First things first. Check the specs for your fork and rear triangle to make sure 2.5″ wide tires will have proper clearance.
Second, what is the internal width of your rims? There exist recommended rim to tire width ratios which you should take into consideration. Here’s a link to the chart I prefer to reference that also includes maximum tire pressure recommendations – https://www.eastoncycling.com/media/Easton%20Rim%20pressure.pdf