Experience on soft beach sand & overland sand mode?

[HaulingAss]

The licking diffs is the one software update that I am most looking forward to.

Locking differentials will make very little difference in deep sand. Locking differentials are worlds better than open differentials on uneven ground because a lifted wheel can absorb no torque, causing no torque to go to the opposite wheel. In deep sand, however, in most instances, both wheels on each axle will be able to absorb roughly the same amount amount of torque so the locking differential is not doing much work. Yes, better than an open differential, but I have seen plenty of rigs with locking differentials left incapacitated, up to their axles in fine, dry sand.

Sand may all look the same, like sand, but it varies widely in regard to how much weight it can support. It's mostly due to the size of the grains (coarser is better), the angularity of the grains (more angular is better) and the moisture content (higher moisture is better until saturation is reached). The worst sand is dry, fine sand that has been polished into smooth dust. Wind can deposit the finer sand in depressions, and this is where many get stuck, but it can also deposit in non-intuitive places too.

How capable a given vehicle setup is in sand is primarily a function of how much weight per square inch the sand can support relative to the load per unit area of the vehicle's contact patches. That means a tire with a larger footprint can be mobile in finer sand. A lighter vehicle, with the same sized tires, is more mobile in finer sand. Also, a nearly worn out tread is better than a new tread. That's right, the tread blocks assist the tire in digging in, a slick will evenly compact the grains and give you a better chance of staying on top.

Anyone buying a Cybertruck primarily for duty in dry sand should use the widest possible tires without deep, aggressive tread blocks and, obviously, avoid unnecessary weight in the vehicle. This will greatly increase the range of the vehicle in fine, dry sand by preventing the vehicle from sinking in as much. Of course, wider tires will have a negative impact on range on hard surfaces.

Also, a tire construction specifically designed to be aired down will be beneficial. This type of tire often has a very low maximum speed rating, it's more of an agricultural type tire. I believed the All-Terrain tires that come on the Foundation Series have a higher speed construction that is not designed to run very-low pressures, the sidewalls are reinforced to not deform much under high cornering and acceleration forces and pressures too low will cause repetitive fatigue failure of the tire structure, ruining them. Airing down moderately will help quite a bit in dry sand, by allowing the face of the tread to "cup" which assists in creating a solid foundation of sand under the tires. You definitely don't want the 50-65 psi cold recommended on the pavement, but don't get lazy and fail to air back up as soon as you don't need the low pressures. This kind of tire, designed for hard, relatively smooth surfaces, can be ruined (lose their good driving characteristics and become much weaker and more susceptible to flats) surprisingly quickly by driving with too low of pressures, especially at highway speeds, due to fatigue from repeated flexing of the fibers comprising the reinforcement, combined with the heat generated from the excessive flexing. More sidewall reinforcement will generate more heat as it flexes repeatedly.

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[Gene]

Locking differentials will make very little difference in deep sand. Locking differentials are worlds better than open differentials on uneven ground because a lifted wheel can absorb no torque, causing no torque to go to the opposite wheel. In deep sand, however, in most instances, both wheels on each axle will be able to absorb roughly the same amount amount of torque so the locking differential is not doing much work. Yes, better than an open differential, but I have seen plenty of rigs with locking differentials left incapacitated, up to their axles in fine, dry sand.

Sand may all look the same, like sand, but it varies widely in regard to how much weight it can support. It's mostly due to the size of the grains (coarser is better), the angularity of the grains (more angular is better) and the moisture content (higher moisture is better until saturation is reached). The worst sand is dry, fine sand that has been polished into smooth dust. Wind can deposit the finer sand in depressions, and this is where many get stuck, but it can also deposit in non-intuitive places too.

How capable a given vehicle setup is in sand is primarily a function of how much weight per square inch the sand can support relative to the load per unit area of the vehicle's contact patches. That means a tire with a larger footprint can be mobile in finer sand. A lighter vehicle, with the same sized tires, is more mobile in finer sand. Also, a nearly worn out tread is better than a new tread. That's right, the tread blocks assist the tire in digging in, a slick will evenly compact the grains and give you a better chance of staying on top.

Anyone buying a Cybertruck primarily for duty in dry sand should use the widest possible tires without deep, aggressive tread blocks and, obviously, avoid unnecessary weight in the vehicle. This will greatly increase the range of the vehicle in fine, dry sand by preventing the vehicle from sinking in as much.

Also, a tire construction specifically designed to be aired down will be beneficial. This type of tire often has a very low maximum speed rating, it's more of an agricultural type tire. I believed the All-Terrain tires that come on the Foundation Series have a higher speed construction that is not designed to run very-low pressures, the sidewalls are reinforced to not deform much under high cornering and acceleration forces and pressures too low will cause repetitive fatigue failure of the tire structure, ruining them. Airing down moderately will help quite a bit in dry sand, by allowing the face of the tread to "cup" which assists in creating a solid foundation of sand under the tires. You definitely don't want the 50-65 psi cold recommended on the pavement, but don't get lazy and fail to air back up as soon as you don't need the low pressures. This kind of tire, designed for hard, relatively smooth surfaces, can be ruined (lose their good driving characteristics and become much weaker and more susceptible to flats) surprisingly quickly by driving with too low of pressures, especially at highway speeds, due to fatigue from repeated flexing of the fibers comprising the reinforcement, combined with the heat generated from the excessive flexing. More sidewall reinforcement will generate more heat as it flexes repeatedly.

Thank you for the long reply. I am completely familiar with sand. Having crossed 6,000 miles of Algerian Sahara twice, in addition to many hundreds of miles of sand in Mexico and the USA. Generally, the locking diff are best left off in sand. Locking diffs can bury you to the axles really quickly. But they can also be used momentarily in sand to get a quick jump out, and then be switched off.

When I said that I was looking forward more than anything to the locking diffs update, I meant for all sorts of purposes. Not just sand.

 

[HaulingAss]

Thank you for the long reply. I am completely familiar with sand. Having crossed 6,000 miles of Algerian Sahara twice, in addition to many hundreds of miles of sand in Mexico and the USA. Generally, the locking diff are best left off in sand. Locking diffs can bury you to the axles really quickly. But they can also be used momentarily in sand to get a quick jump out, and then be switched off.

When I said that I was looking forward more than anything to the locking diffs update, I meant for all sorts of purposes. Not just sand.

Wow! That's a lot of sand driving!

My long answer was not directed to you, or to anyone in particular, more to the topic of driving in soft sand, since you brought up locking differentials.

 

[Gene]

Wow! That's a lot of sand driving!

My long answer was not directed to you, or to anyone in particular, more to the topic of driving in soft sand, since you brought up locking differentials.

Yes, I realize your answer is very helpful for many. Not just directed at me. I'll add to it that in icy pavement conditions, please never use lockers around any curves. On a curvy, icy road, it is the wheels that have the better traction that are keeping you from flying off the road. With open diffs, the power goes to the wheels with less traction which is a good thing for your safety as the open diffs will not apply power and break loose those wheels that do have the traction. By comparison, the locking diffs on curvy, iced roads, will send the power and break loose the traction of the very wheels that are keeping you on the road, and off the cliff you will fly!

My guess is that the Cybertruck software does not allow for diff locks yet as Tesla needs to figure out how to make the lockers fool proof for beginners. I'd suggest "off road" only and maybe up to only 25 mph. And then a bright red warning not to use on pavement and especially icy pavement.

Lockers are an amazing tool to get through the roughest terrain, especially with the Cybertruck's somewhat limited air suspension articulation. Rivian has the same problem of lifting wheels. Kudos to Tesla for using old school lockers rather than Rivian's electric "after the fact" traction control.

If I had the choice, coil springs with lots of articulation would be my preference.

 

[thedownwardmachine]

This conversation is very interesting and helpful for me, as I have no four wheel sand experience, just with motorcycles.

I look forward to adventuring with a CT one day, but I wouldn't go into soft sand without Maxtrax and a shovel. Possibly also a winch and a deadman. Does that track with you guys? All I know, I got from Ronny Dahl.

I'd be curious to read about that Algeria desert trip, if there's a link.

My uninformed guess is the CT's diff lockers won't be actual lockers, in the sense of electronically activating a locking collar within the diff. Instead I would guess Tesla will emulate a locking diff via software, since this is how they like to do things -- lighter, simpler, cheaper, and less parts if you can just program it. Also, toggling a diff lock seems so simple that they would have just provided that functionality from the release. If it's taking longer, then they probably have to fine tune the emulation, which I'd guess comes from differential brake application. Again, this is pure speculation on my part. If anyone has a source confirming one way or the other, I'd love to see it. Otherwise, I'm VERY curious to see what Sandy finds.

 

[Coagulation]

This conversation is very interesting and helpful for me, as I have no four wheel sand experience, just with motorcycles.

I look forward to adventuring with a CT one day, but I wouldn't go into soft sand without Maxtrax and a shovel. Possibly also a winch and a deadman. Does that track with you guys? All I know, I got from Ronny Dahl.

I'd be curious to read about that Algeria desert trip, if there's a link.

My uninformed guess is the CT's diff lockers won't be actual lockers, in the sense of electronically activating a locking collar within the diff. Instead I would guess Tesla will emulate a locking diff via software, since this is how they like to do things -- lighter, simpler, cheaper, and less parts if you can just program it. Also, toggling a diff lock seems so simple that they would have just provided that functionality from the release. If it's taking longer, then they probably have to fine tune the emulation, which I'd guess comes from differential brake application. Again, this is pure speculation on my part. If anyone has a source confirming one way or the other, I'd love to see it. Otherwise, I'm VERY curious to see what Sandy finds.

Yes definitely. No matter the car, I’d have a shovel, maxtrax, rope, compressor, etc at a minimum. Still… better to not get stuck at all!

 

[HaulingAss]

My uninformed guess is the CT's diff lockers won't be actual lockers, in the sense of electronically activating a locking collar within the diff. Instead I would guess Tesla will emulate a locking diff via software, since this is how they like to do things -- lighter, simpler, cheaper, and less parts if you can just program it. Also, toggling a diff lock seems so simple that they would have just provided that functionality from the release. If it's taking longer, then they probably have to fine tune the emulation, which I'd guess comes from differential brake application. Again, this is pure speculation on my part. If anyone has a source confirming one way or the other, I'd love to see it. Otherwise, I'm VERY curious to see what Sandy finds.

Word from Tesla (in print) is that the Dual and Tri Motor Cybertruck have mechanical locking differentials on all axles having a differential (front and rear for Dual Motor, front for Tri Motor).

Implementing locking differentials is not quick or easy in a truck designed to have a high degree of automation. If they do it wrong, warranty expenses could take a hit measured in millions of dollars. Not to mention it could conceivably cause death or injury. If they err on the other side, locking differentials will not engage when you need and want them.

Sure, they could make it an on/off switch and make the operator liable, but that is far from ideal from a warranty perspective. A lot of binding happens when lockers are misused and customers don't like to be told their expensive replacement parts are not covered under warranty. Then the lamestream media picks up on the story and writes reports that the Cybertruck drivetrain is not very robust. It's predictable.

Development requires much testing and code optimization to make it versatile and robust and Tesla likes to keep their software teams busy on the highest priority tasks. From a legal perspective, Tesla has at least 2024 to make good on their promise to deliver this feature and they will do it in a capital efficient manner.

There may also be an element of using locking differentials as a demand lever, free advertising. Because when they enable them, it will create a news cycle around Cybertrucks locking differentials that wouldn't exist had they enabled them upon the start of production.

I'm excited to see what they come up with.

 

[Jeepster]

Looking at the AWD with outside of being a daily driver, the express purpose of also being a beach car (driving and camping on the actual sand).

I’ve seen videos of desert runs, but also the video of that one guy getting stuck on the beach (who knows if he deflated his tires, etc.)

Any real world experience here with beach driving so far? I know there is a “sand” mode which I guess forces something close to 4 wheel drive.

I just posted a similar question, I don't understand how I didn't see yours first as I used the search feature and it did not appear.

I *think*, without any evidence to back it up, that it would be OK provided you air down. I'm still sitting on my invitation to order because I need something that can drive on the beach, but I think it will be OK provided (a) you air down every single time (I know you are always supposed to, but I've been driving Jeeps on the beach for 40 years without having to air down), (b) get smaller wheels like 17-18 inch, combined with tires better equipped to handle soft sand (I'll probably start with Fallen Wildpeak AT3s). But I would love to hear experiences from people who do it regularly before I place my order.

 

[Jeepster]

I’ve been on the sandy beaches here in south Texas… NO problems! I actually went thru real soft sand where a Raptor was being pulled out by a Jeep! The off road modes seem to work quite well, as I’m not at all experienced (yet) with this type of truck and off roading. ??

Do you mind me asking, did you air down in the soft sand? All of the photos I've seen of CTs stuck in the sand, the drivers has obviously not aired down at all.

 

[Wolfgram]

Do you mind me asking, did you air down in the soft sand? All of the photos I've seen of CTs stuck in the sand, the drivers has obviously not aired down at all.

I did not. I just kept moving… ? IF I would have access to an air compressor I certainly would have gone to 30-32 lbs. of pressure. But it did just fine at 50 in the conditions I had. ??

I will say, it would not have been difficult to get stuck… I was fortunate to find the right lines and keep moving until I was thru the soft deep sand. ?

 

[Coagulation]

Seems like no doubt to optimize for beach driving, this thing probably needs new tires and maybe even new wheels.

Sounds like the answer is some combination of

-being 35 inches because that seems to be what can fit
-maybe a little wider or an offset
-has enough sidewall flex to get down to 15 to 20 psi
-can also manage the weight and torque of this truck

I’m not going to pretend I know the answer, but it seems like I know the question at least!

 

[Woodrick]

I did not. I just kept moving… ? IF I would have access to an air compressor I certainly would have gone to 30-32 lbs. of pressure. But it did just fine at 50 in the conditions I had. ??

I will say, it would not have been difficult to get stuck… I was fortunate to find the right lines and keep moving until I was thru the soft deep sand. ?

30-32 psi isn't recommended. From the OffRoad guide cybertruck_offroad_guide.pdf (tesla.com)
Look at #6, 36 psi is suggested lower limit.

I'm not sure which is worse, being stuck in the sand or having a de-beaded tire in the sand. Once it de-beads, it's just going to fill the tire with sand.

 

[Jeepster]

I did not. I just kept moving… ? IF I would have access to an air compressor I certainly would have gone to 30-32 lbs. of pressure. But it did just fine at 50 in the conditions I had. ??

I will say, it would not have been difficult to get stuck… I was fortunate to find the right lines and keep moving until I was thru the soft deep sand. ?

Thanks, I really appreciate the reply. I can say most people recommend going down to 12-14, but I would be afraid of breaking a bead. I carry an air compressor so I really should air down, if I do get the courage to order the CT I will absolutely air down and keep my compressor on board. I have a system that will fill four tires in 2 to 3 minutes so there isn't any reason not to air down, other than I'm lazy and 40 years with Jeeps on the beach I've never been stuck. Of course, I'm sure tomorrow I will get buried but at least I know how to get out myself!

 

[Wolfgram]

30-32 psi isn't recommended. From the OffRoad guide cybertruck_offroad_guide.pdf (tesla.com)
Look at #6, 36 psi is suggested lower limit.

I'm not sure which is worse, being stuck in the sand or having a de-beaded tire in the sand. Once it de-beads, it's just going to fill the tire with sand.

My mistake. I would go with recommended pressure from the guide.

 

[Jeepster]

Seems like no doubt to optimize for beach driving, this thing probably needs new tires and maybe even new wheels.

Sounds like the answer is some combination of

-being 35 inches because that seems to be what can fit
-maybe a little wider or an offset
-has enough sidewall flex to get down to 15 to 20 psi
-can also manage the weight and torque of this truck

I’m not going to pretend I know the answer, but it seems like I know the question at least!

Thanks, you are right. At least, I think - that's why I asked . If I pull the trigger, I will get 17 or 18 inch wheels, and replace the tires with something with softer sidewalls. I've run Wildpeaks AT3s on my past few Jeeps, if they would work I will get them, they are a great tire for both highway and beach. Definitely go down to 15, no reason not to if you are airing down might as well do it right, just a few minutes extra time airing back up.

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