Universal off-roader 4x4 V2

[Zerobricks]

As soon as I saw the new parts in the 42159, I knew I just have to use them to upgrade the previous version of the Universal 4x4 off-roader.

After tinkering for a few weeks in LDD, and actually building it IRL yesterday, it is officially finished:

The V2 has a big list of upgrades comapred to V1.

• Dual independent drive, one for left and other for right wheels - allowing skid steering
• Two 3 speed gearboxes - that's right, this is my first off road vehicle with 3 gears for optimal performance
• Improved steering system - much more direct, accurate and responsive
• Highly modular design - easier access for maintenance and charging
• Top speed has been increased by 40% both in low and high gear - the previous version had ample torque, so I geared up all the ratios by 40% and added a middle gear
• Increased suspension travel at the rear - first time I'm using 11 studs long suspension arms
• Improved drive motor mounting - now they are no longer at a weird angle
• Similar part count to the V1 - even though it's 2 studs longer and has way more functionality it has only 20 or so extra parts, totalling at 796 (I tried to keep it under 800)

Here you can see how the model looks in LDD:

Overview of drive, switching and steering drivelines:

The dual driveline is powered by 4 BuWizz motors, 2 motors for each side.

The lower PU L motor moves the steering rack via an 8 tooth gear.

A second, higher mounted PU L motor spins 4 wave selectors via 8 and 28 tooth gears which in turn switch between the 3 gears.

The gearboxes have the following gear ratios:

• First gear is 20/16 = 1,25 - totalling 4,32:1 gear ratio from motors to the wheels
• Second gear is 24/12 = 2 - totalling 2,7:1 gear ratio from motors to the wheels
• Third gear is 28/8 = 3,5 - totalling a 1,37:1 gear ratio from motors to the wheels

Thanks to the 3 speeds gearboxes, the model has plenty of torque to climb at 45°+ degrees angle, yet can also reach a speed of over 18 km/h, making it my fastest dedicated off-roader to date:

Testing it outside, jumping over pump track course, driving through tall grass, etc... I have yet to encounter any major issues.  The model is reliable, fast and can take a beating/rollover with ease.

So far I'm really happy with it and can't wait to record more media and publish it soon, so stay tuned!

Edited October 25, 2023 by Zerobricks

[1gor]

A bit unusuall question; how is the steering angle using reduction hubs with defender wheels?

[Milan]

Frontpaged, and hopefully, we will see the video of this in action

[2GodBDGlory]

Very cool! Interesting to see a 3-speed in there--I've got a couple questions about it. Why did you use 28T diffs instead of 16T clutch gears? It seems like it takes a lot of space and decreases strength, but was that just the only efficient way to get the gear ratio you wanted? Also, you said you've got both 24:12 and 28:12 ratios--how does that work? 24:12 and 28:8 would make sense for the same 2x3 stud spacing, but in order to get 28:12 you'd need some sort of unusual spacing. Is that correct?

Looking forward to a video!

[Zerobricks]

2 hours ago, 1gor said:

A bit unusuall question; how is the steering angle using reduction hubs with defender wheels?

It's around 25-ish degrees, nothing too extreme, but good enough. That's why skid steering helps if you need to be more maneuverable.

1 hour ago, Milan said:

Frontpaged, and hopefully, we will see the video of this in action

Wow, thank you, Milan. And yes, of course, as soon as there's good weather.

59 minutes ago, 2GodBDGlory said:

Very cool! Interesting to see a 3-speed in there--I've got a couple questions about it. Why did you use 28T diffs instead of 16T clutch gears? It seems like it takes a lot of space and decreases strength, but was that just the only efficient way to get the gear ratio you wanted? Also, you said you've got both 24:12 and 28:12 ratios--how does that work? 24:12 and 28:8 would make sense for the same 2x3 stud spacing, but in order to get 28:12 you'd need some sort of unusual spacing. Is that correct?

Looking forward to a video!

28 diffs act as a 28 tooth clutch gear. All the gears are in L shaped 2-1 spacing, so they are all in correct, legal spacing. The reason gears are spaced in such way is to get the desired raitios and to have the drive axles lower than the moors ones, but still confined to the panels. That is why the low gear is 20:16 and not the other way around, since a 20 tooth gear would touch the panel underneath.

[2GodBDGlory]

41 minutes ago, Zerobricks said:

It's around 25-ish degrees, nothing too extreme, but good enough. That's why skid steering helps if you need to be more maneuverable.

Wow, thank you, Milan. And yes, of course, as soon as there's good weather.

28 diffs act as a 28 tooth clutch gear. All the gears are in L shaped 2-1 spacing, so they are all in correct, legal spacing. The reason gears are spaced in such way is to get the desired raitios and to have the drive axles lower than the moors ones, but still confined to the panels. That is why the low gear is 20:16 and not the other way around, since a 20 tooth gear would touch the panel underneath.

Ok, so it was a clearance issue to avoid the 16:20 ratio. Makes sense!

If it is a 2-1 spacing all around, though, I don't think this can be right:

4 hours ago, Zerobricks said:

Third gear is 28/12 = 3,5 - totalling a 1,37:1 gear ratio from motors to the wheels

since it's usually a 28/8 ratio that fits in that space, right?

[Zerobricks]

1 minute ago, 2GodBDGlory said:

Ok, so it was a clearance issue to avoid the 16:20 ratio. Makes sense!

If it is a 2-1 spacing all around, though, I don't think this can be right:

since it's usually a 28/8 ratio that fits in that space, right?

Ah, yes it's a mistake, it's 28:8, yes. Thanks for noticing.

[LEGO Train 12 Volts]

The video will be amazing!

[glowytheglowbug]

very nice model! good job and love the amount of motors crammed into the build lol

[dustblue]

what's the total weight? 

[SimplyLegoTechnic]

It looks more interesting than what you were doing before!

What is the control mechanism?

Can I see the model's control profile?

And, 2 BuWizz 3 units and 4 BuWizz motors would already cost 480 euros...

Can we expect something similar with 1 BuWizz 3 and 2 BuWizz motors within a model budget of around 300 euros?

[Zerobricks]

12 hours ago, dustblue said:

what's the total weight? 

I will post the weight as soon as I get around to a scale. For now I'd say 1,5 kg.

2 hours ago, SimplyLegoTechnic said:

It looks more interesting than what you were doing before!

What is the control mechanism?

Can I see the model's control profile?

And, 2 BuWizz 3 units and 4 BuWizz motors would already cost 480 euros...

Can we expect something similar with 1 BuWizz 3 and 2 BuWizz motors within a model budget of around 300 euros?

Control mechanism?

I can uplaod the profile along with the LXF file once I publish the video.

Sure, I can make a smaller, lighter but slower model too.

[Daniel-99]

It is always interesting to see redesigns of the old models, because of the changes they have! 

I wonder why you decided to build a two-driveshafts transmission this time? To improve the off-road capabilities, or to reduce the load on each shaft? With dual shaft you use 12/12 bevel gear instead of the differential (28/20). How long 12-gears last? What about the efficiency?

Which part did you use from 42159 Lego set? Will it be possible to get it without a need of purchasing the 42159? (Otherwise it add quite a lot the budget of 2 BuWizz 3 units and 4 BuWizz motors).

I appreciate the total weight of a car, and the weight distribution as well! Also I really enjoyed the color scheme with a black bodywork and yellow / red accents of the suspension! Keep up! 

 

P.S. Really want to see the 3-speed gearbox in action to see what possibilities it gives over the grown complexity.

 

 

[Zerobricks]

11 minutes ago, Daniel-99 said:

I wonder why you decided to build a two-driveshafts transmission this time? To improve the off-road capabilities, or to reduce the load on each shaft? With dual shaft you use 12/12 bevel gear instead of the differential (28/20). How long 12-gears last? What about the efficiency?

Which part did you use from 42159 Lego set? Will it be possible to get it without a need of purchasing the 42159? (Otherwise it add quite a lot the budget of 2 BuWizz 3 units and 4 BuWizz motors).

I appreciate the total weight of a car, and the weight distribution as well! Also I really enjoyed the color scheme with a black bodywork and yellow / red accents of the suspension! Keep up! 

P.S. Really want to see the 3-speed gearbox in action to see what possibilities it gives over the grown complexity.

The old version had an open diff which could reduce performance when one of the wheels would come off the ground. Having dual drive increases maneuverability and reliability, even if one drive fails, the model can still move.

Yes, I had to use 12 tooth bevel gears, which are a bit weaker and less efficient, but they only have to carry the load of one driveline at a time. So far none have slipped/broken and I stress tested it by stalling the wheels.

I used 4x 2473 and 2x 2471. Afaik, they are currently still under license, so not available at Pick A Brick , but I managed to aquire some from offical source.

Weight is coming soon,t but I can tell you that the distribrution is around 50/50. I'd love to have a bit more in the front, but because the model is so low, there are no issues rolling over back even at 50+ degree uphill angle.

Regarding color scheme, i decided to color code things, yellow for suspension arms, red for shock absorbers, grey for steering linkage and the body is black to look more mature (and because the 17x 15 studded flip flop beams are ATM mostly available in black).

I plan to record a video of the model and gearbox in action soon, just waiting for good weather...

[Daniel-99]

2 hours ago, Zerobricks said:

The old version had an open diff which could reduce performance when one of the wheels would come off the ground. Having dual drive increases maneuverability and reliability, even if one drive fails, the model can still move.

Yes, I had to use 12 tooth bevel gears, which are a bit weaker and less efficient, but they only have to carry the load of one driveline at a time. So far none have slipped/broken and I stress tested it by stalling the wheels.

Weight is coming soon,t but I can tell you that the distribrution is around 50/50. I'd love to have a bit more in the front, but because the model is so low, there are no issues rolling over back even at 50+ degree uphill angle.

I plan to record a video of the model and gearbox in action soon, just waiting for good weather...

Thank you for your quick and detailed answer! Another thing I forgot to ask: Do the front the rear have the similar wheel base? As you mentioned in the description that the rear suspension arms are of 11 studs long. But at the front there must be 9 studs, since you use a 9L steering arm. However, driveshaft outputs should being built similarly at the rear an at the front... So calculations say that the rear wheel base should be 4 studs wider than the front one. Am I right?

Edited October 27, 2023 by Daniel-99

[Zerobricks]

2 hours ago, Daniel-99 said:

Thank you for your quick and detailed answer! Another thing I forgot to ask: Do the front the rear have the similar wheel base? As you mentioned in the description that the rear suspension arms are of 11 studs long. But at the front there must be 9 studs, since you use a 9L steering arm. However, driveshaft outputs should being built similarly at the rear an at the front... So calculations say that the rear wheel base should be 4 studs wider than the front one. Am I right?

Both axles have the same width. The front axle uses CV joints, so the base is 7 studs with 9 stud long arms. Rear axle does not use CV joints, but the whole gearboxes swivel around the driveshafts, so the base is 3 studs with arm length of 11. This way I got rid of the CV joints in the rear, increasing reliability, efficiency and suspnsion angle/range.

[Zerobricks]

Took me 2 days of recording, lots of crashes and frustrations, but it was all worth it:

Final technical information:

Dimensions: 35 x 24 x16 cm
Weight: 1450 g
Nr. of Pcs: 796

Download the LDD file here: https://bricksafe.com/files/Zblj/universal-offroader-v2/Universal Offroader V2.lxf

Download the control profile here: https://bricksafe.com/files/Zblj/universal-offroader-v2/universal_v2.zip

To conclude, I am really happy with the performance and especially durability of the model. I was worried about using wave selectors in the gearboxes, but they have shown to be extremely reliable, they have yet to slip a gear even under heavy acceleration or sudden reversing. Same applies for the 12 tooth bevel gears, they have held up really well and have yet to slip or show signs of wear.

Of course the model is not totally indestructable and crashing at high speeds may cause the panels or wheels to fall off, but the central frame/core holding the model together survived all the crashes thanks to the way the flip flop beams are interconnected.

I can't wait to use the controller for it as soon as the gearbox module is supported and to just race it around like a little kid.

[allanp]

I've been looking forward to seeing this video, nice work. Nice to see a MOC with some of the new gearbox parts, glad they are working well for you 

[Milan]

1 hour ago, Zerobricks said:

especially durability

Sorry if you mentioned it, but how are CV joints and CV Ball joints holding up so far?

[Alex Ilea]

Superb build J! It is definitely an improvement over the last version, with some very nice performance. I do think that the 3 speed gearbox is overkill, and I'm not big fan of the oscillating front shock mount, but overall I do really enjoy this model and I can't wait to see it at the Buwizz Camp *wink wink.

[Zerobricks]

1 hour ago, allanp said:

I've been looking forward to seeing this video, nice work. Nice to see a MOC with some of the new gearbox parts, glad they are working well for you 

Thanks. Have to admit I wasn't sure the new, smaller shifter rings will work well with wave selector due to their smaller diameter, but in the end they did.

55 minutes ago, Milan said:

Sorry if you mentioned it, but how are CV joints and CV Ball joints holding up so far?

The big ones in the hubs are the same ones as in older version, there are signs of wear, but I did lubricate all the driveline parts, so that helps. The front small ones are okay too, but they have to carry much smaller load than the rear ones.

41 minutes ago, Alex Ilea said:

Superb build J! It is definitely an improvement over the last version, with some very nice performance. I do think that the 3 speed gearbox is overkill, and I'm not big fan of the oscillating front shock mount, but overall I do really enjoy this model and I can't wait to see it at the Buwizz Camp *wink wink.

Yes, the third gear is more of a let's do it just because we can, but it's still fun. Can't wait to meet up again soon!

[dustblue]

Impressive video!

How does the shift happen? Buwizz 3 can control PU L motor turning angle now? 

[Zerobricks]

7 minutes ago, dustblue said:

Impressive video!

How does the shift happen? Buwizz 3 can control PU L motor turning angle now? 

Thank you!. I'm using the Gearbox module

[dustblue]

Just now, Zerobricks said:

Thank you!. I'm using the Gearbox module

Isn't that module detectinf shifting position by resistance(click)? Otherwise how does it know it is in the right position?  If you are using the new ring there would not be resistance, I am so confused...

[Zerobricks]

27 minutes ago, dustblue said:

Isn't that module detectinf shifting position by resistance(click)? Otherwise how does it know it is in the right position?  If you are using the new ring there would not be resistance, I am so confused...

It calibrates according to the mechanical  limit angle, in my case it's 180 degrees and from that it knows it's 3 positions. It's basically deisgned to be sued with PU L motor and wave selectors.