I am planning on replacing the front rotors on my vehicle and noticed at AZ there are 2 different sizes, 10 1/2 & 11 1/4. Is there anyway to know which ones I need before I remove the old ones?

Thanks

Yea measure your rotors acrossed ......

If they both would work, I'd go with the bigger of the two.
More stopping surface, but the larger one's may not fit inside your rims.... :dunno: