When you replace any part of a vehicle, you have to make sure it is the right fit for it. The same goes for cheap tyres. Mounting the best set of radials will optimise the car operation and keep you protected. In general, when buying a new set of tyres, you have to keep three parameters in mind. These are the tyre dimensions, velocity rating, and weight load index.
You have to check for the manufacturer’s recommendations to find the ultimate set of tyres. Figuring out all the information in regards to this should be simple. You can, of course, find it in the user manual. In addition, this data is also available on the driver’s door jamb. If your existing set of tyres are relatively current (post-2012), you can also find these values on each of its sidewalls.
- Finding the right size
Determining the correct size for tyres may seem complicated at first, but there are only two basic rules that you must abide by.
You can fit tyres of varying sizes on your wheels as long as they fall in the range recommended by the vehicle manufacturer. The same goes for the speed and load indices.
While the above is true, there is another aspect to consider. Among the various dimensions allowed for your car, eliminate the ones smaller than the original particulars.
While the original specifications should be available in the places previously mentioned, you can find the recommended sizing in the vehicle documents. You can also check for a certificate of conformity (CoC) that holds similar details. Besides, it also provides other possible sizes, in case you want to upscale the tyres.
- Reading tyre markings
To be able to swap out tyres correctly, you have to be able to read their measurements. Several markers are used in conjunction to express the dimensions of a tyre.
For instance, say the markings on the tyre sidewall look something like this: 225/45 R 18 95 H. What does this sequence of alphanumeric characters mean?
- Here, 225 is an indicator of the width of the tyre when measured in millimetres.
- The 45 that follows is the aspect ratio in percentage. That means the height is 45% of its width.
- The next one is a letter, here R. It indicates the ‘radial’ casing construction.
- Again, we find a number, which is 18, and it is a measurement of the rim diameter.
- 95 marks the load-carrying capacity of the tyre when it is completely inflated.
- The final letter H is an implication of the tyre’s velocity index.
Terms such as load and velocity indices have been briefly mentioned up until now. Let us find out what they mean before we proceed further.
- Load index
Every tyre has a maximum limit as to what it can carry. This index rating is an indicator of just that when measured from the highest allowed axle weight range between two radials.
- Velocity index
Besides having a weight carrying limit, the maximum speed at which you can run a tyre is also fixed. That value, when measured at full load, is known as the speed index of the tyre. If your vehicle speed exceeds this threshold, your tyres will not give the desired output and wear out.
- Effect of using mismatched tyres
As we already know, fitting tyres, the sizing of which matches with the manufacturer’s guidelines, is crucial. What issues pop up when you do not follow them?
In case of a size mismatch, the ride peak and speedometer readings can also show drastic changes. For instance, if you mount a wheel of 17-inch diameter on a car that originally fits a 14-inch wheel, the ride height will differ. That implies the bodywork is raised quite a bit above the ground.
Given the tyre sizing remains within the recommended range, you can upscale. Consult a tyre expert in this matter to ensure all the changes do not cause any harm or imbalance in your vehicle. It is also to be kept in mind that mixing different tyre constructions, such as radial and bias-ply, is legally forbidden.
- The number of tyres to be replaced
Ideally, you should swap all four tyres when you are performing a replacement. That ensures there are no shortcomings in terms of performance or security. If your target is to switch out only one or two, make sure you abide by the tyre size guide. The load and velocity indices should also be in strict compliance with the manufacturer’s instructions. If you are changing out half of a set, it is best to mount both on the back axle. When you do so, these tyres have a much better adhesion ability. That is particularly helpful in wet roads as it diminishes the risk of hydroplaning by a long shot. As for a singular replacement, it is always recommended to avoid one. That is because it can affect the suspension system and erode the tread.
Tyres carry your vehicle forward through harsh and mild road conditions. If the correct ones are not fitted in your car or SUV, it becomes difficult or sometimes impossible for those to do the job. Be sure to buy tyres that match your vehicle’s requirements. Search car tyres near me online or contact a local dealer to purchase a set.