This article will explore the meaning and different functions of R and ZR tires. Understanding the various capabilities of both tires helps you in picking the suitable one for your car.
In recent times, 98% of cars on the road today have radial-ply tires. Radial, which is “R” in the tire size often refers to the tire’s internal construction. While ZR is a category of speed rating which was introduced for speeds over 149mph.
In other words, ZR and R use the same chains. In both the ZR and R, R means radial. Today, almost every passenger makes use of radial tires. Z is best described as the speed rating of the tire. You see, Z-rated tires are high-performance tires. In selecting tire chains, the Z designations are often not necessary.
Now, the internal construction which is the radial(R) is an important part of a tire. This is because it helps reinforce and strengthen the tire. Let’s look at the various factors that may distinguish this from tires.
What Are R Tire Ratings?
Several views have it that the letter R on tires is considered to symbolize the Radial Construction of tires. Tires have some written combo of letters and numbers. For instance, you might have come across 245/40R18 93H. Now, this often signifies the speed rating of the tire.
Speed rating R allows the speeds up to 106mph that is (170km/h) under optimal conditions. Unlike Q, R tires generally prioritize a particular function. Also, they have a unique performance over a maximum speed capability.
R speed tires are usually rare but could be seen in heavy-duty light truck (LT) tires. They can also be found in studdable studless winter tires.
What Is A ZR Tire Rating?
ZR-rated tires are designed to go faster than 149 mph. And as such top speed has emerged in the past three decades. This prompted manufacturers to create something more specific. Thereby leading to the introduction of W-168 and Y-186 rated tires. In the description, If the W or Y-rated tire’s service is in parentheses, then the tire is rated for speed greater than 168 and 186 respectively.
Because W and Y tires are rated for more than 149 mph, they are also Z-rated. Though this marking is sometimes omitted in the size. In describing the letter construction, the radial letter R; ZR stands for a Z-rated radial. ZR means the tire is adapted for a speed above 149mph. Before 1990, the manufacturers used “ZR” to mean high-performance tires until it was redeveloped into W, Y, and so on.
Differences Between R And Zr Tires
a. Speed rating R allows for speeds up to 106 mph (170 km/h) under optimal conditions. A ZR rating indicates the tire has been approved for speeds of 149+ mph (240+ km/h) under optimal conditions.
b. The ZR speed rating can be found within the structure of the tire size: 235/40ZR18. R speed tires are rare but can be found on some heavy-duty light truck (LT) tires, as well as studded and studless winter tires.
c. In place of a ZR tire, the speed rating will either be W, Y, or (Y). Whereas R tires often specify, it is a radial construction tire.
Similarities Between R And Zr Tires
Both ratings are associated with maximum tire performance and are a match for performance coupes and sedans, sports cars, and supercars.
Can I Mix Zr And R Tires On My Car?
Tires in their sizes usually have letters on them, you might have come across “P” or “LT” letters. These letters sometimes show up at the beginning of the size, and the “R” letter right before the wheel size. For instance, you come across P245/40R18 or LT315/70R17. But what could it possibly mean when the tire says “P245/40ZR18”? And so, you need to know what speed ratings are.
Now, speed ratings are expressed in letters and are usually listed alongside the load index for a tire after the size. For instance, 245/40R18 93H. H appears to be the speed rating and 93 the load index. Both the load index and speed rating could be described as a service description.
You might currently have two 255 35 ZR 20 tires and two 285 30 ZR 20 tires. You could still be wondering if it’s okay to replace them with the same models or with R tires. The ZR designates “performance” or speed rating. Proving you don’t need to exceed normal speeds.
You also can check the owner’s manual for the more preferred size tires your vehicle should use.
Can You Have Two Different Brands Of Tires On Your Car?
To achieve optimal driving, it is recommended that the same tires are fitted on all wheel positions of your vehicle. In other words, tires of the same brand, tread pattern tire size, load index, and speed symbol should be fitted all around.
More important is that the tire size, load, index, and speed symbol are following the vehicle manufacturer’s specification. In many countries, this is a legal requirement. Driving your vehicle with a non-recommended mix of tire sizes, constructions, and speed ratings can be dangerous and illegal.
It is always advisable to follow the vehicle manufacturer’s recommendations and/or seek advice from a trained tire specialist.
Is A Higher Speed Rating Better?
Every letter in the speed rating represents a maximum speed. The main things to know; Generally, the higher in the alphabet a tire is rated, the better it will manage heat and faster speeds.
Your actual speed capacity may be less than a tire’s rating. The rating indicates a new tire’s performance in tightly controlled lab settings, not the open road.
If you have tires with different speed ratings, the limit of the lowest-rated tire is the fastest. You can drive and stay within your tires’ capability.
The most common ratings are S and T (sedans, minivans, light trucks); H (some passenger cars, sports cars, coupes, some light trucks); N, P, Q and R (light trucks); and V, W, and Y (high-performance cars). Most winter tires have Q, S, or T speed ratings.