At this time of year fleets of thousands of gritter lorries take to the roads to spread the grit which fights snow and ice in a bid to prevent accidents. Any sane motorist is thankful for the service as it means the roads are far safer during the cold and bleak months, but the grit they spread can damage your car.
What is the grit spread by gritter lorries?
It’s not actually grit at all, it’s rock salt. Rock salt is not like the salt you put on your chips, it contains various chemicals, such as potassium chloride, which lower the freezing point of water and converts existing ice and snow back into water. For that reason it is great at making the road grippier. We call it grit because years ago that’s what was used, the grit increased friction between the road and car tyres but it didn’t melt ice. Councils do what they can to mitigate the harm potentially caused by the spreading process itself, often wetting the grit before distributing it so it doesn’t bounce so much and hit passing cars.
Can my car be damaged by the grit as it is spread?
Back when actual grit was used, following or passing a gritter lorry was best avoided as the grit would easily cause chips in your paintwork. The rock salt used today is much softer so less likely to cause damage, That’s not to say it can’t cause chips, so the best advice is stay well back from a gritter lorry and pass when completely safe to do so. Overtake at a reasonable and steady pace to minimise the risk of damage.
Can grit already on the road cause damage?
Yes, and actually this is a far bigger concern than damage caused by the lorry as it spreads the grit. Rock salt, and all those ice-melting chemicals found within it, can be corrosive to metal and if you get a lot of it on your car and is likely to accelerate the rusting process. Certain parts of your car are at much more risk than others. The bodywork is not really at risk as most modern cars come with protective paintwork, and you can also add protective coatings using a spray bought from somewhere like Halfords, or you can have it applied by a dealership or workshop. The parts at most risk are the exposed metal parts which are underneath the car, such as the exhaust system, brakes, suspension components and even parts of the engine. These areas can collect grit as your car drives over it and are therefore prone to rusting.
What can I do to prevent grit from damaging my car?
By far the best thing to do is give the underside of your car a regular wash, especially if the roads in your area are being gritted. It’s not nice work, you’ll have to get underneath the car, but it could prevent a big bill in a few months or years. Some car washes offer under-car cleaning services, and you may prefer this option.
Another obvious one is to avoid driving when the temperatures are low, if at all possible. As a rough guide, gritter lorries will be deployed when temperatures are set to fall to around 0-2 degrees Celsius. Of course you shouldn’t inconvenience yourself just to avoid road grit, and if you have to drive don’t let it put you off. When you’re on the roads try to avoid slushy puddles or large areas of water, as the grit which has been spread into puddles turns the water into a ‘salt soup’ which will splash into hard-to-reach crevices on the underside of your car, making it harder to remove.
Read more
Keyword: Will council-spread winter road grit damage my car?