A unidirectional or just a directional tyre is a tyre that is designed to roll in one direction of the rotation. Unidirectional tyres have distinct tread pattern and you can easily locate them from a bunch. The tread pattern kind of looks like an arrow pointing in one direction. Also one can easily guess the direction in which tyre should rotate but I am sure you might have seen a badly bruised Corolla that has been driven in some rural areas or a riced up Civic with a badly made local body kit with inversely mounted unidirectional tyres. On the side of the tyre, on sidewall, you can find an arrow that indicates the direction in which tyre should rotate and whether the tyre should be mounted on the left side of the vehicle or right side of the vehicle.
Other than the obvious tread pattern, you can also notice a thick band/rib in the center of the tyre. The purpose of the center rib is to provide continuous contact with the surface you are driving on. That solid rib is there to provide improved braking and handling in both wet and dry conditions. That one band of solid fat rubber provides improved steering response when you steer and change direction. It improves the response to even the minor steering corrections during your driving.
These tyres provide better water dispersion than the regular tyres, although not as good as full wet tyres. Water disperses circumferentially, meaning tyre will evacuate water from the back when rotating. Some believe that those grooves on directional tyres help in water evacuation from underneath the tyre, and although those grooves are designed to help do that, but in all tyres, even in directional tyres, major portion of the dispersion/evacuation takes place at the rear of the tyre i.e., circumferentially.
To sum it all up, directional tyres are good at dispersing water, and they improve stability when changing direction. They are also considered to be less noisy than your regular off the shelf tyres. And if you mount them the wrong the way, it’s not like they will become a hazard as such, unless until they fail at that tenth of an inch where they wouldn’t have if they were mounted correctly, you are definitely killing the purpose they were build for.
The point of the whole write up is, if unidirectional tyres work for Pakistani road conditions or not. These kinds of tyres are expensive, so it is not like everyone can buy them. Mostly those who have enough cash to spend on something like this would bother with those. It is hard to see the functional use of these tyres here. You can put them in your otherwise ordinary family saloon, but the thing is, how many times do you see them working for you? Maybe people who travel a lot on high speed on motorways, they will benefit for them especially in rainy season. There is no doubt that these tyres actually prove a purpose and in certain conditions, will surpass an ordinary tyre. But you need to ask yourself that how often do you face those types of driving condition in your daily driving.
My personal experience with them wasn’t very great. I had Goodyear unidirectional tyres. Their rubber compound went hard within a year and my car used to skid in dry conditions everywhere on hard braking. But somehow the car felt very planted and stable on high speeds. One area where they actually were worth their cost was driving during rain. The difference between them and ordinary tyres on same alloys was plain obvious. Unidirectional tyres in rainy conditions were just better.
Let us know if you have any kind of experience with unidirectional tyres, good or bad, and if you would go for them again, in the comments section below.