Our team was considering switching to a mecanum system this year. However, this would require the allocation of four CIM motors to the drivetrain, leaving no CIMs left for other features.
What do teams who use 4 wheel drive use for the rest of the robot’s functionality?
A drivetrain, mecanum or otherwise with less than 4 CIMs in it is very, very hard to make competitive.
Use the FPs, Banebots, or Windows. With the right gear reduction and time any motor can lift any load.
Any of the other motors, geared appropriately for the task at hand, or pneumatics.
What they ^^ said.
We’ve never used less than 4 CIMs in the drivetrain. Except Lunacy I suppose.
Is there a rule stating that a team cannot use more than 4 CIM motors?
3205 used two CIMS in the drivetrain last year, and I would definetly agree with what other people are saying here. We could move around fairly quickly, but only becuase our robot only weighted about 70-90 pounds. When it came to pushing, it was almost impossible for us and we were pinned fairly easily.
As for other motors to use, the Fisher price motors have almost as much power as the CIMS do, and so do some of the banebots (the RS-550 goes up to about 75% of the power of a CIM). As long as these are geared low enough so that they don’t burn out, then they can do the same job that you want a CIM to do. There are even special gearboxes that make them so that the can mount into a space that was designed for a CIM to be mounted into.
Yes, you really need to read the rules…
http://usfirst.org/roboticsprograms/frc/content.aspx?id=452
Section 4 tells you all about motors and which you can use of how many 
Okay I’m just going to say it.
Every question I’ve seen you ask could be answered by reading the Manual. Not even that, just searching the manual really quickly.
If you don’t read the rules you’re not going to build a good robot.
What other people said.
As for what motors to use besides the CIMs… Those new 18V RS-775 motors from Banebots are totally sweet, and will own the FPs and RS-550s in practical applications any day of the week.
I know, I know. Sacrilege! Blasphemy! But when you look at the actual stats (not what FIRST posted) you too will be a believer.
~270W power, 13000 RPM, 112 oz-in Stall. This thing has all the power of the RS-550 or FP, at lower RPMs, in a bigger package. Lower RPMs = less reduction = less losses. Bigger package = more mass and surface area = more ability to cope with heat. These puppies will do everything your RS-550s or FPs will do, only they’ll do it longer and harder with less overheating and horrible burning smells.
But, you know, that’s all just theoretical. Perhaps you guys should just wait till I get my order for 5 or so and empirically test them for ya first.
another thing you can use is air pressure to raise and lower an arm. that would be more complex, but saves motors for joints if u decide to have a wrist on your arm
our team’s drivetrain was finalized today, the drive will be using all 4 cims as well as 2 of the new bane bots. our manipulator will be run of a combination of a couple of denso window motors and the remaining bane bots.