1. Turn on X and Z for mirroring and then put 2 or more pistons in front of and behind the base block (I chose 4).
2. Put 4 large powered wheels on the ends.
3. Flip the 2 wheels on the left.
4. Edit one of the wheels to make it left and right (like shown below) and copy-paste it to all the wheels.
5. Put 2 medium powered wheels on the large ones.
6. Put 1 large unpowered wheel on the outer medium wheel.
7. Connect the medium wheels together with a strut on the inside. This is so that they have the same speed.
8. Set all the pistons to toggle and to the maximum speed.
9. Turn Z off for mirroring.
10. Put 1 block up off the large wheel, then 1 block left, then 3 blocks back. Then delete all the blocks except the 2 farthest back ones (If you are confused, check the image).
11. Put hinges all the way from those 2 back blocks to the tip of the medium wheels.
12. Put 1 medium wheel in front of the hinge at the tip of the medium wheels. Then put 1 block on the wheel. Then delete the medium wheel, and place a medium wheel on top of the block. Then place a block on top of the wheel.
13. Delete the medium wheel and the bottom block. Put hinges to the bottom tips of the large wheels from the top block.
14. Delete the top block and hinge. Then put a hinge on the top part of the tracks to connect it with the front part.
15. Repeat steps 10 and 11 for the bottom (If you have to delete a hinge, don't worry).
16. Delete the 2 front hinges and connect the front tracks with the bottom tracks. Repeat steps 12-14.
17. Now you are done! Press space and then H. Drive around with your tank or add some weapons to it.

I hoped I was able to help people who wanted to build tanks without mods. If this was very confusing, I am sorry. Happy building Besiegers!