hamster pee

Question
i have 2 roborovski hamster. why do they like to pee at their running wheel? i thought they are supposed to pee on the bedding or the toilet sand. i bought a Tulipspet odor Eliminator to clean and spray those on the wheels every week when i clean their cage. The instruction says that the spray will eliminate urine odor but they still pee on the wheel and so makes the wheel very sticky and dirty. i'm afraid it might not be hygiene when my hamster run on the wheel. What can i do to train them not to pee at the wheel?  

Answer
A hamster will pee anywhere they please and you really can't train them to not pee on the wheel. My hamster has been peeing on his wheel for months and he's perfectly healthy and happy. I just rinse the wheel out once a week so it won't get so sticky and stinky. I wouldn't worry about the urine getting on your hamsters or anything, they won't get sick from it. I'm actually glad my hamster uses the wheel as the bathroom because it makes cleaning the pee area easier actually and the bedding lasts longer. :)