Help with my Towing/Tire Pressure Issue

[Greg107]

I need some help resolving a towing/tire issue.

I have a 2016 F150 Supercrew FX Ecoboost with Maximum Tow and a Imagine 2600RB. I am using a Reese Steadi Flex weight distributing hitch that works on the same principle as the Equalizer. The tires on the truck are Hankook Dyna Pro AT M's with a 35 PSI when not towing. The truck and trailer are level, the front wheel well measures 37 1/4 when not towing, 37 1/2 with the weight distribution hitch.

When I picked up the trailer a couple weeks ago the tires were left at 35 PSI, the truck and trailer drove great, just a little bouncy. After reading many posts today, I decide to try towing with increased front and rear tire pressures at 46 PSI, maximum on tire says 51 PSI. I thought increasing the PSI would stiffen the side walls and make the driving better.

Today the truck kept feeling like it was moving left to right and vice versa, most noticeable above 52 mph. I decrease the tire pressure to 40 PSI and it was a little less noticeable.

Any idea why the truck would do this? Should I have only increased the rear tire pressure and left the front tires at 35 PSI. Any advice greatly appreciated

Greg

[Steve7]

I think you have the same set up I had on my last rig. I had the same feeling when I towed, kinda like a light front end. Steering was not very responsive. I always towed with the max tire pressure in rear, and found using about 10-15 lbs less than max in front was a better ride and steering was more responsive. I switched to ten ply "E" rated tires and it was a big improvement. I also added air bags to the trailer which helped stabilize the truck when towing. I had 20" rims at that time, so ten plies in that size was limited, but I found a set I really liked.

[Greg107]

I have the 20" rims, which I did not want. Ford putting 20" rims with an FX4 Off Road package makes no sense, they should have been 18". I will try 50 PSI in the rear tires and 38 in the front tires and see what happens.

How would airbags added to the trailer improve the trucks handling? I have virtually no sway from trucks passing, the truck just feels like it is moving side to side above 52mph. Also should I have set the weight distributing hitch with a full 36 gallons of gas? I set it with 1/4 tank full.

Thank you

Greg

[Steve7]

Don't know that how much gas is in truck makes a difference. It changes all the time, and the tank is mid frame. As far as the airbags, my f150 had rear end sag, and the airbags seemed to stabilize the truck on turns, and I didn't get as much bounce when going over heaves or joints in roads, etc. Whn not trailing, I would air down airbags to 5lbs to give a gentler ride. You may not need them. Try one thing at a time, but replacing those tires with "E" rated will help with what your feeling I believe. Also, those Hankooks are prone to punctures in my opinion. I had two Flats within a few months prior to changing them out.

I agree, they never should have been put on that truck.

[Second Chance]

Greg,

Info I can find indicates that your particular Hankook tires come in both a "P" (passenger) and "LT" (light truck) tire. If yours are Ps, that might be your problem. If they are already LTs, revert back to what the other guys are telling you.

Rob

[Greg107]

They are 275/55/R20's with no designation so they must be Passenger tires. Any recommendations on an LT Tire?

Thank you

Greg

[Second Chance]

They are 275/55/R20's with no designation so they must be Passenger tires. Any recommendations on an LT Tire?

Thank you

Greg

They don't say P275/55/R20 or LT275/55/R20? I've personally not seen a tire that doesn't have the designation in front of the size. If in fact you do have Ps, I'm a Michelin Defender fan. Others will have their favorites and there are a lot of good tires out there.

Rob

[Greg107]

Must be P Tires. Tire does say "113T sidewall 2 polyester Max. load 2535 lbs at 51 PSI"

[Second Chance]

Must be P Tires. Tire does say "113T sidewall 2 polyester Max. load 2535 lbs at 51 PSI"

Greg,

Based on the information you've given, I did some "Googling." I cannot find anywhere a P or LT designation for your tires - even on the Hankook web site. The DynaPro ATM tires, however, are specifically for SUVs and light trucks, so it doesn't appear that they are constructed like a P tire. The lower profile (the "55" part of your tire size) tire on a 20" rim should result in less squirming, though. I had load range E LT tires on 20" rims on a Sierra 2500HD I had and it handled very well when towing... might have been the fact that they were load range E and inflated to 65 front and 80 rear.

Rob

[Cate&Rob]

Must be P Tires. Tire does say "113T sidewall 2 polyester Max. load 2535 lbs at 51 PSI"

Greg - Your wheels have a 1825 lb load limit, so even with LT tires, this becomes your limiting factor.
See page 16. https://www.fleet.ford.com/truckbbas...F-150_v1-1.pdf

(another) Rob