Ask Munro: "How the Rivian R1T Earned IIHS Top Safety Pick+."

[Friscorays]

Sponsored

 

[SoCal Rob]

@Friscorays , interesting video and thanks for posting the link!

As someone who watches most (all?) of the Munro Rivian-focused videos, here is the message I am getting from Munro:

1. In one of the earlier teardown videos where they are looking at the frame, my recollection is that they were very critical of the waste and less-sophisticated construction involved, especially in the layered/welded frame parts. I recall that they were quick to point out that are more efficient ways of doing this.

2. Early in this video (2:37) they praise the overall thickness of the layered/welded frame parts for contributing to the crashworthiness.

3. Then they get back to the mass/size/structure of the vehicle working against you at 10:10 in the video.

4. The weight of the battery pack is a constraint of BEVs. (12:34)

5. At 13:10 in this video they're back to harping on optimizing the mass in the future.

6. AT 13:38, a vehicle designed strictly for manufacturing efficiency is very different from one with various performance objectives.

My takeaways as someone with no experience in engineering are:
1. Munro is focused on manufacturing efficiency by reducing material used and reducing cost. (I know: Duh!)

2-6. After recovering from the mental whiplash of the Munro opinions, it looks like Rivian did the right thing to make sure that they got top safety scoring at the cost of efficiency because most of these are used as family vehicles and most people aren't going to pay a premium price to risk harm, regardless of the other vehicle characteristics.

Munro (the organization) cannot seem to reconcile the need for safety, especially at this price point, with their desire to reduce weight in a vehicle which is going to be heavy no matter how much mass is removed from the frame. The battery pack weighs a LOT in these vehicles. Reducing the mass of the frame will probably have relatively little effect on overall vehicle weight as a percentage (compared to the same reduction in frame weight on an ICE vehicle) but it probably WILL have a negative effect on crash performance. I imagine that if there isn't enough structure to keep everything where it belongs (or to redirect parts in a predictable manner) during a crash event then this will affect safety.

Munro seems unable to provide a solution other than, "reduce mass." I don't think I'd be taking any advice from them which could adversely affect safety, and I hope that Rivian leadership carefully considers any of Munro's input which potentially affects safety. I'd like to think that Munro, as a consulting firm, is incorporating both points of view into coherent advice to Rivian... even though we never get to see that as mere viewers.

I'd be curious to see feedback from real engineers about this.

edit:typo

 

[Ventura]

@Friscorays , interesting video and thanks for posting the link!

As someone who watches most (all?) of the Munro Rivian-focused videos, here is the message I am getting from Munro:

1. In one of the earlier teardown videos where they are looking at the frame, my recollection is that they were very critical of the waste and less-sophisticated construction involved, especially in the layered/welded frame parts. I recall that they were quick to point out that are more efficient ways of doing this.

2. Early in this video (2:37) they praise the overall thickness of the layered/welded frame parts for contributing to the crashworthiness.

3. Then they get back to the mass/size/structure of the vehicle working against you at 10:10 in the video.

4. The weight of the battery pack is a constraint of BEVs. (12:34)

5. At 13:10 in this video they're back to harping on optimizing the mass in the future.

6. AT 13:38, a vehicle designed strictly for manufacturing efficiency is very different from one with various performance objectives.

My takeaways as someone with no experience in engineering are:
1. Munro is focused on manufacturing efficiency by reducing material used and reducing cost. (I know: Duh!)

2-6. After recovering from the mental whiplash of the Munro opinions, it looks like Rivian did the right thing to make sure that they got top safety scoring at the cost of efficiency because most of these are used as family vehicles and most people aren't going to paying a premium price to risk harm, regardless of the other vehicle characteristics.

Munro (the organization) cannot seem to reconcile the need for safety, especially at this price point, with their desire to reduce weight in a vehicle which is going to be heavy no matter how much mass is removed from the frame. The battery pack weighs a LOT in these vehicles. Reducing the mass of the frame will probably have relatively little effect on overall vehicle weight as a percentage (compared to the same reduction in frame weight on an ICE vehicle) but it probably WILL have a negative effect on crash performance. I imagine that if there isn't enough structure to keep everything where it belongs (or to redirect parts in a predictable manner) during a crash event then this will affect safety.

Munro seems unable to provide a solution other than, "reduce mass." I don't think I'd be taking any advice from them which could adversely affect safety, and I hope that Rivian leadership carefully considers any of Munro's input which potentially affects safety. I'd like to think that Munro, as a consulting firm, is incorporating both points of view into coherent advice to Rivian... even though we never get to see that as mere viewers.

I'd be curious to see feedback from real engineers about this.

edit:typo

Not an engineer, but I agree with your assessment. Weight will come down when battery weight comes down. The loss of mass will be from more than the battery given the relationship between battery mass and construction. I have a truck now that has a top crash rating - that would be a requirement for purchase if I had not been so excited about getting an electric truck but it has made me breathe a sigh of relief.

 

[RBR1S]

If you're looking for the link to the IIHS report and video






https://www.iihs.org/ratings/vehicle/rivian/r1t-crew-cab-pickup/2023

 

[racekarl]

Reducing the mass of the frame will probably have relatively little effect on overall vehicle weight as a percentage (compared to the same reduction in frame weight on an ICE vehicle) but it probably WILL have a negative effect on crash performance.

I'm not sure I would count on this being true. Newer cars are built with thinner materials than cars from 60 years ago, for example, and are much safer. Depending on how a part is designed and how it fits in with the rest of the vehicle, a thinner-walled part may deform more and therefore dissipate more crash energy. If it really has extra material that's just a manufacturing convenience as Munro asserts then removing it should not affect crashworthiness. Plus, less mass brought to the crash is less energy that has to be dissipated.

 

[virgnia_rivian]

I’ve watched many Munro videos for all types of cars. I’m not sure if I’m an OEM I’d hire them after watching some of their nit pics. Maybe if I’m building a cheap, mass market car that I need to pump out a million units, but I have concerns about some of their comments. And it’s not just with Rivian.

Also, watch their seat tear down. Rivian makes it super clear they use “vegan“ leather, but the interior folks at Munro thought it was real leather. They eventually addressed this in a later video, but never admitted they were wrong. There are simple, easy to find tech specs of vehicles they get wrong.

 

[SoCal Rob]

I'm not sure I would count on this being true. Newer cars are built with thinner materials than cars from 60 years ago, for example, and are much safer. Depending on how a part is designed and how it fits in with the rest of the vehicle, a thinner-walled part may deform more and therefore dissipate more crash energy. If it really has extra material that's just a manufacturing convenience as Munro asserts then removing it should not affect crashworthiness. Plus, less mass brought to the crash is less energy that has to be dissipated.

I may be going down the wrong path because I am taking their analysis as true, but in the video I got the impression that the sections which were to remain rigid and not deform were doing their job in part because Rivian used multiple layers of a thick and strong material. I understand that there are different materials which may provide the same strength but with less weight.

Given the information they've provided... Does it make sense for Rivian to re-engineer this frame and possibly change manufacturing methods on an operating assembly line to gain small benefits in weight savings, especially if it means having to re-do crash testing and/or run the risk of a worse safety rating?

edit:clarity

Sponsored