Our mechanical engineer’s thematic Q&A article this month is about windscreen wipers and driving in the rain.

Portrait of Tammy Strobel
Our mechanical engineer’s thematic Q&A article this month is about windscreen wipers and driving in the rain.

THE windscreen wiper is standard equipment for all moving vehicles with a windscreen. Its main purpose is to clear as much rainwater as possible off the windscreen and provide clear/ clearer vision for the driver. 

The conventional windscreen wiper system used in all motorcars consists of an electric motor, a linkage assembly, wiper arms and wiper blades. What we see are only the arms and the blades (made of rubber) that make contact with and sweep the glass screen. 

Wipers ensure that rain and road grime do not “block” the driver’s view through the windshield. 

How often should we change a car’s wiper blades? 

Here is a little bit of motoring trivia: The wiper blades are the highest-wearing components in your vehicle.

That is particularly true in Singapore. Those rubber strips go through extreme cycles of heat and rain all the time. In hot weather, tiny dust particles stick to the rubber and it loses its suppleness.

In addition, the blades experience wear from dust that settles on the windscreen, which also affects the smoothness of the glass surface.

Hence, unlike most other regular wear-and-tear parts, there is no routine time or mileage interval for replacing wiper blades. 

As a rule of thumb, they should be replaced the moment you see streaks when you use them in wet weather. Any wiper- blade deficiency becomes obvious only when it rains. 

Replacement wipers are relatively inexpensive, and new wiper blades are important to ensure safe vision during thunderstorms. 

To help keep blades in good working order, soap them and give them a generous rinse whenever you clean the car. Make sure that is done at a manual car wash, too. 

What should we look out for when driving in rainy weather?

First of all, make sure that the wiper blades are in good condition. If they leave streaks on the windscreen when it rains, replace them. 

Over several months of very warm weather, the wiper rubber would have hardened and hence not be able to clear the windscreen effectively. 

Top up the windscreen washer fluid. Most petrol stations sell windshield washer additive, which is necessary to keep the screen clean, especially during light drizzles or when rain has stopped but the roads are still wet. Do not use household detergent. 

The most critical factor in wet-weather driving, of course, is tyre condition. Check that there is sufficient tread and that the tyre pressure is to specification. 

Cars with electronic stability program (ESP) and anti-lock braking system (ABS) reduce the risk of skidding on wet roads. But if there is limited or no grip, there is little the electronic aids can do. 

Incorrect tyre pressure will reduce wet-road grip, while tyres with little tread will easily aquaplane (literally float on puddles). 

During heavy rain, there are plenty of puddles which you often cannot avoid. 

Even with the car travelling at just 50km/h, a puddle can cause aquaplaning and a momentary loss of steering control. 

If possible, stay clear of puddles or follow the path of the vehicle in front of you as it would have dispersed the “water ponding” for a few seconds. 

If the ABS is activated during moderate braking in wet weather, it means your car’s tyres have little grip left. Replace them immediately. 

Finally, choose your parking spot with discretion. Although it is not a major problem in Singapore, it is always a good idea to make sure that your car is left in an area that is not likely to flood. 

More: blades weather