Tires: tire replacement, inflation pressure, tire replacement

Question
I replaced some 14" 175 radials on my small car because the tread was down to 4/16, not alot, but enough that I felt everything I hit on the road, from a rock to a cigarette butt! The steering became difficult too. Finally, the back tire must have had a belt problem, because nobody could find a problem with the wheels or shocks. It felt out of round.  They were a store brand, cheapest, and were noisy when new.  After getting new brand name tires (but still bottom of the line), I noticed a tremendous difference.  Is it possible the out of round feel to the back tire was a bad belt? Nobody could see it.  Are some tread designs noisier than others? Is 4/16ths too early to dispose of a tire, unless it stinks?  Thanks for all three hits!

Answer
Ron,

Given that you have a fairly wornout tire, a vibration, and noise, I would guess what you had was irregular wear and not a problem with the belt.  It is fairly common for some folks who should know better to be confused by irregular wear, sometimes using the term "shifted belt".  Irregular wear is caused by insufficient rotation practices, misalignment, and  insufficient inflation pressure.

Generally tread depths are measured in 32nds of an inch, so I assume you meant 4 /32nds, which is what I recommend for removal.  Hydroplaning gets much worse as you approach the legal limit and I prefer to get the tires off BEFORE I discover there is a problem.

Hope this helps.