Portal Axels?

[ct355]

Hi people, I was watching the CT unveil for the thousandth time and noticed something. When the truck went into loading mode (raises front while lowering back) to load the ATV, It seemed like the body raised above half of the wheel. Wouldn't that mean that it has portal axels? It's slight but I'm pretty sure I'm right. Here's the photo:

CT will have half-shaft and fully independent air suspension. Portals are solid-axles much like you find on a Unimog or a farm tractor. These are for ultra-heavy duty work and lower the final drive ratio for more torque to the wheels. Cybertruck will have little use for this. Also, while they do multiply torque, they add weight, complexity, cost, maintenance and dramatically increase I sprung weight. But luckily the trick suspension on the CT will probably embarrass even the mighty Unimog off road: So fear not.

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[TruckElectric]

Portals are solid-axles

Nope

like you find on a Unimog or a farm tractor.

True. Also many military vehicles. Volvo C303 and Pinzgauer vehicles, to name a few.

These are for ultra-heavy duty work and lower the final drive ratio for more torque to the wheels. Cybertruck will have little use for this.

You have point. But it's the speed of the CT that may be a problem using portal axles.

But luckily the trick suspension on the CT will probably embarrass even the mighty Unimog off road

You're being a bit melodramatic. The CT will give Unimogs a good go though.

The pics available do look like the CT uses portal axles.

 

[Crissa]

We do. ?

Bison?

-Crissa

 

[FutureBoy]

????????

 

[Dids]

Bison?

-Crissa

If the smaller one is a Wolverine, then full size a bison seems appropriate, although I'm open to grizzly bear...

 

[Ehninger1212]

Nope

My thoughts exactly ?

A Humvee is a perfect example of portal axles on a fully independent suspension vehicle.

I still stand by my statement CT will not have this.

 

[Deleted member 3316]

If Portal hubs don’t come standard with the Cybertruck it’s going to be a profitable aftermarket product, 100mm lift will give Cybertruck 500mm of ground clearance… that’s the same as a Unimog.

The gear set is also simpler because an extra gear to wouldn’t be required to reverse the drive. Only the polarity of the motor would need to be reversed either manually or through the software.

If you’re not sure what I’m talking about compare OEM portals (Hummer, Bollinger,etc) with aftermarket portals (marks4x4,Tibus, etc)

Bollinger portal hubs are beautiful BTW.

 

[Deleted member 3316]

You have point. But it's the speed of the CT that may be a problem using portal axles.

Because the Cybertruck is electric the final drive ratio can be engineered within a broad range without the need for an idler in the hub. If the owner prioritises top speed the ratio could be 1:2 , if the owner prioritises low speed torque and the ability to wheel winch up vertical faces a 20:1 ratio could be utilised.

I’m guessing having it top out at 130-150kph would be sufficient for most civilian use cases.

 

[Deleted member 3316]

Here’s an aftermarket bolt on portal hub, note the two bilateral idler gears to maintain driven direction.

 

[Qball]

Portal boxes are only good for off-road with significant energy lost so highly doubt they will ever do that because they are so inefficient and not to mention very high cost with added complexity and additional moving parts. Tesla is all about removing parts, and with instant torque of electric motor portal boxes gear reduction feature is completely irrelevant. However raising the hub or lower the wheel/tire is very nice for off-road. Not to say it’s impossible but very unlikely.

plus CT’s 1000hp and 1000lb of torque will probably thread just about any portal boxes into pieces in blink of an eye.

 

[Deleted member 3316]

Portal boxes are only good for off-road with significant energy lost so highly doubt they will ever do that because they are so inefficient.

Tesla is all about removing parts, and with instant torque of electric motor portal boxes gear reduction feature is completely irrelevant. However raising the hub or lower the wheel/tire is very nice for off-road. Not to say it’s impossible but very unlikely.

You might like to revisit that assumption about energy loss. It’s merely a final drive. Those efficiency losses relate to the inefficiency of ICE.
As far as removing parts, it also relates to introducing lightness. With the final reduction gear being placed at the wheel, the drive components proximal to the motor can be lighter as they are subjected to smaller forces.

Bollinger went so far as to place the brakes inboard; reducing unsprung weight and increasing brake force (enabling a smaller disc)

Many of the new public buses have portal axles to enable a lowering of the chassis for easy ingress for wheelchair users. As long as the system is properly engineered the only downside for Cybertruck would be higher CG.

 

[Qball]

You might like to revisit that assumption about energy loss. It’s merely a final drive. Those efficiency losses relate to the inefficiency of ICE.
As far as removing parts, it also relates to introducing lightness. With the final reduction gear being placed at the wheel, the drive components proximal to the motor can be lighter as they are subjected to smaller forces.

Bollinger went so far as to place the brakes inboard; reducing unsprung weight and increasing brake force (enabling a smaller disc)

Many of the new public buses have portal axles to enable a lowering of the chassis for easy ingress for wheelchair users. As long as the system is properly engineered the only downside for Cybertruck would be higher CG.

ANY additional gear transfer of any kind will creat inefficiency not to mention weight, complexity and weight which also equates to inefficiency, Unsprung weight has to be reduced to minimum to improve suspension performance and ride. As you mentioned they are on buses and trucks that are much heavier with MUCH heavier wheel setup so a little extra weight on the end of a huge axle isn’t as big of deal plus they don’t go off-road nor high speed of any kind.

Also inboard brakes are horrible idea! Just ask all the hummer H1 owners who snapped their axles by simply applying brakes, primary example of what not to do. The entire reason for H1’s suspension design is to fit into mine cleaning tanks track, not any other reason! They were never design to have a good ride or even be good off road. For those who wonder, H1 is NOT good for true off-road! It never was designed to be, only reason they are half descent at off-roading in mild situations is because of the huge(for the time) 37 inch tires.

I’ve done extensive research on portal boxes because I thought about getting them for my old solid axle land cruiser but it’s expansive and actually significantly reduces performance, it’s much simpler, cheaper, better overall performance and less headache to just get one size bigger tires. Portal boxes addresses issues CT won’t have to begin with.

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