DeDion Rear

[E90400K]

If Slate wants to use as much part commonality as possible, why not just go struts all around and use the same suspension front and back? Use a suspension link in place of the tiered for the rear hubs. An IRS should easily handle a 1,400 pound payload.

Pickup box intrusion maybe?

 

[AnnDee4444]

Depending on how it's designed, a De Dion suspension could use the same struts as the front suspension.

Related:

Why The Slate EV’s Unconventional Rear Suspension Makes Perfect Sense

https://www.theautopian.com/why-the-slate-evs-unconventional-rear-suspension-makes-perfect-sense/

 

[E90400K]

Depending on how it's designed, a De Dion suspension could use the same struts as the front suspension.

Related:

Why The Slate EV’s Unconventional Rear Suspension Makes Perfect Sense

https://www.theautopian.com/why-the-slate-evs-unconventional-rear-suspension-makes-perfect-sense/

That article doesn't address the question.

 

[Ewwgas]

If Slate wants to use as much part commonality as possible, why not just go struts all around and use the same suspension front and back? Use a suspension link in place of the tiered for the rear hubs. An IRS should easily handle a 1,400 pound payload.

Pickup box intrusion maybe?

This would be a poor design for a few reasons, most obvious to me is the camber curve when the truck is loaded.

Also You would also get bump steer in the back, which would be sktecy. You would also have a weird axis of rotation that would be flat if both front and rear matched, then as the roll center moves around during braking and cornering the tendency to oversteer or understeer would randomly switch depending, the truck would be super unpredictable.

Depending on how it's designed, a De Dion suspension could use the same struts as the front suspension.

Slate would need to add features to the strut for it to mount and pivot through its rage of motion, on the front it would be fixed to steering knuckle and on the rear the lower mount would need to pivot. Then you would have a different spring rate for the rear, so you would need different shock valveing, also it would be a waste of engeering to try to match the packaging... I think different shocks f/r is the correct approach to save money.

 

[E90400K]

This would be a poor design for a few reasons, most obvious to me is the camber curve when the truck is loaded.

Also You would also get bump steer in the back, which would be sktecy. You would also have a weird axis of rotation that would be flat if both front and rear matched, then as the roll center moves around during braking and cornering the tendency to oversteer or understeer would randomly switch depending, the truck would be super unpredictable.



Slate would need to add features to the strut for it to mount and pivot through its rage of motion, on the front it would be fixed to steering knuckle and on the rear the lower mount would need to pivot. Then you would have a different spring rate for the rear, so you would need different shock valveing, also it would be a waste of engeering to try to match the packaging... I think different shocks f/r is the correct approach to save money.

The Lightning has an IRS, as does the Silverado. Shock valving is a simple change in orifice sizing in the strut body, or they could choose a strut body with integral damper in it. Spring rates don't change the strut design.

 

[Ewwgas]

Sure, the lighting has IRS, but not an identical front and rear MacPherson like you suggested. The MacPherson has a pretty aggressive camber curve. Also it has a built in king pin angle designed to be steered. You can't really use it on the back.

With the F/R MacPherson set up, The shocks would need to be vavled different f/r. Slate would have to order them as 4 shocks. Front left, right, rear left, right. 4 different shock part numbers for 4 shocks.

To me it looks like Currently they have front left, front right, and rear. 3 shock PNs for 4 shocks.

 

[AnnDee4444]

Slate would need to add features to the strut for it to mount and pivot through its rage of motion, on the front it would be fixed to steering knuckle and on the rear the lower mount would need to pivot. Then you would have a different spring rate for the rear, so you would need different shock valveing, also it would be a waste of engeering to try to match the packaging... I think different shocks f/r is the correct approach to save money.

Absolutely it's a better design with different parts front & rear. But it's still technically possible for them to be the same, even when mixing IFS & DeDion. I doubt this has been done by a manufacture in the last 80+ years though.

FWIW: spring/damping rates are only a piece of the equation. Motion ratio/ride frequency/load capacity/etc. are of great importance.

 

[Ewwgas]

Absolutely it's a better design with different parts front & rear. But it's still technically possible for them to be the same, even when mixing IFS & DeDion. I doubt this has been done by a manufacture in the last 80+ years though.

FWIW: spring/damping rates are only a piece of the equation. Motion ratio/ride frequency/load capacity/etc. are of great importance.

I agree

 

[E90400K]

Sure, the lighting has IRS, but not an identical front and rear MacPherson like you suggested. The MacPherson has a pretty aggressive camber curve. Also it has a built in king pin angle designed to be steered. You can't really use it on the back.

With the F/R MacPherson set up, The shocks would need to be vavled different f/r. Slate would have to order them as 4 shocks. Front left, right, rear left, right. 4 different shock part numbers for 4 shocks.

To me it looks like Currently they have front left, front right, and rear. 3 shock PNs for 4 shocks.

I'll agree camber could be an issue, but is it solved by a link in the rear the front doesn't need (yes, the DeDion tube axle serves as that link). By using a strut body that has a replaceable shock in the strut body (a few cars have used such a design) then it's just two strut p/n and two shock part numbers and 2 spring numbers.

 

[E90400K]

Absolutely it's a better design with different parts front & rear. But it's still technically possible for them to be the same, even when mixing IFS & DeDion. I doubt this has been done by a manufacture in the last 80+ years though.

FWIW: spring/damping rates are only a piece of the equation. Motion ratio/ride frequency/load capacity/etc. are of great importance.

No one should read my comments as being against the DeDion rear suspension, I am just questioning if commonality between front and rear suspensions could follow the Slate ethos of minimizing part differences. My thought here is two suspension subassemblies using most the same parts that bolt up to the frame.