Even when rolling without tire the prep rolls onto the side wall honestly.
I know that the prep soaked in / evaporated about 4 times quicker then rolling mounted. But it did still get on sidewall.
Randy ransom always suggested un mounted and to use bee bee in the tire to hold flat at equal the prep out
If you really want to know what happens to prep and the side walls roll it un-mounted you will be shocked what you see after only one revolution. Use 15 cc so it does not touch side wall . Just use a old tire to test. The side wall will be saturated to the point it drips off bead. Keep in mind the prep is not touching side wall and as tire rolls the center when touched seems to be dry . I've done this more than once my personal conclusion is the side wall takes on as much prep as the center of tire in a sponge effect . Now I'm sure there are gonna be some to post that I'm out of my mind but through this testing I've come to understand tires and chemicals and the effects of chemicals on tires. I use to roll tires with the amount of prep. In one night but now its done over several days with small amounts to prevent saturation of sidewall. IMO Try it for yourself and draw your own conclusion.
Look man roller turns 1 rev per Min. I don't have a issue.I'm not looking for any answers . This is not a debate I posted to a question on rolling without wheels. Have u ever rolled a tire without a wheel ? If not so be it . I knew there would be 1 that couldn't wait to post and point out a problem that didn't exist.