Guys, this is the 2nd time in less than a year that i've had bubbles develop on the sidewall of my 225/40/18 Sumitomo HTR+.

I'm thinking it may have something to do with how low a profile this is for our pothole ridden city.

Would it make sense for me to upgrade to thicker rubber? If so, what would be a good replacement size? 235/45?

It's going on 18x7 rims by the way.

Thanks.