Darn AOL...I had a reply prepared on this subject and my PC went offline and I lost my words...if they show up later now you know why.
What I was going to say, I tried using Armor All on our car and SUV tires at one time but did not like it. It made the tires shiny for a while and I doubt if it softened the rubber, but it seemed to attract road grime very fast and the grime would not wash off, I ended up using paint thinner to get the tires clean so I could re apply protectant.
I have been using a product called Protect All, it is advertised mainly for the RV crowd, a multi purpose liquid for rubber, vinyl, aluminum, etc. I called the company and they told me the only material NOT to use it on was Sunbrella canvas like boat tops, etc. It's the greatest for tires, a little goes a long way and it lasts much longer than AA, plus it does not attract road grime or put that shiny appearance on sidewalls.
When I see a vehicle with shiny tires, it makes me think the vehicle was prepared for resale...like a detailer does for a used car. My opinion--for a shine use Armor All, for protection choose another product.