You don’t need that much traction on a high gravity planet and the two extra wheels become unnecessary.
On the Moon, Mars, or anywhere else where the gravitational acceleration is below 5 m/s², you want six wheels, because at least two of them will always not contact the ground due to poor traction and movement over uneven terrain.
More wheels is also good on low traction surfaces, or to reduce ground pressure. An extra axel can also reduce the chance of beaching on rough terrain.
Big trucks also want more surface area against the road on their tires, both to reduce wear per tire and to get more traction, which is why some have extra wheels
You don’t need that much traction on a high gravity planet and the two extra wheels become unnecessary.
On the Moon, Mars, or anywhere else where the gravitational acceleration is below 5 m/s², you want six wheels, because at least two of them will always not contact the ground due to poor traction and movement over uneven terrain.
More wheels is also good on low traction surfaces, or to reduce ground pressure. An extra axel can also reduce the chance of beaching on rough terrain.
Big trucks also want more surface area against the road on their tires, both to reduce wear per tire and to get more traction, which is why some have extra wheels
Is the earth considered a high gravity planet?