found this on pirate, figured id post up as future reference
The SRW and DRW front axles are identical EXCEPT for the wheel hub and rotor - same spindle, bearings, and lockout. The DRW wheel hub has a wheel mounting flange mounted on it about 4-5" from where the SRW wheel would mount. This makes the DRW axle 4-5" wider on each side. This was done to more closely match the width of the DRW rear axle, and to allow the DRW trucks to carry a single spare tire mounted on the largely dished "budd" style DRW wheel. Also, the rotor is bolted to the DRW hub with 8 9/16-NC bolts inboard of the wheel mounting flange, in the same position as the SRW hub, allowing the use of the same brakes on either (as opposed to the SRW hub which uses the wheel studs to pin the rotor and hub together). Because of this, the holes in the DRW rotor are smaller than in the SRW rotor, since the DRW rotor holes need only to clear the 9/16 bolts, as opposed to the SRW rotor holes which are larger to fit the knurled shoulder of the SRW wheel studs - other than that, the rotors are identical and DRW rotors can be used with SRW hubs if the 8 holes are drilled larger. The last difference is that between the DRW mounting surface and where the SRW mounting surface would be, the DRW hub 'bulges' - enough so that it will not fit through the center hole in the stock SRW wheel. Aftermarket wheels may not be an issue if they have larger center holes.
