What are the recommendations on tires which can hold studs? Presently I have BFG P235/75R15 M/S Trailmakers which have worked nicely - but need to replace after about 45,000 miles on my 91XLT Explorer (use studded tires from Nov 1 - March 31 in Wash State). Having studded tires on all 4 has saved the situation more than once!