V rated tires or W rated?

[Vroom]

Ok, I've been digging deeper into the summer tire decision. I don't care too much about rain, but it is a bonus. As far as Kumho 712's go, should I get V rated or W rated?

Speed Ratings for Kumho 712:
V rated tires go up to 149mph, and are recommended for Sport Sedans, Coupes & Sports Cars
W rated tires go up to 168 and are recommended for exotic sports cars.

Maximum Load for Kumho 712:
V rated and W rated are both 1521 lbs. How heavy are 97 SHO's?

Tread Life for Kumho 712:
V rated= 340 AA A
W rated= 280 AA A

So, based on those specs, which would be better? I'm definitely looking for as much tread life as possible, so the V's win there. What about speed? Will it matter on the SHO?

 

[shojuan]

W rated for more fun. V rated if you're grandma.

 

[Vroom]

Hmm.. are they constructed very differently? I assume V rated would be enough for top speed, but are the W's better for handling or something?

And approx. how many miles are W rated good for compared to V rated?

 

[97V8SHO]

280 is good for a summer tire. They last about 40K depending on how hard they're driven. As for construction, yes they are done differantly. The higher (340) the number on the tread means that they're harder and the less (280) the number means they're softer and grip better. Personaly I would go with the W rate because of the softer compound and better handleing abilities. Also, most Z,W, and Y rated tires have a 2 ply sidewall wich others don't to add to stability.

 

[stephen newberg]

The speed rating letter refers to maximum sustained speeds. It is more related to the build up of heat in the rubber than to anything else, where that heat can cause the breakdown of the sections where the tread and sidewall connect. With that in mind, you probably want to go to what you are after in handling. Though the tire with the lower tread life numbers will likely have a somewhat softer tread compound, it is possible that in that low a range difference you will not notice it if you are not pushing the car pretty hard. But if you are going to regularly push the car at its adhesive limits on back roads, then the extra softness to increase that adhesion could be handy.

So, though you might consider that since you are probably not going to be going at 160+ for long periods of time, the higher speed rating might be more than you need, you might still want that tire for the slight additionals in handling.

As per the weight numbers, that number is weight per tire, loaded. The calculation on this is actually complicated, since it involves the amount of pressure on the tire at the maximum extension allowed by the suspension and the speed. The SHO is about 3450 pounds or so, and the initial division of this around 4 wheels places you well under the limit, obviously, but if you consider loading in a heavy curve at the adhesive limits of the vehicle, you will get closer to the provided number. Here, for what it may be worth, modern tires designed for sports use such as these are still going to have a major safety margin, so I think from a real world standpoint, you can almost ignore the weight number.

The only other consideration is that the Kumho's have a very well known problem with cooler weather and a serious tendency to follow road defects. Plus, they are only moderately good handling tires. Their major advantage is that they are cheap. If you are serious about handling, or you live in an area where you have cool mornings and are likely to be driving in the morning, they are not a great pick.

pax, smn

pax, smn

 

[Vroom]

Ok, so one last question before I head off to the tires store in a little bit...

Performance aside, I've already heard people's opinions there, how does the tire life on Yokohama ES100 W-rated tires compare to the Kumho 712 W-rated tires?

 

[97V8SHO]

If the tread rate is the same, it will be about the same. If the Kumo's have a higher tread rate they'll last longer, same for the Yoko's. The Yoko's with a 280 tread life sould last you well through the summer, about 40K mabe longer depending on how they're driven. So to sum it up, Kumo's will last longer but on a side note...the Yoko's will give the best handling and ride comfort.

 

[Vroom]

I'm now considering maybe a different category of tires. Maybe ultra high performance all-season? These will be my spring/summer/fall tires, you know. The all-season tires tend to have better tread life.

I've had my car for a little over a year now, and I've only put 6k miles on it. Should this warrant the big fuss over tread life, or should any summer tire be okay? I'm going to keep this car as long as it lives/is practical.

 

[stephen newberg]

Skye, your saying that you are going to use these tires for 3 of 4 seasons implies either that you will have winter tires for the 4th or store the car for winter, but in either case it means you are somewhere that actually has cold weather. With that in mind, unless you are very, very serious about high speeds on windy back roads, I suggest that you go for one of the tires that are listed as high performance 'all season'. And also that you avoid the Kumhos, that just do not do well at all if they are cold.

If you are only putting on 10-15k or less in a year, you will very likely get two years out of the tires regardless of the small differences in the tread wear numbers. So I would not let that particular value be a major influence. There are a pile of pretty good tires out there in this performance all season section. Ask around and check with opinions listed over at Tirerack.com (I think that is the site name), keeping in mind that many people are unwilling to say negatives about something they have purchased, for some reason I have never really understood but likely related to not being willing to admit to error.

Then balance that with price and dive in. Got to eventually.

pax, smn

 

[JaySHOguy]

I can add my $.02 here...

I had a '97 SHO for 2.5 years. I ended up purchasing the Kumho 712's in V-rated form, size 225/55/16 and they were mounted on the stock chrome rims.

On this car, the tires rode well when it was warm out, handled rainy roads pretty good, BUT, IMO, the sidewalls were too flimsy for a GenIII car. With the tire pressure set to 38front/34rear, the car would push into corners extremely bad, and the tires would squeal like crazy. I swear I could almost feel the sidewalls rolling over .


On the other hand, I swapped the SAME tire/rim combo onto my '89 SHO and it handled so much more differently(lighter car). I could take the same highway off-ramp 10mph faster than the '97 could.



Ok, enough rambling. DON'T get V-rated tires if you want to be able to take corners at excessive speeds in your GenIII.

 

[shojuan]

If the tread rate is the same, it will be about the same. If the Kumo's have a higher tread rate they'll last longer, same for the Yoko's. The Yoko's with a 280 tread life sould last you well through the summer, about 40K mabe longer depending on how they're driven. So to sum it up, Kumo's will last longer but on a side note...the Yoko's will give the best handling and ride comfort.

Actually I've heard that the tread life values are pretty much meaningless between brands. IOW, 280 from brand A isn't going to mean the same thing as 280 from brand B.

The only thing the all-season rating brings to the tires is slightly better performance in the snow/ice compared to a 3 season tire. Oh, and probably improved tread life. Rain and dry performance will be compromised. And snow performance isn't even going to come close to a dedicated snow tire.

Since you are thinking of just using the tire as a three season tire the ultra-high performance tires will give the best performance in the dry and in the rain. Just stay out of the snow and be careful when it's cold out. I personally wouldn't buy an all season just to get better performance in the cold. I would rather adjust my driving habits when the seasons change. I feel the all seasons will penalize you in terms of fun all the time. Ultra-highs (or even better, MAX performance!!) will reward you in warm weather or whenever it rains. Note that when tread wears down the rain performance will drop off quite a bit.

Since you are putting very low mileage on the car it seems to me that maximum tread life shouldn't be your #1 priority.

I'd try the Yoko ES100 before the Kumhos. A well respected member here criticized them for low tread life when he got about 20,000 miles out of them. To me 20,000 miles is EXCELLENT tread life out of an ultra-high performance tire. You just have to accept the fact that tires become a noticible consumable like oil and gas when you decide you actually want to enjoy them. Make sure your alignment is good when you get the new tires or you'll notice the tread life goes down quite a bit with uneven tread wear.

 

[Vroom]

Yeah, I guess tread life isn't too terribly important in my case, but I just want to make sure they last quite a while. The reason I'd go with the Kumho 712s is because they're $75 a tire, compared to the Yoko's being $90 a tire.

Keep in mind: I don't drive high-speed twisties, I do a pretty high majority of my driving in town, and it doesn't rain all that often here. I just was a dependable tire that lets the SHO do it's thing, but I'm not one to corner hard very much or (gasp) try burnouts in a SHO. I do make runs to the triple digits on straight roads and I do race people from stop lights or from a roll whenever I get the chance. I don't ever go to the track.

 

[stephen newberg]

I can add my $.02 here...

I had a '97 SHO for 2.5 years. I ended up purchasing the Kumho 712's in V-rated form, size 225/55/16 and they were mounted on the stock chrome rims.

On this car, the tires rode well when it was warm out, handled rainy roads pretty good, BUT, IMO, the sidewalls were too flimsy for a GenIII car. With the tire pressure set to 38front/34rear, the car would push into corners extremely bad, and the tires would squeal like crazy. I swear I could almost feel the sidewalls rolling over .

Ok, enough rambling. DON'T get V-rated tires if you want to be able to take corners at excessive speeds in your GenIII.

Jason, I had the Z-rated versions of the same tire and had exactly the same problems. When pushed you could feel the sidewalls and tread trying to go in different directions during rapid transition type maneuvers. It might be weight, since the Gen III is the only car I have used them on I have no comparison like you do, but I would most certainly not use them again, even if given to me free. I removed mine and junked them with over half the tread depth still left simply because I found them to have unacceptable handling and cold weather characteristics.

But I admit to being very picking when it comes to handling since I do tend to drive the back roads very fast.

Skye, for just a total of $60 more, I would advise going with the Yokos.

pax, smn

 

[SHOZ123]

The Kumho's need more air in them on the GEN3. Run them up to the max rating in the front. I had 245/45/16s and other than being almost impossible to balance a very good tire above 40F.

FWIW All season or M&S ratings only deal with a set minimum amount of spacing between the tread blocks. IIRC

 

[stephen newberg]

Yes, I was running them right at the limit, Paul. 40lb cold in the front, IIRC. That helped a little, but did not correct for what was, at the core, a not very good tire from a handling or cold weather standpoint. With tires, I have found that very often you actually do get what you pay for.

pax, smn