I think I found the reason for your question.
In the below video, I show how to use a Harbor Freight Drill Brush to machine scrub the tires on a Jeep. In the video, you NEVER see white foam after scrubbing. And if we're honest, we don't see black or brown colored foam in the video.
Here's the answer, I have ZERO idea why a brush attached to a drill does not create foam it just doesn't. The tire is still getting clean, it's just for some reason, when using a brush on a drill, you never create any foam of any color with our foaming tire cleaner, which is not on the market yet.
Also, I've tried using a DRILL to machine scrub tires and I absolutely hate it. It's awkward to hold and control especially compared to using a rotary polisher.
The cordless rotar ylike I show in the above video has a LONG tool body. This enables you to grip the tool at the extreme ends of the tool. This gives YOU leverage over the tool and this simply makes it easy to machine scrub anything. With a drill? In my opinion it sucks and I rarely use the word suck when I type, but it's the most accurate way to describe the experience.
Here's the video,
And I also did not title this "shorts" video but the reason it's titled the way it is - is because it's an attention getter and in this day and age of short reals and short shorts videos - Social Media platforms are training up generatios of people with short attention spans.
Mike