Didumos69

I fear your model is either too heavy or there is some friction going on somewhere between the motors and the wheels. I used a 90 degree thin 12t gear vs thin 12t gear mesh in my recent 42129 b model without problems, also with a 1:1 drive ratio (the bracing had to be perfect to make that work). But that was with PU parts.

The way the 5L beams that brace the male part of the CV-joint could be mounted to the 5x7-frame better. Right now this relies on the pins with pinholes, which may be pulled out a little. These pins with pinholes are friction locked, not form locked. It would be better if you can somehow use vertically placed 3L pin with pinholes (the same piece you use to connect the 5L beams and hold the drive axle) and mount them to the 5x7-frame such that the structure relies on pulling pins sideways instead of lengthwise. The issue you're running into is not new. Many people have had problems with combining CV-joints with RC, even with plain PF parts. I don't know your build, but as a rule of thumb I would say: If your model is about speed, I would keep the old CV-joints, lower torque and increase RPM by gearing up the output of the motors. If your model is about trial or crawling, I would use the new CV-joints and the new portal hubs. And also in this case, you probably want to increase RPM by gearing up the output of the motors. That will reduce torque in your drivetrain and somewhat compensate for the gear reduction in the portal hubs. For increased RPM and lower torque in your drivetrain to be an option, it's important to have a drivetrain with low friction. Maybe those knob wheels are a source of friction, I don't know. You could try with different gears and check what happens.

I believe that was in a post by @PorkyMonster. These days you could also use something like: Btw, for the new CV-joints it might be useful to know that you can work with parts around the CV-joint on a diagonal grid:

You're quite right

Alright, let's fix that.

If you could build this Penrose triangle: you can build a strong triangular wall:

Thanks! I had a lot of fun building it!

Cool! That 4-wheel steering is great addition! Thanks for sharing!

Very nice B model! I like your style. You really put in the extra mile in getting the best out of an existing set, where others seem to rush things to a finish.

Congratulations Balazs! Your channel is the only YouTube channel I subscribed to. I'm still grateful for the video you made about my 42099 B model! Cheers!

Just did a slope test. I was not disappointed. Also shot some footage of it on CLAAS tires. When it gets steep, it underperforms the Zetros tires, but other than that it rides smoothly.

One down, one to go. With the power up app I should probably be able to program this.

I got seconds thoughts on the price for the instructions, which I set to 20 euro. I dropped the price from 20 euro to 15 euro. I also refunded the payments that were already made for this MOC, because I don't want to disadvantage anyone.

Instructions are ready: https://rebrickable.com/mocs/MOC-93255/Didumos/42129-b-model-hot-trot/

@Void_S, @pleegwat, @westphald, @2GodBDGlory, in the final video you can see what I mean with the diagonal test. At 2:23 you can see how the model moves back and forward over a hat shelf from a car. Every time when it returns (twice), you can see how one diagonal pair loses grip. It struggles a little, but it keeps on going, because the other diagonal pair still has traction.