"Q" Rated Snow Tires and Highway Driving

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What type of performance issues in good weather am I going to experience outfitting a commuter car (Saturn S-series/Cobalt/Cavalier) that originally speced a higher speed rating (S/T/H I believe)? Commutes contain 5 to 25 miles of highway travel at >=75mph and perhaps a handful of highway trips 200+ miles.
 
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Originally Posted By: 99Saturn
What type of performance issues in good weather am I going to experience
What's good weather? Presumably a cold winter day up north and dry roads? You can expect slightly less crisp steering response from a Q-rated tire, but other than that, no issues really. I've taken my Q-rated Altimax Arctics on my 530i on a number of longer hwy trips over the years with speeds of around 80 mph - never a single issue, even with temps above freezing.
 

99Saturn

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By good weather I meant no precipitation and effectively sunny and dry. I'm in lower NY, so it's not uncommon for 40 degree days and no snow 80% or even 90% of the time.
 
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"Q" rated tires are good up to a sustained 99mph iirc, so that in itself shouldn't be a problem. Winter tires, because of their soft tread compound, large tread blocks and lots of siping will feel a bit less responsive and "squishier" than all-season tires. This will be most evident in steering feel, but it shouldn't be a big deal. They may be slightly noisier than all-season tires as well. Winter tires typically don't have as long a tread life as all-seasons and, as the other poster mentioned, warm/hot weather will accelerate tread wear considerably.
 

JHZR2

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I've driven between DC, Chicago, and Boston, that triangle of the USA on Q and H snow tires plenty. Can't say I've practically noted any real difference. If anything, a q tire with a likely softer tread and sidewall may ride more comfortably.
 
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175/70/14s on my saturn, mush on dry. But when the going gets rough, pizza cutters rule my day.
 
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Originally Posted By: 99Saturn
What type of performance issues in good weather am I going to experience outfitting a commuter car (Saturn S-series/Cobalt/Cavalier) that originally speced a higher speed rating (S/T/H I believe)? Commutes contain 5 to 25 miles of highway travel at >=75mph and perhaps a handful of highway trips 200+ miles.
Get T rated tires such as Bridgestone Blizzak or some other top notch tire. Do not go with cheap alternatives and you will be more then OK with T speed rating.
 
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Upstate NY
You'll be fine. I had such tires on my old Buick LeSabre. A little mushy on dry roads. Otherwise, they drove fairly normally. The higher speed rated tires do tend to be a little quieter. That's important for spending a lot of time in the car, as I do/have done.
 
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there is a slight feel difference. You can feel slightly more tread squirm when you hit a curve or change lanes. If you're one of those people that constantly swerve in and out of traffic, you will definitely feel the squirminess in the tires.
 
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I'd buy tires for your application and weather. Maybe a sport winter tire, or michelin xice xi3 I have michelin xice xi2 175/70r14's on the 2010 accent. at 30F it handles almost the same as the michelin defenders that are on it for the other 9 months.
 
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Originally Posted By: Danh
"Q" rated tires are good up to a sustained 99mph iirc, so that in itself shouldn't be a problem. Winter tires, because of their soft tread compound, large tread blocks and lots of siping will feel a bit less responsive and "squishier" than all-season tires. This will be most evident in steering feel, but it shouldn't be a big deal. They may be slightly noisier than all-season tires as well. Winter tires typically don't have as long a tread life as all-seasons and, as the other poster mentioned, warm/hot weather will accelerate tread wear considerably.
THIS^^^ It is not necessarily a steady speed rating problem, or even wear problem going straight ahead on the highway, as it is a cornering speed problem. The Q rated snows I've had in the past had that spongy, tread scrubbing/folding under, understeering feel to them when pushed even slightly harder than granny speeds through any turns.
 
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I thought that CapriRacer had explained that speed rating is largely independent of the tread.
Quote:
http://www.barrystiretech.com/speedratings.html In speed rating tests, failures are almost always belt area separations - and in particular "belt leaving belt" separations. In other words, tire construction, not tread compound, seems to be the limiting factor. ** ** To get a tire to pass an H speed rating almost requires the tire to have an overlay - commonly called a "cap ply" and nylon is a commonly used material. This overlay restricts the growth of the tire due to centrifugal forces as well as the movement caused by the standing wave. Not only does this result in reduced stresses in the tire, it also reduces heat generation. Adding further overlay layers results in higher speed capability. That is, you achieve higher speed capability with just changes in construction. Rubber compound changes are almost incidental.
So the speed rating doesn't necessarily correlate with handling or performance. Granted - I think it's far more common for winter tires to have lower speed ratings and the inherent nature of a winter tread is going to mean a squishy feel. However, this doesn't necessarily correlate with speed rating. I've also noticed that I can't find many V speed rated tires in the 205/55R16 size for my car. There used to be several on the market.
 
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I think above statement from Capri is generic and may not apply to Q rated winter tires. I do think that their Q ratings come from tread not from construction. Or rather since tread cannot sustaing high speed no need to make carcas handle it either. Krzys as usually opinionated
 
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Originally Posted By: y_p_w
I thought that CapriRacer had explained that speed rating is largely independent of the tread.
Quote:
http://www.barrystiretech.com/speedratings.html In speed rating tests, failures are almost always belt area separations - and in particular "belt leaving belt" separations. In other words, tire construction, not tread compound, seems to be the limiting factor. ** ** To get a tire to pass an H speed rating almost requires the tire to have an overlay - commonly called a "cap ply" and nylon is a commonly used material. This overlay restricts the growth of the tire due to centrifugal forces as well as the movement caused by the standing wave. Not only does this result in reduced stresses in the tire, it also reduces heat generation. Adding further overlay layers results in higher speed capability. That is, you achieve higher speed capability with just changes in construction. Rubber compound changes are almost incidental.
So the speed rating doesn't necessarily correlate with handling or performance. Granted - I think it's far more common for winter tires to have lower speed ratings and the inherent nature of a winter tread is going to mean a squishy feel. However, this doesn't necessarily correlate with speed rating. I've also noticed that I can't find many V speed rated tires in the 205/55R16 size for my car. There used to be several on the market.
Originally Posted By: krzyss
I think above statement from Capri is generic and may not apply to Q rated winter tires. I do think that their Q ratings come from tread not from construction. Or rather since tread cannot sustaing high speed no need to make carcas handle it either.
When I read what I wrote, and applied it to the subject here (winter tires), I realized that winter tires are very likely the exception to the rule - that tread compound DOES play a role in the speed rating.
 
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Originally Posted By: CapriRacer
When I read what I wrote, and applied it to the subject here (winter tires), I realized that winter tires are very likely the exception to the rule - that tread compound DOES play a role in the speed rating.
That being said, would a winter tire still fail in the speed rating test in the same manner as any other tire? (i.e. - lose a piece of tread)
 
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Originally Posted By: leeharvey418
Originally Posted By: CapriRacer
When I read what I wrote, and applied it to the subject here (winter tires), I realized that winter tires are very likely the exception to the rule - that tread compound DOES play a role in the speed rating.
That being said, would a winter tire still fail in the speed rating test in the same manner as any other tire? (i.e. - lose a piece of tread)
Remember that there is a time component and a load component to the speed rating of a tire. That speed rating is good up to a certain speed, for an hour straight at that speed, while under it's maximum load amount, before a defect will occur. So let's say that we're talking about an 89Q load and speed rated tire. This means that the tire, while having 1,279 lbs loaded on it, and it's 3 friends, could drive around the highway at 99 mph, for an hour, in safety, if they were never damaged previously. If you had a flat, or ran it 15 psi low for 20k miles, this 89Q is no longer a valid speed and load rating for the tire. So, unless you're planning on driving around on the interstate for over an hour at 100+ mph, while fully loaded down, there's no issue running snow tires during the year, except from the fact that you're wasting expensive rubber. BC.
 
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Originally Posted By: CapriRacer
When I read what I wrote, and applied it to the subject here (winter tires), I realized that winter tires are very likely the exception to the rule - that tread compound DOES play a role in the speed rating.
OK. But what would the mechanism be for that? I thought that belt separation is the primary mechanism where a tire fails during a speed-rating test. For winter tires, would tread failure be the more likely result? I only looked for that because I remember one of your older posts said that you could probably swap any tread to a certain speed-rated carcass, and it would likely still test for the same speed rating.
 
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