2005 suzuki drz 400 sm conversion tire and inner tube size help?

[Kenny M]

i just bought new warp9 racing wheels front rim 21"X1.60 and rear rim 18"X2.15 i went to suzuki and got stock size inner tubes for an 2005 suzuki drz 400-e do i have to run front 80/100-21 rear 110/100-18 stock size for drz 400-e or can i go a little bigger front 90/100/21 ...rear120/80/18 just wondering if the inner tubes will have to be bigger if not i will stay stock thanks !!