Just picked up a set of tires and did not verify the size while I was there. The tires I got are studded Hakka 9's size 255 50R 19 and the factory tires are 225/55R19. The hakkas are 1.1" wider and 0.3" taller. That difference shouldn't mess with the MPHs, but I am guessing that the width will cause a problem. Has anyone run tires this wide? The seller will take them back, but if they will work, I would keep 'em.

Thanks!

 

I don't see that size mentioned on any Mazda websites which means they likely don't approve.
There are however several tire websites that show that size as "compatible".
I no longer run two sets of tires but back when I did, I ran narrow studded aggressive tread snow tires in the winter.
In general, smaller width tires tend to do much better in the snow than wide tires.
Where I live, we no longer get as much snow as we used to and being retired, I rarely need to drive in it anymore.
If it were me, I'd return them, but I have no idea how much you drive in the snow or how much snow you get where you live.