When I added my Buckstop bumper with 4-6" lights in front of the grill, it made my trans temp almost 30F hotter than stock. A tire may not be so bad because it won't be as close. I ended up going to a larger cooler to compensate (Tru-Cool Max 40,000 GVW). Since then, I've upgraded to a Rigid LED bar to replace the round lights. Now it over-cools and I keep the grill insert in year round unless I'm towing heavy in the summer dessert heat. I've also carried motorcycles up front, and they did not affect trans temps like the lights did.
