Tire speed rating

Put new tires on SWMBO's car last night, 2010 Hyundai Sonata LE V6. Went local to get a local warranty rather than my usual order from Tire Rack. First place we went to had the tire I wanted on the shelf. That is until he looked up the car and told me he would have to order the correct tire, something about the book says the car calls for a 94V speed rating and he only had 93V on stock. Said something about no warranty if the speed rating doesn't match. I turned around and walked out. The second place I went to had the same tire w/proper speed rating on hand so he got the sale and installed the new tires. He appeared more knowledgeable so I asked about the speed ratings. Told him I know about treadwear ratings and the speed ratings of H, V, Z, etc but the 93 or 94 is news to me. He said it's true manufacturers won't warranty improper speed rating on a tire but can go higher and still have warranty. I've ordered numerous sets of tires from Tire Rack & DTD and have bought tires before in the past and this never came up. Please inform me of something new I don't know about. Does it really matter that much? After all this is SWMBO's car and won't see any "spirited" driving, just a grocery getter for someone that a car is just transportation. Was just looking for a safe, reliable tire.

The load rating is as important as the speed rating. People always think of the speed rating as the "top speed". That's wrong. Load rating is often just ignored or people think "Well, it's just 'x' pounds less and we don't carry that much anyway". Also wrong. This is far from "new". I sold tires for 14 years and it was always an issue.

Running an underspec tire can cause the tires to overheat and delaminate causing failures at speed. I don't know about you, but I love my wife and (usually) want her around a long time and the idea of her dealing with a blow out at highway speeds with all the mouth-breathers that she has to drive around is not someting I want to even consider.

Something else to consider is the handling of the car. I have run under-spec'd tires a total of twice. Once for a set of winter wheels and the second because they were on the car when we got it. Talk about a wallowing, wandering pile of crap. I had to overinflate them to max pressures just to get the front end to stop wallowing around on a straight road like a drunken sailor on a 3 day binge.

Trust me, get a good tire with the right ratings. It's worth it in the long run.

Also, if you input the vehicle with the tire rack, it will automatically eliminate the incorrect tires for the vehicle. I suspect DTD does as well but I've never tried it.

Bobzilla is spot on. Load rating is the number component and speed and is alpha component. They are almost almost dependant on the sidewall construction (with rubber compound coming into play with the speed rating component as well).

As noted the proper service ratings make all the difference in the world regarding handling, especially when loaded up, think family weekend trip.

I laugh at rally cross guys who pick up black rocket tires with their marshmallow sidewalls, when they'd be better off running almost any V rated snow tire available.

Yeah, as frustrating as she can be at times, would be next to impossible to find a new one that would put up with me. So yeah would like to keep her around. Cheaper to keep her now after more than 34 years.

Load ratings I know about. Have owned and do own pickups trucks and 4X4's, learned load ratings with those. Very important, I know. Is that what the 93 or 94 means? The tire salesmen just said it was speed rating which I didn't understand.

So what if your vehicle is too old and the tires that tire rack suggests is not available anymore? Is there a formula for what your vehicle weighs?

The 93 or 94 is a number representing the load index.

Load index chart

Thanks theenico, that helps me understand. But now I'm even more upset at the 1st salesman. OEM for the car is a Hankook tire w/93V rating and that is the rating the salesman wouldn't install because of no warranty and liability. Would only install a 94V. According to the chart I also could have gone with a H rated tire which would have been adequate for what the car sees. Installed Michelins w/94V.

And I've had to use the formula for an old car before. On my 1970 Opel GT I changed the stock 13X5 wheels for 14X6 and had to use calculators to find a tire that fit. 14" wheels never came on the car. Don't think load rating was a big factor in a car that weighs less than 2,000lbs but the BFG G-Forces I installed are more than adequate.

The big corporate stores can be a pain. Often enough, the monkey behind the counter only knows what the corporate training videos told them. Only rarely do the possess any critical thinking skills.

When I sold tires for the dealer (technically recommended, the advisors did the "selling") my rule of thumb was if you drop the speed rating, upp the load rating. So you can run an "H" tire on a car requiring a "V" as long as you up the load rating (needs a 93 so use a 94). Speed ratings were rarely about the terminal velocity the tire can handle and more about how that tire behaves at normal speeds on the vehcile. KEep in mind, the OE suspension was designed with the spec'd tire ratings to behave optimally.

What about cars with difference sizes and ratings of tires. My wife's Solara had V rated 17" tires, but those are the optional wheels. The standard was a 16" tire. When I wanted to replace them with 17" H-rated tires, the local independent wouldn't do it, then said if he did, he wouldn't warranty them. So Discount Tire got my business because they had no problems putting this tire on. I tried to do a quick check and the replacement tire I put on has a higher weight rating than the V rated tire.

Do you think Toyota tunes these cars for the particular tire?

the optional bigger wheels might come with different suspension pieces- springs, shocks, sway bars.. might have a tighter ratio steering box or bigger sway bars, too... if it's a truck, it might mean some sort of a towing package...

novaderrik wrote: the optional bigger wheels might come with different suspension pieces- springs, shocks, sway bars.. might have a tighter ratio steering box or bigger sway bars, too... if it's a truck, it might mean some sort of a towing package...

Don't know about Toyota, but that is the case with Honda. Springs all depended on trim level and engine size which also denoted wheel/tire packages.

That's assuming the car is still on fresh factory suspension. After 100k, that's gone out the window anyhow.

Keith Tanner wrote: That's assuming the car is still on fresh factory suspension. After 100k, that's gone out the window anyhow.

Yes and no. It's still a good reference to start from.

Bobzilla wrote: When I sold tires for the dealer (technically recommended, the advisors did the "selling") my rule of thumb was if you drop the speed rating, upp the load rating. So you can run an "H" tire on a car requiring a "V" as long as you up the load rating (needs a 93 so use a 94). Speed ratings were rarely about the terminal velocity the tire can handle and more about how that tire behaves at normal speeds on the vehcile. KEep in mind, the OE suspension was designed with the spec'd tire ratings to behave optimally.

I didn't actually look at speed ratings when ordering my Prius winter tires (because if it's a tire and it's sold in this country, it'll work), but your advice totally justifies what I actually got. I'm a little sad I'm apparently not supposed to take my Nokians above 105 mph, but there's really no sane reason to ever go above 85-90 mph (80 in most states) anywhere on public roads in a consumer car on consumer tires. Even if my R-rated tires are "slower" than stock, my load rating is much higher!

That's what upset me the most. How much of a difference between 93V and 94V on a 4-door sedan grocery getter that never sees over 75 on the highway? Usually driven around town and only around 45 on the major city roads. H-rated tires are capable of well exceeding the speed limit and it calls for V-rated. Don't think a Hyundai Sonata is capable of maxing that tire speed rating, not even the V6 Sonata we have. Weight limit is a little more understandable but again, grocery getter and not ever going to see max load. That's why I also have a truck, to carry the heavy stuff.

Anymore, the speed limiter in the car is set to the speed limit of the factory tires. My wife's '14 Impala shuts off at 130, the limit of the original H-rated tires. If I put T-rated tires on it, it could exceed the rating and that would be the cause of the failure, if it happened. I could run V-rated tires with no problem.

If your car was designed for 93V, it should say that on the tire label on the doorjamb.

What really sucks is that my '96 F-150 shuts off at 93, because of the crappy tires they put on at the factory.