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It's nice that he started out admitting the Solterra was nothing more than a "compliance car" at the beginning of development (or in product-speak, the "Minimum Viable Product" or MVP). In all the interviews I've seen of him, he's never admitted the company wasn't onboard with an electric car from the beginning. Also, they've had an electric vehicle on their corporate global website going back to 2014 when I bought a Crosstrek Hybrid, but this is the first we've heard anything about the timeframe of Solterra development with the quote, "...middle of the preliminary development of EVs in 2017." Really drives home how long they've been working on it.

For those that haven’t seen interviews with the product team, it’s clear they went “all in” and wanted a car that would perform as well or better than any of their existing models. I’m confident Subaru pushed Toyota much harder than they wanted in building their first (and probably in Toyota’s opinion their last) electric vehicle.
 

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Discussion Starter · #3 ·
Agree. Anyone know who (Subaru or Toyota) was in charge of the mechanic engineering, specially the wheel attachement? I suspect high tension between both companies following the recall. It appear to be a beginner mistake....
 

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I would suspect the overwhelming policy was to use everything possible out of the Toyota existing parts bins (because those have better availability in a Toyota factory).

As an example of (what I perceive as) the difference between Subaru and Toyota hardware, in the Wheel Hub Types thread you can see a huge difference between the capability and durability of the Subaru hub (first one) over the Toyota one (second one).

As stated many times on this forum by many people, solving the wheel recall "issue" is as easy as swapping out one hub type for another. So the extreme delay has to be management and strategic and not just engineering. Who knows what they are thinking. From all the snow testing product development videos in the mountains of northern Japan, all I can say is that it looks like Subaru did their part quite well.

It's clear Toyota was more interested in the Crown. It pisses me off they put a proper dashboard and center console design in the Crown and RZ450e, but had to screw around with conceptual designs from the Prius for the Solterra interior.
 

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Agree. Anyone know who (Subaru or Toyota) was in charge of the mechanic engineering, specially the wheel attachement? I suspect high tension between both companies following the recall. It appear to be a beginner mistake....
I'm sure at least one guy is telling all his friends that he said lug bolts were a stupid idea in that meeting.
 

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I would suspect the overwhelming policy was to use everything possible out of the Toyota existing parts bins. As an example of (what I perceive as) the difference between Subaru and Toyota hardware, in the Wheel Hub Types thread you can see a huge difference between the capability and durability of the Subaru hub (first one) over the Toyota one (second one). As stated many times on this forum by many people, solving the wheel recall "issue" is as easy as swapping out one hub type for another. So the extreme delay has to be management and strategic and not just engineering. Who knows what they are thinking. From all the snow testing product development videos in the snow in Japan, all I can say is that it looks like Subaru did their part quite well.

It's clear Toyota was more interested in the Crown. It pisses me off they put a proper dashboard and center console design in the Crown and RZ450e, but had to screw around with conceptual designs from the Prius for the Solterra interior.
Correct me if I am wrong, but the AWD system on the Solterra was developed by Subaru. Are the hubs not part of the drivetrain? Unless Toyota steamrolled Subaru into using Toyota parts, the AWD and bolt issues are on Subaru.
 

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The question is… how did this get passed testing? There are always design problem that crop up on new models, ergo TSBs and recalls. So, the testing regimen is as much to fault as anything.
I agree - I have zero background in automotive testing or anything like that, but for an SUV that is inherently meant to go off-road and that will inevitably experience sudden braking unless you want to rear-end people have its wheels (potentially) fall off due to the stress of said off-roading and braking is asinine. There is more to it than just changing the bolts to a different spec, different alloy, whatever. Full disclosure - I canceled my Solterra order yesterday but placed a reservation on an ID4 six weeks ago. Looking at the ID4, it also uses lug bolts and it's a heavier vehicle due to the battery, just like the Solterra. I spoke to the dealer about the Solterra and he smiled, saying VW uses the same wheel design (and the ID4 can be had in AWD as well) but "our wheels don't fall off".
 

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Correct me if I am wrong, but the AWD system on the Solterra was developed by Subaru. Are the hubs not part of the drivetrain? Unless Toyota steamrolled Subaru into using Toyota parts, the AWD and bolt issues are on Subaru.
I suspect if Subaru was specifying the parts to use, they would use the same thing they use on the Outback, Legacy, and Ascent.

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… It pisses me off they put a proper dashboard and center console design in the Crown and RZ450e, but had to screw around with conceptual designs from the Prius for the Solterra interior.
Yeah, that low-res, blocked by the steering wheel ”pod” looks weird, at best. RZ 450e is much better, in my view.
 

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The question is… how did this get passed testing? There are always design problem that crop up on new models, ergo TSBs and recalls. So, the testing regimen is as much to fault as anything.
Indeed. But we should not forget these are heavy cars, over 4000lbs Although I'm sure that wheel etc is designed in, their scaling might not be all that accurate.
 

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This is purely 3rd party (unverified opinion), Carl Tarum, he is automotive failure mechanism expert as per linkedin and had written this blurb which I accidentally came across...some food for thoughts:

Carl Tarum


If this were just a "torque to spec" issue, I think Toyota would have resolved it by now with a campaign to torque bolts to spec. Since the bZ4X has more mass than a Tacoma truck, I suspect that the forces on the wheel to rotor are higher than typical "car design". BEV also have a different torque/speed curve compared to ICE, which may aggravate issues. The fix may require a redesign including any of the following: class of threads, number of bolts, bolt circle diameter and tolerances, wheel flexural loads, thermal distortion, clamp load, etc. A design change will require re-validation, as well as getting part sourcing for new design and a plan to retrofit current vehicles. The fix may involve replacing rotors, wheels, and/or bolts, along with torque specifications. We have to wait for Toyota to resolve. They own the design, not us, and its not appropriate for us to conclude it is a "low bolt torque" or heavy vehicle issue. I just wanted people to be aware its probably not a simple torque adjustment issue.
 

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Yeah, that low-res, blocked by the steering wheel ”pod” looks weird, at best. RZ 450e is much better, in my view.
I'm honestly thinking the Equinox EV is going to be the best way to go. All the GM vehicles seem to have a similar design and, other than the cruise control being on the wrong side, it looks really nice.

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Discussion Starter · #20 ·
Toyota builds numerous heavier vehicles. This shouldn't be an issue, in this era.
Got it! I'm leading a group of engineers and in our daily work, many calculations are dumb ones because they have been done and confirmed in real life so many times. I would understand miscalculations on new techniques like electric motors vs drivetrain or all the electrical aspect around EVs simply because this is a relatively new domain for car engineering. Sorry, but wheels attachment design is something you can't do wrong. It's been over 100 years car are builts with wheels...
 
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