I made this "flange bender" out of a piece of 1/4" steel scrap. I use it mostly for rolling wheel well lips on cars and trucks. Works very well and is very easy on the paint.
I saw cut the slot on the band saw then opened it up with a .060 cut off wheel in a die grinder.
The slot can be any depth so make it to fit your wheel lip width.
I've been using this thing for years and just did a bit of fine tuning on the rear wheel well lips on the wagon.
I couldn't get good pics under the car so I took some on the bench with a piece of scrap steel
The first thing to do is to determine how much lip needs to be rolled. You don't need to roll the whole lip, just where the tire makes contact. This may be quite a bit in the rear but not all that much in the front. For the fronts, turn the tires both ways until you have contact and mark the fender a couple if inches on either side of the contact points. That's all you really need to roll.
Put on some masking tape to protect the paint and go to work.
Slide the slot over your wheel well lip as shown and SLOWLY bend the lip up.
A little more. Getting to this point took a minute or so. Go in small increments, back and forth, and you will not hurt the paint.
A little more. You can see the nice radius the tool leaves on the outside edge. This makes for a soft contact on the tire if there is any.
After a few passes back and forth I have it at 90 degrees. Most of the time you won't need to go this far.
Remember to go slow, use small bends and, with the tape as a protector, you should have no issues with paint.