Motors, Control Arms and Ground Clearance

[R1TVT]

Last night I was driving behind a Ford Lightning and realized how little ground clearance there is due to the motor and battery. The underbelly of the Lightning is rather unsightly, and has 8.4" of ground clearance. I'm not sure I would want to be driving this thing through some of the dirt mountain gaps we have here in March or April during the freeze / thaw. We can see ruts that are easily a 6-12" deep, which would put those motors in some precarious positions.

One thing I love about the Rivian is the completely flat underbelly with the skateboard platform. Even the lower control arms are tucked up and in, so you get a wide, flat swath of clearance between the tires.

I snapped a photo of the Lighting I was driving behind last night for reference:

By contrast, this is the underbelly of my R1T. With Air, my max clearance is up to 14.9" (I rarely use max height but it is good to know that it is there when needed):

According to Scout, the Terra will have "12+ inches of ground clearance". This leads me to believe that we will see a production truck (with coils) that sits like the concepts sit, and that we may see more clearance with an air option or different wheels and tires or an "off-road" variant. Hopeful we get a nice flat belly on these beasts. Must help with efficiency too.

 

[cyure]

Last night I was driving behind a Ford Lightning and realized how little ground clearance there is due to the motor and battery. The underbelly of the Lightning is rather unsightly, and has 8.4" of ground clearance. I'm not sure I would want to be driving this thing through some of the dirt mountain gaps we have here in March or April during the freeze / thaw. We can see ruts that are easily a 6-12" deep, which would put those motors in some precarious positions.

One thing I love about the Rivian is the completely flat underbelly with the skateboard platform. Even the lower control arms are tucked up and in, so you get a wide, flat swath of clearance between the tires.

I snapped a photo of the Lighting I was driving behind last night for reference:

View attachment 8447

By contrast, this is the underbelly of my R1T. With Air, my max clearance is up to 14.9" (I rarely use max height but it is good to know that it is there when needed):

View attachment 8448

According to Scout, the Terra will have "12+ inches of ground clearance". This leads me to believe that we will see a production truck (with coils) that sits like the concepts sit, and that we may see more clearance with an air option or different wheels and tires or an "off-road" variant. Hopeful we get a nice flat belly on these beasts. Must help with efficiency too.

With the bottom being flat like that does it keep dirt etc out? Have you seen any rust underneath?

 

[R1TVT]

With the bottom being flat like that does it keep dirt etc out? Have you seen any rust underneath?

There's nothing to rust on the underbelly - the flat bottom that is exposed to the road is a carbon fiber composite material. The reinforced shield consists of layers of high strength steel, aluminum and carbon fiber. I added the reinforced underbody shield with the launch edition. I believe the shield is now bundled and included in the gen2 "off-road package".

 

[SpaceEVDriver]

One of the biggest complaints I have about the Lightning is the poorly-designed underbelly. If it were flat and continuous, the truck could have an efficiency at least 10% better than it is now.

The Lightning was never advertised as an off-roader. The relatively low clearance is a compromise I was fine with given my needs for the truck. I couldn't give up the bed length nor the extra $20k.

 

[CP1@scoutmotors]

Remember we will have a solid rear axle set up. You will not see these low hanging control arms in the rear of our vehicle. Every time I see this I just cringe. My opinion it's just not a good look.

 

[Hedrock]

Remember we will have a solid rear axle set up. You will not see these low hanging control arms in the rear of our vehicle. Every time I see this I just cringe. My opinion it's just not a good look.

A question you might not be able to answer about solid rear axle - there have been comments about having air suspension for height adjustment, and I notice most vehicles with anything other than load leveling rear air are independent front and rear suspension.

Are y’all looking at a watts link versus a typical panhard/track bar to keep the axle more centered at various heights?

 

[cyure]

Remember we will have a solid rear axle set up. You will not see these low hanging control arms in the rear of our vehicle. Every time I see this I just cringe. My opinion it's just not a good look.

Thanks for your comment. Sometimes it’s just as helpful to know what it’s not going to have. Appreciate you and the whole team!!

 

[CP1@scoutmotors]

A question you might not be able to answer about solid rear axle - there have been comments about having air suspension for height adjustment, and I notice most vehicles with anything other than load leveling rear air are independent front and rear suspension.

Are y’all looking at a watts link versus a typical panhard/track bar to keep the axle more centered at various heights?

Sorry.... Can't answer. Not involved with the suspension folks. And I would think this is something they are not wanting to publish yet.

 

[Hedrock]

Sorry.... Can't answer. Not involved with the suspension folks. And I would think this is something they are not wanting to publish yet.

All good, I figured as much but had to ask.

 

[SpaceEVDriver]

All good, I figured as much but had to ask.

Not that my experience counts for much, but I’ve never seen an ebeam axle with the support linkage necessary for a Watts-link. I’m certain the cast aluminum could be recast with the necessary bits, but it would be custom and not COTS. Obviously do-able, but might be more expensive.

 

[R1TVT]

Remember we will have a solid rear axle set up. You will not see these low hanging control arms in the rear of our vehicle. Every time I see this I just cringe. My opinion it's just not a good look.

Great point, maybe the title of this should have been a little different and included "solid rear axle" instead of control arms. Interested to see how the whole thing plays out, and where the ground clearance numbers wind up. Air is awesome, but expensive (and can involve expensive servicing when out of warranty). A solid rear axle will be great for true off road adventures and HD activities. The air will provide a much better "daily driving experience" compared to a solid rear axle, and could be an excellent choice for everything that selectable ride-heights have to offer. All trade-offs!

 

[Hedrock]

Not that my experience counts for much, but I’ve never seen an ebeam axle with the support linkage necessary for a Watts-link. I’m certain the cast aluminum could be recast with the necessary bits, but it would be custom and not COTS. Obviously do-able, but might be more expensive.

Interesting. Are most of them aluminum? I thought most traditional straight axles were various flavors of steel and cast iron.

 

[SpaceEVDriver]

Interesting. Are most of them aluminum? I thought most traditional straight axles were various flavors of steel and cast iron.

The center housing with the motor, differential, and (sometimes) inverter is generally aluminum. As far as I know, American Axle—the brand Scout has said they will be using—uses an all aluminum housing and it includes the inverter in the assembly for their ebeams. I believe that aluminum housing is then mated with steel axle housings for the rest of the beam.

Poor example image here:

 

[dreamweaver]

I believe this is the e-beam of interest.

 

[SpaceEVDriver]

I believe this is the e-beam of interest.

View attachment 8455

Thanks!

Do you have the link for it?

 

[dreamweaver]

Thanks!

Do you have the link for it?

Future

AAM is Bringing the Future Faster with our electrification products including electric drive units, wheel end motors and e-beam axles.

www.aam.com

 

[TreeKiller]

Great point, maybe the title of this should have been a little different and included "solid rear axle" instead of control arms. Interested to see how the whole thing plays out, and where the ground clearance numbers wind up. Air is awesome, but expensive (and can involve expensive servicing when out of warranty). A solid rear axle will be great for true off road adventures and HD activities. The air will provide a much better "daily driving experience" compared to a solid rear axle, and could be an excellent choice for everything that selectable ride-heights have to offer. All trade-offs!

Both my wife's Mercedes coupe and my Grand Cherokee have air suspension. Wife needed rear airbags and some related components replaced just out of warranty which the dealer wanted something like $5k for and the car only had around 25k miles on it. Jeep needed the entire air suspension system replaced including the compressor, I want to say in the 50k-60k mile range, but it was warrantied and I think I saw $6k on the paperwork.

I say that only to reinforce your comment about how expensive it can be.

 

[cyure]

Both my wife's Mercedes coupe and my Grand Cherokee have air suspension. Wife needed rear airbags and some related components replaced just out of warranty which the dealer wanted something like $5k for and the car only had around 25k miles on it. Jeep needed the entire air suspension system replaced including the compressor, I want to say in the 50k-60k mile range, but it was warrantied and I think I saw $6k on the paperwork.

I say that only to reinforce your comment about how expensive it can be.

That’s exactly why I don’t think I want them.

I get more comfortable ride but any other reason I should consider them. I don’t tow anything.

 

[SpaceEVDriver]

That’s exactly why I don’t think I want them.

I get more comfortable ride but any other reason I should consider them. I don’t tow anything.

It depends if you have any reasonable expectation that you'll need a wheelchair in your future. Airbags with a kneel mode have been found to be incredibly helpful to people who need a wheelchair for mobility but not necessarily for riding/driving in the vehicle.

 

[cyure]

It depends if you have any reasonable expectation that you'll need a wheelchair in your future. Airbags with a kneel mode have been found to be incredibly helpful to people who need a wheelchair for mobility but not necessarily for riding/driving in the vehicle.

I don’t and I have never had them so I just don’t think it’s worth the extra expense.

As we get closer I need to go test drive a Rivian again. We are so close to the factory you just sign up and they let you take one for 45 minutes. It would be helpful too to have my husband drive it since he has never driven anything electric and that’s an easy way to make that happen.