i would lose the bandits and get some 18 in mxr holeshots or some 18 in kenda klaws... them bandits are way to heavy for a mx track and to tall you want a short tire to get up to speed fast cus you not gonna have very long straight runs... but you said the trck is sandy you might wanna get some 18 in knarlys.. as fpr the shorter swing are it moves the weight back to the back cus you motor is now closer to the rear tires this will give you better traction... and should help with cornering cus you now have a short wheelbase...