When John Mahler was researching his article on Winter Tires on the MFAV, he contacted numerous tire experts and this is the response he received from Toyo Tires.
Sent: Monday, November 16, 2009 10:25 AM
Subject: Re: tires on larger MFAV
...I spoke with someone from our tech department regarding your inquiry.
He advises that the theory is the same for a car as it is for a small bus. Therefore winter tires need to be on every axle to gain the true benefits received from a winter tire. An LT metric tire will not achieve what a true winter tire can in snowy conditions, therefore mixing and matching them is not recommended.
The reason is that an LT metric tire will not have the same gripping capabilities as a winter tire. Therefore if the tires are mixed (ie. winters on one axle and LT on another), then the bus may experience difficulty. For example during breaking, it's possible that the small bus may even spin out of control because of the difference in braking in the snow when compared with a winter tire.
I hope this answers your question. Please let me know if you further clarification is needed.
James de Chavez / Toyo