Most of the BMW X3 roof rack set ups for bikes that I'm seeing are the Thule Racks models, specifically the Thule 450 Crossroad car rack system, which uses the traditional square Thule cross bars, and the Thule 450R Rapid Crossroad car rack system, which uses the aerodynamic elliptical Thule load bars. Personally I think the 450R version looks way better on the X3 because it matches the design lines to a T. It's a bit pricier but looks count for a lot. Both mount right to the X3 rooftop side rails no problem. You can then connect any Thule roof mount bike rack to the load bars on either setup. A heads up on the 450R version though, most bike racks need a set of the Thule Xadapts to mount onto the elliptical bars. The Adapts slide into the slots on the bars and the bike rack then connects to the Xadapts.

A lot of folks use the Thule 232 Step-Up Assist on SUV's so they can access the top of the car better. It straps onto any of the wheels and provides a step for accessing the rooftop much easier than from the ground.

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