hello player99, the noise comes from the belt rubbing on the side guide plates. Try adjusting the wheel so that it runs centrally. I have seen some cars with the side plate furthest from the wheel removed and they seem to run quietly. if you have the old aluminium rear sprocket ( toothed wheel ) they wear out quickly and can be difficult to keep adjusted - steel sprockets seem to be better. sprays may work temporarily but do not cure the underlying problem.
good luck, Phil
