I remember the days when we experienced flat spots on our tires. I have been told by several dealers that it no longer occurs. well then there is something else wrong then. Starting the day for about 15 miles the front end shakes-sometimes violently. after 15 miles or so then things are ok. the dealer cannot
reproduce the problem. he is 25 miles away… i have 30 thousand miles on the tires-they are original…need an answer-really don’t weant to buy new tires…
my car is a 2012 Hyundai santé fe
Bring your car to an INDEPENDENT shop that specializes in alignments, tires and suspension work
NOT a chain store
BTW . . . how old are those tires?
First, the dealers you talked to are wrong. EVERY tire flat spots. It’s a matter of degree.
In the old bias tire era, nylon was frequently used as ply cord material - and nylon takes a set much more readily than polyester or rayon.
When radials were introduced, the construction very quickly evolved to polyester / steel - and it stayed that way for a long time. Very few flat spot issues.
But higher speeds have necessitated the use of nylon cap plies (laid over the top of the belt) and since nylon is more prone to taking a set, flat spotting is back. Since the amount of nylon is considerably less than for bias tires, the problem is fairly rare - but it isn’t non-existent.
The keys to fixing a flat spotting issue are :
inflation pressure. More is better
Changing tires. It isn’t so much brand as it is the presence of the cap ply - but cap plies make for a safer tire. And it seems to vary as to what circumstances produce flat spots vs brand/model. (one brand/model will flat spot in one circumstance and another brand/model flat spots in a different circumstance.)
So why use nylon in tires? Because it has the unusual, and very useful, property that it shrinks when it is heated - so tires with nylon cap plies get more growth restriction at high speeds.