Cherokee WOLF PUP 16FB issues

[Bug_Dah]

Has anyone with a WOLF PUP 16FB had any issues? Our unit is the white fiberglass model.

Issues:
Originally had Vail Sport ST 175/80 D13 tires with a MAX load of 1360 lb per tire. Sticker indicted the MAX cargo would be 55lbs!!! Seemed to be a safety defect!? After contacting Forest River and explaining at length..they were replaced (rims and tires)with Trail Express 205/75 D14. Each tire has a 1760lb Max load capacity. Our cargo weight is now 1066lbs !!!! and SAFE
CHECK YOUR TIRE size!

When we first used our water...our gray water overflowed into the tub/shower??? even though electronic gray H2O indicator 2/3 full? Tested after draining and found after 6th gallon of water to kitchen sink...water backs up in shower/tub ....Nasty...anyone have this issue? Capacity is 13 gallons. Tested Black H2O tank with same method..and water level is FULL at 10 gallons??? Also a problem. Suspect the vent pipe for both tanks is extending too far into drain tanks and thus not able to fill completely..unless the plumbing is incorrect. Anyone actually measure their capacity of drain tanks?

Anyone examine where gray vent/drain joins tank ...as around edges of pipe one can detect 'daylight' from inside the camper around the pipe where it exits in the floor...suspect some sore of seal is missing??

Any info would be appreciated...