i'm guessing front tire spray... see the same on my white 2018 dually

 

 

Tire shine was my first thought. I had to wash it off my truck after I picked it up from the dealer.

Or, you could have driven through some oil or diesel fuel entering/leaving a gas station, especially on the "truck side". If the wheel was turned much it could end up on the rear fenders.

 

I think it's mostly the tire spray from other vehicles. No way to stop it.

 

 

Yup it's tire spray. I had mine wrapped in XPel for that reason.

 

Use a tire spray tat doesn't sling or wipe excess.
I use CarPro Perl diluted 1:1.

 

I have nice large gatorback flaps on my F450. My rear fenders do get dirty, but not that bad. Maybe the Ruby Red hides the slop better than I realized.

 

How was the truck in the snow? We got 2 feet in my area.

 

Absolutely fantastic -- As long as you carefully control momentum since it's 10klbs empty. The Toyo M608Z have been great and pushed through 18" of heavy wet snow, 6" of slush, and snow packed roads at various times this week. As long as you don't try to back up a hill (shifting weight off the rear axle), it hasn't stopped. I did have to make a 20 point turn to get the front end pointed uphill and get weight back on the rears in one spot on a steep driveway. Steering is fine, stopping is surprisingly good, and I'm amazed every day with the traction control while in 2WD in these '17+ trucks. During one early morning last week I chained up to help pull other vehicles up a steep hill, and though it rattled my teeth with double width chains on the rear, it churned through the snow, ice and pavement all morning.

 

Tried it. They still get covered.

 

Yup...it's just part of owning a dually. My 2016 Ram did the same thing...

 

I notice a little more with the pulled up running boards... on my 2012 the boards used to block a lot of the spray