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@heyitsdisty interesting conundrum. Sorry I am no expert in physics, I could be wrong but in the slow motion video you can see that with each swing of the axe the motor accelerates twice. I could be wrong but I think this is the key. In a fixed axe setup you would have 1 thing happening, the motor turns on which accelerates the axe, and that's it. But you have a 2 stage thing going on. Firstly the motor turns on, and having little mechanical resistance it is able to accelerate really fast, building up lots of inertia inside the fast spinning internal motor rotor. Then the "slack" is taken up in the hinge and it is now trying to accelerate the whole arm in an instant, causing the motor to briefly almost come to a complete stop. But all that kinetic energy and inertia inside the fast spinning motor had to go somewhere, and I think it went into bending and stressing the framework and the hinge, but it is not wasted as that energy quickly rebounds, and releases itself like a spring back into the arm. It is at this moment that the arm starts moving, but also the motor can start moving again as well, so now you have a combination of that energy being released like a spring, and the motor adding energy into the system for a second time, to accelerate the arm at a faster rate than would have been if the hinge was not there. It seems that you have created a nicely balanced 2 staged system, with different forms of energy being created at different times, but being released together at the same time, combining to make a bigger wallop!

Well I am trying to be more positive on this forum, too much?!

I have said before that price per piece is not a good way to quantify value, even without PU involved. Price per kg gives a much stronger correlation and it does seem that the CAT has a lot of big panel pieces. Also it has the 42099 gear reduction hubs which aren't cheap. And I also agree with @Jim that the price of 42100 was probably just excellent value compared to this new CAT, which is only just okay value. Not as good a 42100 but not as bad as a lot of people would make it out to be. But to me, price per piece, price per KG or whatever, these are different methods of trying to find out how a set will be priced and that's fair enough. But these methods in no way reflect how much a set is worth to me as the buyer. On paper the CAT may be reasonable value, but as the CAT doesn't offer much of value to me (apart from one new (wide track) and one recoloured (5x7 yellow frame) part which I will be buying separately) the value discussion become less relevant. If it was ----insert wishlist here----- then I'd say it was excellent value and I'd be coming up with all sorts of excuses for the price even if it had less pieces. Value is subjective at the end of the day.

Matthias Wandel?! Sweet! I'm a fan of his YouTube woodworking channel and had no idea he built one if the first air powered Lego engines. You learn something every day! I mean, I'm sure there were engines built before his, but it's just a cool coincidence, I guess, that he was one of the first to document it.

Very nice rig. Have you also built it out of real pieces?

@grohl has a few YouTube videos, like suspension for dummies for example, which you may find helpful. And also second recommendations for Technicopedia and the brick experiments YouTube channel, and also @nicjasno YouTube channel as he shows well the process of designing a MOC. You can also ask here if you are really stuck, although I also recommend just trying, failing, trying, failing, repeat until you get good. Ain't no substitute for learning how to figure things out for yourself. But of course we're happy to help

I hadn't heard of new elementary before. I don't want to steer us off topic but just look at all the new parts the other themes get! Anyway swiftly back on topic, I am looking forward to the reviews even if I'm not really looking forward to the set, is that weird? Although I am looking forward to getting the larger track pieces and the 5x7 frames in yellow

Maybe. I haven't noticed pneumatic components raising the price of sets anymore than LAs would. This year's tow truck is very well priced. But yeah, could be fewer parts but equal in price to 42100, or slightly more, but I think you'd get what you pay for.

The new education set has a new smaller PU motor which might be good for controlling the valves. I think there's room enough for 4 of those, 2 hubs, drive motors and compressor. At least then we'd have more justification for its size and price tag.

So now more details of the CAT dozer are available, it's interesting reading through the results of this poll. Of course the CAT has it's fans, and that's great, but the reception so far has I think been more negative than positive. Although complaints are largely focused on the price, remember that price is only one half of the value equation. Cost is relative. If it was perceived as being vastly superior to what it currently is then the price wouldn't have been complained about so much. And I do think that reading the results of the poll may explain why the CAT doesn't really reach the level of awesome required to justify it's price tag, and also why the tow truck got lots of praise and is still selling quite well as far as I can tell. Many have said that it feels expensive because it has fewer pieces that 42100 and well as 1 less hub and 3 less motors, yet it's the same price! This is indeed crazy! But I think that's largely to do with costs for everything rising so dramatically since the pandemic. As an engineer with a budget, I know full well that you just can't get hold of stuff! Demand has gone up but the world hasn't been producing, so demand now out strips supply, and prices sky rocket. And as Technic flagships take years from initial concept to being on the shelves, it's understandable that TLG were slow to react. Hopefully we can leave this pandemic in the past and get back to normal. So I do understand TLGs position (I think!) but it's right that we let them know, this should not be accepted as the norm for years to come. But what if it did have 2 hubs and 7 motors and the same piece count of 42100, there would still be complaints. The price is just low hanging fruit (an easy target) for detractors. Weather it's a motor for each function, or less motors with more gearbox action, both have their fans and both have their pros and cons, but neither are the most preferred option. There is a third option that people only really think about when it is presented to them, which is just to have more realistic mechanisms to begin with! In the poll, I asked what appeals to you as a technic fan. The top two responses was a variety of mechanisms and realistic mechanisms. Now look at the old argument "one motor for every function" vs "fewer motors but more gearboxes" and you see that neither option necessarily fulfils the top desires of a "variety of mechanisms" or "realistic mechanisms", at least not in the way these two approaches are done in the CAT or 42100. But there is a model that does, the tow truck, and it is almost universally praised and selling well as for as I can tell. SO HERE'S THE BIG QUESTION I HAVE FOR YOU! How could the CAT do this? How would you have designed the CAT o fulfil the desire for realistic mechanisms (LAs are not realistic LOL!) and a variety of mechanisms? How would you design the CAT so it can be worthy of it's price tag? For me, you probably already know, pneumatic, smaller servo to precisely control the valves, tilt sensor in the blade to provide positive feed back to allow for precise control of RC pneumatics, new much higher capacity motor pump (like maybe a 6 barrel axial piston pump or something), etc. And remember, if you do have frustrations for the CAT or any other sets released in future, well you can always come back to this thread and express your feelings all you want!

Yeah we do, but nothing is perfect, and I think they could do a lot to be even better. And companies must evolve to survive.

LAs exist! I want more pneumatics! Also, wheels are too wide yet their hubs are too shallow. They need a much more positive offset. Imagine a truck wheel, 81mm diameter but probably only 20mm wide, with enough positive offset in the rim to be able to pin two back to back without any spacer, and still have a small gap between the tyres, like on a real dually truck! This wheel would be great for trucks, pick ups, cranes, all sorts. Too much internal gearing in the motors. Isn't one of the points of Technic that I get to build all the mechanics?! Their insistence on making colour coding look like colour vomit. I don't mind colour coding but use more tasteful colours. Bright red, bright blue, orange, lime, magenta etc are not tasteful. Colour coded pre cut pneumatic tubes. Would be much better, look much better and possibly even more cost effective to have them all black and include a sticker sheet with coloured/numbered bands to wrap around the hose about 8mm from each end. And instead of pre cutting (and TLG having to store multiple lengths and colours of hose), just supply one long length in black with enough spare for any mishaps. This would (I think) be more cost effective and us fans could potentially buy long uncut lengths for our MOCs. Pneumatics only coming in yellow. Always doing the usual twin wishbone suspension. Why not add McPherson for a realistic hot hatch, or leaf spring for a realistic truck. No mechanically realistic helicopters, or elegant ways to make them. Myself and others have made more realistic MOC helicopters but the main cyclic/collective mech never seems quite as elegant as it could be. TLGs misunderstanding of 18+ and build for real. Build for real shouldn't just be "it looks like a real bulldozer". That's fine for creator but this is Technic. It should WORK like a real bulldozer. You won't find LAs on a real bulldozer. Mechanical authenticity is more important than simply looking authentic. Also, with Technic, 18+ shouldn't be just bigger and more expensive. Make a model so awesome in its mechanical nature and detail that it has to be that big, like the bucket wheel excavator, NOT like this year's CAT. They wanna make an 18+ excavator, well it better be RC pneumatic with rams that are at least 15 stud long retracted! I have more but gotta go now!

I think this might be correct. This year's tow truck especially got lots of praise, well here on Eurobricks at least, so they wanted to show it off. I think he designed the tow truck, no?

Yes, much stronger. It also gives a better gear reduction (both for motorised and non motorised models, because I want my fake engines to spin FAST!). Only flaw with the new one is that the output shafts are still driven by a 12t bevel right on the end of the shafts. But still much stronger than the previous ones.

Remember that the rumoured price and part count was leaked before the first leaked image. So they very likely had the model much closer to its final size before the first image was "leaked"! So if this is TLGs way of showing retailers and maybe also the hardcore fanbase what's to come without revealing too much to the copy cats well I'm fine with that. I guess from now on we will have to keep in mind that leaked images will change much more drastically than before. Besides the black LAs have been known about for a while.

Oh, how wrong I was, silly silly me, the first image came out and I shot from the hip, but now the final image is out, and they made it bigger, oh well golly gosh now I just loves it!!! BAHAHAHAHA!!!!!!!!! Sorry guys, my view hasn't changed, despite I am surprised it's so different from the initial images. If it was a deliberate misdirection to fool the copy cats, well fair play TLG. I do like the new track parts, I'll be getting a bunch of those. But the set is kinda same old unrealistic motors/LAs combo yet again. So for now it's still a hard pass. More details might come out later which make me change my mind and guess what, that's okay! No need to be so high and mighty when someone changes their mind when new info is released. The ability to change one's mind when better info comes out is actually a good thing believe it or not. But like I say, FOR THE TIME BEING it still looks mechanically unrealistic and uninteresting to me so it's still a pass. But for a brief moment I did, perhaps foolishly, get my hopes up that I would change my mind. Just this week I saw the new small motors from the new education set, motors which to me look like they would be great for controlling pneumatic valves in RC models. And with the tow truck bringing pneumatics back I wondered if just maybe we'd finally be getting the first RC pneumatic set, and also a pneumatic flagship which we haven't had for 6 years now. And this bulldozer with its rumoured large size and not that many functions would be a perfect test for much more ambitious sets to come in the future. Alas, not this time.

42070 uses m-motor for steering because in another mode the motor is used to drive other functions of the model. As for motors, the 4x4 stud ones released in 97 with the barcode truck are about the worst ever! They may be efficient using very little power, but their total mechanical power output is really bad. But I find the older early 90s 5x4 9v ungeared motor has around the same mechanical power output as a PF M-motor when geared down to roughly the same speed. So 2 of them may well produce roughly the same power as an XL if done efficiently, so no worm gears as they are very inefficient, or bevel gears. Use spur gears only and maybe a belt drive at the first stage if it's too noisy, but not too tight as that will increase friction. But 1:27 is not a big reduction with these motors. Also beware that the older drive rings appear to be less efficient than the newer ones because the older ones have slightly wedge shaped dog teeth, which pushes the gears out from the drive ring when under load, causing friction against the surrounding frame work. The newer ones have totally straight dog teeth.

5: 10 13: 6 17: 4 19: 3 37: 2 16: 1

Now THIS is how you argue. Good points well made, thank you! This touches on the specialised parts discussion. The thing is, Lego started out with simple bricks to make mostly just buildings. Real life buildings are made of generic bricks, wood and things like that, all generic items. But cars and vehicles in general aren't like that. The majority of their components are specialized. But of course, Technic shouldn't be made of specialized parts only. That would negate the whole point of it being Lego. But I would say that the Technic theme should allow a little more room for specialized parts than other brick based themes. For those that don't like specialized parts, well that's cool, you don't have to use them. But the option could be there for those that do want to. The vast bulk of a model such as the chassis and bodywork doesn't need specialized parts. Besides, do we really need another type of wheel arch (to collect in all colours), another bit of trim to attach to a wheel arch, a new type of connector peg or panel etc. The F1 gearbox shows how the 3 stud long drive ring could be reduced right down in length, to 1 stud ideally (pretty sure the diff lock in the Zetros enguages with less than half a stud) You could have an 8 speed gearbox in the length of 12 studs (more if you want to add extra bracing for motorised models), it would be way better and much simpler to the point that younger fans could build an 8 speed gearbox into their own MOCs. The gears could have their number of teeth moulded into them, like the numbers on panels, to reduce mistakes as the manual would directly call out that number, combined with the fact that they are all different sizes an can only really go together the correct way, and have that gearbox stage in its own bag of parts to make it more mistake proof. Gotta be better than a brightly coloured gear in a sea of other brightly coloured parts where nothing stands out, because it all stands out! I do fully understand the arguments against too many specialized parts but I think in this case the benefits out weigh the negatives.

It looks like childish shit. I want the inside of a gearbox to look and be like the inside of a real gearbox, like this F1 gearbox: Look how elegantly simple, efficient and easy to understand that is, no colour coding required. With all the gears being different sizes you literally can't build it wrong because the gears will only fit together the correct way. Compare that to this 8 speed gearbox: Colour coded to buggery and with more parts and complexity than the real thing, it's still undecipherable and is still prone to people making mistakes and doesn't show how a real gearbox works and does not look or feel like an 18+ product and with it's high friction, reliability issues and overall sloppyness/backlash, it doesn't feel like a quality product either. It's an expensive model aimed at adults that in reality feels like a cheap toy for kids. Colour coding represents a lazy, unimaginative, cost cutting, corporate alternative to a much better solution.

I think I understand now. While 18+ to me should mean "next level" builds for the AFOL (no colour coding, realistic mechanics etc), I think what it actually means is "nice decoration for the shelf" for adults that are not already fans of Lego.

Looking at the Smyth's and Argos websites can give some idea of how well a set is selling. Smyth's currently has the tow truck at number 4 (out of all Lego sets) and top of the Technic theme, while Argos also shows strong sales, top of the Technic theme. The Zetros on Smyth's UK shows it's around 13th across all Lego (not bad TBH considering there's many hundreds of sets and all the new sets released at the same time). But yeah, tow truck is currently doing very very well it appears.

I think it will always be hard for a MOC to get 100's of comments. When an official set comes out, I know it will be available in a store near me, all with shiny new pieces, instruction book and boxed in a neat package, and it might come with some new parts that I don't own, and eventually at a discounted price. So this will have a potential impact on my hobby as a new purchase or parts and something new to build. A MOC is a whole different thing. It will be harder to replicate without instructions, have no new parts and I'll have to gather the parts from my own collection and likely have to buy some crazily over priced pieces on bricklink (now Lego has the same issue with electronc components but whatever). The point is that it's much harder for a MOC to have the same impact on my hobby as an official set, which I guess makes me less inclined to comment on it. But way back when I decided to build Sheepos Landrover, not only did I comment on it but I did a full review of it. I don't post many of my MOCs as they are rarely ever finished. But I do play as lead singer/guitarist in a band, we spend lots of time rehearsing, countless hours practicing at home, decent gig quality instruments, mics, amps are expensive, I do still get stage fright (first few times before I played in front of an audience I was physically sick!) and while most the time we get the room bouncing and rocking, we've been to many gigs and we were nothing more than background music with total silence between songs. If you think not receiving any comments on a MOC on an online forum is bad you wanna try being me, in person, after having poured everything into a rendition of U2's with or without you (try singing that and playing the guitar to it at the same time while the band are out of time with your Edge delay sound, it's hard work I tell ya!), only for the room to be silent! There have been other occasions where we are booked in a venue that we know is practically dead and there's 3 people in the audience. It can feel awful. But the times when you get a great reaction are worth it. There's been other times performing the same song where couples are slow dancing in front of me with literal tears looking into each others eyes and kissing the whole way through. Sometimes they say thankyou, sometimes they just walk away still engrossed in each other without saying anything to me (very understandable!). We also never make much money, we couldn't live off it that's for sure. The point is that if your a MOCcer doing it for little or no money then you shouldn't gauge your work, or question your reasons for sharing based on what others say or don't say, or how many people see it. You know if you've done good. And your motivation for MOCcing and sharing your work with others shouldn't be for comments but because you enjoy it. And if you do get lots of comments and views, well that's awesome, but if not, that's no reason to stop if you enjoy it anyway . Regarding criticisms of MOCs, I agree with Celeri. If you want a bunch of yes people and a wall of "great MOC" posts then this might not be the best place. If you want to learn/improve, be challenged and see what other experience builders really think but in a (hopefully) constructive, polite and positive way then this is THE BEST place for that. It would be interesting to know if people prefer this or would they really prefer the wall of "great MOC" posts. I mean, if all you want to say is "great MOC" then of course just say that, that's infinitely better than no post at all. But we post here assuming we are all adults. Sure we are all flawed individuals and it's easy to take a constructive criticism with some anger, but we are still adults regardless and as such we understand that "I have a different opinion to you" is not equal to "I hate you", something that seems to be so simple and yet forgotten in todays divisive, lefty, identity politics!

Well you do make a lot of good, valid points here. Okay, the competitors are built to a fixed scale, but it's still a scale that's larger than the Zetros, so of course they will manage bigger obstacles. And Lego were looking to hit a certain price point (overpriced granted lol!) and feature set so they were kinda forced to use the size of wheel they did to reach that. And yeah, the whole PU system still feels rather under cooked, a feeling I get with all PU sets, not just the Zetros. As for what to compare it to, maybe the previous Lego crawlers and off roaders? These are sets that all have to meet the same criteria so would probably be a fairer test. I'm sure the Zetros would beat 42070 quite handily. Having said that, I do appreciate that you are fully willing to show any sets short comings. No-one can accuse you if being biased towards TLG that's for sure, so thank you for that honesty, it's always welcome regardless of weather I happen to agree. I don't see the diff locks as a waste of time. Ideally you'd be driving it indoors over little obstacles you set up for this model, with the diff locks open, get stuck, and then marvel at how you can lock the diff to get moving again. It's also a function of the real thing so it's good to see it included here. But I do agree that the turning circle is too large so it's harder to see its benefits. But I'd say that's a failing of the steering rather than the diff locks. Now you mentioned Legos ability to make new parts, which is something I 100% agree with. Happily they did make some new parts, the extending CV joint piece, the new tyres (which admittedly aren't the best for this set but will be great for future sets), and the new alternating beams. But yes, Lego needs to up their game with suspension pieces. It looks like the Zetros would benefit from some slightly softer suspension with more flexibility (as in range of movement) from the axles. And some way of making the axles way less bulky. Lego axles have always been may too massive. I have never understood your pickyness with flimsey doors. To scale you are about the size of King Kong. Of course they'll feel flimsey to you! But by now it's a tradition of your reviews, I'd probably miss it if you didn't mention flimsey doors As for Lego calling it a trial truck, and charging 300 for it, yes I do agree. But here I feel a little sorry for the Zetros. Most if us agree that Legos pricing of PU sets is crazy, and their marketing department have been very questionable as of late (18+ for a racers style simple pickup anyone?!). But is that really the fault of the model itself? Someone could tell lies about me and introduce me to a crowd of people as a master violinist, then they get disappointed when I play the kazoo, would that be my fault, or the fault of the person who incorrectly introduced me? I do agree that the astronomical prices and questionable marketing do a bad job of managing expectations. Maybe if they didn't call it a trial truck, didn't include the trial truck flags, and priced it way more reasonably, would your opinion of the model itself be better? It's certainly better than previous TLG attempts at an off roader, is it not?

Okay, lets compare. Cost. The competitors used S-bricks, multiple rechargeable lithium battery boxes, more axles and wheels and are all quite a bit bigger, so they would all be more expensive than the Zetros. Looks. The competitors all look like hot garbage and lets be honest, if TLG released a set looking like any one of those we would be complaining like crazy. Performance. Okay, the Zetros loses out here, but when you consider that the others would surely be more expensive and have the freedom to look and be proportioned like however they want (hot garbage apparently), while the Zetros has to look and be proportioned like a Zetros, well I think that explains it, and also explains why an argument can be made for this being an unfair comparison. You could argue that it didn;t have to look like a Zetros, it could have been done without a licence. Well okay, but it would still have to look way better than these, as well as being much cheaper. Realism. Two of them had their drive motors mounted directly to their axles. Not realistic at all. The Zetros could also be more mechanically realistic, especially the rear axle, but still it's better than these. Summary. If all four of these where on the shelf I'd choose the Zetros. No, it's not perfect. The PU system just isn't that great yet, and likely won't ever be until we get more powerful motors, hubs with enough grunt to drive more powerful motors, and physical remotes. But while the goal of the others were to be great off road performers, with other factors such as cost, looks and any kind of authenticity not being remotely considered, the Zetros has much more criteria to fill. If looking at one criteria alone, performance, the Zetros loses, but looking at things as a whole, with all other factors considered, the Zetros is the clear winner.