just as the title says.. can you put 245's on the front with 275's on the back on 06 rims?

 

yes you can.. as for how safe that'll be.. iono

we've messed around at work and stuck an old 275/35/19 ps2 on my stock 19"x8.5" OEM rim

 

are there any risks w/ it?

 

When it comes to the safety of my passengers and myself with regard to safe limits of certain modding applications . . . I tend rely on the knowledge of trained professionals in that particular industry. I would not like to test my passengers' and my own safety on the words of anything less. Your question is one of those examples.

As Eric has stated . . . You can, but how safe is it?

 

Recomended rim sizes for 245 35 19 is 8-9.5" and 275 35 19 is 9- 11" so your fronts are on small side of okay but the rear tire is too large for the wheel. This will couse the tire to wear improperly and more importantly isn't really safe. A good shop probably wouldn't want to install these. Spend the money to get proper rims or install appropriate size tires.