tire and rim help

[FAST4x4]

ok, I have a set of 275/40/17's. I need rims. I found some that are 17x9. Bead to Bead measures 9.5 on my tires. Would I get too much sidewall deflection for autocross/road racing? Should I get rims with a 9.5 rim width?

[DevaROH]

thats the exact size tire and rims that i am running, and i have no problems. i believe that don has the same size and look at his car.