Suspension development

[kerbe2705]

@John Voules And imagine if the trailing edge of the front wheel pants could fold mechanically, making the pants shorter during low-speed driving, parking, etc, and extending to their aero position only when the vehicle’s speed reaches 45 mph. #TransformerPants!

[joshua-rosen]

Adjustable wheel pants height is what’s needed more than adjustable suspension. Adjusting the pants should be much simpler than adjusting the suspension. The pictures of the Gamma going over a small speed bump looks like it the pants have no chance of surviving a pothole. The pants only need to be low on highway’s, aero makes a minimal difference on city streets and back roads which is where you’ll encounter speedbumps and potholes, it would be ideal if the pants automatically lifted up when the speed drops below 50MPH.

[bryan.bowes]

I haven’t seen anyone talk about regenerative suspensions (example: GigPerformance.com) on this forum yet, but I don’t read them all.

Gig have a suspension that generates power from all the bumps in the road, similar concept to regenerative breaking. Seems like they are working on products for cars, not just semi trucks.

I could see this being put on the rear wheel, maybe all 3, but perhaps these things don’t work with all the computers the suspension they have had to put into it so far.

Would be fun to see what all you enthusiasts and engineers think.

[john-malcom]

A reminder. The engineereing for the delta (Production intent) Aptera is complete as are the arrangements for production parts. There will be no changes the the production LE other than those require to fix crash testing or other validation testing defects. The vehicle is well engineered for efficiency and production.

[wingsounds13]

I have long wondered why shock absorbers are not electromagnetic. This would certainly allow the recovery of energy from suspension activity as well as allowing the suspension to be actively tuned to the desired state and current driving conditions.

It’s high time that this came to be.

[david-marlow]

Could be a good for Aptera to evalute after production starts.

Especialy with the off road package.

• This reply was modified 1 year, 4 months ago by  David Marlow.

[Ciscokid]

I don’t see why not. I personally would be thrilled to know that an already efficiently designed vehicle can be made even more efficient by allowing add-ons like this. I’d think that thanks to their right-to-repair ethos, upgrades like this would be more than possible, they’d be encouraged! Right?

[Jeff]

Added cost, weight, and complexity.

Probably degrades ride quality.

All for a probably-close-to-negligible efficiency benefit.

No thanks.

If some other established automaker with boat loads of money to burn wants to dabble in this stuff and try to make it viable in an EV, more power to ’em. But I’m very skeptical.

There’s no way Aptera should be wasting any effort on this. K.I.S.S.

[john-malcom]

👍👍 Good response!

[Ciscokid]

Perhaps it’s not a fit, but do we know how much is this device’s claim for potential recovery on a vehicle like the Aptera, and how much it weighs? IMO, knowing this would be a better way to conclude if it’s something worth considering or not.

[george-hughes]

I wouldn’t be too quick to dismiss an active suspension system. That you might be able to engineer that system to be a net positive in regard to energy generation and there is more than enough to recommend the system.

Folks should remember the Xantia Activa still retains the record for the fastest time to pass the Swedish moose test. Citroën was able to achieve such outstanding results thanks to its unique active suspension.

I can’t help but imagine that properly engineered, such an advanced system of control may offer a ‘cloud-like’ ride with superlative handling as a listed extra-cost option whether or not it generates power. But if they can make it add a kilowatt or two when in motion, that’s good.

But what is amazing is when an active suspension anticipates the depth of the pot hole and calculates the degree of retraction to ‘jump’ the obstacle in real time transmitting barely a jostle in the process.

What would be particularly cool would be if the elements could be put in a kit for retrofits.

[john-malcom]

I am pretty quick to dismiss an active suspension system on the Aptera. There is no justification for considering such a thing for the current instantiation of the
Aptera if efficiency, cost, and producibility continue to be important. As such, an adoption of active suspension of any kind would violate all of these factors.

[george-hughes]

I don’t think anyone is suggesting an active suspension component – which incidentally if applied only to Aptera’s trailing wheel would be a quarter of the cost of a conventional active suspension on a four-wheeled vehicle – as anything but an extra-cost option for those who want the best level of comfort possible.

It would certainly not cost more than the rear motor addition and might be available as the premium edition of the FWD model. It’s overall weight would easily fall within the range established by the rear motor and ability of an active suspension for enhanced ride, comfort and handling is unquestioned.

Heck, it may even only be available as an after market addition.

These systems have been around in various format since the Citroen DS in 1955 and appearing on vehicles like the 57 Eldorado, 1999: Mercedes Benz C215 Self leveling fully active hydraulic Active body control. Available on the S, CL and SL models; 2002: Cadillac Seville STS, first MagneRide; 2004: Volvo S60 R and V70 R; 2010: Alfa Romeo MiTo Cloverleaf (DNA System based on Maserati‘s Skyhook technology); 2012: Jaguar XF Sportbrake, self-leveling air suspension; 2013: Mercedes Benz W222: Optional Magic body control. Self leveling fully active hydraulic system with road surface scanning electronics; 2013: Volkswagen Mk7 Golf R User-Selectable Electronically Controlled Shock Dampening (Dynamic Chassis Control (DCC)); 2019: Toyota Avalon Touring model (Adaptive Variable Suspension (AVS))

[Greek]

It actually makes great sense to have the rear wheel with an adaptive suspension. More than likely it will receive the brunt of pot holes and uneven roads. It will be much easier to avoid what comes up the road with the front wheels. There is a lot of merit in your thought, even though APTERA is not in the stage of going beyond prepping for what is on the books right now. It is definitely something that should be pursued once future upgrades are being developed.

• This reply was modified 1 year, 1 month ago by  John Voules.

[jesthorbjorn]

I thought I heard something about regenerative suspension in regards to the Tesla Semi and/or Cybertruck. That in turn brings to mind the relevance of weight. Seems to me that sprung weight will play a major role in the amount of energy that can be extracted by a regenerative suspension system. With the Aptera being so light, it is easy to imagine the diminished return easily tipping over into the not-worth-the-effort category.

All just moderately well educated best guessing on my part.

I don’t mind the KISS principle applied to my Aptera in this regard. I think it will be extraordinary enough.

[joshua-rosen]

It’s certainly an interesting idea. I can’t imagine that they could incorporate it in less than five years. They have to get over the giant hump of getting the car into production and then they have to ramp up production.

[george-hughes]

Active suspension systems are actually components that are inserted into the suspension at the damper/shock absorber.

https://www.clearmotion.com/ was the center of a discussion on Autoline afterhours.

It is pretty clear that this company is actively marketing its solutions and could probably adapt the system to the Aptera rear suspension.

The importance of Aptera in active suspensions is its three-wheel design provides a cost saving as you might be able to justify a single installation. My contention is adding an active suspension element to Aptera’s rear may solve the majority of issues folks have with the riding the crown of the road. I think these guys could build an active replacement for the rear shock in six months, not five years.

• This reply was modified 1 year, 4 months ago by  George Hughes. Reason: add link

[Jonathan]

Something like this could really move the Aptera to a new level in comfort, safety and functionality. My understanding is that this technology was inspired by Bose noise cancelling headphones over twenty years ago. Just as those headphones generate an opposing sound wave to cancel the incoming noise wave, the suspension pushes back when force beneath the wheel is lost. Basically it pushes the wheel down into the pothole to ride along the bottom rather than skip across the hole and collide with the road edge on the other side (which creates the shock that needs to be absorbed).

Push down into the pothole, ride up the other side back to the street = no shock to absorb and the car remains level. Tire contact with the road = control and safe handling. Follow the link to watch car equipped with Bose active suspension from about twenty years ago.

https://m.youtube.com/watch?v=eSi6J-QK1lwhttps://m.youtube.com/watch?v=eSi6J-QK1lw

[israel-contreras]

This is the number one issue for me. I cannot ride in cars that have stiff suspensions or flat wheels. From the looks of it in videos, the suspension looks to be very stiff. Until I can verify my back wont be killing me by riding in an aptera, I have to stay out. I bought a civic si once…i had to take it back. In fact I couldnt do any car with 17 inch or 18 inch wheels. The civic I ended up getting hd thicker tires with 16 inch wheels.

The other issue would be the amount of vocs inside the cabin.

[Mike-Mars]

> ” The civic I ended up getting hd thicker tires with 16 inch wheels.”

You could probably have just asked them to swap the wheels over. I did something like that on my current car (replaced 16s with 15s).

[israel-contreras]

I was torn between that and just getting an ex. I chose the latter since it was also possible the suspension on the si was very stiff. I have loved my ex since i got it.

[Shawgrin]

You may need to look at a seat issue for your back, most likely a lumbar support designed just for you. If you still worry about suspension, then you could go with a vehicle with air suspension. Roush engineered the Aptera suspension and they are known for their racing designs.

[israel-contreras]

I dont think it was a seat issue. The si I had had very thick cushiony seats that basically hugged my back perfectly. Ultimately I think it was a combination of the smaller tires and stiff suspension. Unfortunately, it looks like that is all evs are going to have. I would imagine thicker tires would cause more wheel resistance and reduce range.

• This reply was modified 1 year, 1 month ago by  Israel Contreras.

[Biker]

Aptera posted a video (derived from a previous webinar) about the suspension and chassis:

Chassis & Suspension — Aptera Engineering Update – YouTube

[ROMAD]

OK, starting at about 1:38 into the video, is the Front Suspension Architecture with two (2) fluid reservoirs, one of which is obviously for the brakes. Any idea as to what the “floating” one might be?

[Mike-Mars]

Coolant? The in-wheel motors are water-cooled.

[ROMAD]

It seems awfully small for that, but it may be the filler for a larger reservoir elsewhere.

• This reply was modified 1 year, 1 month ago by  Dennis Swaney. Reason: fixed typo

[wingsounds13]

The need for a large coolant reservoir assumes some degree of coolant loss and also a large range of coolant temperature. Hopefully there will be very little coolant loss in the system. As for temperature, EVs have a much lower coolant temperature than that of ICE vehicles. The lower temperature would result in much less expansion of the coolant and thus a much smaller reservoir would be needed.

[david-marlow]

I have not seen confirmation by Aptera that there are hydrolic brakes, I have seen in Elaphe info that there is an electric brake.

There are 2 other fluid systems;

coolent for the motors, batteries, electrical power componets, AC

windshield washer.

[ROMAD]

Look again, David, it is on top of a master brake cylinder which is mounted to a panel that has the accelerator and brake pedals attached.

• This reply was modified 1 year, 1 month ago by  Dennis Swaney. Reason: Added better description

[paul-schultz]

Most likely the power steering reservoir. Electronic Power Steering (EPS) still has hydraulics. The size of the reservoir fits with this assumption.

[ROMAD]

Interesting, as I understood that electrical power steering was used to RELACE hydraulic power steering.

[kevin-davis]

Reviving an older thread…

I am still concerned with scrub on the front suspension. Both tire scrub and the wheel pants dragging. The suspension is being forced inboard due to the hub motor, torque vectoring can only do so much.

I watched this video about the new Cayenne suspension today, and I’m still wondering why Aptera is going with single pivot instead of duel pivot geometry.

https://youtu.be/bGlNTHMliFY?si=mF8KVPyznNyjaL1o

• This reply was modified 7 months ago by  Kevin Davis.

[george-hughes]

I think the first thing to remember about the problem you point to is that, probably over the lifetime of motion of an Aptera, I’m thinking in terms of driving time, less than a quarter of a percent would have the wheel in full lock position. Those moments where you may experience this are almost always at low speed in a parking maneuver.

Further, the right to repair implies the right to improve or fail to improve. Concerns over this may lead to speed-based mini-skirts that descend at highway speeds and recede at under 25 miles per hour.

Or if that is too technically challenging, just remove the standard pant and install a less aerodynamic fender. It would impact distance at speed but how you use your range is pretty much a personal decision; you know like the decision to buy and Aptera in the first place.

I think it is important to grasp, also, that the reason for the scrub was also a choice by the team to offer a truncated turning circle. Less scrub, wider turning circle, more scrub comes from a tighter circle. Like many things, there are advantages to particular designs and disadvantages.

I’m still hoping for someone wanting to popularize active suspensions in the US will set up an Aptera with a rear wheel installation.

[john-malcom]

A lot of things go into the design/engineering of something like a vehicle suspension. For Aptera, some of those things certainly could be cost, simplicity, ease of manufacture, durability. The current Aptera suspension is the result of early reengineering of the original suspension by Roush. As you probably know, Roush is famous for racing car engineering. I trust that the result of that reengineering is the best fit for an Aptera (All variants) assuming appropriate testing and tuning to optimize performance.

An Aptera is a significantly different vehicle than an ICE Porche or BMW The ICE cars suspension design most likely is not optimal for an Aptera Solar EV.

as stated correctly, the suggested suspension is not new.

[kevin-davis]

This is mostly tongue in cheek, but also slightly a concern:

Roush is known for straight line speed, they work on Mustangs that are notorious for deadly crowd control.

More seriously, suspension geometry is important regardless of the propulsion method. Some vehicles can get away with a poor geometry because they’ll never be pushed.

A three wheel vehicle will need all the help it can get for stability. The amount of anti-dive and track width they have will cause a drastic kingpin axis and scrub. A dual pivot can salvage that.

[john-malcom]

Sounds like an engineer/engineering response. To that I would say only rigorous testing will reveal reality. You cannot discount the fact that Aptera succeeded in passing the Moose Test. A good preliminary sign of a good suspension design. And that was before extensive tuning for the production intent vehicle.

But, I will reserve final judgement until I see the test plan and the data resulting from multiple successful tests under a variety of conditions.

[kevin-davis]

Ha, I am what I am, but I’m also an enthusiast.<div>

I’ll point out that most sports cars fail the moose test… It punishes cars that rotate easily and favors cars that understeer like a wallowing pig

I’ll reserve judgement until I drive it as well, and I have not seen the numbers, but the cost benefit ratio has to be very close here. I want them to succeed as an investor and future owner.

</div>

[Kamakiri]

“I’ll point out that most sports cars fail the moose test… It punishes cars that rotate easily and favors cars that understeer like a wallowing pig”

Did you see the sway bar up front? It appears to me, a fair amount of work went into making it pass the ‘moose test’. In other words, tuning to help it rotate should be quite easy. You know for those of us perhaps crazy enough to want to do so.

[Kamakiri]

“A three wheel vehicle will need all the help it can get for stability. The amount of anti-dive and track width they have will cause a drastic kingpin axis and scrub. A dual pivot can salvage that.”

I’m not sure I understand your concern here. Anti-dive properties and track width don’t require double ball joints to adjust them. KPI and scrub properties, sure, but I don’t see how you’re deriving a problem or issue just from that.

[kevin-davis]

The anti-dive with a single pivot causes the top of the knuckle to be further back than the bottom. With a dual pivot, you can have that more upright and remove the risk of the pants dragging.

The wide track makes the tire scrub worse: the inside tire is traveling an even shorter distance. With the KPI being so far inboard, we’ll be literally dragging that inside tire. A dual pivot will not remove all that, but it will improve it.

[Kamakiri]

Still not sure what your specific issue is. There’s nothing about single ball joints top or bottom that preclude the ability to have 0° Caster if desired. I doubt there will be an issue with turning and spat/pants clearance otherwise I think they’d just give more clearance. Anti-dive properties have more to do with the angle of the inboard mounts.

With the ability to employ torque vectoring…I don’t know what the particular issue with scrub. I’d want double joint lowers but more for camber gain properties. Not even sure that would matter, all things considered.

[kevin-davis]

Yes, torque vectoring can eliminate the issue. However, last video talking about it said it would not be available at launch.

Yes, you can twist the wishbone to correct the caster but you’ll have horrible bump-steer.

Good engineering is worth it, especially when it is all CAD. The small incremental cost and part count are worth it to me. It isn’t for everyone, and that’s ok. Aptera cannot market as an electric supercar if the engineering is compromised. The competition is going to win on price and practicality, not everyone lives in Arizona with full sun… what is the next edge?

I am worried as an investor and hopefully an early owner.

[Kamakiri]

I think ‘tank steering’ won’t be available at launch, but that torque vectoring will. I could have that wrong.

I don’t see any of it being a problem with bumpsteer. Virtual points at the uppers and/or lowers would be more difficult, IMO…because you can’t have a virtual tie rod end or the end of the knuckle inside say the in-wheel motor. Sounds like you’re talking about some platform specific issues that don’t apply to Aptera.

[ROMAD]

“I think ‘tank steering’ won’t be available at launch,…”

Ooh, steering with laterals! BTDT

And yes, I know the M1 MBT uses a motorcycle handlebar-type steering system rather than lateral steering.

[Kamakiri]

More/additional real world problems changing to dual ball joints today would include:

Ruining the low drag of the upper arm

Dumping all the durability testing for cable routing

Complexity of aero covers for the lower arm

Revised bump stops, linkages, bushings, inboard connections, rack & location

Just gets worse the more I think about it…

[Kamakiri]

“I’m still wondering why Aptera is going with single pivot instead of duel pivot geometry.”

At this point in time the level of design completion and costs to revise it come into play.

I’d love such suspension refinement and geometry benefits of VPP/dual ball joint uppers and lowers, but it’s quite and unrealistic request…unless one is offering an 8-figure cash infusion for free. Otherwise, comparing a startup’s suspension design to any modern Porsche just isn’t fair.

[kevin-davis]

My ’06 BMW has dual pivot lower, it isn’t a new design. Also, the CAD work would have been an easy time to make the change… I haven’t heard of suspension castings yet so they still could.

The drawback, to your point, is money. It would require four castings instead of two, same with the ball joints. Not a horrible cost when factoring scale, but it is the kind of refinement that will be required if Aptera wants to claim supercar status. And they need supercar status considering the price point.

[Kamakiri]

Time or lack thereof is a bigger concern in my view. Even if cost wasn’t a real consideration, at this late in design and contract commitment, it would take a bit of Herculean effort to make this change today.

I think time and effort is better spent on the fine tuning of the suspension as it is. Because of the modular nature of the whole front suspension, it wouldn’t be too difficult to make the running change, but would wreak havoc on the part interchangeability of early and late builds. My guess is that a more advanced layout would be reserved for a later model.

[robert-wakeman]

I’ve been watching all the video of the car on test tracks I can find. How it handles on corners is what matters to me. How comfortable the ride is secondary to me. From everything I see it looks like this car will have incredible handling and be very nimble. Can’t wait to drive one!!!

[william-manewal]

I guess I’m greedy, but I want both out of the suspension system: Comfort and handling.

I used to think it was a zero sum game, but then I got a custom setup on Wilburs shocks on a BMW R1200R motorcycle and it was amazing! The bike handled much better through tight turns AND the suspension soaked up quick bumps so that it felt I was gliding on a waterbed.

I’m going to be driving my wife on a daily basis and she’s got enough back pain that I don’t want to add to it. Then I want to hit the twisties on weekends. Give me soft & control please.

[Sam]

I hope to have that comfort and good handling with a stock Aptera. 🤞