42070 and a gear to much?

[dirkberlin]

Long Story:

I have a strange problem, maybe anyone with the all terrain truck can help.I buyed this model second hand and take it down. Weeks later I build it. And I remain a single  94925    Light Bluish Gray Technic, Gear 16 Tooth. I counted the parts, but the model was lighly moded (LED), so I can not say,if there where more then the 13 gears of this type.

And the end, the model has no missing features. I can turn the crane, rise and lower it, whinch working, support works. I can steer, it drives.

So I tried to count the gears, the 5 periphicals where easy, but the rest in the gearbox are partly invisible - without to tear it down again.

Short Test:

The only thing, where I am sceptic: the 6-wheel drive. When I lift it up and drives in the air, the front wheels are moving fast, and the others are moving hardly. whenn I take down the front wheels and the back wheels are in the air, they moving fast. Is this normal? I don't understand the direffentials not realy...

[Zerobricks]

1 hour ago, dirkberlin said:

The only thing, where I am sceptic: the 6-wheel drive. When I lift it up and drives in the air, the front wheels are moving fast, and the others are moving hardly. whenn I take down the front wheels and the back wheels are in the air, they moving fast. Is this normal? I don't understand the direffentials not realy...

Completely normal. Have a look at this video:

 

[Kostq]

Count every differential as power splitter. The chain of power in 42070 is:

XL motor - central diff - hard coupling

Central diff - front and rear drives

Front drive has 2 wheels - less mass to rotate with 50% of the energy from the engine, the rear drive gets 50% too, but splits it to more mass /4 tires/. So they should rotate slower.

For the fast rotation - the diff will route ALL power to the place of least resistance. Air has miniscule resistance compared to the ground, so all power goes to the wheels in the air.

That's how cars and trucks get stuck in mud or when ground contact is lost on a tire or two. The most free wheel gets all the power and spins very fast. In snow, mud or ice you get precisely this. The other wheels get bypassed and do nothing. So when trying to get out of a rut - you block/slow down the fastest wheels and the power starts flowing to the others and eventually they get you out.

Edited February 14, 2023 by GTS

[dirkberlin]

Thx, sounds good. Maybe there will be 14 in this truck. I checked my count list again and the red Technic, Gear 16 Tooth with Clutch on Both Sides  was included 12 times of 13. Maybe the grey one was the replacement for it. Thanks again.