sorry if i make no sense i am new to building fixies and bikes.
my chain keeps falling off even though I have plenty of tension. It looks like the chain is is being pulled to the side and the gears are not aligned. how do i check to make sure the gears are aligned/ spaced properly? is their a cheap and easy way to get the proper spacing/ alignment so my chain doesn't fall off when at tension if they are out of alignment with out having to buy a new wheel?