Towing Tire Pressure
 

I have found threads on autobahn tire pressure, tire brand choices, non-RFT vs. RFT, etc., but I have a question about tire pressure when towing a heavy trailer. I am in the process of buying a travel trailer with a GVWR of about 48oo lbs. and tongue weight of 430 lbs.. I was curious what tire pressure you haulers are running when pulling a trailer. I drive a 2009 X5xDrive35d with a 3rd row and rear air suspension. Thanks and I look forward to your comments.
-CAD

Tow vehicle pressures should be set according the tire pressure label on your door jamb. Those pressures are typically listed for laden and unladen. You will need to determine how much payload you are carrying (which includes the trailer tongue weight) and the effects of weight distributing hitches (if any).

You should also confirm your actual real world tongue weight. Published specs by trailer manufacturers are notorious. Load your trailer as usual, and weigh it to know for sure. Loading the trailer can have a significant impact. Also, weigh your vehicle on a highway scale, loaded, to ensure you aren't exceeding front or rear axle limitations.

Your air suspension has the potential to complicate setting up weight distributing hitches. Just because the vehicle is level doesn't mean it is balanced.

I towed up to 4500 lbs at 32 psi front and rear in my E53. If I was heavily loaded in the rear, I occasionally increased rear tire pressures to 35, and reset them after the trip.

^^^What he said. For a light/med load I dont change my 30-32 rear pressure and can increase to 35 for a long and heavy haul. Front stays at 30-32 all the time.

Thanks for the feedback. I will have to do some research and measuring to determine the safest and best set-up.
-CAD

I tow a 3500# boat with a 2009 X35d and just set the pressure at 32 front and 35 back. I try to not drive over 65 mph as the trailer manufacturer recommends. We trailer to Canada and back twice a year. It's 1500 miles round trip. I've not had any problems.