My blazer has summer 235 75R15's on it.

I have some winter tires that are 225 75R15's.

Can I mount these on my rims and use them without screwing anything up? Like the 4x4?

Thanks!

 

As long as all four tires are the same size, you should be good.

Your speedometer will read a bit slower than with the 235/75R15 tires, but the percentage is small (~2%) so really wouldn't be anything to worry about. The 225/75R15's are roughly .6" smaller in diameter than the 235/75R15's.