My 2007 Honda Accord 4-cyl needs new tires. The original equipment were 205/65R15 92H, maker unknown. From the CR ratings, I chose the Hankook Optimo H727 for its mostly Very Good ratings across the board.
One tire store refuses to mount my choice because the speed rating is only T. They would not say why, only that they will not do it. They recommended Michelin Primacy MXV4 at a 27% increase in price. Another store said that I should not choose the Hankooks because I would have a "drastic" reduction in performance by going to a lower speed rating, and that the tires would have "much slower response". They recommended General Altimax HP. I said I doubted what he said, and he told me that he has 10 years experience in tire sales.
I do not intend ever to exceed 118 mph (as if my Accord ever could!).
I have not found any legal requirements relating to speed ratings. I think that both stores are afraid of being liable for damages if I crash, and I think that is their only credibly valid reason for their stand.
What do you think?
Edgar, it's less a matter of what your car "could" do, or how fast you "might" ever drive as much as what the vehicle manufacturer calls for. I have a 2000 Accord Coupe V6 and the recommendation is for V-rated tires, and while I seriously doubt I'll ever drive 128mph, I have always stuck with V-rated tires, as per specs.
That being said, the prices on the Hankook and the General seem to be pretty comparable.
Well, Richard, I have been hoping to hear something about speed ratings and overall tire performance that I could understand. I believe that you are giving me the benefit of your experience and wanting to be helpful, but I hoped for something more than Honda's specs for the cars. The Car Talk guys have said that the major determinant that a manufacturer uses in setting tire specs is finding the lowest cost tire that will fit the car and the market. In the case of the different Accords, I think it's mainly the market.
Take the 2007 Accord LX and SE. In 2012, the only difference between the LX and SE is a collection of convenience and luxury items added to the SE, AND 16 inch alloy wheels instead of 15 inch steel. I think it was the same in 2007. The '07 LX spec says 65R15 92H and the SE spec says 60R16 91V. Except for wheels and tires the cars are mechanically identical. I believe that the different spec results from the market preference for larger wheels and lower profile tires in higher trim lines, because of the perception that larger wheels and lower profile tires will give the driver a sporty car. Perhaps the SE can outperform the LX in a slalom, but I don't think that is significant for my decision. If I put SE wheels and tires on my LX, it would outperform the SE because of its lower weight, but not because of the V speed rating. I also believe that General 205/60R16 92H and 205/60R16 92V (both are available) would perform exactly the same in traction and braking.
If you know of any instrumented numerical test data that compares T-, H-, and V-rated tires in the same sizes on the same car, that would probably give me something that I could understand.
BTW, my Civic riding on Hankooks performs and handles well enough for me, and also enjoys the superior ice and snow performance that I get from the Hankooks.
Thanks very much for your reply.
Thank you, Mark, for your reply and the reference to the Tire Rack test results.
I have a problem reconciling the Tire Rack and the Consumer Reports test results for the General and the Hankook. Some examples -- especially remembering that the General is a performance all season tire and the Hankook just an all season:
CR test results:Dry braking -- General good, Hankook very goodHandling - General very good, Hankook goodIce braking - General fair, Hankook very goodRide comfort - General good, Hankook very goodSnow traction - General good, Hankook very good
Score General 1, Hankook 4
And finally, Tire Rack rates the Hankook pretty far below the performance all season tires that they compare it to, but the CR ratings within category are Hankook 82 (excellent) and General 70 (very good).
It's not helpful to me that the Tire Rack test results, although presented numerically, appear to be subjective instead of instrumented. I know that some Tire Track tests, e.g., ice braking and snow traction, are instrumented and present observed numerical results, still the formula used to translate these numbers into spider charts and bar charts is pretty obscure to me, the customer.
Please see my reply to Richard for my explanation of what I'm really looking for here.
A brief Google search did not turn up any true comparitive analysis of tire speed ratings, e.g. same tire, different speed ratings. Much of what I've found points to the following:
When you turn the steering wheel, you will notice a delay before the car starts to respond. Although several factors contribute to this delay, the most important seems to be the tire's side wall, and the second most important seems to be the tire's tread. The faster you are going, faster things are happening, and the more critical minimizing this delay becomes. In addition to being sure the tire can withstand its rated speed, tire manufactures do things (like making the sidewalls stiffer) to make higher speed-rated tires respond to your steering input faster. If you would like a cheap and easy demonstration of this effect, make your tire's sidewall stiffer by inflating it to 40 psi, and notice how much crisper the steering becomes even at extremely modest speeds. Of course, there are disadvantages to higher inflation pressures, so just do this as a demo.In the same way, you will READILY notice this difference between an "S" and an "H", even in a Golf or other modest car. The main disadvantage of a higher speed-rated tire is shorter tread life. The second disadvantage is a mild decrease in ride quality.
Some of the referential articles I reviewed are below. As with most things in life, not just tires, your mileage may vary :)
Speed ratings make a difference not only in regards to speed, but in regards to ride comfort, wear and cornering ability. Typically, the higher the speed rating, the better the grip and stopping power, but the lower the tread life. You can always increase the speed rating of the tires on your vehicle for improved performance, but can never decrease it without reducing the vehicle top speed to that of the lower speed rating selected.
Speed ratings identify the maximum speed a tire can sustain for 10 minutes without being in danger. Higher speed rated tires are less likely to have catastrophic sidewall damage or tread failure. Even though your speed rating indicates the maximum speed your tires are equipped to handle, it does not mean your vehicle can safely operate at that speed.
When purchasing new tires, be aware that speed ratings are determined during simulated road performance tests on unstressed and properly inflated tires. New tires should also have the same or a higher speed rating than a vehicle’s original equipment tires to maintain or improve its performance.
All tires are not created equal. Think of your car’s tires like shoes. You wear different shoes for different occasions: office shoes, tennis shoes, running shoes, etc. Your shoes are chosen based on what activities you’ll be partaking in, and often your decisions revolve around speed…
Speed: Tires have speed ratings, meaning certain tires are designed for maximum speeds. For example, if you’re traveling at 115mph with tires ranked “Q” (up to 100mph), you may be in for trouble.
Even if you don’t plan to travel above 149mph, why would one opt to purchase tires with lower speed ratings? There’s a good reason: wear. The faster a tire is rated, the softer its rubber so that it can better grip the road with that malleability. Thus, faster rated tires wear out quicker than slower rated tires. Back to the shoe analogy, you would never wear dress shoes to play tennis, but your tennis shoes will probably be replaced more frequently than your dress shoes because of the material they’re made of. When choosing your car’s tires, consider your diving habits, speed, and how much “grip” is necessary for the roads you frequently travel. This will help you make an informed decision about just how fast and flexible your tires really need to be.
"As the top speed increases, the longevity of the tire decreases. This is why most vehicles are equipped with stock H rated tires; no one really needs to go that fast and they last longer than say, V or Z rated tires. On the other hand, if you purchased a sports car that came stock with Z rated tires, you can most definitely “downgrade” to a cheaper (in most cases) and longer lasting H rated tire. This is, of course, unless you prefer break neck speeds and speeding tickets!"DiscountTire.com
"A tire receives its speed rating by the U.S. Government through meeting minimum standards for reaching and sustaining a specified speed. What does that mean to you? Well, in general, a higher speed rating will result in better car handling.
• Never mix and match tires with different speed ratings on your vehicle. This will cause serious problems with the handling of your vehicle. "
I know where you're coming from. Speed ratings generally correlate with tire performance (that is, higher speed ratings generally appear on tires offering higher performance), but I don't always see value in using the original equipment speed rating. I do typically recommend that folks stay with the OE speed rating as a conservative recommendation, however. A number of thoughts on that.
1) First, as you said, there are sometimes cases where there is legitimately no difference in the suspension tuning or underpinnings of a car where there may be two speed ratings offered from the factory. A number of Cadillac models were this way in the 1990s. For example, the "base" STS would come with H-rated tires, but you could opt for the "Z package" which gave you Z-rated tires along with no speed governor on the car. There were no other changes to the vehicle; the Z-rated tires simply removed the governor. So should an owner of a Z-rated STS keep buying Z-rated tires, when he's not exploiting more performance out of the car than the baseline H-rated tire offers? Clearly, this example (or the one you gave) is not representative of the industry as a whole, and there are sometimes cases where higher rated tires also add more advanced levels of suspension tuning. Because of this, unless there is specific information about the vehicle in question, I generally defer to the OE speed rating.
2) Speed ratings are applied by tire manufacturers not as a result of a specific test (as the UTQG grades are), but as an assurance of some minimum level of performance. For example, a T-rated tire would not necessarily "fail" test conditions for an H- or even V-rated tire. But for one of potentially many reasons, the tire manufacturer has branded that tire with a T rating. This could be because the T-rated market is the intended market for the tire, for example. You certainly can't assume that any T-rated tire could perform at a level of an H- or V-rated tire, but you also can't necessarily assume that any given T-rated tire couldn't perform at a level higher than other T-rated tires.
3) This is really a practical example of thought #2 above. The Tire Rack test that Mark linked to is a great example of one particular T-rated tire performing above and beyond, possibly up into the realm of H-rated tires. Two of the tires tested were very competitive H-rated tires, and Tire Rack compared these with two T-rated tires in the same size. One of the T-rated tires, the Michelin HydroEdge, appeared to be up to the challenge; if not beating the H-rated tires, it at least stayed on-par with them. The other tire, the Hankook Optimo H727, was clearly out of its league, obviously intended for a different application. In this case, the Michelin might be written-off as inappropriate for an H-rated application, when it clearly performed at the level of its H-rated peers in that test.
4) Speed ratings are often cited as a minimum level of performance one should choose for any given vehicle. If the original equipment tire was a V-rated tire, keep V-rated tires on the car, etc. I believe there can be caveats to this as well. For example, the Michelin Energy MXV4 S8 is a very popular OEM tire, and often appears in V-rated guise. As most folks know who have owned these tires, they're extremely quiet and efficient tires that ride well, but ones that have no sporting qualities to them at all. These tires are clearly out-classed, performance-wise, by many H-rated tires (and probably some good T-rated tires as well). By definition, any H-rated tire would not be appropriate for a V-rated application, but if one can find an H-rated tire that will very certainly out-perform the V-rated OEM tire (like the Energy MXV4 S8), and might even come with a longer tread life warranty and/or better light snow traction for use in a pinch for those areas that don't experience a lot of snow, then I see a lot of value in looking at those particular alternatives, even if they don't necessarily share the OEM speed rating.
In short, I usually defer to the OEM speed rating because, as a blanket recommendation, it's the safest and most conservative recommendation to make. I do also think too many eggs are put in the "speed rating" basket, and I do not believe it's a be-all, end-all indicator of tire performance. That's where resources like Consumer Reports and Tire Rack really add value and information to your purchasing decision.
Richard, you have done some research for me and you turned up stuff that I never would have found. Thank you for all that effort, and your knowledge of where to look.
All the quotes do a good job of explaining speed ratings and the implications for tire construction. The quote from DriverSense.com seems to indicate that I could put the Hankooks on if I am willing to sacrifice some potentially better dry pavement performance in favor of ice/snow performance. I don't get the impression that putting Hankooks on would put the car in a dangerous condition.
I will have to digest all that you have found and then decide how to go, and you have given me plenty to consider. For example, the H-rated tires that are being offered in some brands will give equal or better dry pavement performance but in all brands offered they will give inferior ice/snow performance. Here in South Bend, IN, the lake-effect snow region, that is something to consider.
Tire Rack mailings this season say, "Put on real snow tires!" Well, maybe --
Hi, Mark -- Yesterday, 1/9, I had time to buy some tires. After thinking about the advice from all three responders, figuring out what I want for all four seasons and which are most important, and reading all the test results for a few tires, I (think I) followed the advice of all: I settled on H-rated performance all season tires and so kept the speed rating that I had with the OEM tires.
Thanks to all of you for your significant help.
Hi, Jason -- Yesterday, 1/9, I had time to buy some tires. After thinking about the advice from all three responders, figuring out what I want for all four seasons and which are most important, and reading all the test results for a few tires, I (think I) followed the advice of all: I settled on H-rated performance all season tires and so kept the speed rating that I had with the OEM tires.
Hi, Richard -- Yesterday, 1/9, I had time to buy some tires. After thinking about the advice from all three responders, figuring out what I want for all four seasons and which are most important, and reading all the test results for a few tires, I (think I) followed the advice of all: I settled on H-rated performance all season tires and so kept the speed rating that I had with the OEM tires.