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SeaGeo

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They really don't need a "simulated locker," though I get that's easy for people to picture. One tire isn't spinning. Recognize that, and give it more power. That is not.

That being said, I'm sure there is a bunch of nuance needed there to avoid from having people accidently yeet themselves into a tree.
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They really don't need a "simulated locker," though I get that's easy for people to picture. One tire isn't spinning. Recognize that, and give it more power. That is not.

That being said, I'm sure there is a bunch of nuance needed there to avoid from having people accidently yeet themselves into a tree.
Yes, but the problem isn't only about recognizing the need to apply more throttle.

With the rear locker you see the Tunrda easily roll off the rollers with almost zero wheel spin. It's controlled and elegant. Let's transport this scenario to a trail where the Rivian and Toyota with a rear locker go up and over a hard rocky obstacle.

With the Toyota, you most likely just need to let off the brake and barely apply throttle. It will go over with little to no unnecessary wheel spin.

With the Rivian you need to press the throttle A LOT to apply enough torque to the one wheel with traction. All other 3 wheels will be spinning pointlessly kicking up dirt and rocks. There will be wheels which are barely touching a surface which would be burning out creating smoke and rubber marks on the rock below. Not so elegant. Not so controlled.

Now let's say the Rivian shifts weight and those crazy spinning wheels which were once up in the air slam down and gain traction. The tires will grab hard or burnout or worse, the Rivian may lurch forward.

That is the benefit of a locker. Your other wheels are in control. They aren't spinning pointlessly and uncontrollably. When you are crawling your wheels are only spinning at the speed your vehicle is crawling whether they have traction or not. That is control. That is safe.

This is why in my opinion they do need a "simulated locker"
 

godfodder0901

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Yes, but the problem isn't only about recognizing the need to apply more throttle.

With the rear locker you see the Tunrda easily roll off the rollers with almost zero wheel spin. It's controlled and elegant. Let's transport this scenario to a trail where the Rivian and Toyota with a rear locker go up and over a hard rocky obstacle.

With the Toyota, you most likely just need to let off the brake and barely apply throttle. It will go over with little to no unnecessary wheel spin.

With the Rivian you need to press the throttle A LOT to apply enough torque to the one wheel with traction. All other 3 wheels will be spinning pointlessly kicking up dirt and rocks. There will be wheels which are barely touching a surface which would be burning out creating smoke and rubber marks on the rock below. Not so elegant. Not so controlled.

Now let's say the Rivian shifts weight and those crazy spinning wheels which were once up in the air slam down and gain traction. The tires will grab hard or burnout or worse, the Rivian may lurch forward.

That is the benefit of a locker. Your other wheels are in control. They aren't spinning pointlessly and uncontrollably. When you are crawling your wheels are only spinning at the speed your vehicle is crawling whether they have traction or not. That is control. That is safe.

This is why in my opinion they do need a "simulated locker"
I see a little bit of faulty logic in your description. The the wheels without traction didn't spin uncontrollably. They continue to spin, quite slowly I'll add, so that the vehicle can sense if traction is regained. They wouldn't kick up anything unless you were in Soft Sand or potentially Rally mode, both of which would be poor drive selections for the referenced scenario. I will say that a virtual locker for the rear may be beneficial, especially for those with a traditional off-roading background.
 
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Dirtcom_AJ

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I see a little bit of faulty logic in your description. The the wheels without traction didn't spin uncontrollably. They continue to spin, quite slowly I'll add, so that the vehicle can sense if traction is regained. They wouldn't kick up anything unless you were in Soft Sand or potentially Rally mode, both of which would be poor drive selections for the referenced scenario. I will say that a virtual locker for the rear may be beneficial, especially for those with a traditional off-roading background.
I may have a bit over the top with the description but it was to help visualize the scenario. There are plenty of example online showing wheels spinning in the air (perhaps not as uncontrollably as I described). However, my point is, it is unnecessary and it makes the vehicle harder to drive. The real frustration is knowing they can easily implement this. Meanwhile, I'm out on the trails with guys with lockers slowly climbing over things while I look like I'm struggling spinning wheels and trying to find the throttle sweet spot. The rear locker is both about ease of driving and less wear on tires.

This won't be only beneficial to people with traditional offroad backgrounds. It would be beneficial to anyone who offroads their Rivian due to the increased ease of use.
 

SeaGeo

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I may have a bit over the top with the description but it was to help visualize the scenario. There are plenty of example online showing wheels spinning in the air (perhaps not as uncontrollably as I described). However, my point is, it is unnecessary and it makes the vehicle harder to drive. The real frustration is knowing they can easily implement this. Meanwhile, I'm out on the trails with guys with lockers slowly climbing over things while I look like I'm struggling spinning wheels and trying to find the throttle sweet spot. The rear locker is both about ease of driving and less wear on tires.

This won't be only beneficial to people with traditional offroad backgrounds. It would be beneficial to anyone who offroads their Rivian due to the increased ease of use.
Let me preface this with saying that I agree with the desire for this. However, because there isn't a way for it to physically connect, part of the problem seems to be getting feedback to the truck to understand the maximum amount of power it can apply to each wheel without slipping. Thus it needs to apply some small amount of spin to sense that. At least it seems to be that way based on how Rivian has implemented things thus far.

My point was that I've come to accept the wheels with low traction (particularly in the air) are going to spin a little bit. What I want it to do is apply torque to the wheel that is *not* spinning (e.g. the wheel with the most traction), without having to floor it for the same safety concerns you have.
 

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Nice work on the video, it will be helpful to anyone taking their Rivian out on trails! I'm sure there's thermal considerations for a non-spinning motor with current running through it. It might be limited when slowly increasing the accelerator so the motor can thermally handle it indefinitely. Considering the amout of variables in how someone might drive, Rivian is probably being conservative while gathering more data. I do hope they can add a virtual locker mode at some point to make driving through certain obstacles more graceful!
 

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How cool would it be if there was a button in the rock crawl drive mode / screen menu to engage front and/or rear virtual lockers. Please! This would keep it under a speed limit and make the off road community happy.
 

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I may have a bit over the top with the description but it was to help visualize the scenario. There are plenty of example online showing wheels spinning in the air (perhaps not as uncontrollably as I described). However, my point is, it is unnecessary and it makes the vehicle harder to drive. The real frustration is knowing they can easily implement this. Meanwhile, I'm out on the trails with guys with lockers slowly climbing over things while I look like I'm struggling spinning wheels and trying to find the throttle sweet spot. The rear locker is both about ease of driving and less wear on tires.

This won't be only beneficial to people with traditional offroad backgrounds. It would be beneficial to anyone who offroads their Rivian due to the increased ease of use.
After watching the video yesterday, the original description was definitely hyperbolic. It's nice to know there's a workaround of sorts, but it doesn't seem like the problem is quite as bad as originally described. Still, I'm not thrilled with the three-wheel roller test and Rivian really needs to do something so you don't need to mat the throttle in situations like that. Coming from a Toyota background it's going to be awkward to remember that you can't just steadily add throttle until you ATRAC your way to victory on an obstacle.
 

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Yes, but the problem isn't only about recognizing the need to apply more throttle.
...
With the Rivian you need to press the throttle A LOT to apply enough torque to the one wheel with traction.
As you mentioned in the video, not only do you need to press the throttle A LOT, it appears you need to press it down in just the right manner and period --i.e., usually a shorter period than most people attempt. It's very counter intuitive.

I was on a trail this weekend and I was able to repeatedly make it over an obstacle, but when my buddy was driving he was unable to make it over the exact same obstacle. Apparently, I was applying the throttle in just the right manner?
 

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How cool would it be if there was a button in the rock crawl drive mode / screen menu to engage front and/or rear virtual lockers. Please! This would keep it under a speed limit and make the off road community happy.
Better than a button on the screen would be to have the "thumb controls" on the steering wheel lock and unlock the virtual lockers. For example, press the left thumb control to lock the front wheels and right thumb control to lock the rear wheels.

The behaviors for the thumb controls are already contextual --volume, adjust cruise control speed, trailer brake gain, etc. So when in an Off-road mode, the they control the virtual lockers.
 

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They really don't need a "simulated locker," though I get that's easy for people to picture. One tire isn't spinning. Recognize that, and give it more power. That is not.

That being said, I'm sure there is a bunch of nuance needed there to avoid from having people accidently yeet themselves into a tree.
They do need a simulated locker option. The whole point of a locker is to ensure controlled movement in low traction situations. It takes time and wheel revolutions to detect that a wheel is spinning and then to figure out which wheel has grip and then to re-allocate power to the right place. None of that is necessary with a locker, you just keep going which is huge in off road scenarios.
 

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My take away from the test is there is enough torque in a single wheel to propel the vehicle forward, the motor/traction logic just needs to be further refined. The trick workaround of mashing the accelerator proves that, but also highlights the logic profile can be tuned to fix this issue.

Stupid question, do we think the rivian purposely "drags" a wheel, while another tries to push tracton limits, even to a minor degree, to create a real time traction profile? This could be the reason for the bound wheel consistently being under powered.
 

SeaGeo

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They do need a simulated locker option. The whole point of a locker is to ensure controlled movement in low traction situations. It takes time and wheel revolutions to detect that a wheel is spinning and then to figure out which wheel has grip and then to re-allocate power to the right place. None of that is necessary with a locker, you just keep going which is huge in off road scenarios.
I don't disagree that a locker would be an improvement. However, you aren't going to get the the same behavior without that physical connection.

Conceptually Rivian may be able to switch from torque control to speed control with the motors or something, but I suspect that they have reasons not to do that.
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