A freethinker! Flex wheel drivetrain 
Some advice
Your drivetrain’s sagging though; it doesn’t look like it would hold up too well through a competition. Teams generally mitigate this sag with crossbracing, or C-channels that run across the entire drivetrain.
The light gray flex wheels might be allowing the metal on the back to scrape along the ground sometimes, especially because the distance between your front and back wheels is only 5.5 inches (if I counted the holes right) which could encourage tipping back and forth.
When clamping on a mobile goal, many teams use a mechanism that clamps onto a metal piece going under the mobile goal, lifting it. Your mechanism clamps but the friction from the mobile goal dragging on the field will further slow your robot down in addition to the extra mass.
As far as I can tell, your using 200 RPM motors directly driving 4" wheels. It’s generally considered slow, especially for this year’s game.
Try to avoid using plates for parts of your robot that need to be strong.
I admit that sometimes deviating from common thought can be disadvantageous.
Simple & decently durable drivetrain
More drive speeds
Tutorial for drivetrain:
I can see you were going for a small drivetrain though