What is the difference between Turanza ER300 and Potenza RE720 at size 195/50 R15? The two tires have identical speed and load indicators. They also have exactly the same price.
Also, I’ve heared from many people that tires in unusual sizes are more expensive than common ones, even if their size is smaller. However, my wholesale catalogs show that tire price is directly proportional to the tire size (assuming same tire type/compound). What is the straight dope on that?
Tire Rack does not have the two specific tires you named but it looks like the Potenza line are performance tires and the turenza line are touring tires.
The performance tire (Potenza) probably has better grip and lateral stability, but in exchange a slightly harsher ride and shorter treadlife. Do you see a treadlife listing for these tires?
I looked at the Bridgestone web site and couldn’t find either the Turanza ER300 or the Potenza RE270. There was a Turanza ER30, so I looked at that. I also looked at the different models of Potenza and found that only two come in the size 195/50 R15 - the Potenza G 009 and the Potenza RE750 with UNI-T. I will compare these tires, even though they’re not what you asked about, to give you an idea of how to look at tire specifications.
The ER30 has a service desription of 82V and a UTQG of 140 A A. The G 009 has a service description of 82H and a UTQG of 460 A A. The RE750 with UNI-T has a service description of 82W and a UTQG of 340 AA A.
The number in the service description is a load rating, and the letter is a speed rating. All the tires have a load rating of 82, which means their maximum load is 1047 pounds (475 kilograms). A speed rating of V means the tire is rated for 149 mph (240 km/h), H means 130 mph (210 km/h), and W means 168 mph (270 km/h). You can find a explanation of service descriptions here .
UTQG stands for Uniform Tire Quality Grade. It is always shown as a number followed by letter codes. The number is a wear rating, where a higher number means the tire lasts longer, with 100 as a sort of base standard (although a wear rating of 100 is pretty bad). The first letter code is a traction grade, with AA representing the highest traction, then going to A, B and C (where C is the lowest traction). The second letter code is a temperature rating, representing the tires ability to withstand and dissipate heat. The temperature rating can be A, B, or C, with A representing the highest ability to deal with heat. You can find a description of UTQG codes here .
Let’s compare these tires, starting with the speed ratings, from highest to lowest:
RE750, ER30, G 009
Now the wear rating, again from highest to lowest:
G 009, RE750, ER30
The RE750 has a higher traction rating than the G 009 and the ER30, which both have the same traction rating.
The thing that really stands out in comparing these tires is the wear rating of 140 for the ER30. This is pretty low, so this tire won’t last long. With a wear rating of 460, I’d expect you to get about three times as many miles out of the G 009.
I doubt the speed ratings are important for you. If you don’t drive really, really fast, you won’t come anywhere near the limits for these tires.
You might like the traction rating of the RE750. A higher traction rating will give you a shorter emergency stopping distance and better handling in emergency situations. Again, under normal driving condtions you won’t need the extra traction.
Another thing to look at is the survey ratings on TireRack.com. They have numerical ratings for things like traction, comfort, quietness, etc. The G 009 and RE750 outperformed the ER30 in every rated category. One thing to note is that only the G 009 is rated for snow traction - I don’t know whether this means the other two tires are unsuitable for snow (could be).
TireRack.com has both the G 009 and the RE750 for $81 a tire in your size. The ER30 costs $131 a tire.
Given all of this information, the ER30 looks like a bad choice compared to the other two. It has a higher price, wears out faster and isn’t rated as highly in any category of TireRack.com’s survey. The choice between the G 009 and the RE750 depends on which is more important to you: tread life or handling, with the proviso that the RE750 may be unsuitable for driving in snow.