I want to run a pair of winter tires on my 87 Westy.  In Oregon studs or chains are often required to go over passes in winter; we carry cable chains.  

I recently upgraded to 16” wheels with Michelin Defenders, which were good for a summertime cross-country trip, but probably not for snow and ice.  Many years ago I bought a pair of 15” wheels, which I still have (should have gone with 16s originally, but got bum advice on fit).

Does it make sense to permanently mount winter tires on the 15” wheels?  Or should I just stick with 16’s and switch tires for the seasons?  

Thanks!  And Happy Thanksgiving to all.