Thx Alan!
Correct me if i'm wrong but the issue is overall length. 53' is the standard length trailer. However, aren't most teams' tractors long wheel base units? That's why moving the 5th wheel helps. Of course if you're hauling upwards of 65,000lbs, moving your 5th wheel too much can/will screw up your axle weights.
Before this job, I drove for a company that went into BC many times a day. We had several tractors (mainly owner-operators) that were too long for Canada so those tractors never went in.
Eugene, Alan, or some else in the know: what does a fully loaded rig weigh? I'm pretty sure that the "load" has to be below 40-45,000 to run with just 5 axles.