Drive tutorial
These are several tips that you should follow when setting up a bot's drive system.
If some don't want to follow these because it's "building like everyone else" or "not original", you're free to build that do you want, but then don't moan if your drive system sucks.
-Naryar
Drive Motors
Obviously those are spin motors.
The best drive motors are HP Z-teks, and you can use right angle in the lighter weight classes too.
Power
To have a good drive you need to power your bot correctly.
A minimum of 2 small battery packs should power your drive. But if you can, choose a nifty instead. A Nifty is enough for a maximum of 2 HP Z-teks. A Supervolt is enough for a maximum 4 HP Z-teks.
Don't forget your weapons, too - a VS with 2WD Z-tek drive and a HP Z-tek powered weapon needs one nifty.
Multiple Wheel Drive
For maximum efficiency, you should only use these setups:
1 wheel drive, right angle: This is used only on antweights, to make a powerful HS. You can drive forward/backward using the right angle and turn left/right using the recoil of the spinner motor.
2WD, right angle: Most lightweight classes use this setup. Decent speed. Used on MW's where a lot of the weight is put towards heavy weaponry. Ideal for MW horizontal spinner.
2WD, Z-tek : Neat for speedy LW's and decent for MW, although not very fast.
2WD, HP Z-tek: Makes for very fast lightweights (you'll need practice your control while driving), neatly fast middleweights and average heavyweights. Use at least that on a HW if you want decent speed. Better than 4WD Z-tek because lighter for the same power.
3WD: You're on crack, non-symmetrical and hard to work with in Stock. Although, a few Sit & Spins and Full Body Spinners have used a 3WD setup.
4WD, HP Z-tek: Very fast on a MW. That makes a nice drive for a HW.
6WD, HP Z-tek: The best HW Rammers/Pistons use 6WD.
8WD, HP Z-tek: OK, now this is beginning to be too much.
10WD HP Z-tek or more: You're insane.
Wheels
The best wheels are Shiny Hubs because of their low weight and decent diameter. Slipperbottom wheels have a larger diameter and have better grip, and are very useful for when you need guaranteed invertibility. However, they weigh 18kg, 6 more kg than Shiny Hubs. Rubber wheels are also a very smart wheel choice, they give you great traction because of their superb grip, and also give you great ground clearance. Rubber wheels weigh 17kg.
Avoid other wheels, there are heavier and are big targets for your opponent. Using miniwheels is not usually worthy even if they are difficult targets, because they're heavy too.
General Design
You'll notice that often, your bot will drift to the left or right if you go forward, especially in the 2WD category and with fast motors. This is caused by a weight distribution problem.
You simply need to make your bot as symmetric as possible. That is, make a bot where the gravity center is close to the center of the bot. Most cars/trucks/whatever follow this rule. It is all about symmetry.
-When setting up motors, put them aligned horizontally. Like a car, again.
-Try to put the components in a symmetric setup.
-Balance the bot.
-You should also know that batteries doesn't seem to have an effect on weight distribution.
This is extremely important on VS (because of their innate stability problem) and Rammers (because they're supposed to drive straight)
Examples
Bad drive setup
Good drive setup
Yes, the good system could be better, that is, putting the control board at the center. But-I'm not going to build a perfect bot just for that.
But look, the first is heavier and slower than the second one...
Exotic drive systems
(generally not allowed in tournaments)
The most common are discs/tribars with weapons on them used as wheels.
Although they are stronger than usual wheels and make effective damage, they have extremely low grip (get ready to be pushed) and are a slow drive system, besides being frowned upon by Some of the community.
A bot with that drive is called a crawler. Tribar crawlers are generally not used because weaker than disc crawlers and harder to move.
There are also walkers, reproducing a bot with legs, made with servos, burst motors or tribar (tribar crawler).
Note: Correction of my average English writing skills would be welcome, but DON'T modify the content before asking me.