appear to vary within the same range, regardless of suspension mode. BUT, the important thing is the difference in modes will be OBVIOUS if the suspension is working properly.… if you can’t FEEL it, it isn’t working. So, I’ll count you as “not working “. Are you driving a Long Range?

LR with 21" Arachnids.

 

[SteveSchweer]

I just performed an electrical test of my suspension. The adjustable dampers each have a proportional, solenoid controlled valve to adjust compression damping, and another to adjust rebound. I’m not sure, but I believe that these operate by the application of a variable voltage to the solenoid… at 0 volts, a spring holds a tapered plug in an opening, preventing the flow of oil and rendering the damper maximally stiff. As the voltage is raised, the tapered plug is lifted proportionally allowing the oil to flow through more freely and softening the damping. I unplugged one of the two-conductor wires and connected a volt meter. Then, with the car in drive mode, I set the “ride comfort “ to firm…. The reading was 0 volts (as expected). With ride comfort set to soft, however, it STILL read 0 volts. It would appear that no control signal is being applied the dampers which would explain why there is no change in the ride. I had asked Tesla Service to perform this test, but they didn’t do it. I Think that they did a complete visual inspection and computer diagnostic evaluation. So, we know that the system is assembled properly and is at least ready to work properly… it’s just not being told to do anything. This means that the problem is software or firmware.
This is just speculation, but could it be that the “chip shortage “ is involved here? Maybe the limited number of “good “ chips are going into the Plaid models?

 

[maximizese]

I just performed an electrical test of my suspension. The adjustable dampers each have a proportional, solenoid controlled valve to adjust compression damping, and another to adjust rebound. I’m not sure, but I believe that these operate by the application of a variable voltage to the solenoid… at 0 volts, a spring holds a tapered plug in an opening, preventing the flow of oil and rendering the damper maximally stiff. As the voltage is raised, the tapered plug is lifted proportionally allowing the oil to flow through more freely and softening the damping. I unplugged one of the two-conductor wires and connected a volt meter. Then, with the car in drive mode, I set the “ride comfort “ to firm…. The reading was 0 volts (as expected). With ride comfort set to soft, however, it STILL read 0 volts. It would appear that no control signal is being applied the dampers which would explain why there is no change in the ride. I had asked Tesla Service to perform this test, but they didn’t do it. I Think that they did a complete visual inspection and computer diagnostic evaluation. So, we know that the system is assembled properly and is at least ready to work properly… it’s just not being told to do anything. This means that the problem is software or firmware.
This is just speculation, but could it be that the “chip shortage “ is involved here? Maybe the limited number of “good “ chips are going into the Plaid models?

That's very fascinating troubleshooting on your part. The next thing to do would be to talk to Tesla about this (good luck) and try to replicate this on both owners who feel there's no difference among the various adaptive suspension settings AND with owners who feel some difference. Of course this will only prove or disprove your theory and doesn't really do much to actually solve your problem, but you'll be doing Tesla's work for them. But then it makes you wonder if they're already aware of the issue and just not saying anything about it. The sad part is that we generally have a deteriorating trust with the company, though at least this isn't a major factor in drivability and safety.

If your theory is correct, I wouldn't be surprised at all if the Service Advisors/Technicians are kept in the dark from engineering/managment's decision to proceed to build a product where the adaptive dampening system simply does not work from at the time of sale. If it is just a software/firmware glitch, just hope that Dennis Nedry isn't on the job.

 

[SteveSchweer]

Actually, this IS a major factor in both drivability and safety…. The roads here in MI are so awful that trying to negotiate them with this (lack of) suspension is just too much punishment. My wife can’t ride in this car as 10 minutes of violent shaking sets off a 5 day migraine headache. And safety? Encountering bumpy pavement on a hard corner causes this car to go skipping and hopping to the outside of the curve! Scary!

 

[David29]

What tires is Tesla using these days on the Model S? Especially curious for cars with the 19" wheels....

 

[MNDan]

I’ve got 19” wheels at 38 psi and the ride is jarring around the neighborhood. Highway driving is pretty smooth.

 

[SteveSchweer]

If we are going to make the case that many Model S LRs have a service problem, we need one more thing. My test, I believe, shows what the problem cars don’t do…. We need to know what a functioning car does do. So…. I am making a plea. Would one of you happy Plaid owners out there whose suspension makes an obvious mode change, volunteer to perform the same test on your car? It requires no tools or disassembly of the car, and you could become a HERO to Tesladom! Here’s what to do: Raise the suspension to its maximum height. Crank the yoke hard to the left. Look over the top of the left front tire… you will see a black cylinder, about 4 in. Long, attached to the front of the shock strut. It has two wires attached to it, one at the top and one at the bottom. Depress the locking tab and unplug one of them. Looking into the end of the plug, insert a short (1 or 2 in.) piece of solid wire into each conductor. (I think it’s about 25 gauge wire but a small size paper clip might do). Attach a volt meter, set to “DC Volts” to the wires. Now, have an assistant step on the brakes and put the car in drive. Then go to Controls, Suspension, Advanced and select Ride Comfort - firm. Note the voltage. Move the slider successively to the softer settings, noting the voltage at each. That’s it! You would really be doing us a great service. This information will change the argument from “I don’t like the ride “ (answer: ”get over it “) to “there is a measurable, malfunction in my car “…. Fix it!

 

[mswlogo]

One way I used to test the setting on my Raven Model X was finding a not to big speed bump and cruise over it (not crawl). I don’t recall speed. But there was a huge difference in that on sport I had to crawl over the bump and on comfort I could cruise without losing my front teeth. I left it on comfort.

It was hard to tell difference just on the highway. But never had issue in comfort being “harsh”.

 

[mswlogo]

If we are going to make the case that many Model S LRs have a service problem, we need one more thing. My test, I believe, shows what the problem cars don’t do…. We need to know what a functioning car does do. So…. I am making a plea. Would one of you happy Plaid owners out there whose suspension makes an obvious mode change, volunteer to perform the same test on your car? It requires no tools or disassembly of the car, and you could become a HERO to Tesladom! Here’s what to do: Raise the suspension to its maximum height. Crank the yoke hard to the left. Look over the top of the left front tire… you will see a black cylinder, about 4 in. Long, attached to the front of the shock strut. It has two wires attached to it, one at the top and one at the bottom. Depress the locking tab and unplug one of them. Looking into the end of the plug, insert a short (1 or 2 in.) piece of solid wire into each conductor. (I think it’s about 25 gauge wire but a small size paper clip might do). Attach a volt meter, set to “DC Volts” to the wires. Now, have an assistant step on the brakes and put the car in drive. Then go to Controls, Suspension, Advanced and select Ride Comfort - firm. Note the voltage. Move the slider successively to the softer settings, noting the voltage at each. That’s it! You would really be doing us a great service. This information will change the argument from “I don’t like the ride “ (answer: ”get over it “) to “there is a measurable, malfunction in my car “…. Fix it!

I’d consider doing this if I had my car. Still a few weeks to go.

But why restrict your test to Plaid owners.

And what does working vs not working look like on the volt meter?

I agree it sounds like some cars have a service issue based on the wide discrepancy of opinions on harshness and the effect of adjustment.

Have you measured one that works? How do you know if the car doesn’t need to be moving to activate the valve?

 

[SteveSchweer]

I’d consider doing this if I had my car. Still a few weeks to go.

But why restrict your test to Plaid owners.

And what does working vs not working look like on the volt meter?

I agree it sounds like some cars have a service issue based on the wide discrepancy of opinions on harshness and the effect of adjustment.

Have you measured one that works? How do you know if the car doesn’t need to be moving to activate the valve?

Your questions, I believe, are answered… read “show of hands” from the top. Thanks for the offer of help!

 

[MNDan]

I hope you find a volunteer!

 

[DBV1]

Thanks for that input. We need to get a feel for how common this problem is. I think that a lot of owners don’t realize that they have a problem. Service doesn’t help as they, I believe, are too dependent on error codes. If it doesn’t generate an error code, and associated instructions on what part to replace, they insist that nothing is wrong. I tried to get them to take voltage measurements at the shock solonoids or simply bounce the fender up and down to check the damping rate. Simple, time tested diagnostic techniques are simply not in their repertoire. (BTW bouncing the fender on my car is similar to trying to bounce the kitchen granite countertop.).

Same thing happening with my suspension. I would love to drive a refresh S, of someone’s that says it works well. Tesla tells me mine is within specs, which is hard to believe.

 

[SteveSchweer]

They told me that too. The problem is, I don’t believe that their diagnostics CAN measure this problem. They are set up to monitor whether the wiring is intact, (no shorts or opens) and whether the control voltages are within specs. The problem, I think, is that 0 volts is a perfectly reasonable control voltage. The fact that the control voltage is CONTINUOUSLY 0 volts doesn’t throw an error code. That would require the diagnostic system to make judgments about the appropriateness of the settings.… something I’m sure is beyond its ability.

 

[jaguar36]

I suspect this is all coming down to a difference in perception and expectations rather than any actual issues with the system. One mans jarring ride is another mans sporty suspension.

 

[DBV1]

I suspect this is all coming down to a difference in perception and expectations rather than any actual issues with the system. One mans jarring ride is another mans sporty suspension.

I don’t think so. At least coming from BMW, the ride is neither sporty or comfortable. And it is not even a close comparison.

I think there is a real issue, but not all cars are experiencing it. I would ike to ride in one where someone thinks it is a good suspension and then if it a good, I would know that my car is faulty. It is awesome that Steve above is testing it and worth seeing where that goes.

 

[glide]

I suspect this is all coming down to a difference in perception and expectations rather than any actual issues with the system. One mans jarring ride is another mans sporty suspension.

Nope. No change across all 4 options means there is a problem.

No one is debating their perception of what a “sporty” vs. “comfort” ride is.

 

[SteveSchweer]

One thing I should edit… I just tried to access the solenoid without removing the wheel… you CAN reach it, but you’ll have trouble attaching the volt meter. So, best to remove the wheel. Mea culpa! .. those wheels are REALLY wide!

 

[DFWBrad]

I suspect this is all coming down to a difference in perception and expectations rather than any actual issues with the system. One mans jarring ride is another mans sporty suspension.

If Steve's test theory is correct, and it's throwing off 0 volts at all drive "levels" than there is actually an issue and not just perception.

 

[SteveSchweer]

Re-re-edit… it occurred to me that “jack mode” (necessary for removing the wheel) could disable ALL suspension function… not just the air springs. So I did my test again with the wheel on. Also, I used the top wire (easier to access). It was a little harder to get the test wire stubs inserted, but doable.. and easier than removing the wheel. This time the voltage was not quite 0.. it was .045 across all comfort settings (firm to soft). My guess is that to operate a solenoid you will need something like 0 to 12 volts.

 

[nilesborg]

Definitely something wrong with your cars then. There is a very noticeable difference on my plaid between comfort, sport, and track mode.

100% agree. There is a very noticeable difference in the suspension dynamics in each of the modes. The steering modes are noticeable as well. With sport setup I can rally this thing in the twisties like a 911. Maybe ya'll are not driving those refreshed S's like you should be