[MOC] Red Wolf - 4WD RC Race Buggy /w Buwizz

[Didumos69]

5 hours ago, amorti said:

I see something familiar in the background there :)

Now you're apparently back out of a mini dark age, maybe you would publish that?

3 hours ago, Toshi said:

You are not talking about the B-model of the 42129, are you?

2 hours ago, amorti said:

Yes, but it's something of an inside joke. There's another one just like it with different bodywork but not published.

1 hour ago, Toshi said:

I do remember a few posts from a while back about some model without published instructions, I think…

Yes that's correct. @amorti, this is indeed a nice opportunity to fix that. I will send you a PM.

I've already got quite a thread with the Rebrickable admins. I don't think I will get away with putting guessable placeholders in for the 3rd party parts. I'm now working on the PoweredUp version and the admins at Rebrickable are ok with me adding the Buwizz version with 3rd party parts as a bonus pdf in the same MOC submission. as long as its clear that the Buwizz version is a MOD of the original submission.

Edited January 30 by Didumos69

[LEGO Train 12 Volts]

Impressive how powerful and fast this car is!
Great design sturdy suspension.

[Didumos69]

Finally... The instructions are on Rebrickable under the name '4WD RC Race Buggy + BuWizz MOD'. In addition to the instructions for the basic PoweredUp version, the instruction files of this MOC include - as a bonus - a parts list and instructions for the BuWizz version, which uses 2 x BuWizz 3.0 Pro + 4 x BuWizz Motor. -- The parts list for the BuWizz version differs from the inventory listed in this MOC. -- The list of LEGO-parts (.csv) and the list of other parts used (.pdf) for the BuWizz version can also be found here and here respectively.

Edited February 3 by Didumos69

[gyenesvi]

Nice to have the instructions for this model available, thanks @Didumos69! Maybe you could put a bit more images and info up there about the PU version as well though, now it seems too much focused on the Buwizz upgrade.

Also, did you try driving those 3 L motors with a Buwizz3 unit instead of the PU hub? That could have better performance. And using 2 Buwizz3 units and 4 L motors for drive could actually result in a safer but faster model. Just an idea, could still fit into the space of the 2 Buwizz motors.

I read back this thread but I could not find info on why you needed to introduce the liftarms with bearings/washers to the 4WD version? Did you actually damage parts without those? Was the drivetrain lubricated then? You only wrote about the RWD version destroying some parts. So would be interesting to know what are the chances if I try to build the Buwizz version without metal parts!

[Didumos69]

1 hour ago, gyenesvi said:

Nice to have the instructions for this model available, thanks @Didumos69! Maybe you could put a bit more images and info up there about the PU version as well though, now it seems too much focused on the Buwizz upgrade.

Also, did you try driving those 3 L motors with a Buwizz3 unit instead of the PU hub? That could have better performance. And using 2 Buwizz3 units and 4 L motors for drive could actually result in a safer but faster model. Just an idea, could still fit into the space of the 2 Buwizz motors.

I read back this thread but I could not find info on why you needed to introduce the liftarms with bearings/washers to the 4WD version? Did you actually damage parts without those? Was the drivetrain lubricated then? You only wrote about the RWD version destroying some parts. So would be interesting to know what are the chances if I try to build the Buwizz version without metal parts!

Thanks for your message @gyenesvi! The biggest issue was where the rear drive shaft enters the differential area. Because of the 90 degree angle with the big yellow differential gear, the axle pushes itself sideways, away from the differential gear. In turns, the rear axle slows down compared to the front axles and the power only increases. This problem caused the axle and the 5x7 frame around the diff to melt. This melting was very apparent in the RWD version (with 4 Buwizz motors), but also happened in the 4WD version after driving for around 5 minutes straight. I used lubrication (WD-40 Dry PTFE), even PTFE foil which fitted around the axle inside a pin-hole, but to no avail. So I resorted to the 5L metal beams with ball bearings which only cost 8 euros a piece. That made a very big difference. No overheating whatsoever. The only downside was that I could no longer wrap the differential in a 5x7 frame. They offer metal frames with ball bearings as well, but those are way more costly. Not using a 5x7 frame around the differential, resulted in the big yellow bevel gear coming loose from the differential house under heavy load. This I noticed, because the model was getting slower. The buggy motors just keep doing their job. As a result, the disconnected differential carved itself deep into its adjacent parts. This happened only once, but I wanted to solve it. The thin PTFE-coated washers - again not expensive - solved this. Finally, a smaller issue was that the female CV-joints sticking out of the differential gradually found their way out of the small bevel gears inside the differential and once this happened, they started carving a round hole in these bevel gears. This I could easily resolve by adding supports holding the left and right drive shafts half way down the wishbones.

For me the challenge was to keep the insane performance that 4 BuWizz motors give, but without damaging any parts.

I did try a setup with one Buwizz 3 unit and 4 L motors, even bought a converter cable for the 5th PU motor for steering, but the performance was by far not as good as with the Buwizz motors. The main reason is that the 4 PU ports of the BuWizz 3 have lower power output than the 2 PF ports, which I use for the Buwizz motors. From what I can read on my display during operation, the PF ports give almost twice as much current as the PU ports.

Adding a video of the PU version and some photos is a good idea. I will do that. The whole idea of the PU version wasn't planned. The admins at Rebrickable gave me a hard time in getting this model approved. They only allowed this model to be premium if I could guarantee that people buying the instructions wouldn't damage their LEGOs, even if they wouldn't use the metal parts that I suggest. So I made a full PU version, which can't do any harm. To me this PU version only serves as a proxy to make the BuWizz version available. But now that the PU version is part of it, I could add some more info about it.

EDIT: Maybe it's worth mentioning what my motivation behind this kind of models is. I love the endless tweaking and improving. Making small changes, testing, trying to reason why things happen as they happen, making other changes, etc. Until I think it's good enough to offer to others. I've taken it apart so often that I think I can build the complete chassis from the top of my head. The only reason that I sell (ask money for) the instructions is to finance the hobby. So personally, I don't find fulfilment in turning this into a PU version after all the iterations I've gone through, but again, now that the PU version is there, I could give it a little more attention.

Edited February 4 by Didumos69

[Didumos69]

The black version has also been approved on Rebrickable.

[Toshi]

Hm…

Any difference besides the color?

[Didumos69]

1 minute ago, Toshi said:

Hm…

Any difference besides the color?

No. Only the inventory and the instructions are different. They reflect the different color.

[Toshi]

Okay, thank you! 

[gyenesvi]

13 hours ago, Didumos69 said:

The biggest issue was where the rear drive shaft enters the differential area..

Thanks for all the detailed explanation! I also wondered that using the 5L liftarm with the bearing probably excludes the use of the 5x7 frame around the diff, and that would bring about other problems, but good to hear you solved that as well.

13 hours ago, Didumos69 said:

For me the challenge was to keep the insane performance that 4 BuWizz motors give, but without damaging any parts.

I wonder if you experimented with setups using 4 BuWizz motors up-geared slightly (5:3) and then to planetary wheel hubs? I have a model with such a setup, I used it in last year's BuWizz camp, the speed was pretty much good enough, already hard to control even with Xbox controller (though the steering setup needs improvement, hence I haven't yet published it). Anyways, with that setup I did not yet have melting even after a race run of a few minutes on off-road terrain, using only plastic parts and lubrication (though I need to check the model thoroughly after disassembly, maybe I do that soon).

13 hours ago, Didumos69 said:

I did try a setup with one Buwizz 3 unit and 4 L motors, even bought a converter cable for the 5th PU motor for steering, but the performance was by far not as good as with the Buwizz motors. The main reason is that the 4 PU ports of the BuWizz 3 have lower power output than the 2 PF ports, which I use for the Buwizz motors. From what I can read on my display during operation, the PF ports give almost twice as much current as the PU ports.

Interesting that the PU ports provide less power, I didn't know that. Anyways, I only proposed the swap-in of the Buwizz3 unit(s) instead of the PU hub as a low-hanging fruit to improve the PU motor version now that that became the 'official' one on RB. But I understand that you don't want to focus too much on that one, maybe a pure PU variant is better to have then.

 

[Toshi]

18 hours ago, Didumos69 said:

They offer metal frames with ball bearings as well, but those are way more costly.

I had a look at their frames and I don‘t think they have ball bearings!?

I was thinking about getting one and leaving out the washers… As far as I understand their description, the central holes on each side are a bit deeper, so there is less play for the components to move in the first place!

Did you buy the parts from their website or from eBay? Their website refers to eBay in order to be transparent about additional cost, but their German store is empty and eBay UK lists the prices in £, so I am not sure they really include all costs!?

By the way: did you see they offer metal wheel hubs now?! They are expensive but look pretty wild to me! 

[amorti]

Just wondering if apart from metaltechnicparts, you are aware of these guys? That frame (I don't know if they ever got past "coming soon") could solve the need for all the special parts, maybe.

https://tf-engineering.at/diffcase/

I imagine they'd be willing to design a wheel hub with bearings, for the new CV joints.

Edited February 5 by amorti

[Toshi]

I for my part was not aware of them…

Yes, a diff frame with bearings would be very cool!

The one from the link is plastic though, right?

[amorti]

10 minutes ago, Toshi said:

I for my part was not aware of them…

Yes, a diff frame with bearings would be very cool!

The one from the link is plastic though, right?

It is.

I have some of their wheel hubs. They're 3D printed, but the print quality is very good.

I made a video, but nobody really noticed it. Pretty niche, apparently.

https://youtu.be/wvKhLBN7UZo?si=j1hbqf7NqiWHpQNm

[Didumos69]

56 minutes ago, Toshi said:

I had a look at their frames and I don‘t think they have ball bearings!?

You're right. I've been mistaken, sorry for the confusion.

57 minutes ago, Toshi said:

Did you buy the parts from their website or from eBay? Their website refers to eBay in order to be transparent about additional cost, but their German store is empty and eBay UK lists the prices in £, so I am not sure they really include all costs!?

I bought them in their online store. At the time (a year ago) I bought 8 of them for 63.60 euros, shipping was 29.95 euros.

1 hour ago, Toshi said:

By the way: did you see they offer metal wheel hubs now?! They are expensive but look pretty wild to me! 

12 minutes ago, amorti said:

Just wondering if apart from metaltechnicparts, you are aware of these guys? That frame (I don't know if they ever got past "coming soon") could solve the need for all the special parts, maybe.

https://tf-engineering.at/diffcase/

I imagine they'd be willing to design a wheel hub with bearings, for the new CV joints.

Nice stuff. Searching for solutions I also found this site to be very interesting. They also sell wheelhubs and brushless motors etc. It all looks very tempting, but for me it must also remain a challenge to stay as close to LEGO as possible.

https://www.zenebricks.com/collections/technics-super-speed-rc/products/lego-rc-metal-differential

 

[amorti]

3 minutes ago, Didumos69 said:

https://www.zenebricks.com/collections/technics-super-speed-rc/products/lego-rc-metal-differential

 

Their stuff is pretty crazy. Definitely cheat parts.

@aFrInaTi0n had some parts from them and was impressed.

Edited February 5 by amorti

[Toshi]

1 hour ago, amorti said:

I made a video, but nobody really noticed it. Pretty niche, apparently.

Nice part and good video! 

1 hour ago, Didumos69 said:

I bought them in their online store. At the time (a year ago) I bought 8 of them for 63.60 euros, shipping was 29.95 euros.

…

https://www.zenebricks.com/collections/technics-super-speed-rc/products/lego-rc-metal-differential

 

Quite expensive!

Did you have to pay import fees / taxes in addition to that?

And these RC parts look sick, but are a bit much for my taste too!

I don‘t mind if the part looks like Lego but is made of a different material, but this does not feel right!

[Didumos69]

1 hour ago, Toshi said:

Did you have to pay import fees / taxes in addition to that?

No, I didn't, but maybe I was lucky.

[Woodstock89]

10 hours ago, Didumos69 said:

No, I didn't, but maybe I was lucky.

As preparation for the Red Wolf I purchased two from their store. Shipping was 10.95, no other fees. (And they added a bazillion of their MTP stickers to the parcel)

[New_User]

Is the front and the rear axles locked against each other?

If it is, when turning, isn't front axle have to spin faster than the rear to avoid transmission winding?

Just curious how would this perform if center differential is added between front and rear axle?

[Didumos69]

4 hours ago, New_User said:

Is the front and the rear axles locked against each other?

If it is, when turning, isn't front axle have to spin faster than the rear to avoid transmission winding?

Just curious how would this perform if center differential is added between front and rear axle?

The front and rear axles are not connected. In the PU version 1 L moter drives the front and 2L motors drive the rear. In the BuWizz version 2 BuWizz motors drive the front and 2 BuWizz motors drive the rear.

[Knott]

Very nice construction, did you need to modify the tires to fit the rims? I plan to buy this or some other thread pattern, but according to my calculation 1,9in inner tire size is a bit too small for mercedes G500 wheel,

Please Google AliExpress TN1007 tyre, is it the same that you have purchased?

Edited February 16 by Knott

[Didumos69]

3 hours ago, Knott said:

Very nice construction, did you need to modify the tires to fit the rims? I plan to buy this or some other thread pattern, but according to my calculation 1,9in inner tire size is a bit too small for mercedes G500 wheel,

Please Google AliExpress TN1007 tyre, is it the same that you have purchased?

I think these AliExpress TN1007 tires are indeed the ones I have. The rubber is much softer, so they easily fit the G500 rims without modification. The G500 rim has 2 ridges on each side. The LEGO tires fall between these 2 ridges, but the crawler tires need to fall just inside the inner ridge to fit nicely.

[Woodstock89]

I used the Easter weekend to disassemble the Greyhound and prepare all the parts needed for the Red Wolf. Like I did with the Hammerhead, I am planning to do a few cosmetic changes by replacing the visible blue pins by black ones.

@Didumos69, do you mind sharing the digital file of this model? This would make this task a lot easier.

[Didumos69]

On 4/21/2025 at 6:55 PM, Woodstock89 said:

I used the Easter weekend to disassemble the Greyhound and prepare all the parts needed for the Red Wolf. Like I did with the Hammerhead, I am planning to do a few cosmetic changes by replacing the visible blue pins by black ones.

@Didumos69, do you mind sharing the digital file of this model? This would make this task a lot easier.

I'm afraid I won't be able to do that. I've had some bad experiences with sharing digital designs of my models. I'm sorry.