When a car (ANY car) makes a left or right hand turn, the outside wheel HAS TO rotate faster than the inside wheel, in order to maintain traction at both wheels. The tighter the turn radius, the faster the outside wheel must turn in relation to the inside wheel. Obviously, a spool does not allow that to happen, so something has to give, which usually means the inside tire slips as you negotiate the turn. That's what's happens to ANY car with a spool, and your back tires will wear out faster because of it.