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Old 11-01-2010, 04:19 PM   #1
jtmann
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Winter tires - speed rating & downsizing Hello: A couple of questions for the forum. I have an 07 Camry LE. I am buying winter tires for her. I am

Hello:

A couple of questions for the forum. I have an 07 Camry LE. I am buying winter tires for her. I am considering a set of General Altimax Arctics. These fit my budget and are highly rated across multiple sources, including Consumer Reports and several others.

For tires, the OEM/Camry owners manual specs are 215 60 R16 94 V - i.e., 16 inch with load rating of 94 and speed rating of V.

Question 1 - I am having a difficult time finding WINTER tires that have a speed rating of V. In fact, many of the winters (including the aforementioned Altimax) seem to be rated a Q, with an odd one here or there rated an S or T. I know that a Q is rated for 160 km/hr and that I will not even come close to driving that fast, let alone for any length of time! But does a higher rating (in this case an S or T) mean the tire is "higher quality" and will last longer?
Also will the lower Q rating mean performance problems or drawbacks of any kind for my "V-rated" Camry?

Question 2 - I have heard that the concept of putting on a smaller tire for winter (in my case 15 inchers instead of 16s) is somewhat an outdated concept and debatable benefits. Any experience to share?

Question 3 - I assume it is ok to put on a tire with a higher load rating (in my case a 95 vs. the OEM rated 94)

Apologies if these are newbie questions but my first winter!

Thanks!!
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Old 11-03-2010, 11:43 AM   #2
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Re: Winter tires - speed rating & downsizing Hello: A couple of questions for the forum. I have an 07 Camry LE. I am buying winter tires for her. I

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Originally Posted by jtmann View Post
Hello:

A couple of questions for the forum. I have an 07 Camry LE. I am buying winter tires for her. I am considering a set of General Altimax Arctics. These fit my budget and are highly rated across multiple sources, including Consumer Reports and several others.

For tires, the OEM/Camry owners manual specs are 215 60 R16 94 V - i.e., 16 inch with load rating of 94 and speed rating of V.

Question 1 - I am having a difficult time finding WINTER tires that have a speed rating of V. In fact, many of the winters (including the aforementioned Altimax) seem to be rated a Q, with an odd one here or there rated an S or T. I know that a Q is rated for 160 km/hr and that I will not even come close to driving that fast, let alone for any length of time! But does a higher rating (in this case an S or T) mean the tire is "higher quality" and will last longer?
Also will the lower Q rating mean performance problems or drawbacks of any kind for my "V-rated" Camry?

Question 2 - I have heard that the concept of putting on a smaller tire for winter (in my case 15 inchers instead of 16s) is somewhat an outdated concept and debatable benefits. Any experience to share?

Question 3 - I assume it is ok to put on a tire with a higher load rating (in my case a 95 vs. the OEM rated 94)

Apologies if these are newbie questions but my first winter!

Thanks!!
also. Another question - I understand that by reading the sidewall you can tell when the tires were made. What is an "acceptable" age for the tires to be when I buy them/installing for first time?
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Old 11-16-2010, 10:32 PM   #3
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Re: Winter tires - speed rating & downsizing Hello: A couple of questions for the forum. I have an 07 Camry LE. I am buying winter tires for her. I

IMO don't get too wound up about tire age. A new tire that is actually a few months old is just fine. When you store your tires, keep them in a cool, dry place out of direct sunlight, ad they will last a long time.

Also, do not worry about the speed rating. A higher rated tire is not necessarily higher quality, it just has design characteristics intended for higher speeds.

Often, tire designs are compromises. Higher speed tires often have less load rating, because they have thinner sidewalls. These thin sidewalls dissapate the extra heat generated by high speed, but do not have the high strength of heavier tires. Also, higher speed tires often have larger tread blocks. Such blocks are great for dry road grip but do not function as well in slippery conditions.

Tire size...... the theory is to use a narrower tire in winter, for better control in the snow. A 15 inch tire is shorter than a 16 inch, but not necessarily narrower. Also, your suspension, steering, ABS, traction control, transmission, speedometer, etc are all designed for a 16 inch wheel. It's probalby good to leave it as-is.
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Old 11-18-2010, 10:07 AM   #4
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Re: Winter tires - speed rating & downsizing Hello: A couple of questions for the forum. I have an 07 Camry LE. I am buying winter tires for her. I

First let me apologize for not answering your questions. Is it possible you posted similar questions elsewhere on the Internet and I responded there?

1) Speed ratings for winter tires. The vehicle manufacturer specified the speed ratings for a number of different reasons - and one of them had to do with handling. Obviously Toyota was targeting for a more responsive tire when they specified a V rating.

However, winter driving conditions change the usage picture considerably. It is OK to use Q rated winter tires, just be aware that they will not handle as well as a V rated tire. Plus you don't want to go too far into the spring before removing those tires as not only will the tread compound wear pretty fast in warm weather, the tread compound also generates more heat than normal and that has implications for durability.

2) Using a smaller diameter wheel - with corresponding increased aspect ratio, but narrower width tires - is a common winter tire trick. You have to check to see the brakes on your vehicle will allow that (Tire Rack says no!) The theory is that a narrower tire will be more likely to penetrate through the snow to the pavement - and pavement always has more traction than snow!

3) Shelf life on new tires. Properly stored, tires can be stored for up to 3 years and be considered "new". But it is common for tires to be discounted as they get older in order to get them off the shelf - so please do not complain if your "1/2 off" tires are 2 1/2 years old when you buy them.

And lastly: There's a lot wrong with MagicRat's post.

a) Higher speed ratings indicate more capability in a tire. In the sense that it has higher capabilities, higher speed rated tires have higher "quality". Clearly tires with higher capabilities are less prone to failure. However, if you use the term "quality" to mean "more round" or "longer wearing", speed ratings do not indicate that one way or the other. As MagicRat said, higher speed ratings are more an indication of a design characteristic.

b) Speed ratings are independent of load carrying capacity. Plus, higher speed rated tires are not designed with thinner sidewalls. Higher speed rated tires have things like cap plies to better resist the centrifugal forces generated by high speeds.

Thinner sidewalls do not significantly affect the operating temperature of a tire as most of the heat is generated and retained in the thickest part of the tire - the tread shoulder - which is much thicker than the sidewall. Plus it is easy to increase the strength of a tire without increasing its thickness.

Tread compound has a significant effect on a tire's operating temperature, which is why you will see many winter tires with Q speed ratings. As opposed to all season tires with S and T speed ratings, winter tires can be made with tread compounds that generate more grip in cold weather, but that same tread compound generates more heat - hence the lower speed rating.
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