Open the driver door and write down the front and rear axle ratings on the label plate there. Also note the maximum payload, gross combination weight (trailer and car) and maximum trailer weight rating. Get down and look at the hitch on the back of the car and get it's tow ratings, both with and without weight distribution and maximum trailer weight rating.
Does the car have auto leveling suspension system?
Take the rig to a set of scales with full propane and water tank (the latter tends to be in front of axle) and some basic camping stuff. Have passenger and camping stuff in the car. Cross the scales with weight distribution loose.
Cross the scales with weight distribution engaged. Tell the scale master it is a re-weigh for discounted second pass charge.
Detach trailer and cross scales just with the car loaded the same. Tell the scale master it is a re-weigh for discounted third pass charge.
Note gap between top of tire and arch of wheel well with empty vehicle for all four wheels. Note the gaps when loaded before the trailer is attached. Then measure the gaps with trailer attached with no hitch adjustments. Then again with weight distribution engaged.
All thus information helps you set the weight distribution system to be most effective.
While gap measurements can give some information, the scales tell the absolute story whether the car is overloaded in any parameter and if any of the trailer weight is being transferred to the front car axle thus doing weight distribution.
WBCCI Life Member 5123, AIR 70341, 4CU, WD9EMC
TV - 2012 Dodge 2500 4x4 Cummins HO, automatic, Centramatics, Kelderman level ride airbag suspension, bed shell
2014 31' Classic model 30 twin beds, 50 amp service, 900 watt solar system, Centramatics, Dill TPMS, disc brakes, 16" tires & wheels