K9. Drive tray Final design

This is my final drive tray and it works brilliantly. I have moved the drive wheels not to the back but just of center, slightly to the rear, with a larger leading caster. I have added a rear caster but it rides just of the ground, more like a wheelie wheel. The batteries have been placed behing the drive wheels and lower keeping the center of gravity very low,  stopping tipping .It took a while to get it all balanced and set up correctly but it works so much better. With the drive wheels effectively in the center the turning looks more natural and it is certainly much easier to control. I do have the dreaded front caster problems in that it will not go over rough ground but the compromise was worth it in terms of driveability.