ANSWER: The vehicle will still sit level with 312 lbs on top of the carrier. You can safely add more weight, but you will see you vehicle’s suspension gradually begin to compress with the additional weight added. You may also see a rougher ride as the vehicles suspension will begin to compress with the additional weight as well. If you are hauling a sport bike then I would recommend the VH-SPORT RO sport carrier. It has a longer and wider rail and ramp.
Please see www.versahaul.com for other vehicle and hitch limitations that may apply.