Thread: Designing my first robot - Advice Needed

Thanks for the feedback everyone. The design has evolved in the past week but I am at a bit of a crossroads. I added the battery and finished the weapon's gearbox. The reduction is 81:1 and is chain driven to the lifter. After this I decided to weigh the main parts and get an estimate on how much the robot weighs and costs. This came out at 7.3kg so I decided to try a redesign with 100mm diameter wheels. The current ones are 50mm and as Shakeesc pointed out, they would make me slower. So I would need to design another gearbox for the drive or reconfigure the robot to fit the bigger wheels. I have started by placing the motors at the far rear at the robot. The bulkheads have had to be raised and lengthened and the armour will have to be redesigned. I'm reluctant to continue with the redesign as I don't think it is as efficient and the motors might be more vulnerable from a spinner hitting the rear than the side. Thoughts?