More BS will put the wheel in closer to the frame of the car. Less puts it away from the frame. Good if you have the room and need to clear the outer fender. Bad when you dont. Keep in mind,.. you can not alter the length of the axle,.. only the wheel.

With coil overs you 'LOSE' space on the inside. To compensate you reduce the BS. Yes this will put the wheel closer to the fender. In a drag application with a 15" wheel and large 28x10.5 tire (275/60) this can become problematic. With low profile tires on larger (Diameter) wheels you have a little more wiggle room. I'll use mine as an example. I can not fit a 17x10.5 6.5" BS rim with a 315/35 tire on my car right now with the rear coil overs. I can how ever fit a 18x10 with 6" BS.

Here is an example.


In this example I have used less BS to create more room on the inside of the wheel (Between the coil overs and wheel) while still retaining the original wheel to fender clearance on the outside. This is what I am trying to explain. Unless you cut an axle and tub the rear,.. there is only so much BS you can use. So with the axle being the stationary point,.. we use the offset/BS of the wheel to get it positioned where we want inside the fender.



Hurst