I assume mfrs. spec tires to the maximum the vehicle is capable of.
May be a few lawyers involved in that decision…
;-]
S tires are Walmart quality. T tires are k-mart quality. Quite a few cheapo H tires to be found also. Stick with a name brand H rated tire.
Your stereo can be played at maximum volume yet you do not turn the knob up to 100% to listen to your music. Does that mean you should buy a stereo with less power since you don’t use all that extra power? Of course not! Just like stereos, and many other electronic and mechanical items, cars come with all sorts of capabilities that we don’t use on a daily basis but allow us to use them more efficiently and safely while providing a “reserve” for safety in extreme circumstances. Think of how your current, modern, vehicle feels at 80 mph compared to cars of 30 or 40 years ago. Also, think of how your current car would react to sudden inputs at 80 mph compared to those older cars. Your car is now loaded with technology, including tires, that make all sorts of things possible to save your life in an emergency or during “at the limit” handling.
At the risk of repeating myself, never skimp on tires and brakes. You can buy cheap spark plugs and light bulbs but nothing is worse than the regret you will feel moments before an impact of thinking “I should have bought better tires/brakes”.
I don’t buy less safe tires. My Accord came with H rated tires, and I currently have V rated tires on it. The additional cost was just a few bucks a tire, and it was no financial hardship. I buy the OEM rating for the other 3 cars too. @insightful is likely on the mark with the liability aspect.
Yes, the price difference is very small to get the correct tires specified for this car. In fact, the cheapest tires in that size on Tire Rack are H rated, cheaper than the first of the few T rated tires.
My 2010 Kia Forte SX came with OEM Goodyear Eagle V rated. 149mph tires on a 135mph vehicle was appropriate. When I replaced them at a little past 18,000 miles (quite disappointing wear resistance) I chose Toyo W rated. My car will only achieve 168mph if dropped out of an airplane but they were only a couple dollars more than V rated and were in stock. They are now over 20,000 miles and measure 7/32nds tread depth with very even wear…
Now…I get that speed rating can have performance differences that don’t require driving as fast as rated speeds to realize. I get that it might be “penny wise, pound foolish” to cheap out on tires for a vehicle that otherwise handles adeptly–you’r paying for performance that cheap tires won’t let you have.
BUT…as far as safety…what’s the big deal? I mean, putting on a lower-rated set of tires (may) “narrow the performance envelope” a bit–but, assuming you’re cognizant of that narrowing, and adjust accordingly, I don’t see the safety angle. Can’t a “T” rated tire perform every legal, or even quasi-legal, maneuver that a “H” rated tire can on public roads? I mean, towing a vehicle will narrow your performance envelope FAR more than a set of tires will…and as long as you account for the narrowed performance envelope and adjust your driving accordingly, it’s perfectly safe!
If I am looking to buy a used car, and you’re the seller . . . the FIRST thing I’m going to do is make sure the tires have the correct speed rating
And if they don’t, I’m going to lowball you
Something tells me you probably wouldn’t accept a lowball offer, based solely on you having installed the incorrect tires 
I suspect the outcome would be that I walk away and purchase a car from somebody else
I’m basing this on your remarks from a few minutes ago, FYI
Now days it would be difficult to find a tire shop who would sell you lower than OEM speed rated tires.
A place I used to deal with would sell the next speed rating down from OEM spec.
Independent or even regional tire shops may take the time to research the manufacturer’s authorized substitutes. The big box stores will mindlessly insist on factory original specification tires only. I’ve been there.
With a lawyer on every street corner in the United States I can’t criticize a business for only wanting to sell what the factory tires rating was.
As I said: what is the SAFETY basis for using the speed rated tires? So far, I’ve heard a lot of “ZOMG lawyers gonna get ya!” which is, I suppose, is valid for a SELLER of tires…but as a CONSUMER, what does an “H” rated tire do, that a “T” rated tires fails to do, at semi legal* speeds, that is a safety issue (not a performance or driving satisfaction issue)?
(I’m not being belligerent, mind you, I’d really like to know for my own benefit. It wasn’t all that long ago that most tires weren’t speed rated; now, it seems like they all are.)
*Let’s define “semi-legal” as: PSL +10. Given that the highest PSL I’m aware of is 80, that’s 90 (not that I can afford to go tooling around at 90 for long, mind you.)
It’s not just about the speed rating of the tire, it’s about the handling. If your car was designed to run with H rated tires and you replace them with T it might not drive as well.
I once replaced a set of H rated tires with T rated. Obviously the T rated didn’t have as substantial a sidewall as the H. The customer complained that when he changed lanes at freeway speeds the car swayed more than it used to.
@meanjoe75fan there’s more to it than just the speed rating. An H rated tire will likely have better grip than an T rated tire. There’s a reason why the Z or W rated tires I get for my Mustang only make it 25k-30k miles before the wear bars start showing. Generally speaking tires with a higher speed rating also have better traction, and a good way to get better traction is with a softer compound, and softer compounds wear out sooner.
If a manufacturer specs a H rated or V rated tire over an S or T rated tire, they did so because they felt that a tire with better traction was needed. If you decide to to go with a lower rated tire that sacrifices traction for treadwear, then your car will no longer have the capability it’s engineers intended it to and in an emergency situation it could very well be a safety issue.
There seems to be an assumption that the quality of the tire goes up with the speed rating. That is not necessarily true, Some manufacturers offer the same tire in different speed ratings for only a few dollars difference in price, but as the speed rating goes up the UTOG number goes down because the tire tread has less depth to save tread weight to be safe at the higher speeds.
Since I am much older and completely retired, I no longer feel the need to go the 100++ speeds I used to and have no problem stepping the rating down one notch. Indeed many manufacturers put S or T rated tire on their base models and if you move up to the next model put on H rated tires and alloy wheels. Both cars have exactly the same speed capabilities.
OK, lots of misinformation being laid down here. Allow me to clarify:
First, the speed capability of a tire is pretty much all about the construction - and in particular, the cap plies - nylon inserts (usually) over the steel belts that restrict the growth of the tire at speed. S and T rated tires don’t need cap plies, H rated tires pretty much need one, and V and higher need 2 plies.
Quality? If you consider “quality” to include a stronger construction, then, yes, higher speed rated tires are a better quality. (Please note: I think the term “quality” should be used only in the sense of consistency from individual product to individual product, so I think of higher speed rated tires as being more capable, not better quality.)
Speed rating vs other characteristics: There is nothing about the speed rating that says that a higher speed rating = better grip. HOWEVER, higher speed rated tires TEND to be used in situations where better grip is a plus (at the expense of long wear and fuel economy), as well as better handling and low aspect ratios. Just keep in mind that each of those characteristics is governed by something other than the speed rating.
And to address the need for higher speed rated tires on low performance cars: I had a professor who used to say: “Over-design, Under-utilize” - which is a way of saying engineers need to design things to exceed the minimum standards, and folks specifying things need to over specify.
That’s why cars come with over sized (more load carrying capacity), higher speed rated tires - as well as over sized bolts, stronger seat belts, etc.
Every step up reduces the risk of failure. (and, by the way, this is the argument that lawyers use - but they do that by having people like me testify to that effect!)