If you are putting 912's in then why not go to 33x12.5 r15? Here are some examples:

http://www.discounttiredirect.com/di...sw=false&cs=33

http://www.discounttiredirect.com/di...sw=false&cs=33

So are these the 32x11.5 r15 you are thinking of:

http://www.discounttiredirect.com/di...sw=false&cs=32

http://www.discounttiredirect.com/di...sw=false&cs=32