Explain speed rating T vs. H vs. V

Messages
8,051
Location
MI
Gentlemen, In an all season, radial M+S tire, for a mid-size sedan (Buick Regal) driven by a little old lady in Michigan (Snow and sun) - what are the decision criteria for deciding which speed rating to buy? Winter driving is an important factor (but no separate snow tires). Does a higher rating give better grip/traction? If so, do you get less durability (softer compound)? Why choose a higher rating than T? (more $) Thank you. (started this thread in the BFGoodrich TA thread).
 
Messages
8,711
Location
Nothern USA
The speed rating simply is the maximum speed a tire should not fail for sustained use. Listen to 427Z06. Go to Tire Rack and look for something inexpensive that has a nice ride, good wet traction, quiet, and reasonable tread wear for he price. The little old lady will brag about how smart you are. For most people, paying much attention to speed ratings in American is a waste. Those that pay much attention to the speed rating farce correct me, but I believe unrated tires are good for sustained speeds up to 85 mph. There are very few places where you can get away with more than that, and even fewer where it is reasonable. Now if she is from Pasadena, you may want to look into a speed rated tire. Good advice for any that ever do run over 85.
 
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6,091
Location
northern Alabama
When I bought tires for my car, 205/55/16, I had to get H rated tires to get an A temp rating to go along with the A traction rating. So it appears that the speed rating can sometimes play a factor in more than just the top speed.
 
Messages
44
Location
Ann Arbor, Michigan
Higher speed rated tires tend to have a stiffer construction too. This will mean more responsive and improved handling, but it can also be to the detriment of a smooth ride. And typically, higher speed rated tires don't last quite as long either. A 'T' speed rating for a Buick everyday driver that's not going to be driven like mad will be just fine. If I'm not mistaken, a 'T' speed rating is around 110 to 115 mph anyway... M+S ratings are overused these days. It doesn't have much bearing at all in my opinion. Neither does the term "All-Season" here in Michigan. Once you've driven in the snow with real purpose-built snow tires, all-season seems pretty bad in comparison. All that extra siping works very very well... along with the softer compound. Not great for treadwear, but great for traction. Most snow tires also come with a "Q" speed rating, which is really about the slowest rating you can have on the streets I think. Of course there's always more expensive high-performance H-rated snow tires too [Razz] I probably won't convince you of purchasing snow tires anyway, but it was worth a shot. Anyway, the higher speed rating may give you improved grip in dry, ideal conditions. But in rain and especially snow, that doesn't mean much at all. For your application, a 'T' rating would do just fine. Probably wouldn't really notice a difference anyway if the car isn't being driven hard (Except for the possibly harder ride that may come with a higher speed-rated tire)
 

JHZR2

Staff member
Messages
46,169
Location
New Jersey
you need to get the right speed rating or higher or else the sidewall will be too flexible, and handling will suffer. SOme tire shops will not sell tires more than one speed rating below spec. Id go with H rated for most any car, unless its lower than OE. Look for A or AA traction as well, as this indicates wet braking ability. A temperature is good too, as it tells its ability to withstand heat from high speed driving. I think it correlates somewhat to the tire's oxidation resistance. JMH
 
Messages
12,385
Location
Northern CA
quote:
Originally posted by 427Z06: I would pick on other criteria: http://www.tirerack.com/tires/surveyresults/surveydisplay.jsp?type=ST
I addition to 427s good advice, also take alook at the Performance all season catagory. Pick decide which characteristics are most important to her, then pick from the top 4 or so tires on the list. If she isn't putting alot of miles on her car, then tread life shouldn't be a big factor. Any of the top rated tires in those classes will probably last her until they are too old to perform at their best. I recently got a set of Yoki Avid S/t Tires which are "The Yokohama Avid S/T was developed to provide All-Season performance for muscle cars, light trucks and full size vans." They are very quiet and smooth in addition to nice handling. I'm using them on a light pickup, but they would be nice comfortable, yet decent handling Buick tires. They are T rated and were $51 in 225/70-15 Read the tire rack ratings and user reviews carefully, if you sort through the BS, it's one of the best sources of info there is. The lol will like the tires, and you won't mind them if you drive her car. [Smile]
 
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1,139
Location
USA
quote:
Now if she is from Pasadena, you may want to look into a speed rated tire.
HA! I can't believe someone didn't pick up on that.
 
Messages
12,385
Location
Northern CA
quote:
Originally posted by seotaji:
quote:
Now if she is from Pasadena, you may want to look into a speed rated tire.
HA! I can't believe someone didn't pick up on that.

What makes you think that several of us didn't pick up on it? It was so obvious that even I didn't comment on it. [Big Grin]
 
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1,715
Location
Texas & BWI Area
Michelin Pilot A/S for example UTQC 400 DOT AA/A 400 signifies on a goverment track how long it wore compare to a standard tire lasting "1"...hence 4 tires longer than the goverments lowest denominator minumum mule. AA: Is wet braking, always stick to AA or A no matter what tire. Sears Guardsman, and many econo lethal tires are B rated which makes me puke. B: Is temperature rating...I am not to clear but it has something to do with the tread/structural resistance to temperature breakdown. 245/50/ZR16 98W All this decoded means: 245: Tread width in millimeters 50: Aspect ratio of sidewall thickness 16: You should know this number at least *lol* R: Radial Z: Speed rated at 150mph or above** 98: Load Rating in pounds W: Speed rating at 168mph** Other questions: S: Speed Rated to 112mph T: Speed Rated to 118mph **Speed rating under experimental/treadmill conditions at rated speed for 24hrs To answer your question do not let your OE tires force you into H, V, ZR rated tires unneccesarily. More often than not if your simply looking for a comfortable and quiet all season touring radial I feel you have superior options in S & T tires. Not only will they last longer, but they are much better in rain and snow (for the most part) I would recommend Michelin Harmony/Agility, Goodyear TripleTread or Comfort Tread, etc any day over OE H rated tires in North America. Unless you are some high speed loving, oval track weekender S & T tires may be much more practical for you. H and other ratings were more in mind for the Autobahn *lol*
 

doitmyself

Thread starter
Messages
8,051
Location
MI
Thank you all for some excellent answers. EXCEPT FOR MATT-TDI - I don't accept any opinions from ANN ARBOR. Randy from MOO U in East Lansing.
 
Messages
342
Location
North Kingstown, RI
quote:
Originally posted by outrun: To answer your question do not let your OE tires force you into H, V, ZR rated tires unneccesarily.
In my experience, shops won't install a tire with a speed rating lower than OEM. It's a liability thing. Obviously, common sense CAN be utilized here, but it could be a hassle at an installer.
quote:
245: Tread width in millimeters 50: Aspect ratio of sidewall thickness
Just wanted to expand on these a little. The tread width number actually corresponds to the width at the tire's widest point, the sidewall. A lot of tires have a bulge at the sidewall and narrower tread. The aspect ratio is in percent, so the height of a 245/50 sidewall would be 245/2 = 122.5mm.
 
Messages
709
Location
CT
quote:
you need to get the right speed rating or higher or else the sidewall will be too flexible, and handling will suffer. Some tire shops will not sell tires more than one speed rating below spec. - JHZR
I think most people just look at speed rating as top end speed and forget about the safety issue. Shops may push a higher speed rating in an attempt to get you "more" than what you need, but it does totally come down to liability when they will not go below the manufacturer's specs. I have no data to back this up, but I feel manufacturers use two apsects in slecting a tire's speed rating. 1) What is the top end speed the vehicle is capable of and 2) How does the vehicle behave in emergency maneuvers. My sedan came with V rated tires. When it came to replacing my tires, I almost went with an H-rated tire because I could never see myself driving faster than 130mph. In the end I chose the more expensive V-rating because I didn't want to jeopardize my cars handling (or my life) in an emergency situation.
 
Messages
44
Location
Ann Arbor, Michigan
quote:
Originally posted by doitmyself: Thank you all for some excellent answers. EXCEPT FOR MATT-TDI - I don't accept any opinions from ANN ARBOR. Randy from MOO U in East Lansing.
LOL. I am not a U of M student (one of my siblings are, though), but OK... my actual address is Milan, but I'm really closer to Ann Arbor/Ypsilanti than Milan... plus I spend most of my time in those areas as opposed to Milan. I grew up in Jackson, which is more pro-State anyway [Razz] I work in a Belle Tire shop literally a couple hundred feet West of US-23 in Ann Arbor [Smile]
 
S & T speed tires can be high quality and have very high tread wear numbers. They usually have a "B" temperature rating because of the thick tread they have. Suitable for most people. and most driving. H rated are moving towards high performance driving where sharp handeling and high traction are paramount and ride comfort and long life are sacrificed a little. V & W are for speed freaks who lost their licenses a long time ago and don't care if they cost $250 each and last only 15,000 miles. They want 1.2 G's on a skid pad above all else...
 
Messages
121
Location
Vancouver, British Columbia
quote:
Originally posted by Fuelrod: S & T speed tires can be high quality and have very high tread wear numbers. They usually have a "B" temperature rating because of the thick tread they have. Suitable for most people. and most driving. H rated are moving towards high performance driving where sharp handeling and high traction are paramount and ride comfort and long life are sacrificed a little. V & W are for speed freaks who lost their licenses a long time ago and don't care if they cost $250 each and last only 15,000 miles. They want 1.2 G's on a skid pad above all else...
This was so worth bumping a thread back up... [Roll Eyes]
 
Messages
1,420
Location
Balto.
I have ordered lower ratings than factory original from Tirerack. They will let you know that it is lower but still ship the tires if you agree. IMO, for a little old lady in Michigan, the speed rating wont mean much.
 
Messages
3,667
Location
St. Charles County, Missouri
Sort of brought up in the last few postings, but... Just gave my daughter my Elantra GLS which came with Michelin Energies (terrible tire BTW), that sort of locked me into H rated tires. My new Malibu Maxx has a lot more top end and yet it comes with tires with a lower speed rating. When the OEM Bridgestones wear out I'll probably get a long lasting touring tire with an A traction, B temp rating. My suspicion is that Hyundai put the Energies on in the first place (rather than the Kumhos that they'd been fitting) because they got a good deal with Michelin and thought the name had value not because of the top speed of the car or the suspension settings which were rather soft, certainly more so than the Maxx. Once you have H's on the car, however, most tire retaillers won't replace with anything else and most give you horror stories. One retailler would have fit T rated Coopers and I almost wish I'd taken them up on it since it would have taken me out of the T trap and 40K rather than 60K tires.
 
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