Are the chrome trucker lady mudflaps speed rated?
Some are rated but I don't think it is for speed.
The flaps with the chrome figure of a guy are rated different for example.
As for salt brushes on a racer tire you gotta figure where it is going to go next when you turn it loose.
It might be good to keep it there and maybe not.
A slick/flexible surface won't let it build as much up.
You are actually going to pick up most of it on the unprepared turnouts and during the towing operation.
Then is when you can decide what and where it is and leave it or clean it before a run.
Sometimes it can be your friend and limit the amount of low pressure air you have pocketed to carry along or at least highlight it for you.
The clean spot tells you something else.