How do we know whether a wheel clears those big Brembo brake caliper or not?

Ever wondered how people determine if a wheel can clear the Brembo brakes or other BBKs?

Let us explain this to you today. You might have heard lots of people talk about "I had a set of wheels that were x inch wide and x offset, therefore yours will clear the Brembo brakes too." This is only true to a certain extent. 

There is this measurement call the X-Factor, which is the depth measured 1 inch out from the edge of the wheel's mounting pad. This length determines whether there is enough room for caliper clearance. This is also why two wheels with the same specification might have different amount of lip or concavity in the design. TLDR version: Width and offset of the wheel does not determine caliper clearance, but X-Factor does.