Turning Diameter Comparison with Lego

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  • Опубликовано: 17 май 2024
  • Testing the wall-to-wall U-turn diameter (turning radius) of different steering systems. Aiming for a sharp U-turn. The length and width of the vehicle stay the same throughout the video. Enjoy!
    Base rules for all vehicles:
    -length is 35 Lego studs (28 cm)
    -width is 18 Lego studs (14.4 cm)
    -only Lego parts used
    0:00 front-wheel steering & rear-wheel drive
    0:17 differential
    0:37 rear-wheel steering & drive
    0:58 4-wheel steering
    1:23 articulated steering
    1:55 differential steering
    2:17 differential steering + trailer
    2:51 transforming vehicle
    Radio control was done with BuWizz 2.0, PS4 controller and BrickController 2 app
    buwizz.com/shop/1-buwizz-2/?r...
    www.playstation.com/en-fi/acc...
    play.google.com/store/apps/de...
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Комментарии • 541

  • @Garthaxius
    @Garthaxius 7 месяцев назад +3078

    the best way is of course to disassemble the vehicle and rebuild it in the orientation you want it to go

    • @Tjbilo
      @Tjbilo 7 месяцев назад +43

      Genius

    • @pobvic
      @pobvic 7 месяцев назад +26

      Have you seen a field gun race, they take it apart, over a gorge, through a small hole and put it back together again, the ultimate destination of your comment.
      The guys that do/did it were super fit and the competition is insane

    • @ninjafruitchilled
      @ninjafruitchilled 7 месяцев назад +5

      ​@@pobvicthere is a similar thing involving disassembling some kind of small army jeep.

    • @BierBart12
      @BierBart12 6 месяцев назад +13

      Reconstructive steering

    • @mandarbamane4268
      @mandarbamane4268 6 месяцев назад +2

      That's a great idea. Now I know what to do when car is stuck in parking.

  • @georgeofhamilton
    @georgeofhamilton 7 месяцев назад +3404

    At a certain point, it’s just the vehicle’s size that matters and not its turning angle.

    • @Slug99
      @Slug99 7 месяцев назад +261

      True, which is why after certain point you see concepts that are only used in city buses because nobody sane would ever want to think ""Why yes sir I would very much like to have to do a 12 points turn following at least six dimensions of rotation whenever I'm interested in changing direction on a 1½ lane street."

    • @IamSaud_YT
      @IamSaud_YT 7 месяцев назад +2

      Exactly!

    • @Sandman-0
      @Sandman-0 7 месяцев назад +2

      or the diffencial pignon make a wheel left or right turn faster and then have more speed of left or right@@IamSaud_YT

    • @vladimirlenin4512
      @vladimirlenin4512 7 месяцев назад +3

      If i say that the turning diameter of differential steering is 0, it wasn't wrong

    • @Reverend_Salem
      @Reverend_Salem 6 месяцев назад +5

      ​@@Slug99i now want to see a city buss with the lifting trailer.

  • @Hunter_Dawso
    @Hunter_Dawso 7 месяцев назад +922

    For those who don’t know, differential steering is how most heavy equipment such as skid loaders, excavators, dozers, etc steer.

    • @PhoenixClank
      @PhoenixClank 7 месяцев назад +9

      Do skid loaders get their name from that?

    • @theastuteangler
      @theastuteangler 7 месяцев назад +46

      @@PhoenixClank yes, they are most often called skid-steer, not skid loaders (at least where I'm from).

    • @hamizannaruto
      @hamizannaruto 7 месяцев назад +4

      That's a real concept?!

    • @Hunter_Dawso
      @Hunter_Dawso 7 месяцев назад +1

      @@theastuteangler I’ve heard both.

    • @Hunter_Dawso
      @Hunter_Dawso 7 месяцев назад +1

      @@hamizannaruto yessir.

  • @JubJubAc
    @JubJubAc 7 месяцев назад +1022

    If anyone is curious, quite a few actual production cars did successfully implement 4 wheel steering in their vehicles, Nissans HICAS system comes to mind but there's a few more

    • @BritishTrainspotting
      @BritishTrainspotting 7 месяцев назад +69

      And many trucks designed for heavy loads or rough terrain such as quarries utilise multiple steering axles, and trailers used in cities where loading spaces are often tight utilise steerable axles on the trailer. The trailer steering axles are typically automatic but can be manually controlled when required.

    • @sandman_-_
      @sandman_-_ 7 месяцев назад +76

      Acura, Audi, BMW, Lexus, Porsche, Ferrari, and Mercedes have all got a few modern cars with all-wheel steering. The rear wheels might not turn as much as the front ones but they certainly do.

    • @ljt3084
      @ljt3084 7 месяцев назад +26

      @@sandman_-_
      Toyota Celica GT4 also has 4 wheel steer. Built in the 1980's.
      The rear wheels only turn approx 5 degrees from center but it drastically enhances high speed cornering and grip.
      The problem in that period was it was a complex control system but with modern electronics 4WS has made a comeback.

    • @RCmies
      @RCmies 7 месяцев назад +7

      Cybertruck

    • @seanmobley117
      @seanmobley117 7 месяцев назад +23

      Quadrasteer GMT800

  • @addi498
    @addi498 7 месяцев назад +658

    We need to see one with Ackerman geometry

    • @ARKWOLF20000
      @ARKWOLF20000 7 месяцев назад +16

      What's Ackerman geometry

    • @lizhou3639
      @lizhou3639 7 месяцев назад +143

      @@ARKWOLF20000geometry made by Ackerman

    • @joshuagreen5613
      @joshuagreen5613 7 месяцев назад +87

      In a nutshell, the outside and inside wheels have to cover a different turning radius
      Ackerman makes it so the inside wheels turn a bit tighter than the outside wheels

    • @chrisparussin5359
      @chrisparussin5359 7 месяцев назад +3

      @@joshuagreen5613so, a differential ?

    • @jerac7379
      @jerac7379 7 месяцев назад +57

      No, differential allows for different rotation speeds but is not affecting turn angle itself. You need both (and this is what most cars have).

  • @rabbitenjoyer6320
    @rabbitenjoyer6320 7 месяцев назад +192

    Dude one-ups himself with every camera cut. Love the creativity

  • @liliowen2132
    @liliowen2132 7 месяцев назад +170

    The differential one before the trailer's my favourite, I like how it turns without the wheels turning left or right

    • @NotGrimman
      @NotGrimman 7 месяцев назад +44

      That's how tanks steer

    • @CollinTheSav
      @CollinTheSav 7 месяцев назад +3

      Neutral steering is the technical term IIRC

    • @Emerald_Night
      @Emerald_Night 7 месяцев назад +1

      This method is actually used for real vehicles. Skid Steers use 2 sets of wheels or tracks, tanks do the same with tracks. I believe the electric Hummer also supports that form of steering but I'd imagine it's not good for the tires.

    • @Yadobler
      @Yadobler 7 месяцев назад +3

      But it hurts the wheels on solid ground. But on sand, mud, soil, snow and gravel the ground will shift around the wheels as it is dragged sideways, so it's not so bad.

  • @jiraph52
    @jiraph52 7 месяцев назад +214

    It would be interesting to also include the effect of wheelbase on the turning circle, and show how a compact car can turn much better than a large truck or SUV, and how even long buses can achieve reasonable turning circles with large rear overhangs.

    • @saggezzamaconprudenza1090
      @saggezzamaconprudenza1090 7 месяцев назад +14

      THIS! The overhang of a vehicle does wonders to its steering circle. When i first got my truck licence i was amazed how the reverse-manuevers behave differently from my no-overhang compact car. Would be even more interesting seeing it for a BUS! From the sky view even!!

    • @oskarikosola7676
      @oskarikosola7676 7 месяцев назад +2

      I was a bit disappointed that the overhang wasn't ever altered.

    • @oliverfern8039
      @oliverfern8039 7 месяцев назад +2

      I think the point was to show the turning radius with the same length vehicle.
      He also kind of shows this with his last "transforming vehicle"

    • @kantpredict
      @kantpredict 7 месяцев назад +3

      It's all about the wheelbase. London has its iconic Routemaster red buses with wheels near the ends, for a terrible turning circle. But also modern city buses with short wheelbase and a lot of overhang that can take much tighter bends

  • @cocoeclipse32
    @cocoeclipse32 7 месяцев назад +115

    I love how as the videos go on, the ideas just get more and more insane!

  • @mailbox.3539
    @mailbox.3539 7 месяцев назад +7

    It’s weird this channel is part Lego for fun and half way between a science and education and partly asmr, I love it

  • @MrHamof
    @MrHamof 7 месяцев назад +41

    I think the 4 wheel steering one would have been better with a central differential. It sounded distinctly unhappy and that's the first thing that I can think of that might have caused that.

    • @martinxXsuto
      @martinxXsuto 7 месяцев назад +3

      could also be because the steering linkage is inexact. the inner wheel should turn more than the outer
      also, the wheels are thick, so you will have some friction regardless

    • @MrFukyutube
      @MrFukyutube 7 месяцев назад +2

      Ackermann steering- surprisingly simple.

  • @kaz49
    @kaz49 7 месяцев назад +50

    You know what, all vehicles should be able to fold up like that. Imagine how much less space we'd need for parking! xD

    • @kentoncompton3009
      @kentoncompton3009 7 месяцев назад +1

      Modern logging trailers do (sometimes) fold up right into the semi-truck. Completing essentially the same task, taking something very long and unwieldy, and making it turn much tighter than it’s normal length would allow.

    • @anteshell
      @anteshell 7 месяцев назад +1

      I agree to this idea! What a wonderful silence afterwards when I left my kids waiting in the car while going for shopping. Don't have to buy minced meat either.

    • @thatguythatdoesstuff5899
      @thatguythatdoesstuff5899 7 месяцев назад +16

      @kaz49 Or better yet, implement better public transportation and have less people drive cars. Then we wouldn't need as much parking and there would be less traffic. Plus more jobs.
      Essentially a win for everyone.

    • @mewmew8932
      @mewmew8932 7 месяцев назад +1

      @@thatguythatdoesstuff5899 no

    • @ng.tr.s.p.1254
      @ng.tr.s.p.1254 6 месяцев назад +2

      @@mewmew8932 yes

  • @Waran-Ess
    @Waran-Ess 7 месяцев назад +1

    I will never get bored of these videos

  • @dis-fuction1425
    @dis-fuction1425 4 месяца назад

    I’m more suprised by how perfect of a circle those drive lines are , good job bro

  • @PureRushXevus
    @PureRushXevus 7 месяцев назад

    I love these so much, short and very interesting to watch :)

  • @margathapai4010
    @margathapai4010 7 месяцев назад +5

    "Babe, why are you taking notes?"

  • @KurzawaJakub
    @KurzawaJakub 7 месяцев назад

    You are the best at Lego experiments. Please do not stop doing these videos.

  • @Bricks.Master.Builders
    @Bricks.Master.Builders 7 месяцев назад +1

    Your videos are so educational. I love them so much, please try to make two videos per month not just one ❤

  • @gain96
    @gain96 7 месяцев назад +3

    You are a smart and creative person. I wish you success❤

  • @Neimperec
    @Neimperec 7 месяцев назад +1

    Superb explanation! Thanks

  • @SeanMirrsen
    @SeanMirrsen 7 месяцев назад +7

    One that's slightly more useful (and insane) than the transforming vehicle: One that's programmed to do a wheelie and balance on its two rear wheels like a hoverboard as it turns around. :P

  • @jackpomeroy5855
    @jackpomeroy5855 7 месяцев назад

    This new video you made is like a virtual birthday gift

  • @legojoseph
    @legojoseph 6 месяцев назад

    I always watch your videos without any distractions.

  • @fregtz735
    @fregtz735 6 месяцев назад +3

    It would have been fun seeing a design involving differential steering but using clutch braking. Maybe for a future video? Love your stuff❤

  • @ILKOSTFU
    @ILKOSTFU 2 месяца назад

    Love these designs 👌

  • @uncleFestr
    @uncleFestr 7 месяцев назад +2

    3 and a half minutes and i was captivated the entire time. I don't even play with legos.

  • @7.12_am
    @7.12_am 7 месяцев назад +1

    it's a good day when BEC uploads

  • @SWellWellWell
    @SWellWellWell 7 месяцев назад

    Nice work! It's really funny )

  • @TraydonDunkheel
    @TraydonDunkheel 7 месяцев назад +8

    I loved this video a ton. I don’t know if you’ve ever heard of a “front dig” before but that would be an interesting one to try with legos. Rock crawlers use it to do way tight turns in the back country. They disengage 4wd and lock the rear brakes then they use power just to the front axle to pull the truck around tighter obstacles. It’s super cool.

    • @scottthewaterwarrior
      @scottthewaterwarrior 6 месяцев назад

      Not sure the LEGO motors would be strong enough for that, in my experience they are quite underpowered.

    • @garethbaus5471
      @garethbaus5471 6 месяцев назад

      ​@@scottthewaterwarrior A lower gear ratio can give you the torque.

    • @scottthewaterwarrior
      @scottthewaterwarrior 6 месяцев назад

      @@garethbaus5471 Yes, but then you take the LEGO vehicle from an already slow speed to a downright painful speed.

  • @Delerane
    @Delerane 7 месяцев назад

    As always, it's insane.

  • @jhsevs
    @jhsevs 7 месяцев назад +5

    0:44 you forgot to add a center differential. In a conventional car, both wheels on the front axle has a larger turning radius than the rear axle, causing a 4wd to skid and skip some, but not as much as if the front or rear diffs were locked

  • @Scott.E.H
    @Scott.E.H 7 месяцев назад

    What a neat little video.

  • @and_gelitan
    @and_gelitan Месяц назад +1

    This is better than most hybrids nowadays

  • @Braznovoel2
    @Braznovoel2 7 месяцев назад

    Legend is back...

  • @TheAdvertisement
    @TheAdvertisement 3 месяца назад +1

    Bro made his own transformer at the end.

  • @jakeilano6821
    @jakeilano6821 7 месяцев назад

    Loving this.

  • @phylippusvonhohenheim3232
    @phylippusvonhohenheim3232 4 месяца назад

    This was beautyfull

  • @stickdude1014
    @stickdude1014 7 месяцев назад

    Nice! Now perfect the spin

  • @RobertoRodriguez-iw2zf
    @RobertoRodriguez-iw2zf 7 месяцев назад

    You are the best bro
    I see all your vids

  • @nihilconsortium5518
    @nihilconsortium5518 7 месяцев назад

    The last one made me smile !

  • @_errornowifi_
    @_errornowifi_ 6 месяцев назад

    Where did you get the peices for all of your creations. Especially did the mega tank how did you get the test things that go in the twrack of the wheel things

  • @Sillybutts
    @Sillybutts 7 месяцев назад

    Love these videos :)

  • @FrietjeOorlog
    @FrietjeOorlog 7 месяцев назад +3

    RWD + LSD can net you a very small turning circle by turning the wheel and blipping the throttle for a second or so 😉

  • @spatialguy5571
    @spatialguy5571 7 месяцев назад +5

    OMG. How long did it take you from basically not knowing about all this mechanical know-how (100% beginner), up until now with videos like that? It’s so far beyond impressive! Thanks for showing us! 👏👏👏

    • @bakielh229
      @bakielh229 7 месяцев назад

      Weird question

  • @Cearb
    @Cearb 7 месяцев назад +39

    Awesome as usual.
    Could you by any means do a comparison with front-wheel steering and drive? Since most modern cars are front-wheel drive.

    • @thecommenternobodycaresabout
      @thecommenternobodycaresabout 7 месяцев назад +15

      Yes, please! Maybe a full comparison of AWD, FWD and RWD with and/or without differential

    • @icefreezer7
      @icefreezer7 7 месяцев назад

      Yes please

    • @straightpipediesel
      @straightpipediesel 7 месяцев назад +6

      In the low-speed low-slip case it makes no difference. Where it makes a difference is with real, pneumatic tires that the contact patch deforms under load which isn't modeled here. In basic models of real cars, that's modeled as a sidewall stiffness factor.

    • @kantpredict
      @kantpredict 7 месяцев назад +1

      Makes no difference at this speed. Only at speed will you get understeer

  • @lombridious
    @lombridious 7 месяцев назад +2

    This guy in a few days - 1:64 Working jet engine producing real thrust with Lego

  • @mealex303
    @mealex303 7 месяцев назад

    EPIC GENIUS

  • @quentinquaadgras
    @quentinquaadgras 6 месяцев назад

    Why is this video so funny!

  • @MartinMuch
    @MartinMuch 4 месяца назад

    Oh my gosh 😱😱 amazing🎊🎊🎊👍🏼👍🏼👍🏼

  • @brother_matt8289
    @brother_matt8289 2 месяца назад

    is there a reason you use the power function motors instead of the powered up ones?

  • @bunnythekid
    @bunnythekid 7 месяцев назад +13

    A vehicle with differential steering and a single or dual caster wheel (like a roomba) would only be limited by its physical size.

    • @Marci124
      @Marci124 7 месяцев назад

      Alternatively, one might use mecanum wheels and never need to turn again. Thankfully you'd still be able to, if you wanted to.

    • @bakielh229
      @bakielh229 7 месяцев назад

      and the marks you'd leave every time you take a turn

  • @xpatrstarx
    @xpatrstarx 4 месяца назад

    I've been wanting to do a demonstration like this to help my driving students understand vehicle steering better. I never thought to use Legos like this

  • @MrMichalMalek
    @MrMichalMalek 7 месяцев назад +1

    Now I know how to mod my daily car for better maneuverability.

  • @decract
    @decract 7 месяцев назад

    The fact that he still haven't run out of ideas is insane.

  • @TT.357
    @TT.357 Месяц назад

    Differential steering is also often called neutral steering. Most modern tanks and other tracked vehicles have this feature so they can maneuver about in very tight spaces or in areas with inconsistent terrain.

  • @karvavarba2700
    @karvavarba2700 2 месяца назад +1

    Can you test the Ackermann principle in lego? Would be interesting and educative since i bet its not a familiar principle to many

  • @raoofshetaya2136
    @raoofshetaya2136 7 месяцев назад

    Love your vids can you try and make a lego forklift it would be awesome

  • @BT2SS
    @BT2SS 27 дней назад

    That’s cool!

  • @zervidas
    @zervidas 7 месяцев назад

    Notifications from your channel are very rare

  • @Akotski-ys9rr
    @Akotski-ys9rr 7 месяцев назад

    I wish I had all the Legos to build stuff like this

  • @NotGrimman
    @NotGrimman 7 месяцев назад +1

    Tank steering was pretty awesome in lego

  • @krishnaswami-lj4rd
    @krishnaswami-lj4rd 7 месяцев назад +1

    i want some of these lego tooo❤

  • @Queerio_lol
    @Queerio_lol 5 месяцев назад +1

    For a regular car, front wheel steering and drive has a pretty small turning circle

  • @Infrared73
    @Infrared73 7 месяцев назад +5

    I wanted so much more. Any ability to incorporate some casters in front/behind some drive wheels? I think some function to perform as well to make the designs meet a constraint.

    • @dominiknovosel883
      @dominiknovosel883 7 месяцев назад +1

      I know, right? Honestly, I fully expected him to make something super overkill or ridiculous by the end, like omnidirectional wheels or a hamster ball. This was... almost underwhelming. Surely there's a part 2 in the works.

  • @randomducc
    @randomducc 7 месяцев назад

    nice video 👍👍

  • @Heisen21
    @Heisen21 6 месяцев назад +2

    It would be interesting if we can get length to dia ratio of the vehicle to know the efficiency of the turning radius. As length of the vehicle is playing a huge role in it.

  • @SlavikCool
    @SlavikCool 7 месяцев назад

    Honey wake up, BEC uploaded a new video

  • @xjerrylee22x
    @xjerrylee22x 6 месяцев назад +1

    I kept guessing the number of centimetres correctly, it was incredible. I don't know why I can't do this with something that matters!

  • @TheBedroomSimRacer
    @TheBedroomSimRacer 6 месяцев назад

    Me: I'll go to sleep early tonight
    Also me at 5am:

  • @nhanthanh303
    @nhanthanh303 7 месяцев назад

    I love your video a lot 10000000000000000000000000 sub

  • @murthisrikanth
    @murthisrikanth 2 месяца назад

    Would've been good to see Ackerman vs anti Ackerman turning radius too. Still an exceptional video as always🙏

  • @JAMESMANHUNT9
    @JAMESMANHUNT9 7 месяцев назад +1

    Rough terrain cranes have conventional 4 wheel steering but they also have crab steering

  • @ashscott6068
    @ashscott6068 6 месяцев назад

    That's a lot of trouble to go to, just to avoid learning to reverse! :P

  • @justinblin
    @justinblin 7 месяцев назад

    I love how it just sorta turned into a tank

  • @antimattered3921
    @antimattered3921 7 месяцев назад +1

    a side by side comparioson would be nice

  • @the_dork77
    @the_dork77 7 месяцев назад +1

    He took pull a u turn to the absolute extreme

  • @MattNeufy
    @MattNeufy 5 месяцев назад

    Me: transforming vehicle? This is stupid…
    Also me: I LOVE IT!

  • @bakayaro6473
    @bakayaro6473 7 месяцев назад

    Nice👍

  • @shivamsanas8863
    @shivamsanas8863 2 месяца назад

    I really hope that these videos are played in schools and colleges.

  • @guitar0fan
    @guitar0fan 5 месяцев назад

    What are the lego parts/set needed for this?

  • @K-H-28
    @K-H-28 7 месяцев назад +79

    Good experiment, but the different vehicle lengths are giving us different results. Id like to see this done again, but all vehicles are the same length

    • @UrsaMinor-69
      @UrsaMinor-69 7 месяцев назад +26

      Read description

    • @alexlarex7773
      @alexlarex7773 7 месяцев назад +18

      it's kinda hard to see, but i'm pretty sure all vehicles were the same length, i guess that's the reason the normal differential steering one was so much longer than needed

    • @akseliritola1890
      @akseliritola1890 6 месяцев назад +2

      They are all the same length......

  • @mazicort_
    @mazicort_ 6 месяцев назад

    Would be great to see Ackerman and turntable in addition to ones you shown!

  • @JazzbLu
    @JazzbLu 7 месяцев назад

    Oh Hahaha! A smaller turning radius than the length of the vehicle! You're funny!😅

  • @KellyBeeSan
    @KellyBeeSan 6 месяцев назад

    Designer: **Shows a transforming vehicle design** "Three-point turns will cease to exist!!"
    Engineer: "Yeah, keep dreaming bucko..."

  • @ElCapitan88
    @ElCapitan88 5 месяцев назад

    I need one of those engines for my ford gt.

  • @MrSaemichlaus
    @MrSaemichlaus 7 месяцев назад

    And then there are tracked dumpers with a tracked undercarriage and a rotating dump body and cab. It can drive both directions without needing to turn the tracks and then it only rotates the upper part 180° whenever it gets to the loading or unloading spot.

  • @kasaeuberlichproduction5981
    @kasaeuberlichproduction5981 5 месяцев назад

    I'd like to see you prototype a suspension setup with the benefits of an independent and a solid axle. For example, solid axles are unstable at speed and have clearance issues. In contrast, Independent suspension has clearance and stability but no truly redemptive factors on a challenging trail, where solid axles belong.

  • @cauameira8108
    @cauameira8108 7 месяцев назад

    Nice

  • @jonnycaputo2267
    @jonnycaputo2267 7 месяцев назад

    I would love to see a video on Lego boat tow strength

  • @cherylbowman8652
    @cherylbowman8652 5 месяцев назад

    Wow that is awesome 0:28 0:29

  • @fastbricksrc6084
    @fastbricksrc6084 7 месяцев назад +1

    Interesting that a differential makes a difference like that.

  • @383mazda
    @383mazda 6 месяцев назад

    You should try the first few again with akerman steering (where inside wheel makes a tighter turn).

  • @hexlart8481
    @hexlart8481 Месяц назад

    I think it would be interesting to compare these in terms of ratio between car length and turning radius.

  • @Nixgg
    @Nixgg 7 месяцев назад

    No way anyone is better than him in being scientific in LEGO.

  • @wolff_anime
    @wolff_anime 6 месяцев назад

    Bro really thought he could sneak the best drift of 2023 just like that

  • @user-iq5cf2cp7t
    @user-iq5cf2cp7t 7 месяцев назад

    What does the transforming vehicle need its tail for??

  • @Aaditya__Singh__Thakurz
    @Aaditya__Singh__Thakurz 7 месяцев назад +2

    You are very creative ❤

  • @maxseppelt8916
    @maxseppelt8916 7 месяцев назад

    If someone pulled into my driveway to do a u turn with that articulated method i would open fire immediately

  • @nardic15
    @nardic15 Месяц назад

    Jackknifed the Heck outta that first Trailer.

  • @freedomofmotion
    @freedomofmotion 7 месяцев назад

    What about differential steering + turnable front and rear wheels.
    There's a few ultra vehicles with that set up.